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boost-1.21
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116
Assignable.html
Normal file
116
Assignable.html
Normal file
@@ -0,0 +1,116 @@
|
||||
<HTML>
|
||||
<!--
|
||||
-- Copyright (c) Jeremy Siek 2000
|
||||
--
|
||||
-- Permission to use, copy, modify, distribute and sell this software
|
||||
-- and its documentation for any purpose is hereby granted without fee,
|
||||
-- provided that the above copyright notice appears in all copies and
|
||||
-- that both that copyright notice and this permission notice appear
|
||||
-- in supporting documentation. Silicon Graphics makes no
|
||||
-- representations about the suitability of this software for any
|
||||
-- purpose. It is provided "as is" without express or implied warranty.
|
||||
-->
|
||||
<Head>
|
||||
<Title>Assignable</Title>
|
||||
</HEAD>
|
||||
<BODY BGCOLOR="#ffffff" LINK="#0000ee" TEXT="#000000" VLINK="#551a8b"
|
||||
ALINK="#ff0000">
|
||||
<IMG SRC="../../c++boost.gif"
|
||||
ALT="C++ Boost" width="277" height="86">
|
||||
<!--end header-->
|
||||
<BR Clear>
|
||||
<H1>Assignable</H1>
|
||||
|
||||
<h3>Description</h3>
|
||||
A type is Assignable if it is possible to assign one object of the type
|
||||
to another object of that type.
|
||||
|
||||
|
||||
<h3>Notation</h3>
|
||||
<Table>
|
||||
<TR>
|
||||
<TD VAlign=top>
|
||||
<tt>T</tt>
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
is type that is a model of Assignable
|
||||
</TD>
|
||||
</TR>
|
||||
|
||||
<TR>
|
||||
<TD VAlign=top>
|
||||
<tt>t</tt>
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
is an object of type <tt>T</tt>
|
||||
</TD>
|
||||
</tr>
|
||||
|
||||
<TR>
|
||||
<TD VAlign=top>
|
||||
<tt>u</tt>
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
is an object of type <tt>T</tt> or possibly <tt>const T</tt>
|
||||
</TD>
|
||||
</tr>
|
||||
|
||||
</table>
|
||||
<h3>Definitions</h3>
|
||||
<h3>Valid expressions</h3>
|
||||
<Table border>
|
||||
<TR>
|
||||
<TH>
|
||||
Name
|
||||
</TH>
|
||||
<TH>
|
||||
Expression
|
||||
</TH>
|
||||
<TH>
|
||||
Return type
|
||||
</TH>
|
||||
<TH>
|
||||
Semantics
|
||||
</TH>
|
||||
</TR>
|
||||
<TR>
|
||||
<TD VAlign=top>
|
||||
Assignment
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
<tt>t = u</tt>
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
<tt>T&</tt>
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
<tt>t</tt> is equivalent to <tt>u</tt>
|
||||
</TD>
|
||||
</TR>
|
||||
|
||||
</table>
|
||||
|
||||
|
||||
</table>
|
||||
<h3>Models</h3>
|
||||
|
||||
<UL>
|
||||
<LI><tt>int</tt>
|
||||
<LI><tt>std::pair</tt>
|
||||
</UL>
|
||||
|
||||
<h3>See also</h3>
|
||||
<a href="http://www.sgi.com/Technology/STL/DefaultConstructible.html">DefaultConstructible</A>
|
||||
and
|
||||
<A href="./CopyConstructible.html">CopyConstructible</A>
|
||||
|
||||
<br>
|
||||
<HR>
|
||||
<TABLE>
|
||||
<TR valign=top>
|
||||
<TD nowrap>Copyright © 2000</TD><TD>
|
||||
<A HREF=http://www.lsc.nd.edu/~jsiek>Jeremy Siek</A>, Univ.of Notre Dame (<A HREF="mailto:jsiek@lsc.nd.edu">jsiek@lsc.nd.edu</A>)
|
||||
</TD></TR></TABLE>
|
||||
|
||||
</BODY>
|
||||
</HTML>
|
210
CopyConstructible.html
Normal file
210
CopyConstructible.html
Normal file
@@ -0,0 +1,210 @@
|
||||
<HTML>
|
||||
<!--
|
||||
-- Copyright (c) Jeremy Siek 2000
|
||||
--
|
||||
-- Permission to use, copy, modify, distribute and sell this software
|
||||
-- and its documentation for any purpose is hereby granted without fee,
|
||||
-- provided that the above copyright notice appears in all copies and
|
||||
-- that both that copyright notice and this permission notice appear
|
||||
-- in supporting documentation. Silicon Graphics makes no
|
||||
-- representations about the suitability of this software for any
|
||||
-- purpose. It is provided "as is" without express or implied warranty.
|
||||
-->
|
||||
<Head>
|
||||
<Title>CopyConstructible</Title>
|
||||
</HEAD>
|
||||
<BODY BGCOLOR="#ffffff" LINK="#0000ee" TEXT="#000000" VLINK="#551a8b"
|
||||
ALINK="#ff0000">
|
||||
<IMG SRC="../../c++boost.gif"
|
||||
ALT="C++ Boost" width="277" height="86">
|
||||
<!--end header-->
|
||||
<BR Clear>
|
||||
<H1>CopyConstructible</H1>
|
||||
|
||||
<h3>Description</h3>
|
||||
A type is CopyConstructible if it is possible to copy objects of that
|
||||
type.
|
||||
|
||||
<h3>Notation</h3>
|
||||
<Table>
|
||||
<TR>
|
||||
<TD VAlign=top>
|
||||
<tt>T</tt>
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
is type that is a model of CopyConstructible
|
||||
</TD>
|
||||
</TR>
|
||||
|
||||
<TR>
|
||||
<TD VAlign=top>
|
||||
<tt>t</tt>
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
is an object of type <tt>T</tt>
|
||||
</TD>
|
||||
</tr>
|
||||
|
||||
<TR>
|
||||
<TD VAlign=top>
|
||||
<tt>u</tt>
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
is an object of type <tt>const T</tt>
|
||||
</TD>
|
||||
</tr>
|
||||
|
||||
</table>
|
||||
<h3>Definitions</h3>
|
||||
<h3>Valid expressions</h3>
|
||||
<Table border>
|
||||
<TR>
|
||||
<TH>
|
||||
Name
|
||||
</TH>
|
||||
<TH>
|
||||
Expression
|
||||
</TH>
|
||||
<TH>
|
||||
Return type
|
||||
</TH>
|
||||
<TH>
|
||||
Semantics
|
||||
</TH>
|
||||
</TR>
|
||||
<TR>
|
||||
<TD VAlign=top>
|
||||
Copy constructor
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
<tt>T(t)</tt>
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
<tt>T</tt>
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
<tt>t</tt> is equivalent to <tt>T(t)</tt>
|
||||
</TD>
|
||||
</TR>
|
||||
|
||||
|
||||
<TR>
|
||||
<TD VAlign=top>
|
||||
Copy constructor
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
<pre>
|
||||
T(u)
|
||||
</pre>
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
<tt>T</tt>
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
<tt>u</tt> is equivalent to <tt>T(u)</tt>
|
||||
</TD>
|
||||
</TR>
|
||||
|
||||
|
||||
<TR>
|
||||
<TD VAlign=top>
|
||||
Destructor
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
<pre>
|
||||
t.~T()
|
||||
</pre>
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
<tt>T</tt>
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
|
||||
</TD>
|
||||
</TR>
|
||||
|
||||
<TR>
|
||||
<TD VAlign=top>
|
||||
Address Operator
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
<pre>
|
||||
&t
|
||||
</pre>
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
<tt>T*</tt>
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
denotes the address of <tt>t</tt>
|
||||
</TD>
|
||||
</TR>
|
||||
|
||||
<TR>
|
||||
<TD VAlign=top>
|
||||
Address Operator
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
<pre>
|
||||
&u
|
||||
</pre>
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
<tt>T*</tt>
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
denotes the address of <tt>u</tt>
|
||||
</TD>
|
||||
</TR>
|
||||
|
||||
|
||||
|
||||
</table>
|
||||
|
||||
|
||||
</table>
|
||||
<h3>Models</h3>
|
||||
|
||||
<UL>
|
||||
<LI><tt>int</tt>
|
||||
<LI><tt>std::pair</tt>
|
||||
</UL>
|
||||
|
||||
<h3>Concept Checking Class</h3>
|
||||
|
||||
<pre>
|
||||
template <class T>
|
||||
struct CopyConstructibleConcept
|
||||
{
|
||||
void constraints() {
|
||||
T a(b); // require copy constructor
|
||||
T* ptr = &a; // require address of operator
|
||||
const_constraints(a);
|
||||
ignore_unused_variable_warning(ptr);
|
||||
}
|
||||
void const_constraints(const T& a) {
|
||||
T c(a); // require const copy constructor
|
||||
const T* ptr = &a; // require const address of operator
|
||||
ignore_unused_variable_warning(c);
|
||||
ignore_unused_variable_warning(ptr);
|
||||
}
|
||||
T b;
|
||||
};
|
||||
</pre>
|
||||
|
||||
<h3>See also</h3>
|
||||
<A
|
||||
href="http://www.sgi.com/Technology/STL/DefaultConstructible.html">DefaultConstructible</A>
|
||||
and
|
||||
<A href="http://www.sgi.com/Technology/STL/Assignable.html">Assignable</A>
|
||||
|
||||
<br>
|
||||
<HR>
|
||||
<TABLE>
|
||||
<TR valign=top>
|
||||
<TD nowrap>Copyright © 2000</TD><TD>
|
||||
<A HREF=http://www.lsc.nd.edu/~jsiek>Jeremy Siek</A>, Univ.of Notre Dame (<A HREF="mailto:jsiek@lsc.nd.edu">jsiek@lsc.nd.edu</A>)
|
||||
</TD></TR></TABLE>
|
||||
|
||||
</BODY>
|
||||
</HTML>
|
212
LessThanComparable.html
Normal file
212
LessThanComparable.html
Normal file
@@ -0,0 +1,212 @@
|
||||
<HTML>
|
||||
<!--
|
||||
-- Copyright (c) Jeremy Siek 2000
|
||||
--
|
||||
-- Permission to use, copy, modify, distribute and sell this software
|
||||
-- and its documentation for any purpose is hereby granted without fee,
|
||||
-- provided that the above copyright notice appears in all copies and
|
||||
-- that both that copyright notice and this permission notice appear
|
||||
-- in supporting documentation. Silicon Graphics makes no
|
||||
-- representations about the suitability of this software for any
|
||||
-- purpose. It is provided "as is" without express or implied warranty.
|
||||
-->
|
||||
<!--
|
||||
-- Copyright (c) 1996-1999
|
||||
-- Silicon Graphics Computer Systems, Inc.
|
||||
--
|
||||
-- Permission to use, copy, modify, distribute and sell this software
|
||||
-- and its documentation for any purpose is hereby granted without fee,
|
||||
-- provided that the above copyright notice appears in all copies and
|
||||
-- that both that copyright notice and this permission notice appear
|
||||
-- in supporting documentation. Silicon Graphics makes no
|
||||
-- representations about the suitability of this software for any
|
||||
-- purpose. It is provided "as is" without express or implied warranty.
|
||||
--
|
||||
-- Copyright (c) 1994
|
||||
-- Hewlett-Packard Company
|
||||
--
|
||||
-- Permission to use, copy, modify, distribute and sell this software
|
||||
-- and its documentation for any purpose is hereby granted without fee,
|
||||
-- provided that the above copyright notice appears in all copies and
|
||||
-- that both that copyright notice and this permission notice appear
|
||||
-- in supporting documentation. Hewlett-Packard Company makes no
|
||||
-- representations about the suitability of this software for any
|
||||
-- purpose. It is provided "as is" without express or implied warranty.
|
||||
--
|
||||
-->
|
||||
<Head>
|
||||
<Title>LessThanComparable</Title>
|
||||
</Head>
|
||||
<BODY BGCOLOR="#ffffff" LINK="#0000ee" TEXT="#000000" VLINK="#551a8b"
|
||||
ALINK="#ff0000">
|
||||
<IMG SRC="../../c++boost.gif"
|
||||
ALT="C++ Boost" width="277" height="86">
|
||||
<!--end header-->
|
||||
<BR Clear>
|
||||
<H1>LessThanComparable</H1>
|
||||
|
||||
<h3>Description</h3>
|
||||
A type is LessThanComparable if it is ordered: it must
|
||||
be possible to compare two objects of that type using <tt>operator<</tt>, and
|
||||
<tt>operator<</tt> must be a strict weak ordering relation.
|
||||
|
||||
|
||||
<h3>Refinement of</h3>
|
||||
<h3>Associated types</h3>
|
||||
<h3>Notation</h3>
|
||||
<Table>
|
||||
<TR>
|
||||
<TD VAlign=top>
|
||||
<tt>X</tt>
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
A type that is a model of LessThanComparable
|
||||
</TD>
|
||||
</TR>
|
||||
<TR>
|
||||
<TD VAlign=top>
|
||||
<tt>x</tt>, <tt>y</tt>, <tt>z</tt>
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
Object of type <tt>X</tt>
|
||||
</TD>
|
||||
</tr>
|
||||
</table>
|
||||
<h3>Definitions</h3>
|
||||
Consider the relation <tt>!(x < y) && !(y < x)</tt>. If this relation is
|
||||
transitive (that is, if <tt>!(x < y) && !(y < x) && !(y < z) && !(z < y)</tt>
|
||||
implies <tt>!(x < z) && !(z < x)</tt>), then it satisfies the mathematical
|
||||
definition of an equivalence relation. In this case, <tt>operator<</tt>
|
||||
is a <i>strict weak ordering</i>.
|
||||
<P>
|
||||
If <tt>operator<</tt> is a strict weak ordering, and if each equivalence class
|
||||
has only a single element, then <tt>operator<</tt> is a <i>total ordering</i>.
|
||||
<h3>Valid expressions</h3>
|
||||
<Table border>
|
||||
<TR>
|
||||
<TH>
|
||||
Name
|
||||
</TH>
|
||||
<TH>
|
||||
Expression
|
||||
</TH>
|
||||
<TH>
|
||||
Type requirements
|
||||
</TH>
|
||||
<TH>
|
||||
Return type
|
||||
</TH>
|
||||
</TR>
|
||||
<TR>
|
||||
<TD VAlign=top>
|
||||
Less
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
<tt>x < y</tt>
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
Convertible to <tt>bool</tt>
|
||||
</TD>
|
||||
</TR>
|
||||
</table>
|
||||
|
||||
|
||||
|
||||
<h3>Expression semantics</h3>
|
||||
<Table border>
|
||||
<TR>
|
||||
<TH>
|
||||
Name
|
||||
</TH>
|
||||
<TH>
|
||||
Expression
|
||||
</TH>
|
||||
<TH>
|
||||
Precondition
|
||||
</TH>
|
||||
<TH>
|
||||
Semantics
|
||||
</TH>
|
||||
<TH>
|
||||
Postcondition
|
||||
</TH>
|
||||
</TR>
|
||||
<TR>
|
||||
<TD VAlign=top>
|
||||
Less
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
<tt>x < y</tt>
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
<tt>x</tt> and <tt>y</tt> are in the domain of <tt><</tt>
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
|
||||
</TD>
|
||||
</table>
|
||||
|
||||
|
||||
<h3>Complexity guarantees</h3>
|
||||
<h3>Invariants</h3>
|
||||
<Table border>
|
||||
<TR>
|
||||
<TD VAlign=top>
|
||||
Irreflexivity
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
<tt>x < x</tt> must be false.
|
||||
</TD>
|
||||
</TR>
|
||||
<TR>
|
||||
<TD VAlign=top>
|
||||
Antisymmetry
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
<tt>x < y</tt> implies !(y < x) <A href="#2">[2]</A>
|
||||
</TD>
|
||||
</TR>
|
||||
<TR>
|
||||
<TD VAlign=top>
|
||||
Transitivity
|
||||
</TD>
|
||||
<TD VAlign=top>
|
||||
<tt>x < y</tt> and <tt>y < z</tt> implies <tt>x < z</tt> <A href="#3">[3]</A>
|
||||
</TD>
|
||||
</tr>
|
||||
</table>
|
||||
<h3>Models</h3>
|
||||
<UL>
|
||||
<LI>
|
||||
int
|
||||
</UL>
|
||||
<h3>Notes</h3>
|
||||
<P><A name="1">[1]</A>
|
||||
Only <tt>operator<</tt> is fundamental; the other inequality operators
|
||||
are essentially syntactic sugar.
|
||||
<P><A name="2">[2]</A>
|
||||
Antisymmetry is a theorem, not an axiom: it follows from
|
||||
irreflexivity and transitivity.
|
||||
<P><A name="3">[3]</A>
|
||||
Because of irreflexivity and transitivity, <tt>operator<</tt> always
|
||||
satisfies the definition of a <i>partial ordering</i>. The definition of
|
||||
a <i>strict weak ordering</i> is stricter, and the definition of a
|
||||
<i>total ordering</i> is stricter still.
|
||||
<h3>See also</h3>
|
||||
<A href="http://www.sgi.com/Technology/STL/EqualityComparable.html">EqualityComparable</A>, <A href="http://www.sgi.com/Technology/STL/StrictWeakOrdering.html">StrictWeakOrdering</A>
|
||||
|
||||
|
||||
|
||||
<br>
|
||||
<HR>
|
||||
<TABLE>
|
||||
<TR valign=top>
|
||||
<TD nowrap>Copyright © 2000</TD><TD>
|
||||
<A HREF=http://www.lsc.nd.edu/~jsiek>Jeremy Siek</A>, Univ.of Notre Dame (<A HREF="mailto:jsiek@lsc.nd.edu">jsiek@lsc.nd.edu</A>)
|
||||
</TD></TR></TABLE>
|
||||
|
||||
</BODY>
|
||||
</HTML>
|
92
MultiPassInputIterator.html
Normal file
92
MultiPassInputIterator.html
Normal file
@@ -0,0 +1,92 @@
|
||||
<HTML>
|
||||
<!--
|
||||
-- Copyright (c) Jeremy Siek 2000
|
||||
--
|
||||
-- Permission to use, copy, modify, distribute and sell this software
|
||||
-- and its documentation for any purpose is hereby granted without fee,
|
||||
-- provided that the above copyright notice appears in all copies and
|
||||
-- that both that copyright notice and this permission notice appear
|
||||
-- in supporting documentation. Silicon Graphics makes no
|
||||
-- representations about the suitability of this software for any
|
||||
-- purpose. It is provided "as is" without express or implied warranty.
|
||||
-->
|
||||
<Head>
|
||||
<Title>MultiPassInputIterator</Title>
|
||||
<BODY BGCOLOR="#ffffff" LINK="#0000ee" TEXT="#000000" VLINK="#551a8b"
|
||||
ALINK="#ff0000">
|
||||
<IMG SRC="../../c++boost.gif"
|
||||
ALT="C++ Boost" width="277" height="86">
|
||||
|
||||
<BR Clear>
|
||||
|
||||
<H2>
|
||||
<A NAME="concept:MultiPassInputIterator"></A>
|
||||
MultiPassInputIterator
|
||||
</H2>
|
||||
|
||||
This concept is a refinement of <a
|
||||
href="http://www.sgi.com/Technology/STL/InputIterator.html">InputIterator</a>,
|
||||
adding the requirements that the iterator can be used to make multiple
|
||||
passes through a range, and that if <TT>it1 == it2</TT> and
|
||||
<TT>it1</TT> is dereferenceable then <TT>++it1 == ++it2</TT>. The
|
||||
MultiPassInputIterator is very similar to the <a
|
||||
href="http://www.sgi.com/Technology/STL/ForwardIterator.hmtl">ForwardIterator</a>. The
|
||||
only difference is that a <a
|
||||
href="http://www.sgi.com/Technology/STL/ForwardIterator.hmtl">ForwardIterator</a>
|
||||
requires the <TT>reference</TT> type to be <TT>value_type&</TT>, whereas
|
||||
MultiPassInputIterator is like <a
|
||||
href="http://www.sgi.com/Technology/STL/InputIterator.html">InputIterator</a>
|
||||
in that the <TT>reference</TT> type merely has to be convertible to
|
||||
<TT>value_type</TT>.
|
||||
|
||||
|
||||
<h3>Design Notes</h3>
|
||||
|
||||
comments by Valentin Bonnard:
|
||||
|
||||
<p> I think that introducing MultiPassInputIterator isn't the right
|
||||
solution. Do you also want to define MultiPassBidirectionnalIterator
|
||||
and MultiPassRandomAccessIterator ? I don't, definitly. It only
|
||||
confuses the issue. The problem lies into the existing hierarchy of
|
||||
iterators, which mixes movabillity, modifiabillity and lvalue-ness,
|
||||
and these are clearly independant.
|
||||
|
||||
<p> The terms Forward, Bidirectionnal and RandomAccess are about
|
||||
movabillity and shouldn't be used to mean anything else. In a
|
||||
completly orthogonal way, iterators can be immutable, mutable, or
|
||||
neither. Lvalueness of iterators is also orthogonal with
|
||||
immutabillity. With these clean concepts, your MultiPassInputIterator
|
||||
is just called a ForwardIterator.
|
||||
|
||||
<p>
|
||||
Other translations are:<br>
|
||||
std::ForwardIterator -> ForwardIterator & LvalueIterator<br>
|
||||
std::BidirectionnalIterator -> BidirectionnalIterator & LvalueIterator<br>
|
||||
std::RandomAccessIterator -> RandomAccessIterator & LvalueIterator<br>
|
||||
|
||||
<p>
|
||||
Note that in practice the only operation not allowed on my
|
||||
ForwardIterator which is allowed on std::ForwardIterator is
|
||||
<tt>&*it</tt>. I think that <tt>&*</tt> is rarely needed in generic code.
|
||||
|
||||
<p>
|
||||
reply by Jeremy Siek:
|
||||
|
||||
<p>
|
||||
The above analysis by Valentin is right on. Of course, there is
|
||||
the problem with backward compatibility. The current STL implementations
|
||||
are based on the old definition of ForwardIterator. The right course
|
||||
of action is to get ForwardIterator, etc. changed in the C++ standard.
|
||||
Once that is done we can drop MultiPassInputIterator.
|
||||
|
||||
|
||||
<br>
|
||||
<HR>
|
||||
<TABLE>
|
||||
<TR valign=top>
|
||||
<TD nowrap>Copyright © 2000</TD><TD>
|
||||
<A HREF=http://www.boost.org/people/jeremy_siek.htm>Jeremy Siek</A>, Univ.of Notre Dame (<A HREF="mailto:jsiek@lsc.nd.edu">jsiek@lsc.nd.edu</A>)
|
||||
</TD></TR></TABLE>
|
||||
|
||||
</BODY>
|
||||
</HTML>
|
@@ -1,423 +0,0 @@
|
||||
|
||||
/*
|
||||
*
|
||||
* Copyright (c) 1999
|
||||
* Dr John Maddock
|
||||
*
|
||||
* Permission to use, copy, modify, distribute and sell this software
|
||||
* and its documentation for any purpose is hereby granted without fee,
|
||||
* provided that the above copyright notice appear in all copies and
|
||||
* that both that copyright notice and this permission notice appear
|
||||
* in supporting documentation. Dr John Maddock makes no representations
|
||||
* about the suitability of this software for any purpose.
|
||||
* It is provided "as is" without express or implied warranty.
|
||||
*
|
||||
* This file provides some example of type_traits usage -
|
||||
* by "optimising" various algorithms:
|
||||
*
|
||||
* opt::copy - optimised for trivial copy (cf std::copy)
|
||||
* opt::fill - optimised for trivial copy/small types (cf std::fill)
|
||||
* opt::destroy_array - an example of optimisation based upon omitted destructor calls
|
||||
* opt::iter_swap - uses type_traits to determine whether the iterator is a proxy
|
||||
* in which case it uses a "safe" approach, otherwise calls swap
|
||||
* on the assumption that swap may be specialised for the pointed-to type.
|
||||
*
|
||||
*/
|
||||
|
||||
/* Release notes:
|
||||
23rd July 2000:
|
||||
Added explicit failure for broken compilers that don't support these examples.
|
||||
Fixed broken gcc support (broken using directive).
|
||||
Reordered tests slightly.
|
||||
*/
|
||||
|
||||
#include <iostream>
|
||||
#include <typeinfo>
|
||||
#include <algorithm>
|
||||
#include <iterator>
|
||||
#include <vector>
|
||||
#include <memory>
|
||||
|
||||
#include <boost/timer.hpp>
|
||||
#include <boost/type_traits.hpp>
|
||||
#include <boost/call_traits.hpp>
|
||||
|
||||
using std::cout;
|
||||
using std::endl;
|
||||
using std::cin;
|
||||
|
||||
#ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
|
||||
#error "Sorry, without template partial specialisation support there isn't anything to test here..."
|
||||
#endif
|
||||
|
||||
namespace opt{
|
||||
|
||||
//
|
||||
// algorithm destroy_array:
|
||||
// The reverse of std::unitialized_copy, takes a block of
|
||||
// unitialized memory and calls destructors on all objects therein.
|
||||
//
|
||||
|
||||
namespace detail{
|
||||
|
||||
template <bool>
|
||||
struct array_destroyer
|
||||
{
|
||||
template <class T>
|
||||
static void destroy_array(T* i, T* j){ do_destroy_array(i, j); }
|
||||
};
|
||||
|
||||
template <>
|
||||
struct array_destroyer<true>
|
||||
{
|
||||
template <class T>
|
||||
static void destroy_array(T*, T*){}
|
||||
};
|
||||
|
||||
template <class T>
|
||||
void do_destroy_array(T* first, T* last)
|
||||
{
|
||||
while(first != last)
|
||||
{
|
||||
first->~T();
|
||||
++first;
|
||||
}
|
||||
}
|
||||
|
||||
}; // namespace detail
|
||||
|
||||
template <class T>
|
||||
inline void destroy_array(T* p1, T* p2)
|
||||
{
|
||||
detail::array_destroyer<boost::has_trivial_destructor<T>::value>::destroy_array(p1, p2);
|
||||
}
|
||||
|
||||
//
|
||||
// unoptimised versions of destroy_array:
|
||||
//
|
||||
template <class T>
|
||||
void destroy_array1(T* first, T* last)
|
||||
{
|
||||
while(first != last)
|
||||
{
|
||||
first->~T();
|
||||
++first;
|
||||
}
|
||||
}
|
||||
template <class T>
|
||||
void destroy_array2(T* first, T* last)
|
||||
{
|
||||
for(; first != last; ++first) first->~T();
|
||||
}
|
||||
|
||||
|
||||
//
|
||||
// opt::copy
|
||||
// same semantics as std::copy
|
||||
// calls memcpy where appropiate.
|
||||
//
|
||||
|
||||
namespace detail{
|
||||
|
||||
template <bool b>
|
||||
struct copier
|
||||
{
|
||||
template<typename I1, typename I2>
|
||||
static I2 do_copy(I1 first, I1 last, I2 out);
|
||||
};
|
||||
|
||||
template <bool b>
|
||||
template<typename I1, typename I2>
|
||||
I2 copier<b>::do_copy(I1 first, I1 last, I2 out)
|
||||
{
|
||||
while(first != last)
|
||||
{
|
||||
*out = *first;
|
||||
++out;
|
||||
++first;
|
||||
}
|
||||
return out;
|
||||
}
|
||||
|
||||
template <>
|
||||
struct copier<true>
|
||||
{
|
||||
template<typename I1, typename I2>
|
||||
static I2* do_copy(I1* first, I1* last, I2* out)
|
||||
{
|
||||
memcpy(out, first, (last-first)*sizeof(I2));
|
||||
return out+(last-first);
|
||||
}
|
||||
};
|
||||
|
||||
|
||||
}
|
||||
|
||||
template<typename I1, typename I2>
|
||||
inline I2 copy(I1 first, I1 last, I2 out)
|
||||
{
|
||||
typedef typename boost::remove_cv<typename std::iterator_traits<I1>::value_type>::type v1_t;
|
||||
typedef typename boost::remove_cv<typename std::iterator_traits<I2>::value_type>::type v2_t;
|
||||
enum{ can_opt = boost::is_same<v1_t, v2_t>::value
|
||||
&& boost::is_pointer<I1>::value
|
||||
&& boost::is_pointer<I2>::value
|
||||
&& boost::has_trivial_assign<v1_t>::value };
|
||||
return detail::copier<can_opt>::do_copy(first, last, out);
|
||||
}
|
||||
|
||||
//
|
||||
// fill
|
||||
// same as std::fill, uses memset where appropriate, along with call_traits
|
||||
// to "optimise" parameter passing.
|
||||
//
|
||||
namespace detail{
|
||||
|
||||
template <bool opt>
|
||||
struct filler
|
||||
{
|
||||
template <typename I, typename T>
|
||||
static void do_fill(I first, I last, typename boost::call_traits<T>::param_type val);
|
||||
};
|
||||
|
||||
template <bool b>
|
||||
template <typename I, typename T>
|
||||
void filler<b>::do_fill(I first, I last, typename boost::call_traits<T>::param_type val)
|
||||
{
|
||||
while(first != last)
|
||||
{
|
||||
*first = val;
|
||||
++first;
|
||||
}
|
||||
}
|
||||
|
||||
template <>
|
||||
struct filler<true>
|
||||
{
|
||||
template <typename I, typename T>
|
||||
static void do_fill(I first, I last, T val)
|
||||
{
|
||||
memset(first, val, last-first);
|
||||
}
|
||||
};
|
||||
|
||||
}
|
||||
|
||||
template <class I, class T>
|
||||
inline void fill(I first, I last, const T& val)
|
||||
{
|
||||
enum{ can_opt = boost::is_pointer<I>::value
|
||||
&& boost::is_arithmetic<T>::value
|
||||
&& (sizeof(T) == 1) };
|
||||
typedef detail::filler<can_opt> filler_t;
|
||||
filler_t::template do_fill<I,T>(first, last, val);
|
||||
}
|
||||
|
||||
//
|
||||
// iter_swap:
|
||||
// tests whether iterator is a proxying iterator or not, and
|
||||
// uses optimal form accordingly:
|
||||
//
|
||||
namespace detail{
|
||||
|
||||
template <bool b>
|
||||
struct swapper
|
||||
{
|
||||
template <typename I>
|
||||
static void do_swap(I one, I two)
|
||||
{
|
||||
typedef typename std::iterator_traits<I>::value_type v_t;
|
||||
v_t v = *one;
|
||||
*one = *two;
|
||||
*two = v;
|
||||
}
|
||||
};
|
||||
|
||||
#ifdef __GNUC__
|
||||
using std::swap;
|
||||
#endif
|
||||
|
||||
template <>
|
||||
struct swapper<true>
|
||||
{
|
||||
template <typename I>
|
||||
static void do_swap(I one, I two)
|
||||
{
|
||||
using std::swap;
|
||||
swap(*one, *two);
|
||||
}
|
||||
};
|
||||
|
||||
}
|
||||
|
||||
template <typename I1, typename I2>
|
||||
inline void iter_swap(I1 one, I2 two)
|
||||
{
|
||||
typedef typename std::iterator_traits<I1>::reference r1_t;
|
||||
typedef typename std::iterator_traits<I2>::reference r2_t;
|
||||
enum{ can_opt = boost::is_reference<r1_t>::value && boost::is_reference<r2_t>::value && boost::is_same<r1_t, r2_t>::value };
|
||||
detail::swapper<can_opt>::do_swap(one, two);
|
||||
}
|
||||
|
||||
|
||||
}; // namespace opt
|
||||
|
||||
//
|
||||
// define some global data:
|
||||
//
|
||||
const int array_size = 1000;
|
||||
int i_array[array_size] = {0,};
|
||||
const int ci_array[array_size] = {0,};
|
||||
char c_array[array_size] = {0,};
|
||||
const char cc_array[array_size] = { 0,};
|
||||
|
||||
const int iter_count = 1000000;
|
||||
|
||||
|
||||
int main()
|
||||
{
|
||||
//
|
||||
// test destroy_array,
|
||||
// compare destruction time of an array of ints
|
||||
// with unoptimised form.
|
||||
//
|
||||
cout << "Measuring times in micro-seconds per 1000 elements processed" << endl << endl;
|
||||
cout << "testing destroy_array...\n"
|
||||
"[Some compilers may be able to optimise the \"unoptimised\"\n versions as well as type_traits does.]" << endl;
|
||||
/*cache load*/ opt::destroy_array(i_array, i_array + array_size);
|
||||
boost::timer t;
|
||||
double result;
|
||||
int i;
|
||||
for(i = 0; i < iter_count; ++i)
|
||||
{
|
||||
opt::destroy_array(i_array, i_array + array_size);
|
||||
}
|
||||
result = t.elapsed();
|
||||
cout << "destroy_array<int>: " << result << endl;
|
||||
/*cache load*/ opt::destroy_array1(i_array, i_array + array_size);
|
||||
t.restart();
|
||||
for(i = 0; i < iter_count; ++i)
|
||||
{
|
||||
opt::destroy_array1(i_array, i_array + array_size);
|
||||
}
|
||||
result = t.elapsed();
|
||||
cout << "destroy_array<int>(unoptimised#1): " << result << endl;
|
||||
/*cache load*/ opt::destroy_array2(i_array, i_array + array_size);
|
||||
t.restart();
|
||||
for(i = 0; i < iter_count; ++i)
|
||||
{
|
||||
opt::destroy_array2(i_array, i_array + array_size);
|
||||
}
|
||||
result = t.elapsed();
|
||||
cout << "destroy_array<int>(unoptimised#2): " << result << endl << endl;
|
||||
|
||||
cout << "testing fill(char)...\n"
|
||||
"[Some standard library versions may already perform this optimisation.]" << endl;
|
||||
/*cache load*/ opt::fill<char*, char>(c_array, c_array + array_size, (char)3);
|
||||
t.restart();
|
||||
for(i = 0; i < iter_count; ++i)
|
||||
{
|
||||
opt::fill<char*, char>(c_array, c_array + array_size, (char)3);
|
||||
}
|
||||
result = t.elapsed();
|
||||
cout << "opt::fill<char*, char>: " << result << endl;
|
||||
/*cache load*/ std::fill(c_array, c_array + array_size, (char)3);
|
||||
t.restart();
|
||||
for(i = 0; i < iter_count; ++i)
|
||||
{
|
||||
std::fill(c_array, c_array + array_size, (char)3);
|
||||
}
|
||||
result = t.elapsed();
|
||||
cout << "std::fill<char*, char>: " << result << endl << endl;
|
||||
|
||||
cout << "testing fill(int)...\n"
|
||||
"[Tests the effect of call_traits pass-by-value optimisation -\nthe value of this optimisation may depend upon hardware characteristics.]" << endl;
|
||||
/*cache load*/ opt::fill<int*, int>(i_array, i_array + array_size, 3);
|
||||
t.restart();
|
||||
for(i = 0; i < iter_count; ++i)
|
||||
{
|
||||
opt::fill<int*, int>(i_array, i_array + array_size, 3);
|
||||
}
|
||||
result = t.elapsed();
|
||||
cout << "opt::fill<int*, int>: " << result << endl;
|
||||
/*cache load*/ std::fill(i_array, i_array + array_size, 3);
|
||||
t.restart();
|
||||
for(i = 0; i < iter_count; ++i)
|
||||
{
|
||||
std::fill(i_array, i_array + array_size, 3);
|
||||
}
|
||||
result = t.elapsed();
|
||||
cout << "std::fill<int*, int>: " << result << endl << endl;
|
||||
|
||||
cout << "testing copy...\n"
|
||||
"[Some standard library versions may already perform this optimisation.]" << endl;
|
||||
/*cache load*/ opt::copy<const int*, int*>(ci_array, ci_array + array_size, i_array);
|
||||
t.restart();
|
||||
for(i = 0; i < iter_count; ++i)
|
||||
{
|
||||
opt::copy<const int*, int*>(ci_array, ci_array + array_size, i_array);
|
||||
}
|
||||
result = t.elapsed();
|
||||
cout << "opt::copy<const int*, int*>: " << result << endl;
|
||||
/*cache load*/ std::copy<const int*, int*>(ci_array, ci_array + array_size, i_array);
|
||||
t.restart();
|
||||
for(i = 0; i < iter_count; ++i)
|
||||
{
|
||||
std::copy<const int*, int*>(ci_array, ci_array + array_size, i_array);
|
||||
}
|
||||
result = t.elapsed();
|
||||
cout << "std::copy<const int*, int*>: " << result << endl;
|
||||
/*cache load*/ opt::detail::copier<false>::template do_copy<const int*, int*>(ci_array, ci_array + array_size, i_array);
|
||||
t.restart();
|
||||
for(i = 0; i < iter_count; ++i)
|
||||
{
|
||||
opt::detail::copier<false>::template do_copy<const int*, int*>(ci_array, ci_array + array_size, i_array);
|
||||
}
|
||||
result = t.elapsed();
|
||||
cout << "standard \"unoptimised\" copy: " << result << endl << endl;
|
||||
|
||||
/*cache load*/ opt::copy<const char*, char*>(cc_array, cc_array + array_size, c_array);
|
||||
t.restart();
|
||||
for(i = 0; i < iter_count; ++i)
|
||||
{
|
||||
opt::copy<const char*, char*>(cc_array, cc_array + array_size, c_array);
|
||||
}
|
||||
result = t.elapsed();
|
||||
cout << "opt::copy<const char*, char*>: " << result << endl;
|
||||
/*cache load*/ std::copy<const char*, char*>(cc_array, cc_array + array_size, c_array);
|
||||
t.restart();
|
||||
for(i = 0; i < iter_count; ++i)
|
||||
{
|
||||
std::copy<const char*, char*>(cc_array, cc_array + array_size, c_array);
|
||||
}
|
||||
result = t.elapsed();
|
||||
cout << "std::copy<const char*, char*>: " << result << endl;
|
||||
/*cache load*/ opt::detail::copier<false>::template do_copy<const char*, char*>(cc_array, cc_array + array_size, c_array);
|
||||
t.restart();
|
||||
for(i = 0; i < iter_count; ++i)
|
||||
{
|
||||
opt::detail::copier<false>::template do_copy<const char*, char*>(cc_array, cc_array + array_size, c_array);
|
||||
}
|
||||
result = t.elapsed();
|
||||
cout << "standard \"unoptimised\" copy: " << result << endl << endl;
|
||||
|
||||
|
||||
//
|
||||
// testing iter_swap
|
||||
// really just a check that it does in fact compile...
|
||||
std::vector<int> v1;
|
||||
v1.push_back(0);
|
||||
v1.push_back(1);
|
||||
std::vector<bool> v2;
|
||||
v2.push_back(0);
|
||||
v2.push_back(1);
|
||||
opt::iter_swap(v1.begin(), v1.begin()+1);
|
||||
opt::iter_swap(v2.begin(), v2.begin()+1);
|
||||
|
||||
cout << "Press any key to exit...";
|
||||
cin.get();
|
||||
}
|
||||
|
||||
|
||||
|
||||
|
||||
|
@@ -1,489 +0,0 @@
|
||||
<html>
|
||||
|
||||
<head>
|
||||
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
|
||||
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
|
||||
<meta name="ProgId" content="FrontPage.Editor.Document">
|
||||
<title>C++ Type traits</title>
|
||||
</head>
|
||||
|
||||
<body bgcolor="#FFFFFF" link="#0000FF" vlink="#800080">
|
||||
|
||||
<h2 align="center">C++ Type traits</h2>
|
||||
<p align="center"><em>by John Maddock and Steve Cleary</em></p>
|
||||
<p align="center"><em>This is a draft of an article that will appear in a future
|
||||
issue of </em><a href="http://www.ddj.com"><em>Dr Dobb's Journal</em></a></p>
|
||||
<p>Generic programming (writing code which works with any data type meeting a
|
||||
set of requirements) has become the method of choice for providing reusable
|
||||
code. However, there are times in generic programming when "generic"
|
||||
just isn't good enough - sometimes the differences between types are too large
|
||||
for an efficient generic implementation. This is when the traits technique
|
||||
becomes important - by encapsulating those properties that need to be considered
|
||||
on a type by type basis inside a traits class, we can minimise the amount of
|
||||
code that has to differ from one type to another, and maximise the amount of
|
||||
generic code.</p>
|
||||
<p>Consider an example: when working with character strings, one common
|
||||
operation is to determine the length of a null terminated string. Clearly it's
|
||||
possible to write generic code that can do this, but it turns out that there are
|
||||
much more efficient methods available: for example, the C library functions <font size="2" face="Courier New">strlen</font>
|
||||
and <font size="2" face="Courier New">wcslen</font> are usually written in
|
||||
assembler, and with suitable hardware support can be considerably faster than a
|
||||
generic version written in C++. The authors of the C++ standard library realised
|
||||
this, and abstracted the properties of <font size="2" face="Courier New">char</font>
|
||||
and <font size="2" face="Courier New">wchar_t</font> into the class <font size="2" face="Courier New">char_traits</font>.
|
||||
Generic code that works with character strings can simply use <font size="2" face="Courier New">char_traits<>::length</font>
|
||||
to determine the length of a null terminated string, safe in the knowledge that
|
||||
specialisations of <font size="2" face="Courier New">char_traits</font> will use
|
||||
the most appropriate method available to them.</p>
|
||||
<h4>Type traits</h4>
|
||||
<p>Class <font size="2" face="Courier New">char_traits</font> is a classic
|
||||
example of a collection of type specific properties wrapped up in a single class
|
||||
- what Nathan Myers termed a <i>baggage class</i>[1]. In the Boost type-traits
|
||||
library, we[2] have written a set of very specific traits classes, each of which
|
||||
encapsulate a single trait from the C++ type system; for example, is a type a
|
||||
pointer or a reference type? Or does a type have a trivial constructor, or a
|
||||
const-qualifier? The type-traits classes share a unified design: each class has
|
||||
a single member <i>value</i>, a compile-time constant that is true if the type
|
||||
has the specified property, and false otherwise. As we will show, these classes
|
||||
can be used in generic programming to determine the properties of a given type
|
||||
and introduce optimisations that are appropriate for that case.</p>
|
||||
<p>The type-traits library also contains a set of classes that perform a
|
||||
specific transformation on a type; for example, they can remove a top-level
|
||||
const or volatile qualifier from a type. Each class that performs a
|
||||
transformation defines a single typedef-member <i>type</i> that is the result of
|
||||
the transformation. All of the type-traits classes are defined inside namespace <font size="2" face="Courier New">boost</font>;
|
||||
for brevity, namespace-qualification is omitted in most of the code samples
|
||||
given.</p>
|
||||
<h4>Implementation</h4>
|
||||
<p>There are far too many separate classes contained in the type-traits library
|
||||
to give a full implementation here - see the source code in the Boost library
|
||||
for the full details - however, most of the implementation is fairly repetitive
|
||||
anyway, so here we will just give you a flavour for how some of the classes are
|
||||
implemented. Beginning with possibly the simplest class in the library, is_void<T>
|
||||
has a member <i>value</i> that is true only if T is void.</p>
|
||||
<pre>template <typename T>
|
||||
struct is_void
|
||||
{ static const bool value = false; };
|
||||
|
||||
template <>
|
||||
struct is_void<void>
|
||||
{ static const bool value = true; };</pre>
|
||||
<p>Here we define a primary version of the template class <font size="2" face="Courier New">is_void</font>,
|
||||
and provide a full-specialisation when T is void. While full specialisation of a
|
||||
template class is an important technique, sometimes we need a solution that is
|
||||
halfway between a fully generic solution, and a full specialisation. This is
|
||||
exactly the situation for which the standards committee defined partial
|
||||
template-class specialisation. As an example, consider the class
|
||||
boost::is_pointer<T>: here we needed a primary version that handles all
|
||||
the cases where T is not a pointer, and a partial specialisation to handle all
|
||||
the cases where T is a pointer:</p>
|
||||
<pre>template <typename T>
|
||||
struct is_pointer
|
||||
{ static const bool value = false; };
|
||||
|
||||
template <typename T>
|
||||
struct is_pointer<T*>
|
||||
{ static const bool value = true; };</pre>
|
||||
<p>The syntax for partial specialisation is somewhat arcane and could easily
|
||||
occupy an article in its own right; like full specialisation, in order to write
|
||||
a partial specialisation for a class, you must first declare the primary
|
||||
template. The partial specialisation contains an extra <<EFBFBD>> after the
|
||||
class name that contains the partial specialisation parameters; these define the
|
||||
types that will bind to that partial specialisation rather than the default
|
||||
template. The rules for what can appear in a partial specialisation are somewhat
|
||||
convoluted, but as a rule of thumb if you can legally write two function
|
||||
overloads of the form:</p>
|
||||
<pre>void foo(T);
|
||||
void foo(U);</pre>
|
||||
<p>Then you can also write a partial specialisation of the form:</p>
|
||||
<pre>template <typename T>
|
||||
class c{ /*details*/ };
|
||||
|
||||
template <typename T>
|
||||
|
||||
class c<U>{ /*details*/ };</pre>
|
||||
<p>This rule is by no means foolproof, but it is reasonably simple to remember
|
||||
and close enough to the actual rule to be useful for everyday use.</p>
|
||||
<p>As a more complex example of partial specialisation consider the class
|
||||
remove_bounds<T>. This class defines a single typedef-member <i>type</i>
|
||||
that is the same type as T but with any top-level array bounds removed; this is
|
||||
an example of a traits class that performs a transformation on a type:</p>
|
||||
<pre>template <typename T>
|
||||
struct remove_bounds
|
||||
{ typedef T type; };
|
||||
|
||||
template <typename T, std::size_t N>
|
||||
struct remove_bounds<T[N]>
|
||||
{ typedef T type; };</pre>
|
||||
<p>The aim of remove_bounds is this: imagine a generic algorithm that is passed
|
||||
an array type as a template parameter, <font size="2" face="Courier New">remove_bounds</font>
|
||||
provides a means of determining the underlying type of the array. For example <code>remove_bounds<int[4][5]>::type</code>
|
||||
would evaluate to the type <code>int[5]</code>. This example also shows that the
|
||||
number of template parameters in a partial specialisation does not have to match
|
||||
the number in the default template. However, the number of parameters that
|
||||
appear after the class name do have to match the number and type of the
|
||||
parameters in the default template.</p>
|
||||
<h4>Optimised copy</h4>
|
||||
<p>As an example of how the type traits classes can be used, consider the
|
||||
standard library algorithm copy:</p>
|
||||
<pre>template<typename Iter1, typename Iter2>
|
||||
Iter2 copy(Iter1 first, Iter1 last, Iter2 out);</pre>
|
||||
<p>Obviously, there's no problem writing a generic version of copy that works
|
||||
for all iterator types Iter1 and Iter2; however, there are some circumstances
|
||||
when the copy operation can best be performed by a call to <font size="2" face="Courier New">memcpy</font>.
|
||||
In order to implement copy in terms of <font size="2" face="Courier New">memcpy</font>
|
||||
all of the following conditions need to be met:</p>
|
||||
<ul>
|
||||
<li>Both of the iterator types Iter1 and Iter2 must be pointers.</li>
|
||||
<li>Both Iter1 and Iter2 must point to the same type - excluding <font size="2" face="Courier New">const</font>
|
||||
and <font size="2" face="Courier New">volatile</font>-qualifiers.</li>
|
||||
<li>The type pointed to by Iter1 must have a trivial assignment operator.</li>
|
||||
</ul>
|
||||
<p>By trivial assignment operator we mean that the type is either a scalar
|
||||
type[3] or:</p>
|
||||
<ul>
|
||||
<li>The type has no user defined assignment operator.</li>
|
||||
<li>The type does not have any data members that are references.</li>
|
||||
<li>All base classes, and all data member objects must have trivial assignment
|
||||
operators.</li>
|
||||
</ul>
|
||||
<p>If all these conditions are met then a type can be copied using <font size="2" face="Courier New">memcpy</font>
|
||||
rather than using a compiler generated assignment operator. The type-traits
|
||||
library provides a class <i>has_trivial_assign</i>, such that <code>has_trivial_assign<T>::value</code>
|
||||
is true only if T has a trivial assignment operator. This class "just
|
||||
works" for scalar types, but has to be explicitly specialised for
|
||||
class/struct types that also happen to have a trivial assignment operator. In
|
||||
other words if <i>has_trivial_assign</i> gives the wrong answer, it will give
|
||||
the "safe" wrong answer - that trivial assignment is not allowable.</p>
|
||||
<p>The code for an optimised version of copy that uses <font size="2" face="Courier New">memcpy</font>
|
||||
where appropriate is given in listing 1. The code begins by defining a template
|
||||
class <i>copier</i>, that takes a single Boolean template parameter, and has a
|
||||
static template member function <font size="2" face="Courier New">do_copy</font>
|
||||
which performs the generic version of <font size="2">copy</font> (in other words
|
||||
the "slow but safe version"). Following that there is a specialisation
|
||||
for <i>copier<true></i>: again this defines a static template member
|
||||
function <font size="2" face="Courier New">do_copy</font>, but this version uses
|
||||
memcpy to perform an "optimised" copy.</p>
|
||||
<p>In order to complete the implementation, what we need now is a version of
|
||||
copy, that calls <code>copier<true>::do_copy</code> if it is safe to use <font size="2" face="Courier New">memcpy</font>,
|
||||
and otherwise calls <code>copier<false>::do_copy</code> to do a
|
||||
"generic" copy. This is what the version in listing 1 does. To
|
||||
understand how the code works look at the code for <font size="2" face="Courier New">copy</font>
|
||||
and consider first the two typedefs <i>v1_t</i> and <i>v2_t</i>. These use <code>std::iterator_traits<Iter1>::value_type</code>
|
||||
to determine what type the two iterators point to, and then feed the result into
|
||||
another type-traits class <i>remove_cv</i> that removes the top-level
|
||||
const-volatile-qualifiers: this will allow copy to compare the two types without
|
||||
regard to const- or volatile-qualifiers. Next, <font size="2" face="Courier New">copy</font>
|
||||
declares an enumerated value <i>can_opt</i> that will become the template
|
||||
parameter to copier - declaring this here as a constant is really just a
|
||||
convenience - the value could be passed directly to class <font size="2" face="Courier New">copier</font>.
|
||||
The value of <i>can_opt</i> is computed by verifying that all of the following
|
||||
are true:</p>
|
||||
<ul>
|
||||
<li>first that the two iterators point to the same type by using a type-traits
|
||||
class <i>is_same</i>.</li>
|
||||
<li>Then that both iterators are real pointers - using the class <i>is_pointer</i>
|
||||
described above.</li>
|
||||
<li>Finally that the pointed-to types have a trivial assignment operator using
|
||||
<i>has_trivial_assign</i>.</li>
|
||||
</ul>
|
||||
<p>Finally we can use the value of <i>can_opt</i> as the template argument to
|
||||
copier - this version of copy will now adapt to whatever parameters are passed
|
||||
to it, if its possible to use <font size="2" face="Courier New">memcpy</font>,
|
||||
then it will do so, otherwise it will use a generic copy.</p>
|
||||
<h4>Was it worth it?</h4>
|
||||
<p>It has often been repeated in these columns that "premature optimisation
|
||||
is the root of all evil" [4]. So the question must be asked: was our
|
||||
optimisation premature? To put this in perspective the timings for our version
|
||||
of copy compared a conventional generic copy[5] are shown in table 1.</p>
|
||||
<p>Clearly the optimisation makes a difference in this case; but, to be fair,
|
||||
the timings are loaded to exclude cache miss effects - without this accurate
|
||||
comparison between algorithms becomes difficult. However, perhaps we can add a
|
||||
couple of caveats to the premature optimisation rule:</p>
|
||||
<ul>
|
||||
<li>If you use the right algorithm for the job in the first place then
|
||||
optimisation will not be required; in some cases, <font size="2" face="Courier New">memcpy</font>
|
||||
is the right algorithm.</li>
|
||||
<li>If a component is going to be reused in many places by many people then
|
||||
optimisations may well be worthwhile where they would not be so for a single
|
||||
case - in other words, the likelihood that the optimisation will be
|
||||
absolutely necessary somewhere, sometime is that much higher. Just as
|
||||
importantly the perceived value of the stock implementation will be higher:
|
||||
there is no point standardising an algorithm if users reject it on the
|
||||
grounds that there are better, more heavily optimised versions available.</li>
|
||||
</ul>
|
||||
<h4>Table 1: Time taken to copy 1000 elements using copy<const T*, T*>
|
||||
(times in micro-seconds)</h4>
|
||||
<table border="1" cellpadding="7" cellspacing="1" width="529">
|
||||
<tr>
|
||||
<td valign="top" width="33%">
|
||||
<p align="center">Version</p>
|
||||
</td>
|
||||
<td valign="top" width="33%">
|
||||
<p align="center">T</p>
|
||||
</td>
|
||||
<td valign="top" width="33%">
|
||||
<p align="center">Time</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="33%">"Optimised" copy</td>
|
||||
<td valign="top" width="33%">char</td>
|
||||
<td valign="top" width="33%">0.99</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="33%">Conventional copy</td>
|
||||
<td valign="top" width="33%">char</td>
|
||||
<td valign="top" width="33%">8.07</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="33%">"Optimised" copy</td>
|
||||
<td valign="top" width="33%">int</td>
|
||||
<td valign="top" width="33%">2.52</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="33%">Conventional copy</td>
|
||||
<td valign="top" width="33%">int</td>
|
||||
<td valign="top" width="33%">8.02</td>
|
||||
</tr>
|
||||
</table>
|
||||
<p> </p>
|
||||
<h4>Pair of References</h4>
|
||||
<p>The optimised copy example shows how type traits may be used to perform
|
||||
optimisation decisions at compile-time. Another important usage of type traits
|
||||
is to allow code to compile that otherwise would not do so unless excessive
|
||||
partial specialization is used. This is possible by delegating partial
|
||||
specialization to the type traits classes. Our example for this form of usage is
|
||||
a pair that can hold references [6].</p>
|
||||
<p>First, let us examine the definition of "std::pair", omitting the
|
||||
comparision operators, default constructor, and template copy constructor for
|
||||
simplicity:</p>
|
||||
<pre>template <typename T1, typename T2>
|
||||
struct pair
|
||||
{
|
||||
typedef T1 first_type;
|
||||
typedef T2 second_type;
|
||||
|
||||
T1 first;
|
||||
T2 second;
|
||||
|
||||
pair(const T1 & nfirst, const T2 & nsecond)
|
||||
:first(nfirst), second(nsecond) { }
|
||||
};</pre>
|
||||
<p>Now, this "pair" cannot hold references as it currently stands,
|
||||
because the constructor would require taking a reference to a reference, which
|
||||
is currently illegal [7]. Let us consider what the constructor's parameters
|
||||
would have to be in order to allow "pair" to hold non-reference types,
|
||||
references, and constant references:</p>
|
||||
<table border="1" cellpadding="7" cellspacing="1" width="638">
|
||||
<tr>
|
||||
<td valign="top" width="50%">Type of "T1"</td>
|
||||
<td valign="top" width="50%">Type of parameter to initializing constructor</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="50%">
|
||||
<pre>T</pre>
|
||||
</td>
|
||||
<td valign="top" width="50%">
|
||||
<pre>const T &</pre>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="50%">
|
||||
<pre>T &</pre>
|
||||
</td>
|
||||
<td valign="top" width="50%">
|
||||
<pre>T &</pre>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="50%">
|
||||
<pre>const T &</pre>
|
||||
</td>
|
||||
<td valign="top" width="50%">
|
||||
<pre>const T &</pre>
|
||||
</td>
|
||||
</tr>
|
||||
</table>
|
||||
<p>A little familiarity with the type traits classes allows us to construct a
|
||||
single mapping that allows us to determine the type of parameter from the type
|
||||
of the contained class. The type traits classes provide a transformation "add_reference",
|
||||
which adds a reference to its type, unless it is already a reference.</p>
|
||||
<table border="1" cellpadding="7" cellspacing="1" width="580">
|
||||
<tr>
|
||||
<td valign="top" width="21%">Type of "T1"</td>
|
||||
<td valign="top" width="27%">Type of "const T1"</td>
|
||||
<td valign="top" width="53%">Type of "add_reference<const
|
||||
T1>::type"</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="21%">
|
||||
<pre>T</pre>
|
||||
</td>
|
||||
<td valign="top" width="27%">
|
||||
<pre>const T</pre>
|
||||
</td>
|
||||
<td valign="top" width="53%">
|
||||
<pre>const T &</pre>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="21%">
|
||||
<pre>T &</pre>
|
||||
</td>
|
||||
<td valign="top" width="27%">
|
||||
<pre>T & [8]</pre>
|
||||
</td>
|
||||
<td valign="top" width="53%">
|
||||
<pre>T &</pre>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="21%">
|
||||
<pre>const T &</pre>
|
||||
</td>
|
||||
<td valign="top" width="27%">
|
||||
<pre>const T &</pre>
|
||||
</td>
|
||||
<td valign="top" width="53%">
|
||||
<pre>const T &</pre>
|
||||
</td>
|
||||
</tr>
|
||||
</table>
|
||||
<p>This allows us to build a primary template definition for "pair"
|
||||
that can contain non-reference types, reference types, and constant reference
|
||||
types:</p>
|
||||
<pre>template <typename T1, typename T2>
|
||||
struct pair
|
||||
{
|
||||
typedef T1 first_type;
|
||||
typedef T2 second_type;
|
||||
|
||||
T1 first;
|
||||
T2 second;
|
||||
|
||||
pair(boost::add_reference<const T1>::type nfirst,
|
||||
boost::add_reference<const T2>::type nsecond)
|
||||
:first(nfirst), second(nsecond) { }
|
||||
};</pre>
|
||||
<p>Add back in the standard comparision operators, default constructor, and
|
||||
template copy constructor (which are all the same), and you have a std::pair
|
||||
that can hold reference types!</p>
|
||||
<p>This same extension <i>could</i> have been done using partial template
|
||||
specialization of "pair", but to specialize "pair" in this
|
||||
way would require three partial specializations, plus the primary template. Type
|
||||
traits allows us to define a single primary template that adjusts itself
|
||||
auto-magically to any of these partial specializations, instead of a brute-force
|
||||
partial specialization approach. Using type traits in this fashion allows
|
||||
programmers to delegate partial specialization to the type traits classes,
|
||||
resulting in code that is easier to maintain and easier to understand.</p>
|
||||
<h4>Conclusion</h4>
|
||||
<p>We hope that in this article we have been able to give you some idea of what
|
||||
type-traits are all about. A more complete listing of the available classes are
|
||||
in the boost documentation, along with further examples using type traits.
|
||||
Templates have enabled C++ uses to take the advantage of the code reuse that
|
||||
generic programming brings; hopefully this article has shown that generic
|
||||
programming does not have to sink to the lowest common denominator, and that
|
||||
templates can be optimal as well as generic.</p>
|
||||
<h4>Acknowledgements</h4>
|
||||
<p>The authors would like to thank Beman Dawes and Howard Hinnant for their
|
||||
helpful comments when preparing this article.</p>
|
||||
<h4>References</h4>
|
||||
<ol>
|
||||
<li>Nathan C. Myers, C++ Report, June 1995.</li>
|
||||
<li>The type traits library is based upon contributions by Steve Cleary, Beman
|
||||
Dawes, Howard Hinnant and John Maddock: it can be found at www.boost.org.</li>
|
||||
<li>A scalar type is an arithmetic type (i.e. a built-in integer or floating
|
||||
point type), an enumeration type, a pointer, a pointer to member, or a
|
||||
const- or volatile-qualified version of one of these types.</li>
|
||||
<li>This quote is from Donald Knuth, ACM Computing Surveys, December 1974, pg
|
||||
268.</li>
|
||||
<li>The test code is available as part of the boost utility library (see
|
||||
algo_opt_examples.cpp), the code was compiled with gcc 2.95 with all
|
||||
optimisations turned on, tests were conducted on a 400MHz Pentium II machine
|
||||
running Microsoft Windows 98.</li>
|
||||
<li>John Maddock and Howard Hinnant have submitted a "compressed_pair"
|
||||
library to Boost, which uses a technique similar to the one described here
|
||||
to hold references. Their pair also uses type traits to determine if any of
|
||||
the types are empty, and will derive instead of contain to conserve space --
|
||||
hence the name "compressed".</li>
|
||||
<li>This is actually an issue with the C++ Core Language Working Group (issue
|
||||
#106), submitted by Bjarne Stroustrup. The tentative resolution is to allow
|
||||
a "reference to a reference to T" to mean the same thing as a
|
||||
"reference to T", but only in template instantiation, in a method
|
||||
similar to multiple cv-qualifiers.</li>
|
||||
<li>For those of you who are wondering why this shouldn't be const-qualified,
|
||||
remember that references are always implicitly constant (for example, you
|
||||
can't re-assign a reference). Remember also that "const T &"
|
||||
is something completely different. For this reason, cv-qualifiers on
|
||||
template type arguments that are references are ignored.</li>
|
||||
</ol>
|
||||
<h2>Listing 1</h2>
|
||||
<pre>namespace detail{
|
||||
|
||||
template <bool b>
|
||||
struct copier
|
||||
{
|
||||
template<typename I1, typename I2>
|
||||
static I2 do_copy(I1 first,
|
||||
I1 last, I2 out);
|
||||
};
|
||||
|
||||
template <bool b>
|
||||
template<typename I1, typename I2>
|
||||
I2 copier<b>::do_copy(I1 first,
|
||||
I1 last,
|
||||
I2 out)
|
||||
{
|
||||
while(first != last)
|
||||
{
|
||||
*out = *first;
|
||||
++out;
|
||||
++first;
|
||||
}
|
||||
return out;
|
||||
}
|
||||
|
||||
template <>
|
||||
struct copier<true>
|
||||
{
|
||||
template<typename I1, typename I2>
|
||||
static I2* do_copy(I1* first, I1* last, I2* out)
|
||||
{
|
||||
memcpy(out, first, (last-first)*sizeof(I2));
|
||||
return out+(last-first);
|
||||
}
|
||||
};
|
||||
|
||||
}
|
||||
|
||||
template<typename I1, typename I2>
|
||||
inline I2 copy(I1 first, I1 last, I2 out)
|
||||
{
|
||||
typedef typename
|
||||
boost::remove_cv<
|
||||
typename std::iterator_traits<I1>
|
||||
::value_type>::type v1_t;
|
||||
|
||||
typedef typename
|
||||
boost::remove_cv<
|
||||
typename std::iterator_traits<I2>
|
||||
::value_type>::type v2_t;
|
||||
|
||||
enum{ can_opt =
|
||||
boost::is_same<v1_t, v2_t>::value
|
||||
&& boost::is_pointer<I1>::value
|
||||
&& boost::is_pointer<I2>::value
|
||||
&& boost::
|
||||
has_trivial_assign<v1_t>::value
|
||||
};
|
||||
|
||||
return detail::copier<can_opt>::
|
||||
do_copy(first, last, out);
|
||||
}</pre>
|
||||
<hr>
|
||||
<p><EFBFBD> Copyright John Maddock and Steve Cleary, 2000</p>
|
||||
|
||||
</body>
|
||||
|
||||
</html>
|
@@ -27,10 +27,16 @@ never occur, and that parameters are passed in the most efficient
|
||||
manner possible (see <a href="#examples">examples</a>). In each
|
||||
case if your existing practice is to use the type defined on the
|
||||
left, then replace it with the call_traits defined type on the
|
||||
right. Note that for compilers that do not support partial
|
||||
specialization, no benefit will occur from using call_traits: the
|
||||
call_traits defined types will always be the same as the existing
|
||||
practice in this case.</p>
|
||||
right. </p>
|
||||
|
||||
<p>Note that for compilers that do not support either partial
|
||||
specialization or member templates, no benefit will occur from
|
||||
using call_traits: the call_traits defined types will always be
|
||||
the same as the existing practice in this case. In addition if
|
||||
only member templates and not partial template specialisation is
|
||||
support by the compiler (for example Visual C++ 6) then
|
||||
call_traits can not be used with array types (although it can be
|
||||
used to solve the reference to reference problem).</p>
|
||||
|
||||
<table border="0" cellpadding="7" cellspacing="1" width="797">
|
||||
<tr>
|
||||
@@ -73,7 +79,8 @@ practice in this case.</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="17%"><p align="center">const T&<br>
|
||||
<td valign="top" width="17%"><p align="center">const
|
||||
T&<br>
|
||||
(return value)</p>
|
||||
</td>
|
||||
<td valign="top" width="35%"><p align="center"><code>call_traits<T>::const_reference</code></p>
|
||||
@@ -85,7 +92,8 @@ practice in this case.</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="17%"><p align="center">const T&<br>
|
||||
<td valign="top" width="17%"><p align="center">const
|
||||
T&<br>
|
||||
(function parameter)</p>
|
||||
</td>
|
||||
<td valign="top" width="35%"><p align="center"><code>call_traits<T>::param_type</code></p>
|
||||
@@ -326,8 +334,8 @@ possible:</p>
|
||||
<p>The following table shows the effect that call_traits has on
|
||||
various types, the table assumes that the compiler supports
|
||||
partial specialization: if it doesn't then all types behave in
|
||||
the same way as the entry for "myclass", and call_traits
|
||||
can not be used with reference or array types.</p>
|
||||
the same way as the entry for "myclass", and
|
||||
call_traits can not be used with reference or array types.</p>
|
||||
|
||||
<table border="0" cellpadding="7" cellspacing="1" width="766">
|
||||
<tr>
|
||||
@@ -382,7 +390,8 @@ can not be used with reference or array types.</p>
|
||||
</td>
|
||||
<td valign="top" width="17%"><p align="center">int&</p>
|
||||
</td>
|
||||
<td valign="top" width="17%"><p align="center">const int&</p>
|
||||
<td valign="top" width="17%"><p align="center">const
|
||||
int&</p>
|
||||
</td>
|
||||
<td valign="top" width="17%"><p align="center">int const</p>
|
||||
</td>
|
||||
@@ -414,7 +423,8 @@ can not be used with reference or array types.</p>
|
||||
</td>
|
||||
<td valign="top" width="17%"><p align="center">int&</p>
|
||||
</td>
|
||||
<td valign="top" width="17%"><p align="center">const int&</p>
|
||||
<td valign="top" width="17%"><p align="center">const
|
||||
int&</p>
|
||||
</td>
|
||||
<td valign="top" width="17%"><p align="center">int&</p>
|
||||
</td>
|
||||
@@ -426,13 +436,17 @@ can not be used with reference or array types.</p>
|
||||
<td valign="top" width="17%" bgcolor="#C0C0C0"><p
|
||||
align="center">const int&</p>
|
||||
</td>
|
||||
<td valign="top" width="17%"><p align="center">const int&</p>
|
||||
<td valign="top" width="17%"><p align="center">const
|
||||
int&</p>
|
||||
</td>
|
||||
<td valign="top" width="17%"><p align="center">const int&</p>
|
||||
<td valign="top" width="17%"><p align="center">const
|
||||
int&</p>
|
||||
</td>
|
||||
<td valign="top" width="17%"><p align="center">const int&</p>
|
||||
<td valign="top" width="17%"><p align="center">const
|
||||
int&</p>
|
||||
</td>
|
||||
<td valign="top" width="17%"><p align="center">const int&</p>
|
||||
<td valign="top" width="17%"><p align="center">const
|
||||
int&</p>
|
||||
</td>
|
||||
<td valign="top" width="17%"><p align="center">All
|
||||
constant-references.</p>
|
||||
@@ -480,8 +494,8 @@ can not be used with reference or array types.</p>
|
||||
|
||||
<p>The following class is a trivial class that stores some type T
|
||||
by value (see the <a href="call_traits_test.cpp">call_traits_test.cpp</a>
|
||||
file), the aim is to illustrate how each of the available call_traits
|
||||
typedefs may be used:</p>
|
||||
file), the aim is to illustrate how each of the available
|
||||
call_traits typedefs may be used:</p>
|
||||
|
||||
<pre>template <class T>
|
||||
struct contained
|
||||
@@ -517,14 +531,14 @@ problem):</h4>
|
||||
|
||||
<pre>template <class Operation>
|
||||
class binder1st :
|
||||
public unary_function<Operation::second_argument_type, Operation::result_type>
|
||||
public unary_function<typename Operation::second_argument_type, typename Operation::result_type>
|
||||
{
|
||||
protected:
|
||||
Operation op;
|
||||
Operation::first_argument_type value;
|
||||
typename Operation::first_argument_type value;
|
||||
public:
|
||||
binder1st(const Operation& x, const Operation::first_argument_type& y);
|
||||
Operation::result_type operator()(const Operation::second_argument_type& x) const;
|
||||
binder1st(const Operation& x, const typename Operation::first_argument_type& y);
|
||||
typename Operation::result_type operator()(const typename Operation::second_argument_type& x) const;
|
||||
}; </pre>
|
||||
|
||||
<p>Now consider what happens in the relatively common case that
|
||||
@@ -535,7 +549,7 @@ reference to a reference as an argument, and that is not
|
||||
currently legal. The solution here is to modify <code>operator()</code>
|
||||
to use call_traits:</p>
|
||||
|
||||
<pre>Operation::result_type operator()(call_traits<Operation::second_argument_type>::param_type x) const;</pre>
|
||||
<pre>typename Operation::result_type operator()(typename call_traits<typename Operation::second_argument_type>::param_type x) const;</pre>
|
||||
|
||||
<p>Now in the case that <code>Operation::second_argument_type</code>
|
||||
is a reference type, the argument is passed as a reference, and
|
||||
@@ -569,7 +583,9 @@ std::pair<
|
||||
degraded to pointers if the deduced types are arrays, similar
|
||||
situations occur in the standard binders and adapters: in
|
||||
principle in any function that "wraps" a temporary
|
||||
whose type is deduced.</p>
|
||||
whose type is deduced. Note that the function arguments to
|
||||
make_pair are not expressed in terms of call_traits: doing so
|
||||
would prevent template argument deduction from functioning.</p>
|
||||
|
||||
<h4><a name="ex4"></a>Example 4 (optimising fill):</h4>
|
||||
|
||||
@@ -632,6 +648,14 @@ Exactly how much mileage you will get from this depends upon your
|
||||
compiler - we could really use some accurate benchmarking
|
||||
software as part of boost for cases like this.</p>
|
||||
|
||||
<p>Note that the function arguments to fill are not expressed in
|
||||
terms of call_traits: doing so would prevent template argument
|
||||
deduction from functioning. Instead fill acts as a "thin
|
||||
wrapper" that is there to perform template argument
|
||||
deduction, the compiler will optimise away the call to fill all
|
||||
together, replacing it with the call to filler<>::do_fill,
|
||||
which does use call_traits.</p>
|
||||
|
||||
<h3>Rationale</h3>
|
||||
|
||||
<p>The following notes are intended to briefly describe the
|
||||
@@ -650,10 +674,10 @@ be any worse than existing practice.</p>
|
||||
<p>Pointers follow the same rational as small built-in types.</p>
|
||||
|
||||
<p>For reference types the rational follows <a href="#refs">Example
|
||||
2</a> - references to references are not allowed, so the call_traits
|
||||
members must be defined such that these problems do not occur.
|
||||
There is a proposal to modify the language such that "a
|
||||
reference to a reference is a reference" (issue #106,
|
||||
2</a> - references to references are not allowed, so the
|
||||
call_traits members must be defined such that these problems do
|
||||
not occur. There is a proposal to modify the language such that
|
||||
"a reference to a reference is a reference" (issue #106,
|
||||
submitted by Bjarne Stroustrup), call_traits<T>::value_type
|
||||
and call_traits<T>::param_type both provide the same effect
|
||||
as that proposal, without the need for a language change (in
|
||||
@@ -671,11 +695,11 @@ struct A
|
||||
void foo(T t);
|
||||
};</pre>
|
||||
|
||||
<p><font face="Times New Roman">In this case if we instantiate A<int[2]>
|
||||
then the declared type of the parameter passed to member function
|
||||
foo is int[2], but it's actual type is const int*, if we try to
|
||||
use the type T within the function body, then there is a strong
|
||||
likelyhood that our code will not compile:</font></p>
|
||||
<p><font face="Times New Roman">In this case if we instantiate
|
||||
A<int[2]> then the declared type of the parameter passed to
|
||||
member function foo is int[2], but it's actual type is const int*,
|
||||
if we try to use the type T within the function body, then there
|
||||
is a strong likelyhood that our code will not compile:</font></p>
|
||||
|
||||
<pre>template <class T>
|
||||
void A<T>::foo(T t)
|
||||
@@ -690,13 +714,13 @@ declared type:</p>
|
||||
<pre>template <class T>
|
||||
struct A
|
||||
{
|
||||
void foo(call_traits<T>::value_type t);
|
||||
void foo(typename call_traits<T>::value_type t);
|
||||
};
|
||||
|
||||
template <class T>
|
||||
void A<T>::foo(call_traits<T>::value_type t)
|
||||
void A<T>::foo(typename call_traits<T>::value_type t)
|
||||
{
|
||||
call_traits<T>::value_type dup(t); // OK even if T is an array type.
|
||||
typename call_traits<T>::value_type dup(t); // OK even if T is an array type.
|
||||
}</pre>
|
||||
|
||||
<p>For value_type (return by value), again only a pointer may be
|
||||
@@ -713,7 +737,7 @@ specialisation).</p>
|
||||
|
||||
<hr>
|
||||
|
||||
<p>Revised 18 June 2000</p>
|
||||
<p>Revised 01 September 2000</p>
|
||||
|
||||
<p><EFBFBD> Copyright boost.org 2000. Permission to copy, use, modify,
|
||||
sell and distribute this document is granted provided this
|
||||
|
@@ -6,6 +6,8 @@
|
||||
// warranty, and with no claim as to its suitability for any purpose.
|
||||
|
||||
// standalone test program for <boost/call_traits.hpp>
|
||||
// 03 Oct 2000:
|
||||
// Enabled extra tests for VC6.
|
||||
|
||||
#include <cassert>
|
||||
#include <iostream>
|
||||
@@ -14,7 +16,7 @@
|
||||
#include <typeinfo>
|
||||
#include <boost/call_traits.hpp>
|
||||
|
||||
#include "type_traits_test.hpp"
|
||||
#include <boost/type_traits/type_traits_test.hpp>
|
||||
//
|
||||
// struct contained models a type that contains a type (for example std::pair)
|
||||
// arrays are contained by value, and have to be treated as a special case:
|
||||
@@ -96,18 +98,18 @@ std::pair<
|
||||
using namespace std;
|
||||
|
||||
//
|
||||
// struct checker:
|
||||
// struct call_traits_checker:
|
||||
// verifies behaviour of contained example:
|
||||
//
|
||||
template <class T>
|
||||
struct checker
|
||||
struct call_traits_checker
|
||||
{
|
||||
typedef typename boost::call_traits<T>::param_type param_type;
|
||||
void operator()(param_type);
|
||||
};
|
||||
|
||||
template <class T>
|
||||
void checker<T>::operator()(param_type p)
|
||||
void call_traits_checker<T>::operator()(param_type p)
|
||||
{
|
||||
T t(p);
|
||||
contained<T> c(t);
|
||||
@@ -115,18 +117,19 @@ void checker<T>::operator()(param_type p)
|
||||
assert(t == c.value());
|
||||
assert(t == c.get());
|
||||
assert(t == c.const_get());
|
||||
|
||||
cout << "typeof contained<" << typeid(T).name() << ">::v_ is: " << typeid(&contained<T>::v_).name() << endl;
|
||||
#ifndef __ICL
|
||||
//cout << "typeof contained<" << typeid(T).name() << ">::v_ is: " << typeid(&contained<T>::v_).name() << endl;
|
||||
cout << "typeof contained<" << typeid(T).name() << ">::value() is: " << typeid(&contained<T>::value).name() << endl;
|
||||
cout << "typeof contained<" << typeid(T).name() << ">::get() is: " << typeid(&contained<T>::get).name() << endl;
|
||||
cout << "typeof contained<" << typeid(T).name() << ">::const_get() is: " << typeid(&contained<T>::const_get).name() << endl;
|
||||
cout << "typeof contained<" << typeid(T).name() << ">::call() is: " << typeid(&contained<T>::call).name() << endl;
|
||||
cout << endl;
|
||||
#endif
|
||||
}
|
||||
|
||||
#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
|
||||
template <class T, std::size_t N>
|
||||
struct checker<T[N]>
|
||||
struct call_traits_checker<T[N]>
|
||||
{
|
||||
typedef typename boost::call_traits<T[N]>::param_type param_type;
|
||||
void operator()(param_type t)
|
||||
@@ -174,33 +177,34 @@ void check_make_pair(T c, U u, V v)
|
||||
}
|
||||
|
||||
|
||||
struct UDT
|
||||
struct comparible_UDT
|
||||
{
|
||||
int i_;
|
||||
UDT() : i_(2){}
|
||||
bool operator == (const UDT& v){ return v.i_ == i_; }
|
||||
comparible_UDT() : i_(2){}
|
||||
bool operator == (const comparible_UDT& v){ return v.i_ == i_; }
|
||||
};
|
||||
|
||||
int main()
|
||||
int main(int argc, char *argv[ ])
|
||||
{
|
||||
checker<UDT> c1;
|
||||
UDT u;
|
||||
call_traits_checker<comparible_UDT> c1;
|
||||
comparible_UDT u;
|
||||
c1(u);
|
||||
checker<int> c2;
|
||||
call_traits_checker<int> c2;
|
||||
int i = 2;
|
||||
c2(i);
|
||||
int* pi = &i;
|
||||
checker<int*> c3;
|
||||
#if defined(BOOST_MSVC6_MEMBER_TEMPLATES) || !defined(BOOST_NO_MEMBER_TEMPLATES)
|
||||
call_traits_checker<int*> c3;
|
||||
c3(pi);
|
||||
#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
|
||||
checker<int&> c4;
|
||||
call_traits_checker<int&> c4;
|
||||
c4(i);
|
||||
checker<const int&> c5;
|
||||
call_traits_checker<const int&> c5;
|
||||
c5(i);
|
||||
|
||||
#if !defined (BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
|
||||
int a[2] = {1,2};
|
||||
checker<int[2]> c6;
|
||||
call_traits_checker<int[2]> c6;
|
||||
c6(a);
|
||||
#endif
|
||||
#endif
|
||||
|
||||
check_wrap(wrap(2), 2);
|
||||
@@ -217,10 +221,10 @@ int main()
|
||||
typedef int& r_type;
|
||||
typedef const r_type cr_type;
|
||||
|
||||
type_test(UDT, boost::call_traits<UDT>::value_type)
|
||||
type_test(UDT&, boost::call_traits<UDT>::reference)
|
||||
type_test(const UDT&, boost::call_traits<UDT>::const_reference)
|
||||
type_test(const UDT&, boost::call_traits<UDT>::param_type)
|
||||
type_test(comparible_UDT, boost::call_traits<comparible_UDT>::value_type)
|
||||
type_test(comparible_UDT&, boost::call_traits<comparible_UDT>::reference)
|
||||
type_test(const comparible_UDT&, boost::call_traits<comparible_UDT>::const_reference)
|
||||
type_test(const comparible_UDT&, boost::call_traits<comparible_UDT>::param_type)
|
||||
type_test(int, boost::call_traits<int>::value_type)
|
||||
type_test(int&, boost::call_traits<int>::reference)
|
||||
type_test(const int&, boost::call_traits<int>::const_reference)
|
||||
@@ -229,7 +233,7 @@ int main()
|
||||
type_test(int*&, boost::call_traits<int*>::reference)
|
||||
type_test(int*const&, boost::call_traits<int*>::const_reference)
|
||||
type_test(int*const, boost::call_traits<int*>::param_type)
|
||||
#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
|
||||
#if defined(BOOST_MSVC6_MEMBER_TEMPLATES) || !defined(BOOST_NO_MEMBER_TEMPLATES)
|
||||
type_test(int&, boost::call_traits<int&>::value_type)
|
||||
type_test(int&, boost::call_traits<int&>::reference)
|
||||
type_test(const int&, boost::call_traits<int&>::const_reference)
|
||||
@@ -248,6 +252,7 @@ int main()
|
||||
type_test(const int&, boost::call_traits<const int&>::reference)
|
||||
type_test(const int&, boost::call_traits<const int&>::const_reference)
|
||||
type_test(const int&, boost::call_traits<const int&>::param_type)
|
||||
#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
|
||||
type_test(const int*, boost::call_traits<int[3]>::value_type)
|
||||
type_test(int(&)[3], boost::call_traits<int[3]>::reference)
|
||||
type_test(const int(&)[3], boost::call_traits<int[3]>::const_reference)
|
||||
@@ -256,15 +261,18 @@ int main()
|
||||
type_test(const int(&)[3], boost::call_traits<const int[3]>::reference)
|
||||
type_test(const int(&)[3], boost::call_traits<const int[3]>::const_reference)
|
||||
type_test(const int*const, boost::call_traits<const int[3]>::param_type)
|
||||
#else
|
||||
std::cout << "You're compiler does not support partial template instantiation, skipping 8 tests (8 errors)" << std::endl;
|
||||
failures += 8;
|
||||
test_count += 8;
|
||||
#endif
|
||||
#else
|
||||
std::cout << "You're compiler does not support partial template instantiation, skipping 20 tests (20 errors)" << std::endl;
|
||||
failures += 20;
|
||||
test_count += 20;
|
||||
#endif
|
||||
|
||||
std::cout << std::endl << test_count << " tests completed (" << failures << " failures)... press any key to exit";
|
||||
std::cin.get();
|
||||
return failures;
|
||||
return check_result(argc, argv);
|
||||
}
|
||||
|
||||
//
|
||||
@@ -318,7 +326,7 @@ struct call_traits_test<T, true>
|
||||
};
|
||||
|
||||
template <typename T>
|
||||
void call_traits_test<T, true>::assert_construct(boost::call_traits<T>::param_type val)
|
||||
void call_traits_test<T, true>::assert_construct(typename boost::call_traits<T>::param_type val)
|
||||
{
|
||||
//
|
||||
// this is to check that the call_traits assertions are valid:
|
||||
@@ -347,9 +355,23 @@ void call_traits_test<T, true>::assert_construct(boost::call_traits<T>::param_ty
|
||||
template struct call_traits_test<int>;
|
||||
template struct call_traits_test<const int>;
|
||||
template struct call_traits_test<int*>;
|
||||
#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
|
||||
#if defined(BOOST_MSVC6_MEMBER_TEMPLATES) || !defined(BOOST_NO_MEMBER_TEMPLATES)
|
||||
template struct call_traits_test<int&>;
|
||||
template struct call_traits_test<const int&>;
|
||||
#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
|
||||
template struct call_traits_test<int[2], true>;
|
||||
#endif
|
||||
#endif
|
||||
|
||||
#ifdef BOOST_MSVC
|
||||
unsigned int expected_failures = 10;
|
||||
#elif defined(__BORLANDC__)
|
||||
unsigned int expected_failures = 2;
|
||||
#elif defined(__GNUC__)
|
||||
unsigned int expected_failures = 4;
|
||||
#else
|
||||
unsigned int expected_failures = 0;
|
||||
#endif
|
||||
|
||||
|
||||
|
||||
|
148
cast.htm
148
cast.htm
@@ -1,148 +0,0 @@
|
||||
<html>
|
||||
|
||||
<head>
|
||||
<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
|
||||
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
|
||||
<meta name="ProgId" content="FrontPage.Editor.Document">
|
||||
<title>Header boost/cast.hpp Documentation</title>
|
||||
</head>
|
||||
|
||||
<body bgcolor="#FFFFFF" text="#000000">
|
||||
|
||||
<h1><img src="../../c++boost.gif" alt="c++boost.gif (8819 bytes)" align="center" width="277" height="86">Header
|
||||
<a href="../../boost/cast.hpp">boost/cast.hpp</a></h1>
|
||||
<h2><a name="Cast Functions">Cast Functions</a></h2>
|
||||
<p>The <code>header <a href="../../boost/cast.hpp">boost/cast.hpp</a></code>
|
||||
provides <a href="#Polymorphic_cast"><b>polymorphic_cast</b></a>, <a href="#Polymorphic_cast"><b>polymorphic_downcast</b></a>,
|
||||
and <a href="#numeric_cast"><b>numeric_cast</b></a> template functions designed
|
||||
to complement the C++ Standard's built-in casts.</p>
|
||||
<p>The program <a href="cast_test.cpp">cast_test.cpp</a> can be used to
|
||||
verify these function templates work as expected.</p>
|
||||
<p><b>polymorphic_cast</b> was suggested by Bjarne Stroustrup in "The C++
|
||||
Programming Language".<br>
|
||||
<b>polymorphic_downcast</b> was contributed by <a href="../../people/dave_abrahams.htm">Dave
|
||||
Abrahams</a>.<b><br>
|
||||
numeric_cast</b> was contributed by <a href="../../people/kevlin_henney.htm">Kevlin
|
||||
Henney</a>.</p>
|
||||
<h3>Namespace synopsis</h3>
|
||||
<blockquote>
|
||||
<pre>namespace boost {
|
||||
namespace cast {
|
||||
// all synopsis below included here
|
||||
}
|
||||
using ::boost::cast::polymorphic_cast;
|
||||
using ::boost::cast::polymorphic_downcast;
|
||||
using ::boost::cast::bad_numeric_cast;
|
||||
using ::boost::cast::numeric_cast;
|
||||
}</pre>
|
||||
</blockquote>
|
||||
<h3><a name="Polymorphic_cast">Polymorphic casts</a></h3>
|
||||
<p>Pointers to polymorphic objects (objects of classes which define at least one
|
||||
virtual function) are sometimes downcast or crosscast. Downcasting means
|
||||
casting from a base class to a derived class. Crosscasting means casting
|
||||
across an inheritance hierarchy diagram, such as from one base to the other in a
|
||||
<b>Y</b> diagram hierarchy.</p>
|
||||
<p>Such casts can be done with old-style casts, but this approach is never to be
|
||||
recommended. Old-style casts are sorely lacking in type safety, suffer
|
||||
poor readability, and are difficult to locate with search tools.</p>
|
||||
<p>The C++ built-in <b>static_cast</b> can be used for efficiently downcasting
|
||||
pointers to polymorphic objects, but provides no error detection for the case
|
||||
where the pointer being cast actually points to the wrong derived class. The <b>polymorphic_downcast</b>
|
||||
template retains the efficiency of <b>static_cast</b> for non-debug
|
||||
compilations, but for debug compilations adds safety via an assert() that a <b>dynamic_cast</b>
|
||||
succeeds. <b> </b></p>
|
||||
<p>The C++ built-in <b>dynamic_cast</b> can be used for downcasts and crosscasts
|
||||
of pointers to polymorphic objects, but error notification in the form of a
|
||||
returned value of 0 is inconvenient to test, or worse yet, easy to forget to
|
||||
test. The <b>polymorphic_cast</b> template performs a <b>dynamic_cast</b>,
|
||||
and throws an exception if the <b>dynamic_cast</b> returns 0.</p>
|
||||
<p>A <b>polymorphic_downcast</b> is preferred when debug-mode tests will cover
|
||||
100% of the object types possibly cast and when non-debug-mode efficiency is an
|
||||
issue. If these two conditions are not present, <b>polymorphic_cast</b> is
|
||||
preferred. It must also be used for crosscasts. It does an assert(
|
||||
dynamic_cast<Derived>(x) == x ) where x is the base pointer, ensuring that
|
||||
not only is a non-zero pointer returned, but also that it correct in the
|
||||
presence of multiple inheritance. .<b> Warning:</b>: Because <b>polymorphic_downcast</b>
|
||||
uses assert(), it violates the One Definition Rule if NDEBUG is inconsistently
|
||||
defined across translation units.</p>
|
||||
<p>The C++ built-in <b>dynamic_cast</b> must be used to cast references rather
|
||||
than pointers. It is also the only cast that can be used to check whether
|
||||
a given interface is supported; in that case a return of 0 isn't an error
|
||||
condition.</p>
|
||||
<h3>polymorphic_cast and polymorphic_downcast synopsis</h3>
|
||||
<blockquote>
|
||||
<pre>template <class Derived, class Base>
|
||||
inline Derived polymorphic_cast(Base* x);
|
||||
// Throws: std::bad_cast if ( dynamic_cast<Derived>(x) == 0 )
|
||||
// Returns: dynamic_cast<Derived>(x)
|
||||
|
||||
template <class Derived, class Base>
|
||||
inline Derived polymorphic_downcast(Base* x);
|
||||
// Effects: assert( dynamic_cast<Derived>(x) == x );
|
||||
// Returns: static_cast<Derived>(x)</pre>
|
||||
</blockquote>
|
||||
<h3>polymorphic_downcast example</h3>
|
||||
<blockquote>
|
||||
<pre>#include <boost/cast.hpp>
|
||||
...
|
||||
class Fruit { public: virtual ~Fruit(){}; ... };
|
||||
class Banana : public Fruit { ... };
|
||||
...
|
||||
void f( Fruit * fruit ) {
|
||||
// ... logic which leads us to believe it is a Banana
|
||||
Banana * banana = boost::polymorphic_downcast<Banana*>(fruit);
|
||||
...</pre>
|
||||
</blockquote>
|
||||
<h3><a name="numeric_cast">numeric_cast</a></h3>
|
||||
<p>A <b>static_cast</b>, <b>implicit_cast</b> or implicit conversion will not
|
||||
detect failure to preserve range for numeric casts. The <b>numeric_cast</b>
|
||||
template function are similar to <b>static_cast</b> and certain (dubious)
|
||||
implicit conversions in this respect, except that they detect loss of numeric
|
||||
range. An exception is thrown when a runtime value preservation check fails.</p>
|
||||
<p>The requirements on the argument and result types are:</p>
|
||||
<blockquote>
|
||||
<ul>
|
||||
<li>Both argument and result types are CopyConstructible [20.1.3].</li>
|
||||
<li>Both argument and result types are Numeric, defined by <code>std::numeric_limits<>::is_specialized</code>
|
||||
being true.</li>
|
||||
<li>The argument can be converted to the result type using <b>static_cast</b>.</li>
|
||||
</ul>
|
||||
</blockquote>
|
||||
<h3>numeric_cast synopsis</h3>
|
||||
<blockquote>
|
||||
<pre>class bad_numeric_cast : public std::bad_cast {...};
|
||||
|
||||
template<typename Target, typename Source>
|
||||
inline Target numeric_cast(Source arg);
|
||||
// Throws: bad_numeric_cast unless, in converting arg from Source to Target,
|
||||
// there is no loss of negative range, and no underflow, and no
|
||||
// overflow, as determined by std::numeric_limits
|
||||
// Returns: static_cast<Target>(arg)</pre>
|
||||
</blockquote>
|
||||
<h3>numeric_cast example</h3>
|
||||
<blockquote>
|
||||
<pre>#include <boost/cast.hpp>
|
||||
using namespace boost::cast;
|
||||
|
||||
void ariane(double vx)
|
||||
{
|
||||
...
|
||||
unsigned short dx = numeric_cast<unsigned short>(vx);
|
||||
...
|
||||
}</pre>
|
||||
</blockquote>
|
||||
<h3>numeric_cast rationale</h3>
|
||||
<p>The form of the throws condition is specified so that != is not a required
|
||||
operation.</p>
|
||||
<hr>
|
||||
<p>Revised <!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %B, %Y" startspan
|
||||
-->28 June, 2000<!--webbot bot="Timestamp" endspan i-checksum="19846"
|
||||
--></p>
|
||||
<p><EFBFBD> Copyright boost.org 1999. Permission to copy, use, modify, sell and
|
||||
distribute this document is granted provided this copyright notice appears in
|
||||
all copies. This document is provided "as is" without express or
|
||||
implied warranty, and with no claim as to its suitability for any purpose.</p>
|
||||
|
||||
</body>
|
||||
|
||||
</html>
|
149
cast_test.cpp
149
cast_test.cpp
@@ -1,149 +0,0 @@
|
||||
// boost utility cast test program -----------------------------------------//
|
||||
|
||||
// (C) Copyright boost.org 1999. Permission to copy, use, modify, sell
|
||||
// and distribute this software is granted provided this copyright
|
||||
// notice appears in all copies. This software is provided "as is" without
|
||||
// express or implied warranty, and with no claim as to its suitability for
|
||||
// any purpose.
|
||||
|
||||
// See http://www.boost.org for most recent version including documentation.
|
||||
|
||||
// Revision History
|
||||
// 28 Jun 00 implicit_cast removed (Beman Dawes)
|
||||
// 30 Aug 99 value_cast replaced by numeric_cast
|
||||
// 3 Aug 99 Initial Version
|
||||
|
||||
#include <iostream>
|
||||
#include <climits>
|
||||
#include <limits>
|
||||
#include <boost/cast.hpp>
|
||||
|
||||
# if SCHAR_MAX == LONG_MAX
|
||||
# error "This test program doesn't work if SCHAR_MAX == LONG_MAX"
|
||||
# endif
|
||||
|
||||
using namespace boost;
|
||||
using std::cout;
|
||||
|
||||
namespace
|
||||
{
|
||||
struct Base
|
||||
{
|
||||
virtual char kind() { return 'B'; }
|
||||
};
|
||||
|
||||
struct Base2
|
||||
{
|
||||
virtual char kind2() { return '2'; }
|
||||
};
|
||||
|
||||
struct Derived : public Base, Base2
|
||||
{
|
||||
virtual char kind() { return 'D'; }
|
||||
};
|
||||
}
|
||||
|
||||
|
||||
int main( int argc, char * argv[] )
|
||||
{
|
||||
cout << "Usage: test_casts [n], where n omitted or is:\n"
|
||||
" 1 = execute #1 assert failure (#ifndef NDEBUG)\n"
|
||||
" 2 = execute #2 assert failure (#ifndef NDEBUG)\n"
|
||||
"Example: test_casts 2\n\n";
|
||||
|
||||
# ifdef NDEBUG
|
||||
cout << "NDEBUG is defined\n";
|
||||
# else
|
||||
cout << "NDEBUG is not defined\n";
|
||||
# endif
|
||||
|
||||
cout << "\nBeginning tests...\n";
|
||||
|
||||
// test polymorphic_cast ---------------------------------------------------//
|
||||
|
||||
// tests which should succeed
|
||||
Base * base = new Derived;
|
||||
Base2 * base2 = 0;
|
||||
Derived * derived = 0;
|
||||
derived = polymorphic_downcast<Derived*>( base ); // downcast
|
||||
assert( derived->kind() == 'D' );
|
||||
|
||||
derived = 0;
|
||||
derived = polymorphic_cast<Derived*>( base ); // downcast, throw on error
|
||||
assert( derived->kind() == 'D' );
|
||||
|
||||
base2 = polymorphic_cast<Base2*>( base ); // crosscast
|
||||
assert( base2->kind2() == '2' );
|
||||
|
||||
// tests which should result in errors being detected
|
||||
int err_count = 0;
|
||||
base = new Base;
|
||||
|
||||
if ( argc > 1 && *argv[1] == '1' )
|
||||
{ derived = polymorphic_downcast<Derived*>( base ); } // #1 assert failure
|
||||
|
||||
bool caught_exception = false;
|
||||
try { derived = polymorphic_cast<Derived*>( base ); }
|
||||
catch (std::bad_cast)
|
||||
{ cout<<"caught bad_cast\n"; caught_exception = true; }
|
||||
if ( !caught_exception ) ++err_count;
|
||||
// the following is just so generated code can be inspected
|
||||
if ( derived->kind() == 'B' ) ++err_count;
|
||||
|
||||
// test implicit_cast and numeric_cast -------------------------------------//
|
||||
|
||||
// tests which should succeed
|
||||
long small_value = 1;
|
||||
long small_negative_value = -1;
|
||||
long large_value = std::numeric_limits<long>::max();
|
||||
long large_negative_value = std::numeric_limits<long>::min();
|
||||
signed char c = 0;
|
||||
|
||||
c = large_value; // see if compiler generates warning
|
||||
|
||||
c = numeric_cast<signed char>( small_value );
|
||||
assert( c == 1 );
|
||||
c = 0;
|
||||
c = numeric_cast<signed char>( small_value );
|
||||
assert( c == 1 );
|
||||
c = 0;
|
||||
c = numeric_cast<signed char>( small_negative_value );
|
||||
assert( c == -1 );
|
||||
|
||||
// tests which should result in errors being detected
|
||||
|
||||
caught_exception = false;
|
||||
try { c = numeric_cast<signed char>( large_value ); }
|
||||
catch (bad_numeric_cast)
|
||||
{ cout<<"caught bad_numeric_cast #1\n"; caught_exception = true; }
|
||||
if ( !caught_exception ) ++err_count;
|
||||
|
||||
caught_exception = false;
|
||||
try { c = numeric_cast<signed char>( large_negative_value ); }
|
||||
catch (bad_numeric_cast)
|
||||
{ cout<<"caught bad_numeric_cast #2\n"; caught_exception = true; }
|
||||
if ( !caught_exception ) ++err_count;
|
||||
|
||||
unsigned long ul;
|
||||
caught_exception = false;
|
||||
try { ul = numeric_cast<unsigned long>( large_negative_value ); }
|
||||
catch (bad_numeric_cast)
|
||||
{ cout<<"caught bad_numeric_cast #3\n"; caught_exception = true; }
|
||||
if ( !caught_exception ) ++err_count;
|
||||
|
||||
caught_exception = false;
|
||||
try { ul = numeric_cast<unsigned long>( small_negative_value ); }
|
||||
catch (bad_numeric_cast)
|
||||
{ cout<<"caught bad_numeric_cast #4\n"; caught_exception = true; }
|
||||
if ( !caught_exception ) ++err_count;
|
||||
|
||||
caught_exception = false;
|
||||
try { numeric_cast<int>( std::numeric_limits<double>::max() ); }
|
||||
catch (bad_numeric_cast)
|
||||
{ cout<<"caught bad_numeric_cast #5\n"; caught_exception = true; }
|
||||
if ( !caught_exception ) ++err_count;
|
||||
|
||||
cout << err_count << " errors detected\nTest "
|
||||
<< (err_count==0 ? "passed\n" : "failed\n");
|
||||
return err_count;
|
||||
} // main
|
@@ -6,21 +6,18 @@
|
||||
// warranty, and with no claim as to its suitability for any purpose.
|
||||
|
||||
// standalone test program for <boost/compressed_pair.hpp>
|
||||
// Revised 03 Oct 2000:
|
||||
// Enabled tests for VC6.
|
||||
|
||||
#include <iostream>
|
||||
#include <typeinfo>
|
||||
#include <cassert>
|
||||
|
||||
#include <boost/compressed_pair.hpp>
|
||||
#include "type_traits_test.hpp"
|
||||
#include <boost/type_traits/type_traits_test.hpp>
|
||||
|
||||
using namespace boost;
|
||||
|
||||
struct empty_POD_UDT{};
|
||||
struct empty_UDT
|
||||
{
|
||||
~empty_UDT(){};
|
||||
};
|
||||
namespace boost {
|
||||
#ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION
|
||||
template <> struct is_empty<empty_UDT>
|
||||
@@ -39,8 +36,25 @@ template <> struct is_POD<empty_POD_UDT>
|
||||
#endif
|
||||
}
|
||||
|
||||
struct non_empty1
|
||||
{
|
||||
int i;
|
||||
non_empty1() : i(1){}
|
||||
non_empty1(int v) : i(v){}
|
||||
friend bool operator==(const non_empty1& a, const non_empty1& b)
|
||||
{ return a.i == b.i; }
|
||||
};
|
||||
|
||||
int main()
|
||||
struct non_empty2
|
||||
{
|
||||
int i;
|
||||
non_empty2() : i(3){}
|
||||
non_empty2(int v) : i(v){}
|
||||
friend bool operator==(const non_empty2& a, const non_empty2& b)
|
||||
{ return a.i == b.i; }
|
||||
};
|
||||
|
||||
int main(int argc, char *argv[ ])
|
||||
{
|
||||
compressed_pair<int, double> cp1(1, 1.3);
|
||||
assert(cp1.first() == 1);
|
||||
@@ -53,15 +67,25 @@ int main()
|
||||
assert(cp1b.second() == 1.3);
|
||||
assert(cp1.first() == 2);
|
||||
assert(cp1.second() == 2.3);
|
||||
#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
|
||||
compressed_pair<non_empty1, non_empty2> cp1c(non_empty1(9));
|
||||
assert(cp1c.second() == non_empty2());
|
||||
assert(cp1c.first() == non_empty1(9));
|
||||
compressed_pair<non_empty1, non_empty2> cp1d(non_empty2(9));
|
||||
assert(cp1d.second() == non_empty2(9));
|
||||
assert(cp1d.first() == non_empty1());
|
||||
|
||||
compressed_pair<int, double> cp1e(cp1);
|
||||
|
||||
compressed_pair<empty_UDT, int> cp2(2);
|
||||
assert(cp2.second() == 2);
|
||||
#endif
|
||||
compressed_pair<int, empty_UDT> cp3(1);
|
||||
assert(cp3.first() ==1);
|
||||
compressed_pair<empty_UDT, empty_UDT> cp4;
|
||||
compressed_pair<empty_UDT, empty_POD_UDT> cp5;
|
||||
#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
|
||||
compressed_pair<int, empty_UDT> cp9(empty_UDT());
|
||||
compressed_pair<int, empty_UDT> cp10(1);
|
||||
assert(cp10.first() == 1);
|
||||
#if defined(BOOST_MSVC6_MEMBER_TEMPLATES) || !defined(BOOST_NO_MEMBER_TEMPLATES) || !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
|
||||
int i = 0;
|
||||
compressed_pair<int&, int&> cp6(i,i);
|
||||
assert(cp6.first() == i);
|
||||
@@ -72,15 +96,13 @@ int main()
|
||||
cp7.first();
|
||||
double* pd = cp7.second();
|
||||
#endif
|
||||
value_test(true, (sizeof(compressed_pair<empty_UDT, int>) < sizeof(std::pair<empty_UDT, int>)))
|
||||
value_test(true, (sizeof(compressed_pair<int, empty_UDT>) < sizeof(std::pair<int, empty_UDT>)))
|
||||
value_test(true, (sizeof(compressed_pair<empty_UDT, empty_UDT>) < sizeof(std::pair<empty_UDT, empty_UDT>)))
|
||||
value_test(true, (sizeof(compressed_pair<empty_UDT, empty_POD_UDT>) < sizeof(std::pair<empty_UDT, empty_POD_UDT>)))
|
||||
value_test(true, (sizeof(compressed_pair<empty_UDT, compressed_pair<empty_POD_UDT, int> >) < sizeof(std::pair<empty_UDT, std::pair<empty_POD_UDT, int> >)))
|
||||
soft_value_test(true, (sizeof(compressed_pair<empty_UDT, int>) < sizeof(std::pair<empty_UDT, int>)))
|
||||
soft_value_test(true, (sizeof(compressed_pair<int, empty_UDT>) < sizeof(std::pair<int, empty_UDT>)))
|
||||
soft_value_test(true, (sizeof(compressed_pair<empty_UDT, empty_UDT>) < sizeof(std::pair<empty_UDT, empty_UDT>)))
|
||||
soft_value_test(true, (sizeof(compressed_pair<empty_UDT, empty_POD_UDT>) < sizeof(std::pair<empty_UDT, empty_POD_UDT>)))
|
||||
soft_value_test(true, (sizeof(compressed_pair<empty_UDT, compressed_pair<empty_POD_UDT, int> >) < sizeof(std::pair<empty_UDT, std::pair<empty_POD_UDT, int> >)))
|
||||
|
||||
std::cout << std::endl << test_count << " tests completed (" << failures << " failures)... press any key to exit";
|
||||
std::cin.get();
|
||||
return failures;
|
||||
return check_result(argc, argv);
|
||||
}
|
||||
|
||||
//
|
||||
@@ -102,25 +124,30 @@ template class boost::compressed_pair<empty_UDT, empty_POD_UDT>;
|
||||
#endif
|
||||
|
||||
#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
|
||||
#ifndef __MWERKS__
|
||||
//
|
||||
// now some for which only a few specific members can be instantiated,
|
||||
// first references:
|
||||
template double& compressed_pair<double, int&>::first();
|
||||
template int& compressed_pair<double, int&>::second();
|
||||
#if !(defined(__GNUC__) && (__GNUC__ == 2) && (__GNUC_MINOR__ < 95))
|
||||
template compressed_pair<double, int&>::compressed_pair(int&);
|
||||
#endif
|
||||
template compressed_pair<double, int&>::compressed_pair(call_traits<double>::param_type,int&);
|
||||
//
|
||||
// and then arrays:
|
||||
#ifndef __MWERKS__
|
||||
#ifndef __BORLANDC__
|
||||
template call_traits<int[2]>::reference compressed_pair<double, int[2]>::second();
|
||||
#endif
|
||||
template call_traits<double>::reference compressed_pair<double, int[2]>::first();
|
||||
template compressed_pair<double, int[2]>::compressed_pair(const double&);
|
||||
#if !(defined(__GNUC__) && (__GNUC__ == 2) && (__GNUC_MINOR__ < 95))
|
||||
template compressed_pair<double, int[2]>::compressed_pair(call_traits<double>::param_type);
|
||||
#endif
|
||||
template compressed_pair<double, int[2]>::compressed_pair();
|
||||
#endif // __MWERKS__
|
||||
#endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
|
||||
|
||||
unsigned int expected_failures = 0;
|
||||
|
||||
|
||||
|
||||
|
325
counting_iterator.htm
Normal file
325
counting_iterator.htm
Normal file
@@ -0,0 +1,325 @@
|
||||
<html>
|
||||
|
||||
<head>
|
||||
<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
|
||||
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
|
||||
<meta name="ProgId" content="FrontPage.Editor.Document">
|
||||
<title>Counting Iterator Adaptor Documentation</title>
|
||||
</head>
|
||||
|
||||
<body bgcolor="#FFFFFF" text="#000000">
|
||||
|
||||
<img src="../../c++boost.gif" alt="c++boost.gif (8819 bytes)"
|
||||
align="center" width="277" height="86">
|
||||
|
||||
<h1>Counting Iterator Adaptor</h1>
|
||||
|
||||
Defined in header
|
||||
<a href="../../boost/counting_iterator.hpp">boost/counting_iterator.hpp</a>
|
||||
|
||||
<p>
|
||||
How would you fill up a vector with the numbers zero
|
||||
through one hundred using <a
|
||||
href="http://www.sgi.com/tech/stl/copy.html"><tt>std::copy()</tt></a>? The
|
||||
only iterator operation missing from builtin integer types is an
|
||||
<tt>operator*()</tt> that returns the current
|
||||
value of the integer. The counting iterator adaptor adds this crucial piece of
|
||||
functionality to whatever type it wraps. One can use the
|
||||
counting iterator adaptor not only with integer types, but with any
|
||||
type that is <tt>Incrementable</tt> (see type requirements <a href="#requirements">below</a>). The
|
||||
following <b>pseudo-code</b> shows the general idea of how the
|
||||
counting iterator is implemented.
|
||||
</p>
|
||||
|
||||
<pre>
|
||||
// inside a hypothetical counting_iterator class...
|
||||
typedef Incrementable value_type;
|
||||
value_type counting_iterator::operator*() const {
|
||||
return this->base; // no dereference!
|
||||
}
|
||||
</pre>
|
||||
|
||||
All of the other operators of the counting iterator behave in the same
|
||||
fashion as the <tt>Incrementable</tt> base type.
|
||||
|
||||
<h2>Synopsis</h2>
|
||||
|
||||
<pre>
|
||||
namespace boost {
|
||||
template <class Incrementable>
|
||||
struct <a href="#counting_iterator_traits">counting_iterator_traits</a>;
|
||||
|
||||
template <class Incrementable>
|
||||
struct <a href="#counting_iterator_generator">counting_iterator_generator</a>;
|
||||
|
||||
template <class Incrementable>
|
||||
typename counting_iterator_generator<Incrementable>::type
|
||||
<a href="#make_counting_iterator">make_counting_iterator</a>(Incrementable x);
|
||||
}
|
||||
</pre>
|
||||
|
||||
<hr>
|
||||
|
||||
<h2><a name="counting_iterator_generator">The Counting Iterator Type
|
||||
Generator</a></h2>
|
||||
|
||||
The class template <tt>counting_iterator_generator<Incrementable></tt> is a <a href="../../more/generic_programming.html#type_generator">type generator</a> for counting iterators.
|
||||
|
||||
<pre>
|
||||
template <class Incrementable>
|
||||
class counting_iterator_generator
|
||||
{
|
||||
public:
|
||||
typedef <a href="./iterator_adaptors.htm#iterator_adaptor">iterator_adaptor</a><...> type;
|
||||
};
|
||||
</pre>
|
||||
|
||||
<h3>Example</h3>
|
||||
|
||||
In this example we use the counting iterator generator to create a
|
||||
counting iterator, and count from zero to four.
|
||||
|
||||
<pre>
|
||||
#include <boost/config.hpp>
|
||||
#include <iostream>
|
||||
#include <boost/counting_iterator.hpp>
|
||||
|
||||
int main(int, char*[])
|
||||
{
|
||||
// Example of using counting_iterator_generator
|
||||
std::cout << "counting from 0 to 4:" << std::endl;
|
||||
boost::counting_iterator_generator<int>::type first(0), last(4);
|
||||
std::copy(first, last, std::ostream_iterator<int>(std::cout, " "));
|
||||
std::cout << std::endl;
|
||||
|
||||
// to be continued...
|
||||
</pre>
|
||||
The output from this part is:
|
||||
<pre>
|
||||
counting from 0 to 4:
|
||||
0 1 2 3
|
||||
</pre>
|
||||
|
||||
<h3>Template Parameters</h3>
|
||||
|
||||
<Table border>
|
||||
<TR>
|
||||
<TH>Parameter</TH><TH>Description</TH>
|
||||
</TR>
|
||||
|
||||
<TR>
|
||||
<TD><tt>Incrementable</tt></TD>
|
||||
<TD>The type being wrapped by the adaptor.</TD>
|
||||
</TR>
|
||||
|
||||
</Table>
|
||||
|
||||
<h3>Model of</h3>
|
||||
|
||||
If the <tt>Incrementable</tt> type has all of the functionality of a
|
||||
<a href="http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random
|
||||
Access Iterator</a> except the <tt>operator*()</tt>, then the counting
|
||||
iterator will be a model of <a
|
||||
href="http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random
|
||||
Access Iterator</a>. If the <tt>Incrementable</tt> type has less
|
||||
functionality, then the counting iterator will have correspondingly
|
||||
less functionality.
|
||||
|
||||
<h3><a name="requirements">Type Requirements</a></h3>
|
||||
|
||||
The <tt>Incrementable</tt> type must be <a
|
||||
href="http://www.sgi.com/tech/stl/DefaultConstructible.html">Default
|
||||
Constructible</a>, <a href="./CopyConstructible.html">Copy
|
||||
Constructible</a>, and <a href="./Assignable.html">Assignable</a>.
|
||||
Also, the <tt>Incrementable</tt> type must provide access to an
|
||||
associated <tt>difference_type</tt> and <tt>iterator_category</tt>
|
||||
through the <a
|
||||
href="#counting_iterator_traits"><tt>counting_iterator_traits</tt></a>
|
||||
class.
|
||||
|
||||
<p>
|
||||
Furthermore, if you wish to create a counting iterator that is a <a
|
||||
href="http://www.sgi.com/tech/stl/ForwardIterator.html"> Forward
|
||||
Iterator</a>, then the following expressions must be valid:
|
||||
<pre>
|
||||
Incrementable i, j;
|
||||
++i // pre-increment
|
||||
i == j // operator equal
|
||||
</pre>
|
||||
If you wish to create a counting iterator that is a <a
|
||||
href="http://www.sgi.com/tech/stl/BidirectionalIterator.html">
|
||||
Bidirectional Iterator</a>, then pre-decrement is also required:
|
||||
<pre>
|
||||
--i
|
||||
</pre>
|
||||
If you wish to create a counting iterator that is a <a
|
||||
href="http://www.sgi.com/tech/stl/RandomAccessIterator.html"> Random
|
||||
Access Iterator</a>, then these additional expressions are also required:
|
||||
<pre>
|
||||
<a href="#counting_iterator_traits">counting_iterator_traits</a><Incrementable>::difference_type n;
|
||||
i += n
|
||||
n = i - j
|
||||
i < j
|
||||
</pre>
|
||||
|
||||
|
||||
|
||||
<h3>Members</h3>
|
||||
|
||||
The counting iterator type implements the member functions and
|
||||
operators required of the <a
|
||||
href="http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random
|
||||
Access Iterator</a> concept. In addition it has the following
|
||||
constructor:
|
||||
|
||||
<pre>
|
||||
counting_iterator_generator::type(const Incrementable& i)
|
||||
</pre>
|
||||
|
||||
<p>
|
||||
<hr>
|
||||
<p>
|
||||
|
||||
|
||||
<h2><a name="make_counting_iterator">The Counting Iterator Object Generator</a></h2>
|
||||
|
||||
<pre>
|
||||
template <class Incrementable>
|
||||
typename counting_iterator_generator<Incrementable>::type
|
||||
make_counting_iterator(Incrementable base);
|
||||
</pre>
|
||||
|
||||
An <a href="../../more/generic_programming.html#object_generator">object
|
||||
generator</a> function that provides a convenient way to create counting
|
||||
iterators.<p>
|
||||
|
||||
|
||||
|
||||
<h3>Example</h3>
|
||||
|
||||
In this example we count from negative five to positive five, this
|
||||
time using the <tt>make_counting_iterator()</tt> function to save some
|
||||
typing.
|
||||
|
||||
<pre>
|
||||
// continuing from previous example...
|
||||
|
||||
std::cout << "counting from -5 to 4:" << std::endl;
|
||||
std::copy(boost::make_counting_iterator(-5),
|
||||
boost::make_counting_iterator(5),
|
||||
std::ostream_iterator<int>(std::cout, " "));
|
||||
std::cout << std::endl;
|
||||
|
||||
// to be continued...
|
||||
</pre>
|
||||
The output from this part is:
|
||||
<pre>
|
||||
counting from -5 to 4:
|
||||
-5 -4 -3 -2 -1 0 1 2 3 4
|
||||
</pre>
|
||||
|
||||
In the next example we create an array of numbers, and then create a
|
||||
second array of pointers, where each pointer is the address of a
|
||||
number in the first array. The counting iterator makes it easy to do
|
||||
this since dereferencing a counting iterator that is wrapping an
|
||||
iterator over the array of numbers just returns a pointer to the
|
||||
current location in the array. We then use the <a
|
||||
href="./indirect_iterator.htm">indirect iterator adaptor</a> to print
|
||||
out the number in the array by accessing the numbers through the array
|
||||
of pointers.
|
||||
|
||||
<pre>
|
||||
// continuing from previous example...
|
||||
|
||||
const int N = 7;
|
||||
std::vector<int> numbers;
|
||||
// Fill "numbers" array with [0,N)
|
||||
std::copy(boost::make_counting_iterator(0), boost::make_counting_iterator(N),
|
||||
std::back_inserter(numbers));
|
||||
|
||||
std::vector<std::vector<int>::iterator> pointers;
|
||||
|
||||
// Use counting iterator to fill in the array of pointers.
|
||||
std::copy(boost::make_counting_iterator(numbers.begin()),
|
||||
boost::make_counting_iterator(numbers.end()),
|
||||
std::back_inserter(pointers));
|
||||
|
||||
// Use indirect iterator to print out numbers by accessing
|
||||
// them through the array of pointers.
|
||||
std::cout << "indirectly printing out the numbers from 0 to "
|
||||
<< N << std::endl;
|
||||
std::copy(boost::make_indirect_iterator(pointers.begin()),
|
||||
boost::make_indirect_iterator(pointers.end()),
|
||||
std::ostream_iterator<int>(std::cout, " "));
|
||||
std::cout << std::endl;
|
||||
</pre>
|
||||
The output is:
|
||||
<pre>
|
||||
indirectly printing out the numbers from 0 to 7
|
||||
0 1 2 3 4 5 6
|
||||
</pre>
|
||||
|
||||
<hr>
|
||||
|
||||
<h2><a name="counting_iterator_traits">Counting Iterator Traits</a></h2>
|
||||
|
||||
The counting iterator adaptor needs to determine the appropriate
|
||||
<tt>difference_type</tt> and <tt>iterator_category</tt> to use based on the
|
||||
<tt>Incrementable</tt> type supplied by the user. The
|
||||
<tt>counting_iterator_traits</tt> class provides these types. If the
|
||||
<tt>Incrementable</tt> type is an integral type or an iterator, these types
|
||||
will be correctly deduced by the <tt>counting_iterator_traits</tt> provided by
|
||||
the library. Otherwise, the user must specialize
|
||||
<tt>counting_iterator_traits</tt> for her type or add nested typedefs to
|
||||
her type to fulfill the needs of
|
||||
<a href="http://www.sgi.com/tech/stl/iterator_traits.html">
|
||||
<tt>std::iterator_traits</tt></a>.
|
||||
|
||||
<p>The following pseudocode describes how the <tt>counting_iterator_traits</tt> are determined:
|
||||
|
||||
<pre>
|
||||
template <class Incrementable>
|
||||
struct counting_iterator_traits
|
||||
{
|
||||
if (numeric_limits<Incrementable>::is_specialized) {
|
||||
if (!numeric_limits<Incrementable>::is_integer)
|
||||
COMPILE_TIME_ERROR;
|
||||
|
||||
if (!numeric_limits<Incrementable>::is_bounded
|
||||
&& numeric_limits<Incrementable>::is_signed) {
|
||||
typedef Incrementable difference_type;
|
||||
}
|
||||
else if (numeric_limits<Incrementable>::is_integral) {
|
||||
typedef <i>next-larger-signed-type-or-intmax_t</i> difference_type;
|
||||
}
|
||||
typedef std::random_access_iterator_tag iterator_category;
|
||||
} else {
|
||||
typedef std::iterator_traits<Incrementable>::difference_type difference_type;
|
||||
typedef std::iterator_traits<Incrementable>::iterator_category iterator_category;
|
||||
}
|
||||
};
|
||||
</pre>
|
||||
|
||||
<p>The italicized sections above are implementation details, but it is important
|
||||
to know that the <tt>difference_type</tt> for integral types is selected so that
|
||||
it can always represent the difference between two values if such a built-in
|
||||
integer exists. On platforms with a working <tt>std::numeric_limits</tt>
|
||||
implementation, the <tt>difference_type</tt> for any variable-length signed
|
||||
integer type <tt>T</tt> is <tt>T</tt> itself.
|
||||
|
||||
<hr>
|
||||
<p>Revised <!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %b %Y" startspan -->28 Feb 2001<!--webbot bot="Timestamp" endspan i-checksum="14390" --></p>
|
||||
<p><EFBFBD> Copyright Jeremy Siek 2000. Permission to copy, use,
|
||||
modify, sell and distribute this document is granted provided this copyright
|
||||
notice appears in all copies. This document is provided "as is"
|
||||
without express or implied warranty, and with no claim as to its suitability for
|
||||
any purpose.</p>
|
||||
|
||||
</body>
|
||||
|
||||
</html>
|
||||
<!-- LocalWords: html charset alt gif hpp incrementable const namespace htm
|
||||
-->
|
||||
<!-- LocalWords: struct typename iostream int Siek CopyConstructible pre
|
||||
-->
|
||||
|
53
counting_iterator_example.cpp
Normal file
53
counting_iterator_example.cpp
Normal file
@@ -0,0 +1,53 @@
|
||||
// (C) Copyright Jeremy Siek 2000. Permission to copy, use, modify, sell and
|
||||
// distribute this software is granted provided this copyright notice appears
|
||||
// in all copies. This software is provided "as is" without express or implied
|
||||
// warranty, and with no claim as to its suitability for any purpose.
|
||||
|
||||
|
||||
#include <boost/config.hpp>
|
||||
#include <iostream>
|
||||
#include <iterator>
|
||||
#include <vector>
|
||||
#include <boost/counting_iterator.hpp>
|
||||
#include <boost/iterator_adaptors.hpp>
|
||||
|
||||
int main(int, char*[])
|
||||
{
|
||||
// Example of using counting_iterator_generator
|
||||
std::cout << "counting from 0 to 4:" << std::endl;
|
||||
boost::counting_iterator_generator<int>::type first(0), last(4);
|
||||
std::copy(first, last, std::ostream_iterator<int>(std::cout, " "));
|
||||
std::cout << std::endl;
|
||||
|
||||
// Example of using make_counting_iterator()
|
||||
std::cout << "counting from -5 to 4:" << std::endl;
|
||||
std::copy(boost::make_counting_iterator(-5),
|
||||
boost::make_counting_iterator(5),
|
||||
std::ostream_iterator<int>(std::cout, " "));
|
||||
std::cout << std::endl;
|
||||
|
||||
// Example of using counting iterator to create an array of pointers.
|
||||
const int N = 7;
|
||||
std::vector<int> numbers;
|
||||
// Fill "numbers" array with [0,N)
|
||||
std::copy(boost::make_counting_iterator(0), boost::make_counting_iterator(N),
|
||||
std::back_inserter(numbers));
|
||||
|
||||
std::vector<std::vector<int>::iterator> pointers;
|
||||
|
||||
// Use counting iterator to fill in the array of pointers.
|
||||
std::copy(boost::make_counting_iterator(numbers.begin()),
|
||||
boost::make_counting_iterator(numbers.end()),
|
||||
std::back_inserter(pointers));
|
||||
|
||||
// Use indirect iterator to print out numbers by accessing
|
||||
// them through the array of pointers.
|
||||
std::cout << "indirectly printing out the numbers from 0 to "
|
||||
<< N << std::endl;
|
||||
std::copy(boost::make_indirect_iterator(pointers.begin()),
|
||||
boost::make_indirect_iterator(pointers.end()),
|
||||
std::ostream_iterator<int>(std::cout, " "));
|
||||
std::cout << std::endl;
|
||||
|
||||
return 0;
|
||||
}
|
263
counting_iterator_test.cpp
Normal file
263
counting_iterator_test.cpp
Normal file
@@ -0,0 +1,263 @@
|
||||
// (C) Copyright David Abrahams 2001. Permission to copy, use, modify, sell and
|
||||
// distribute this software is granted provided this copyright notice appears in
|
||||
// all copies. This software is provided "as is" without express or implied
|
||||
// warranty, and with no claim as to its suitability for any purpose.
|
||||
//
|
||||
// See http://www.boost.org for most recent version including documentation.
|
||||
//
|
||||
// Revision History
|
||||
// 16 Feb 2001 Added a missing const. Made the tests run (somewhat) with
|
||||
// plain MSVC again. (David Abrahams)
|
||||
// 11 Feb 2001 #if 0'd out use of counting_iterator on non-numeric types in
|
||||
// MSVC without STLport, so that the other tests may proceed
|
||||
// (David Abrahams)
|
||||
// 04 Feb 2001 Added use of iterator_tests.hpp (David Abrahams)
|
||||
// 28 Jan 2001 Removed not_an_iterator detritus (David Abrahams)
|
||||
// 24 Jan 2001 Initial revision (David Abrahams)
|
||||
|
||||
#include <boost/config.hpp>
|
||||
#ifdef BOOST_MSVC
|
||||
# pragma warning(disable:4786) // identifier truncated in debug info
|
||||
#endif
|
||||
|
||||
#include <boost/pending/iterator_tests.hpp>
|
||||
#include <boost/counting_iterator.hpp>
|
||||
#include <boost/detail/iterator.hpp>
|
||||
#include <iostream>
|
||||
#include <climits>
|
||||
#include <iterator>
|
||||
#include <stdlib.h>
|
||||
#include <boost/utility.hpp>
|
||||
#include <vector>
|
||||
#include <list>
|
||||
#include <cassert>
|
||||
#ifndef BOOST_NO_LIMITS
|
||||
# include <limits>
|
||||
#endif
|
||||
#ifndef BOOST_NO_SLIST
|
||||
# include <slist>
|
||||
#endif
|
||||
|
||||
template <class T> struct is_numeric
|
||||
{
|
||||
enum { value =
|
||||
#ifndef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
|
||||
std::numeric_limits<T>::is_specialized
|
||||
#else
|
||||
// Causes warnings with GCC, but how else can I detect numeric types at
|
||||
// compile-time?
|
||||
(boost::is_convertible<int,T>::value &&
|
||||
boost::is_convertible<T,int>::value)
|
||||
#endif
|
||||
};
|
||||
};
|
||||
|
||||
// Special tests for RandomAccess CountingIterators.
|
||||
template <class CountingIterator>
|
||||
void category_test(
|
||||
CountingIterator start,
|
||||
CountingIterator finish,
|
||||
std::random_access_iterator_tag)
|
||||
{
|
||||
typedef typename
|
||||
boost::detail::iterator_traits<CountingIterator>::difference_type
|
||||
difference_type;
|
||||
difference_type distance = boost::detail::distance(start, finish);
|
||||
|
||||
// Pick a random position internal to the range
|
||||
difference_type offset = (unsigned)rand() % distance;
|
||||
assert(offset >= 0);
|
||||
CountingIterator internal = start;
|
||||
std::advance(internal, offset);
|
||||
|
||||
// Try some binary searches on the range to show that it's ordered
|
||||
assert(std::binary_search(start, finish, *internal));
|
||||
CountingIterator x,y;
|
||||
boost::tie(x,y) = std::equal_range(start, finish, *internal);
|
||||
assert(boost::detail::distance(x, y) == 1);
|
||||
|
||||
// Show that values outside the range can't be found
|
||||
assert(!std::binary_search(start, boost::prior(finish), *finish));
|
||||
|
||||
// Do the generic random_access_iterator_test
|
||||
typedef typename CountingIterator::value_type value_type;
|
||||
std::vector<value_type> v;
|
||||
for (value_type z = *start; z != *finish; ++z)
|
||||
v.push_back(z);
|
||||
if (v.size() >= 2)
|
||||
{
|
||||
// Note that this test requires a that the first argument is
|
||||
// dereferenceable /and/ a valid iterator prior to the first argument
|
||||
boost::random_access_iterator_test(start + 1, v.size() - 1, v.begin() + 1);
|
||||
}
|
||||
}
|
||||
|
||||
// Special tests for bidirectional CountingIterators
|
||||
template <class CountingIterator>
|
||||
void category_test(CountingIterator start, CountingIterator finish, std::bidirectional_iterator_tag)
|
||||
{
|
||||
if (finish != start
|
||||
&& finish != boost::next(start)
|
||||
&& finish != boost::next(boost::next(start)))
|
||||
{
|
||||
// Note that this test requires a that the first argument is
|
||||
// dereferenceable /and/ a valid iterator prior to the first argument
|
||||
boost::bidirectional_iterator_test(boost::next(start), boost::next(*start), boost::next(boost::next(*start)));
|
||||
}
|
||||
}
|
||||
|
||||
template <class CountingIterator>
|
||||
void category_test(CountingIterator start, CountingIterator finish, std::forward_iterator_tag)
|
||||
{
|
||||
if (finish != start && finish != boost::next(start))
|
||||
boost::forward_iterator_test(start, *start, boost::next(*start));
|
||||
}
|
||||
|
||||
template <class CountingIterator>
|
||||
void test_aux(CountingIterator start, CountingIterator finish)
|
||||
{
|
||||
typedef typename CountingIterator::iterator_category category;
|
||||
typedef typename CountingIterator::value_type value_type;
|
||||
|
||||
// If it's a RandomAccessIterator we can do a few delicate tests
|
||||
category_test(start, finish, category());
|
||||
|
||||
// Okay, brute force...
|
||||
for (CountingIterator p = start; p != finish && boost::next(p) != finish; ++p)
|
||||
{
|
||||
assert(boost::next(*p) == *boost::next(p));
|
||||
}
|
||||
|
||||
// prove that a reference can be formed to these values
|
||||
typedef typename CountingIterator::value_type value;
|
||||
const value* q = &*start;
|
||||
(void)q; // suppress unused variable warning
|
||||
}
|
||||
|
||||
template <class Incrementable>
|
||||
void test(Incrementable start, Incrementable finish)
|
||||
{
|
||||
test_aux(boost::make_counting_iterator(start), boost::make_counting_iterator(finish));
|
||||
}
|
||||
|
||||
template <class Integer>
|
||||
void test_integer(Integer* = 0) // default arg works around MSVC bug
|
||||
{
|
||||
Integer start = 0;
|
||||
Integer finish = 120;
|
||||
test(start, finish);
|
||||
}
|
||||
|
||||
template <class Container>
|
||||
void test_container(Container* = 0) // default arg works around MSVC bug
|
||||
{
|
||||
Container c(1 + (unsigned)rand() % 1673);
|
||||
|
||||
const typename Container::iterator start = c.begin();
|
||||
|
||||
// back off by 1 to leave room for dereferenceable value at the end
|
||||
typename Container::iterator finish = start;
|
||||
std::advance(finish, c.size() - 1);
|
||||
|
||||
test(start, finish);
|
||||
|
||||
typedef typename Container::const_iterator const_iterator;
|
||||
test(const_iterator(start), const_iterator(finish));
|
||||
}
|
||||
|
||||
class my_int1 {
|
||||
public:
|
||||
my_int1() { }
|
||||
my_int1(int x) : m_int(x) { }
|
||||
my_int1& operator++() { ++m_int; return *this; }
|
||||
bool operator==(const my_int1& x) const { return m_int == x.m_int; }
|
||||
private:
|
||||
int m_int;
|
||||
};
|
||||
|
||||
namespace boost {
|
||||
template <>
|
||||
struct counting_iterator_traits<my_int1> {
|
||||
typedef std::ptrdiff_t difference_type;
|
||||
typedef std::forward_iterator_tag iterator_category;
|
||||
};
|
||||
}
|
||||
|
||||
class my_int2 {
|
||||
public:
|
||||
typedef void value_type;
|
||||
typedef void pointer;
|
||||
typedef void reference;
|
||||
typedef std::ptrdiff_t difference_type;
|
||||
typedef std::bidirectional_iterator_tag iterator_category;
|
||||
|
||||
my_int2() { }
|
||||
my_int2(int x) : m_int(x) { }
|
||||
my_int2& operator++() { ++m_int; return *this; }
|
||||
my_int2& operator--() { --m_int; return *this; }
|
||||
bool operator==(const my_int2& x) const { return m_int == x.m_int; }
|
||||
private:
|
||||
int m_int;
|
||||
};
|
||||
|
||||
class my_int3 {
|
||||
public:
|
||||
typedef void value_type;
|
||||
typedef void pointer;
|
||||
typedef void reference;
|
||||
typedef std::ptrdiff_t difference_type;
|
||||
typedef std::random_access_iterator_tag iterator_category;
|
||||
|
||||
my_int3() { }
|
||||
my_int3(int x) : m_int(x) { }
|
||||
my_int3& operator++() { ++m_int; return *this; }
|
||||
my_int3& operator+=(std::ptrdiff_t n) { m_int += n; return *this; }
|
||||
std::ptrdiff_t operator-(const my_int3& x) const { return m_int - x.m_int; }
|
||||
my_int3& operator--() { --m_int; return *this; }
|
||||
bool operator==(const my_int3& x) const { return m_int == x.m_int; }
|
||||
bool operator!=(const my_int3& x) const { return m_int != x.m_int; }
|
||||
bool operator<(const my_int3& x) const { return m_int < x.m_int; }
|
||||
private:
|
||||
int m_int;
|
||||
};
|
||||
|
||||
int main()
|
||||
{
|
||||
// Test the built-in integer types.
|
||||
test_integer<char>();
|
||||
test_integer<unsigned char>();
|
||||
test_integer<signed char>();
|
||||
test_integer<wchar_t>();
|
||||
test_integer<short>();
|
||||
test_integer<unsigned short>();
|
||||
test_integer<int>();
|
||||
test_integer<unsigned int>();
|
||||
test_integer<long>();
|
||||
test_integer<unsigned long>();
|
||||
#if defined(ULLONG_MAX) || defined(ULONG_LONG_MAX)
|
||||
test_integer<long long>();
|
||||
test_integer<unsigned long long>();
|
||||
#endif
|
||||
|
||||
// wrapping an iterator or non-built-in integer type causes an INTERNAL
|
||||
// COMPILER ERROR in MSVC without STLport. I'm clueless as to why.
|
||||
#if !defined(BOOST_MSVC) || defined(__SGI_STL_PORT)
|
||||
// Test user-defined type.
|
||||
test_integer<my_int1>();
|
||||
test_integer<my_int2>();
|
||||
test_integer<my_int3>();
|
||||
|
||||
// Some tests on container iterators, to prove we handle a few different categories
|
||||
test_container<std::vector<int> >();
|
||||
test_container<std::list<int> >();
|
||||
# ifndef BOOST_NO_SLIST
|
||||
test_container<BOOST_STD_EXTENSION_NAMESPACE::slist<int> >();
|
||||
# endif
|
||||
|
||||
// Also prove that we can handle raw pointers.
|
||||
int array[2000];
|
||||
test(boost::make_counting_iterator(array), boost::make_counting_iterator(array+2000-1));
|
||||
#endif
|
||||
std::cout << "test successful " << std::endl;
|
||||
return 0;
|
||||
}
|
273
filter_iterator.htm
Normal file
273
filter_iterator.htm
Normal file
@@ -0,0 +1,273 @@
|
||||
<html>
|
||||
|
||||
<head>
|
||||
<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
|
||||
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
|
||||
<meta name="ProgId" content="FrontPage.Editor.Document">
|
||||
<title>Filter Iterator Adaptor Documentation</title>
|
||||
</head>
|
||||
|
||||
<body bgcolor="#FFFFFF" text="#000000">
|
||||
|
||||
<img src="../../c++boost.gif" alt="c++boost.gif (8819 bytes)"
|
||||
align="center" width="277" height="86">
|
||||
|
||||
<h1>Filter Iterator Adaptor</h1>
|
||||
|
||||
Defined in header
|
||||
<a href="../../boost/iterator_adaptors.hpp">boost/iterator_adaptors.hpp</a>
|
||||
|
||||
|
||||
<p>
|
||||
The filter iterator adaptor creates a view of an iterator range in
|
||||
which some elements of the range are skipped over. A <a
|
||||
href="http://www.sgi.com/tech/stl/Predicate.html">Predicate</a>
|
||||
function object controls which elements are skipped. When the
|
||||
predicate is applied to an element, if it returns <tt>true</tt> then
|
||||
the element is retained and if it returns <tt>false</tt> then the
|
||||
element is skipped over.
|
||||
|
||||
|
||||
<h2>Synopsis</h2>
|
||||
|
||||
<pre>
|
||||
namespace boost {
|
||||
template <class Predicate, class BaseIterator, ...>
|
||||
class filter_iterator_generator;
|
||||
|
||||
template <class Predicate, class BaseIterator>
|
||||
typename filter_iterator_generator<Predicate, BaseIterator>::type
|
||||
make_filter_iterator(BaseIterator first, BaseIterator last, const Predicate& p = Predicate());
|
||||
}
|
||||
</pre>
|
||||
|
||||
<hr>
|
||||
|
||||
<h2><a name="filter_iterator_generator">The Filter Iterator Type
|
||||
Generator</a></h2>
|
||||
|
||||
The class <tt>filter_iterator_generator</tt> is a helper class whose
|
||||
purpose is to construct a filter iterator type. The template
|
||||
parameters for this class are the <tt>Predicate</tt> function object
|
||||
type and the <tt>BaseIterator</tt> type that is being wrapped. In
|
||||
most cases the associated types for the wrapped iterator can be
|
||||
deduced from <tt>std::iterator_traits</tt>, but in some situations the
|
||||
user may want to override these types, so there are also template
|
||||
parameters for each of the iterator's associated types.
|
||||
|
||||
<pre>
|
||||
template <class Predicate, class BaseIterator,
|
||||
class Value, class Reference, class Pointer, class Category, class Distance>
|
||||
class filter_iterator_generator
|
||||
{
|
||||
public:
|
||||
typedef <tt><a href="./iterator_adaptors.htm#iterator_adaptor">iterator_adaptor</a><...></tt> type; // the resulting filter iterator type
|
||||
}
|
||||
</pre>
|
||||
|
||||
|
||||
<h3>Example</h3>
|
||||
|
||||
The following example uses filter iterator to print out all the
|
||||
positive integers in an array.
|
||||
|
||||
<pre>
|
||||
struct is_positive_number {
|
||||
bool operator()(int x) { return 0 < x; }
|
||||
};
|
||||
int main() {
|
||||
int numbers[] = { 0, -1, 4, -3, 5, 8, -2 };
|
||||
const int N = sizeof(numbers)/sizeof(int);
|
||||
|
||||
typedef boost::filter_iterator_generator<is_positive_number, int*, int>::type FilterIter;
|
||||
is_positive_number predicate;
|
||||
FilterIter::policies_type policies(predicate, numbers + N);
|
||||
FilterIter filter_iter_first(numbers, policies);
|
||||
FilterIter filter_iter_last(numbers + N, policies);
|
||||
|
||||
std::copy(filter_iter_first, filter_iter_last, std::ostream_iterator<int>(std::cout, " "));
|
||||
std::cout << std::endl;
|
||||
return 0;
|
||||
}
|
||||
</pre>
|
||||
The output is:
|
||||
<pre>
|
||||
4 5 8
|
||||
</pre>
|
||||
|
||||
|
||||
<h3>Template Parameters</h3>
|
||||
|
||||
<Table border>
|
||||
<TR>
|
||||
<TH>Parameter</TH><TH>Description</TH>
|
||||
</TR>
|
||||
|
||||
<TR>
|
||||
<TD><a href="http://www.sgi.com/tech/stl/Predicate.html"><tt>Predicate</tt></a></TD>
|
||||
<TD>The function object that determines which elements are retained and which elements are skipped.
|
||||
</TR>
|
||||
|
||||
<TR>
|
||||
<TD><tt>BaseIterator</tt></TD>
|
||||
<TD>The iterator type being wrapped. This type must at least be a model
|
||||
of the <a href="http://www.sgi.com/tech/stl/InputIterator">InputIterator</a> concept.</TD>
|
||||
</TR>
|
||||
|
||||
<TR>
|
||||
<TD><tt>Value</tt></TD>
|
||||
<TD>The <tt>value_type</tt> of the resulting iterator,
|
||||
unless const. If const, a conforming compiler strips constness for the
|
||||
<tt>value_type</tt>. Typically the default for this parameter is the
|
||||
appropriate type<a href="#1">[1]</a>.<br> <b>Default:</b>
|
||||
<tt>std::iterator_traits<BaseIterator>::value_type</TD>
|
||||
</TR>
|
||||
|
||||
<TR>
|
||||
<TD><tt>Reference</tt></TD>
|
||||
<TD>The <tt>reference</tt> type of the resulting iterator, and in
|
||||
particular, the result type of <tt>operator*()</tt>. Typically the default for
|
||||
this parameter is the appropriate type.<br> <b>Default:</b> If
|
||||
<tt>Value</tt> is supplied, <tt>Value&</tt> is used. Otherwise
|
||||
<tt>std::iterator_traits<BaseIterator>::reference</tt> is
|
||||
used.</TD>
|
||||
</TR>
|
||||
|
||||
<TR>
|
||||
<TD><tt>Pointer</tt></TD>
|
||||
<TD>The <tt>pointer</tt> type of the resulting iterator, and in
|
||||
particular, the result type of <tt>operator->()</tt>.
|
||||
Typically the default for
|
||||
this parameter is the appropriate type.<br>
|
||||
<b>Default:</b> If <tt>Value</tt> was supplied, then <tt>Value*</tt>,
|
||||
otherwise <tt>std::iterator_traits<BaseIterator>::pointer</tt>.</TD>
|
||||
</TR>
|
||||
|
||||
|
||||
<TR>
|
||||
<TD><tt>Category</tt></TD>
|
||||
<TD>The <tt>iterator_category</tt> type for the resulting iterator.
|
||||
Typically the
|
||||
default for this parameter is the appropriate type. If you override
|
||||
this parameter, do not use <tt>bidirectional_iterator_tag</tt>
|
||||
because filter iterators can not go in reverse.<br>
|
||||
<b>Default:</b> <tt>std::iterator_traits<BaseIterator>::iterator_category</tt></TD>
|
||||
</TR>
|
||||
|
||||
<TR>
|
||||
<TD><tt>Distance</tt></TD>
|
||||
<TD>The <tt>difference_type</tt> for the resulting iterator. Typically the default for
|
||||
this parameter is the appropriate type.<br>
|
||||
<b>Default:</b> <tt>std::iterator_traits<BaseIterator>::difference_type</TD>
|
||||
</TR>
|
||||
|
||||
</table>
|
||||
|
||||
|
||||
<h3>Model of</h3>
|
||||
|
||||
The filter iterator adaptor (the type
|
||||
<tt>filter_iterator_generator<...>::type</tt>) may be a model of <a
|
||||
href="http://www.sgi.com/tech/stl/InputIterator.html">InputIterator</a> or <a
|
||||
href="http://www.sgi.com/tech/stl/ForwardIterator.html">ForwardIterator</a>
|
||||
depending on the adapted iterator type.
|
||||
|
||||
|
||||
<h3>Members</h3>
|
||||
|
||||
The filter iterator type implements all of the member functions and
|
||||
operators required of the <a
|
||||
href="http://www.sgi.com/tech/stl/ForwardIterator.html">ForwardIterator</a>
|
||||
concept. In addition it has the following constructor:
|
||||
|
||||
<pre>filter_iterator_generator::type(const BaseIterator& it, const Policies& p = Policies())</pre>
|
||||
|
||||
<p>
|
||||
The policies type has only one public function, which is its constructor:
|
||||
|
||||
<pre>filter_iterator_generator::policies_type(const Predicate& p, const BaseIterator& end)</pre>
|
||||
|
||||
<p>
|
||||
<hr>
|
||||
<p>
|
||||
|
||||
<h2><a name="make_filter_iterator">The Make Filter Iterator Function</a></h2>
|
||||
|
||||
<pre>
|
||||
template <class Predicate, class BaseIterator>
|
||||
typename detail::filter_generator<Predicate, BaseIterator>::type
|
||||
make_filter_iterator(BaseIterator first, BaseIterator last, const Predicate& p = Predicate())
|
||||
</pre>
|
||||
|
||||
This function provides a convenient way to create filter iterators.
|
||||
|
||||
<h3>Example</h3>
|
||||
|
||||
In this example we print out all numbers in the array that are
|
||||
greater than negative two.
|
||||
|
||||
<pre>
|
||||
int main()
|
||||
{
|
||||
int numbers[] = { 0, -1, 4, -3, 5, 8, -2 };
|
||||
const int N = sizeof(numbers)/sizeof(int);
|
||||
|
||||
std::copy(boost::make_filter_iterator(numbers, numbers + N,
|
||||
std::bind2nd(std::greater<int>(), -2)),
|
||||
boost::make_filter_iterator(numbers + N, numbers + N,
|
||||
std::bind2nd(std::greater<int>(), -2)),
|
||||
std::ostream_iterator<int>(std::cout, " "));
|
||||
std::cout << std::endl;
|
||||
|
||||
}
|
||||
</pre>
|
||||
The output is:
|
||||
<pre>
|
||||
0 -1 4 5 8
|
||||
</pre>
|
||||
|
||||
<p>
|
||||
In the next example we print the positive numbers using the
|
||||
<tt>make_filter_iterator()</tt> function.
|
||||
|
||||
<pre>
|
||||
struct is_positive_number {
|
||||
bool operator()(int x) { return 0 < x; }
|
||||
};
|
||||
int main()
|
||||
{
|
||||
int numbers[] = { 0, -1, 4, -3, 5, 8, -2 };
|
||||
const int N = sizeof(numbers)/sizeof(int);
|
||||
|
||||
std::copy(boost::make_filter_iterator<is_positive_number>(numbers, numbers + N),
|
||||
boost::make_filter_iterator<is_positive_number>(numbers + N, numbers + N),
|
||||
std::ostream_iterator<int>(std::cout, " "));
|
||||
std::cout << std::endl;
|
||||
return 0;
|
||||
}
|
||||
</pre>
|
||||
The output is:
|
||||
<pre>
|
||||
4 5 8
|
||||
</pre>
|
||||
|
||||
|
||||
<h3>Notes</h3>
|
||||
|
||||
<a name="1">[1]</a> If the compiler does not support partial
|
||||
specialization and the wrapped iterator type is a builtin pointer then
|
||||
the <tt>Value</tt> type must be explicitly specified (don't use the
|
||||
default).
|
||||
|
||||
|
||||
<hr>
|
||||
<p>Revised <!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %b %Y" startspan -->09 Mar 2001<!--webbot bot="Timestamp" endspan i-checksum="14894" --></p>
|
||||
<p><EFBFBD> Copyright Jeremy Siek 2000. Permission to copy, use,
|
||||
modify, sell and distribute this document is granted provided this copyright
|
||||
notice appears in all copies. This document is provided "as is"
|
||||
without express or implied warranty, and with no claim as to its suitability for
|
||||
any purpose.</p>
|
||||
|
||||
</body>
|
||||
|
||||
</html>
|
53
filter_iterator_example.cpp
Normal file
53
filter_iterator_example.cpp
Normal file
@@ -0,0 +1,53 @@
|
||||
// Example of using the filter iterator adaptor from
|
||||
// boost/iterator_adaptors.hpp.
|
||||
|
||||
// (C) Copyright Jeremy Siek 1999. Permission to copy, use, modify,
|
||||
// sell and distribute this software is granted provided this
|
||||
// copyright notice appears in all copies. This software is provided
|
||||
// "as is" without express or implied warranty, and with no claim as
|
||||
// to its suitability for any purpose.
|
||||
|
||||
|
||||
#include <boost/config.hpp>
|
||||
#include <algorithm>
|
||||
#include <functional>
|
||||
#include <iostream>
|
||||
#include <boost/iterator_adaptors.hpp>
|
||||
|
||||
struct is_positive_number {
|
||||
bool operator()(int x) { return 0 < x; }
|
||||
};
|
||||
|
||||
int main()
|
||||
{
|
||||
int numbers[] = { 0, -1, 4, -3, 5, 8, -2 };
|
||||
const int N = sizeof(numbers)/sizeof(int);
|
||||
|
||||
// Example using make_filter_iterator()
|
||||
std::copy(boost::make_filter_iterator<is_positive_number>(numbers, numbers + N),
|
||||
boost::make_filter_iterator<is_positive_number>(numbers + N, numbers + N),
|
||||
std::ostream_iterator<int>(std::cout, " "));
|
||||
std::cout << std::endl;
|
||||
|
||||
// Example using filter_iterator_generator
|
||||
typedef boost::filter_iterator_generator<is_positive_number, int*, int>::type
|
||||
FilterIter;
|
||||
is_positive_number predicate;
|
||||
FilterIter::policies_type policies(predicate, numbers + N);
|
||||
FilterIter filter_iter_first(numbers, policies);
|
||||
FilterIter filter_iter_last(numbers + N, policies);
|
||||
|
||||
std::copy(filter_iter_first, filter_iter_last, std::ostream_iterator<int>(std::cout, " "));
|
||||
std::cout << std::endl;
|
||||
|
||||
// Another example using make_filter_iterator()
|
||||
std::copy(boost::make_filter_iterator(numbers, numbers + N,
|
||||
std::bind2nd(std::greater<int>(), -2)),
|
||||
boost::make_filter_iterator(numbers + N, numbers + N,
|
||||
std::bind2nd(std::greater<int>(), -2)),
|
||||
std::ostream_iterator<int>(std::cout, " "));
|
||||
std::cout << std::endl;
|
||||
|
||||
|
||||
return 0;
|
||||
}
|
41
fun_out_iter_example.cpp
Normal file
41
fun_out_iter_example.cpp
Normal file
@@ -0,0 +1,41 @@
|
||||
// (C) Copyright Jeremy Siek 2001. Permission to copy, use, modify,
|
||||
// sell and distribute this software is granted provided this
|
||||
// copyright notice appears in all copies. This software is provided
|
||||
// "as is" without express or implied warranty, and with no claim as
|
||||
// to its suitability for any purpose.
|
||||
|
||||
// Revision History:
|
||||
|
||||
// 27 Feb 2001 Jeremy Siek
|
||||
// Initial checkin.
|
||||
|
||||
#include <iostream>
|
||||
#include <string>
|
||||
#include <vector>
|
||||
|
||||
#include <boost/function_output_iterator.hpp>
|
||||
|
||||
struct string_appender {
|
||||
string_appender(std::string& s) : m_str(s) { }
|
||||
void operator()(const std::string& x) const {
|
||||
m_str += x;
|
||||
}
|
||||
std::string& m_str;
|
||||
};
|
||||
|
||||
int main(int, char*[])
|
||||
{
|
||||
std::vector<std::string> x;
|
||||
x.push_back("hello");
|
||||
x.push_back(" ");
|
||||
x.push_back("world");
|
||||
x.push_back("!");
|
||||
|
||||
std::string s = "";
|
||||
std::copy(x.begin(), x.end(),
|
||||
boost::make_function_output_iterator(string_appender(s)));
|
||||
|
||||
std::cout << s << std::endl;
|
||||
|
||||
return 0;
|
||||
}
|
169
function_output_iterator.htm
Normal file
169
function_output_iterator.htm
Normal file
@@ -0,0 +1,169 @@
|
||||
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 3.2//EN">
|
||||
|
||||
<html>
|
||||
<head>
|
||||
<meta name="generator" content="HTML Tidy, see www.w3.org">
|
||||
<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
|
||||
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
|
||||
<meta name="ProgId" content="FrontPage.Editor.Document">
|
||||
|
||||
<title>Function Output Iterator Adaptor Documentation</title>
|
||||
</head>
|
||||
|
||||
<body bgcolor="#FFFFFF" text="#000000">
|
||||
|
||||
<img src="../../c++boost.gif" alt="c++boost.gif (8819 bytes)" align=
|
||||
"center" width="277" height="86">
|
||||
|
||||
<h1>Function Output Iterator Adaptor</h1>
|
||||
Defined in header <a href=
|
||||
"../../boost/function_output_iterator.hpp">boost/function_output_iterator.hpp</a>
|
||||
|
||||
<p>The function output iterator adaptor makes it easier to create
|
||||
custom output iterators. The adaptor takes a <a
|
||||
href="http://www.sgi.com/tech/stl/UnaryFunction.html">Unary
|
||||
Function</a> and creates a model of <a
|
||||
href="http://www.sgi.com/tech/stl/OutputIterator.html">Output
|
||||
Iterator</a>. Each item assigned to the output iterator is passed
|
||||
as an argument to the unary function. The motivation for this
|
||||
iterator is that creating a C++ Standard conforming output
|
||||
iterator is non-trivial, particularly because the proper
|
||||
implementation usually requires a proxy object. On the other hand,
|
||||
creating a function (or function object) is much simpler.
|
||||
|
||||
<h2>Synopsis</h2>
|
||||
|
||||
<blockquote>
|
||||
<pre>
|
||||
namespace boost {
|
||||
template <class UnaryFunction>
|
||||
class function_output_iterator;
|
||||
|
||||
template <class UnaryFunction>
|
||||
function_output_iterator<UnaryFunction>
|
||||
make_function_output_iterator(const UnaryFunction& f = UnaryFunction())
|
||||
}
|
||||
</pre>
|
||||
</blockquote>
|
||||
|
||||
<h3>Example</h3>
|
||||
|
||||
In this example we create an output iterator that appends
|
||||
each item onto the end of a string, using the <tt>string_appender</tt>
|
||||
function.
|
||||
|
||||
<blockquote>
|
||||
<pre>
|
||||
#include <iostream>
|
||||
#include <string>
|
||||
#include <vector>
|
||||
|
||||
#include <boost/function_output_iterator.hpp>
|
||||
|
||||
struct string_appender {
|
||||
string_appender(std::string& s) : m_str(s) { }
|
||||
void operator()(const std::string& x) const {
|
||||
m_str += x;
|
||||
}
|
||||
std::string& m_str;
|
||||
};
|
||||
|
||||
int main(int, char*[])
|
||||
{
|
||||
std::vector<std::string> x;
|
||||
x.push_back("hello");
|
||||
x.push_back(" ");
|
||||
x.push_back("world");
|
||||
x.push_back("!");
|
||||
|
||||
std::string s = "";
|
||||
std::copy(x.begin(), x.end(),
|
||||
boost::make_function_output_iterator(string_appender(s)));
|
||||
|
||||
std::cout << s << std::endl;
|
||||
|
||||
return 0;
|
||||
}
|
||||
</pre>
|
||||
</blockquote>
|
||||
|
||||
<hr>
|
||||
|
||||
<h2><a name="function_output_iterator">The Function Output Iterator Class</a></h2>
|
||||
|
||||
<blockquote>
|
||||
<pre>
|
||||
template <class UnaryFunction>
|
||||
class function_output_iterator;
|
||||
</pre>
|
||||
</blockquote>
|
||||
|
||||
The <tt>function_output_iterator</tt> class creates an <a
|
||||
href="http://www.sgi.com/tech/stl/OutputIterator.html">Output
|
||||
Iterator</a> out of a
|
||||
<a href="http://www.sgi.com/tech/stl/UnaryFunction.html">Unary
|
||||
Function</a>. Each item assigned to the output iterator is passed
|
||||
as an argument to the unary function.
|
||||
|
||||
<h3>Template Parameters</h3>
|
||||
|
||||
<table border>
|
||||
<tr>
|
||||
<th>Parameter
|
||||
|
||||
<th>Description
|
||||
|
||||
<tr>
|
||||
<td><tt>UnaryFunction</tt>
|
||||
|
||||
<td>The function type being wrapped. The return type of the
|
||||
function is not used, so it can be <tt>void</tt>. The
|
||||
function must be a model of <a
|
||||
href="http://www.sgi.com/tech/stl/UnaryFunction.html">Unary
|
||||
Function</a>.</td>
|
||||
</table>
|
||||
|
||||
<h3>Concept Model</h3>
|
||||
The function output iterator class is a model of <a
|
||||
href="http://www.sgi.com/tech/stl/OutputIterator.html">Output
|
||||
Iterator</a>.
|
||||
|
||||
<h2>Members</h3>
|
||||
The function output iterator implements the member functions
|
||||
and operators required of the <a
|
||||
href="http://www.sgi.com/tech/stl/OutputIterator.html">Output
|
||||
Iterator</a> concept. In addition it has the following constructor:
|
||||
<pre>
|
||||
explicit function_output_iterator(const UnaryFunction& f = UnaryFunction())
|
||||
</pre>
|
||||
<br>
|
||||
<br>
|
||||
|
||||
<hr>
|
||||
<h2><a name="make_function_output_iterator">The Function Output Iterator Object
|
||||
Generator</a></h2>
|
||||
|
||||
The <tt>make_function_output_iterator()</tt> function provides a
|
||||
more convenient way to create function output iterator objects. The
|
||||
function saves the user the trouble of explicitly writing out the
|
||||
iterator types. If the default argument is used, the function
|
||||
type must be provided as an explicit template argument.
|
||||
|
||||
<blockquote>
|
||||
<pre>
|
||||
template <class UnaryFunction>
|
||||
function_output_iterator<UnaryFunction>
|
||||
make_function_output_iterator(const UnaryFunction& f = UnaryFunction())
|
||||
</pre>
|
||||
</blockquote>
|
||||
|
||||
<hr>
|
||||
|
||||
<p>© Copyright Jeremy Siek 2001. Permission to copy, use,
|
||||
modify, sell and distribute this document is granted provided this
|
||||
copyright notice appears in all copies. This document is provided
|
||||
"as is" without express or implied warranty, and with no claim as
|
||||
to its suitability for any purpose.
|
||||
|
||||
</body>
|
||||
</html>
|
366
half_open_range_test.cpp
Normal file
366
half_open_range_test.cpp
Normal file
@@ -0,0 +1,366 @@
|
||||
// (C) Copyright David Abrahams 2001. Permission to copy, use, modify, sell and
|
||||
// distribute this software is granted provided this copyright notice appears in
|
||||
// all copies. This software is provided "as is" without express or implied
|
||||
// warranty, and with no claim as to its suitability for any purpose.
|
||||
//
|
||||
// See http://www.boost.org for most recent version including documentation.
|
||||
//
|
||||
// Revision History
|
||||
// 11 Feb 2001 Compile with Borland, re-enable failing tests (David Abrahams)
|
||||
// 29 Jan 2001 Initial revision (David Abrahams)
|
||||
|
||||
#include <boost/half_open_range.hpp>
|
||||
#include <boost/utility.hpp>
|
||||
#include <iterator>
|
||||
#include <stdlib.h>
|
||||
#include <vector>
|
||||
#include <list>
|
||||
#include <cassert>
|
||||
#include <stdexcept>
|
||||
#ifndef BOOST_NO_LIMITS
|
||||
# include <limits>
|
||||
#endif
|
||||
#ifndef BOOST_NO_SLIST
|
||||
# include <slist>
|
||||
#endif
|
||||
|
||||
inline unsigned unsigned_random(unsigned max)
|
||||
{
|
||||
return (max > 0) ? (unsigned)rand() % max : 0;
|
||||
}
|
||||
|
||||
// Special tests for ranges supporting random access
|
||||
template <class T>
|
||||
void category_test_1(
|
||||
const boost::half_open_range<T>& r, std::random_access_iterator_tag)
|
||||
{
|
||||
typedef boost::half_open_range<T> range;
|
||||
typedef typename range::size_type size_type;
|
||||
size_type size = r.size();
|
||||
|
||||
// pick a random offset
|
||||
size_type offset = unsigned_random(size);
|
||||
|
||||
typename range::value_type x = *(r.begin() + offset);
|
||||
// test contains(value_type)
|
||||
assert(r.contains(r.start()) == !r.empty());
|
||||
assert(!r.contains(r.finish()));
|
||||
assert(r.contains(x) == (offset != size));
|
||||
|
||||
range::const_iterator p = r.find(x);
|
||||
assert((p == r.end()) == (x == r.finish()));
|
||||
assert(r.find(r.finish()) == r.end());
|
||||
|
||||
if (offset != size)
|
||||
{
|
||||
assert(x == r[offset]);
|
||||
assert(x == r.at(offset));
|
||||
}
|
||||
|
||||
bool caught_out_of_range = false;
|
||||
try {
|
||||
bool never_initialized = x == r.at(size);
|
||||
(void)never_initialized;
|
||||
}
|
||||
catch(std::out_of_range&)
|
||||
{
|
||||
caught_out_of_range = true;
|
||||
}
|
||||
catch(...)
|
||||
{
|
||||
}
|
||||
assert(caught_out_of_range);
|
||||
}
|
||||
|
||||
// Those tests must be skipped for other ranges
|
||||
template <class T>
|
||||
void category_test_1(
|
||||
const boost::half_open_range<T>&, std::forward_iterator_tag)
|
||||
{
|
||||
}
|
||||
|
||||
unsigned indices[][2] = { {0,0},{0,1},{0,2},{0,3},
|
||||
{1,1},{1,2},{1,3},
|
||||
{2,2},{2,3},
|
||||
{3,3}};
|
||||
|
||||
template <class Range>
|
||||
void category_test_2(
|
||||
const std::vector<Range>& ranges, unsigned i, unsigned j, std::random_access_iterator_tag)
|
||||
{
|
||||
typedef Range range;
|
||||
const range& ri = ranges[i];
|
||||
const range& rj = ranges[j];
|
||||
|
||||
if (indices[i][0] <= indices[j][0] && indices[i][1] >= indices[j][1])
|
||||
assert(ri.contains(rj));
|
||||
|
||||
if (ri.contains(rj))
|
||||
assert((ri & rj) == rj);
|
||||
assert(boost::intersects(ri, rj) == !(ri & rj).empty());
|
||||
|
||||
range t1(ri);
|
||||
t1 &= rj;
|
||||
assert(t1 == range(indices[i][0] > indices[j][0] ? ri.start() : rj.start(),
|
||||
indices[i][1] < indices[j][1] ? ri.finish() : rj.finish()));
|
||||
assert(t1 == (ri & rj));
|
||||
|
||||
range t2(ri);
|
||||
t2 |= rj;
|
||||
|
||||
if (ri.empty())
|
||||
assert(t2 == rj);
|
||||
else if (rj.empty())
|
||||
assert(t2 == ri);
|
||||
else
|
||||
assert(t2 == range(indices[i][0] < indices[j][0] ? ri.start() : rj.start(),
|
||||
indices[i][1] > indices[j][1] ? ri.finish() : rj.finish()));
|
||||
assert(t2 == (ri | rj));
|
||||
if (i == j)
|
||||
assert(ri == rj);
|
||||
|
||||
if (ri.empty() || rj.empty())
|
||||
assert((ri == rj) == (ri.empty() && rj.empty()));
|
||||
else
|
||||
assert((ri == rj) == (ri.start() == rj.start() && ri.finish() == rj.finish()));
|
||||
|
||||
assert((ri == rj) == !(ri != rj));
|
||||
|
||||
bool same = ri == rj;
|
||||
bool one_empty = ri.empty() != rj.empty();
|
||||
|
||||
std::less<range> less;
|
||||
std::less_equal<range> less_equal;
|
||||
std::greater<range> greater;
|
||||
std::greater_equal<range> greater_equal;
|
||||
|
||||
if (same)
|
||||
{
|
||||
assert(greater_equal(ri,rj));
|
||||
assert(less_equal(ri,rj));
|
||||
assert(!greater(ri,rj));
|
||||
assert(!less(ri,rj));
|
||||
}
|
||||
else if (one_empty)
|
||||
{
|
||||
const range& empty = ri.empty() ? ri : rj;
|
||||
const range& non_empty = rj.empty() ? ri : rj;
|
||||
|
||||
assert(less(empty,non_empty));
|
||||
assert(less_equal(empty,non_empty));
|
||||
assert(!greater(empty,non_empty));
|
||||
assert(!greater_equal(empty,non_empty));
|
||||
assert(!less(non_empty,empty));
|
||||
assert(!less_equal(non_empty,empty));
|
||||
assert(greater(non_empty,empty));
|
||||
assert(greater_equal(non_empty,empty));
|
||||
}
|
||||
else {
|
||||
if (indices[i][0] < indices[j][0] ||
|
||||
indices[i][0] == indices[j][0] && indices[i][1] < indices[j][1])
|
||||
{
|
||||
assert(!greater_equal(ri,rj));
|
||||
assert(less(ri,rj));
|
||||
}
|
||||
|
||||
if (indices[i][0] < indices[j][0] ||
|
||||
indices[i][0] == indices[j][0] && indices[i][1] <= indices[j][1])
|
||||
{
|
||||
assert(!greater(ri,rj));
|
||||
assert(less_equal(ri,rj));
|
||||
}
|
||||
|
||||
if (indices[i][0] > indices[j][0] ||
|
||||
indices[i][0] == indices[j][0] && indices[i][1] > indices[j][1])
|
||||
{
|
||||
assert(!less_equal(ri,rj));
|
||||
assert(greater(ri,rj));
|
||||
}
|
||||
|
||||
if (indices[i][0] > indices[j][0] ||
|
||||
indices[i][0] == indices[j][0] && indices[i][1] >= indices[j][1])
|
||||
{
|
||||
assert(!less(ri,rj));
|
||||
assert(greater_equal(ri,rj));
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
template <class Range>
|
||||
void category_test_2(
|
||||
const std::vector<Range>&, unsigned, unsigned, std::forward_iterator_tag)
|
||||
{
|
||||
}
|
||||
|
||||
template <class T>
|
||||
void category_test_2(
|
||||
const std::vector<boost::half_open_range<T> >&, unsigned, unsigned, std::bidirectional_iterator_tag)
|
||||
{
|
||||
}
|
||||
|
||||
template <class Range>
|
||||
void test_back(Range& x, std::bidirectional_iterator_tag)
|
||||
{
|
||||
assert(x.back() == boost::prior(x.finish()));
|
||||
}
|
||||
|
||||
template <class Range>
|
||||
void test_back(Range& x, std::forward_iterator_tag)
|
||||
{
|
||||
}
|
||||
|
||||
template <class T>
|
||||
boost::half_open_range<T> range_identity(const boost::half_open_range<T>& x)
|
||||
{
|
||||
return x;
|
||||
}
|
||||
|
||||
template <class T>
|
||||
void test(T x0, T x1, T x2, T x3)
|
||||
{
|
||||
std::vector<boost::half_open_range<T> > ranges;
|
||||
typedef boost::half_open_range<T> range;
|
||||
|
||||
T bounds[4] = { x0, x1, x2, x3 };
|
||||
|
||||
const std::size_t num_ranges = sizeof(indices)/sizeof(*indices);
|
||||
// test construction
|
||||
for (std::size_t n = 0; n < num_ranges;++n)
|
||||
{
|
||||
T start = bounds[indices[n][0]];
|
||||
T finish = bounds[indices[n][1]];
|
||||
boost::half_open_range<T> r(start, finish);
|
||||
ranges.push_back(r);
|
||||
}
|
||||
|
||||
// test implicit conversion from std::pair<T,T>
|
||||
range converted = std::pair<T,T>(x0,x0);
|
||||
(void)converted;
|
||||
|
||||
// test assignment, equality and inequality
|
||||
range r00 = range(x0, x0);
|
||||
assert(r00 == range(x0,x0));
|
||||
assert(r00 == range(x1,x1)); // empty ranges are all equal
|
||||
if (x3 != x0)
|
||||
assert(r00 != range(x0, x3));
|
||||
r00 = range(x0, x3);
|
||||
assert(r00 == range(x0, x3));
|
||||
if (x3 != x0)
|
||||
assert(r00 != range(x0, x0));
|
||||
|
||||
typedef typename range::iterator iterator;
|
||||
typedef typename iterator::iterator_category category;
|
||||
|
||||
for (unsigned i = 0; i < num_ranges; ++i)
|
||||
{
|
||||
const range& r = ranges[i];
|
||||
|
||||
// test begin(), end(), basic iteration.
|
||||
unsigned count = 0;
|
||||
for (range::const_iterator p = r.begin(), finish = r.end();
|
||||
p != finish;
|
||||
++p, ++count)
|
||||
{
|
||||
assert(count < 2100);
|
||||
}
|
||||
|
||||
// test size(), empty(), front(), back()
|
||||
assert((unsigned)r.size() == count);
|
||||
if (indices[i][0] == indices[i][1])
|
||||
assert(r.empty());
|
||||
if (r.empty())
|
||||
assert(r.size() == 0);
|
||||
if (!r.empty())
|
||||
{
|
||||
assert(r.front() == r.start());
|
||||
test_back(r, category());
|
||||
}
|
||||
|
||||
// test swap
|
||||
range r1(r);
|
||||
range r2(x0,x3);
|
||||
const bool same = r1 == r2;
|
||||
r1.swap(r2);
|
||||
assert(r1 == range(x0,x3));
|
||||
assert(r2 == r);
|
||||
if (!same) {
|
||||
assert(r1 != r);
|
||||
assert(r2 != range(x0,x3));
|
||||
}
|
||||
|
||||
// do individual tests for random-access iterators
|
||||
category_test_1(r, category());
|
||||
}
|
||||
|
||||
for (unsigned j = 0; j < num_ranges; ++j) {
|
||||
for (unsigned k = 0; k < num_ranges; ++k) {
|
||||
category_test_2(ranges, j, k, category());
|
||||
}
|
||||
}
|
||||
|
||||
}
|
||||
|
||||
template <class Integer>
|
||||
void test_integer(Integer* = 0) // default arg works around MSVC bug
|
||||
{
|
||||
Integer a = 0;
|
||||
Integer b = a + unsigned_random(128 - a);
|
||||
Integer c = b + unsigned_random(128 - b);
|
||||
Integer d = c + unsigned_random(128 - c);
|
||||
|
||||
test(a, b, c, d);
|
||||
}
|
||||
|
||||
template <class Container>
|
||||
void test_container(Container* = 0) // default arg works around MSVC bug
|
||||
{
|
||||
Container c(unsigned_random(1673));
|
||||
|
||||
const typename Container::size_type offset1 = unsigned_random(c.size());
|
||||
const typename Container::size_type offset2 = unsigned_random(c.size() - offset1);
|
||||
typename Container::iterator internal1 = c.begin();
|
||||
std::advance(internal1, offset1);
|
||||
typename Container::iterator internal2 = internal1;
|
||||
std::advance(internal2, offset2);
|
||||
|
||||
test(c.begin(), internal1, internal2, c.end());
|
||||
|
||||
typedef typename Container::const_iterator const_iterator;
|
||||
test(const_iterator(c.begin()),
|
||||
const_iterator(internal1),
|
||||
const_iterator(internal2),
|
||||
const_iterator(c.end()));
|
||||
}
|
||||
|
||||
int main()
|
||||
{
|
||||
// Test the built-in integer types.
|
||||
test_integer<char>();
|
||||
test_integer<unsigned char>();
|
||||
test_integer<signed char>();
|
||||
test_integer<wchar_t>();
|
||||
test_integer<short>();
|
||||
test_integer<unsigned short>();
|
||||
test_integer<int>();
|
||||
test_integer<unsigned int>();
|
||||
test_integer<long>();
|
||||
test_integer<unsigned long>();
|
||||
#if defined(ULLONG_MAX) || defined(ULONG_LONG_MAX)
|
||||
test_integer<long long>();
|
||||
test_integer<unsigned long long>();
|
||||
#endif
|
||||
// Some tests on container iterators, to prove we handle a few different categories
|
||||
test_container<std::vector<int> >();
|
||||
test_container<std::list<int> >();
|
||||
#ifndef BOOST_NO_SLIST
|
||||
test_container<BOOST_STD_EXTENSION_NAMESPACE::slist<int> >();
|
||||
#endif
|
||||
// Also prove that we can handle raw pointers.
|
||||
int array[2000];
|
||||
const std::size_t a = 0;
|
||||
const std::size_t b = a + unsigned_random(2000 - a);
|
||||
const std::size_t c = b + unsigned_random(2000 - b);
|
||||
test(array, array+b, array+c, array+2000);
|
||||
return 0;
|
||||
}
|
@@ -23,8 +23,11 @@
|
||||
#include <boost/config.hpp>
|
||||
#endif
|
||||
|
||||
#ifndef BOOST_TYPE_TRAITS_HPP
|
||||
#include <boost/type_traits.hpp>
|
||||
#ifndef BOOST_ARITHMETIC_TYPE_TRAITS_HPP
|
||||
#include <boost/type_traits/arithmetic_traits.hpp>
|
||||
#endif
|
||||
#ifndef BOOST_COMPOSITE_TYPE_TRAITS_HPP
|
||||
#include <boost/type_traits/composite_traits.hpp>
|
||||
#endif
|
||||
|
||||
namespace boost{
|
||||
|
@@ -19,8 +19,11 @@
|
||||
#define BOOST_DETAIL_COMPRESSED_PAIR_HPP
|
||||
|
||||
#include <algorithm>
|
||||
#ifndef BOOST_TYPE_TRAITS_HPP
|
||||
#include <boost/type_traits.hpp>
|
||||
#ifndef BOOST_OBJECT_TYPE_TRAITS_HPP
|
||||
#include <boost/type_traits/object_traits.hpp>
|
||||
#endif
|
||||
#ifndef BOOST_SAME_TRAITS_HPP
|
||||
#include <boost/type_traits/same_traits.hpp>
|
||||
#endif
|
||||
#ifndef BOOST_CALL_TRAITS_HPP
|
||||
#include <boost/call_traits.hpp>
|
||||
@@ -75,7 +78,9 @@ namespace details
|
||||
template <typename T>
|
||||
inline void cp_swap(T& t1, T& t2)
|
||||
{
|
||||
#ifndef __GNUC__
|
||||
using std::swap;
|
||||
#endif
|
||||
swap(t1, t2);
|
||||
}
|
||||
|
||||
@@ -420,3 +425,4 @@ swap(compressed_pair<T1, T2>& x, compressed_pair<T1, T2>& y)
|
||||
#endif // BOOST_DETAIL_COMPRESSED_PAIR_HPP
|
||||
|
||||
|
||||
|
||||
|
@@ -9,6 +9,14 @@
|
||||
// Crippled version for crippled compilers:
|
||||
// see libs/utility/call_traits.htm
|
||||
//
|
||||
|
||||
/* Release notes:
|
||||
01st October 2000:
|
||||
Fixed call_traits on VC6, using "poor man's partial specialisation",
|
||||
using ideas taken from "Generative programming" by Krzysztof Czarnecki
|
||||
& Ulrich Eisenecker.
|
||||
*/
|
||||
|
||||
#ifndef BOOST_OB_CALL_TRAITS_HPP
|
||||
#define BOOST_OB_CALL_TRAITS_HPP
|
||||
|
||||
@@ -16,12 +24,94 @@
|
||||
#include <boost/config.hpp>
|
||||
#endif
|
||||
|
||||
#ifndef BOOST_TYPE_TRAITS_HPP
|
||||
#include <boost/type_traits.hpp>
|
||||
#ifndef BOOST_ARITHMETIC_TYPE_TRAITS_HPP
|
||||
#include <boost/type_traits/arithmetic_traits.hpp>
|
||||
#endif
|
||||
#ifndef BOOST_COMPOSITE_TYPE_TRAITS_HPP
|
||||
#include <boost/type_traits/composite_traits.hpp>
|
||||
#endif
|
||||
|
||||
namespace boost{
|
||||
|
||||
#if defined(BOOST_MSVC6_MEMBER_TEMPLATES) || !defined(BOOST_NO_MEMBER_TEMPLATES)
|
||||
//
|
||||
// use member templates to emulate
|
||||
// partial specialisation:
|
||||
//
|
||||
namespace detail{
|
||||
|
||||
template <class T>
|
||||
struct standard_call_traits
|
||||
{
|
||||
typedef T value_type;
|
||||
typedef T& reference;
|
||||
typedef const T& const_reference;
|
||||
typedef const T& param_type;
|
||||
};
|
||||
template <class T>
|
||||
struct simple_call_traits
|
||||
{
|
||||
typedef T value_type;
|
||||
typedef T& reference;
|
||||
typedef const T& const_reference;
|
||||
typedef const T param_type;
|
||||
};
|
||||
template <class T>
|
||||
struct reference_call_traits
|
||||
{
|
||||
typedef T value_type;
|
||||
typedef T reference;
|
||||
typedef T const_reference;
|
||||
typedef T param_type;
|
||||
};
|
||||
template <bool simple, bool reference>
|
||||
struct call_traits_chooser
|
||||
{
|
||||
template <class T>
|
||||
struct rebind
|
||||
{
|
||||
typedef standard_call_traits<T> type;
|
||||
};
|
||||
};
|
||||
template <>
|
||||
struct call_traits_chooser<true, false>
|
||||
{
|
||||
template <class T>
|
||||
struct rebind
|
||||
{
|
||||
typedef simple_call_traits<T> type;
|
||||
};
|
||||
};
|
||||
template <>
|
||||
struct call_traits_chooser<false, true>
|
||||
{
|
||||
template <class T>
|
||||
struct rebind
|
||||
{
|
||||
typedef reference_call_traits<T> type;
|
||||
};
|
||||
};
|
||||
} // namespace detail
|
||||
template <typename T>
|
||||
struct call_traits
|
||||
{
|
||||
private:
|
||||
typedef detail::call_traits_chooser<(is_pointer<T>::value || is_arithmetic<T>::value) && sizeof(T) <= sizeof(void*), is_reference<T>::value> chooser;
|
||||
typedef typename chooser::template rebind<T> bound_type;
|
||||
typedef typename bound_type::type call_traits_type;
|
||||
public:
|
||||
typedef typename call_traits_type::value_type value_type;
|
||||
typedef typename call_traits_type::reference reference;
|
||||
typedef typename call_traits_type::const_reference const_reference;
|
||||
typedef typename call_traits_type::param_type param_type;
|
||||
};
|
||||
|
||||
#else
|
||||
//
|
||||
// sorry call_traits is completely non-functional
|
||||
// blame your broken compiler:
|
||||
//
|
||||
|
||||
template <typename T>
|
||||
struct call_traits
|
||||
{
|
||||
@@ -31,6 +121,8 @@ struct call_traits
|
||||
typedef const T& param_type;
|
||||
};
|
||||
|
||||
#endif // member templates
|
||||
|
||||
}
|
||||
|
||||
#endif // BOOST_OB_CALL_TRAITS_HPP
|
||||
|
@@ -8,6 +8,12 @@
|
||||
// see libs/utility/compressed_pair.hpp
|
||||
//
|
||||
/* Release notes:
|
||||
20 Jan 2001:
|
||||
Fixed obvious bugs (David Abrahams)
|
||||
07 Oct 2000:
|
||||
Added better single argument constructor support.
|
||||
03 Oct 2000:
|
||||
Added VC6 support (JM).
|
||||
23rd July 2000:
|
||||
Additional comments added. (JM)
|
||||
Jan 2000:
|
||||
@@ -20,8 +26,11 @@
|
||||
#define BOOST_OB_COMPRESSED_PAIR_HPP
|
||||
|
||||
#include <algorithm>
|
||||
#ifndef BOOST_TYPE_TRAITS_HPP
|
||||
#include <boost/type_traits.hpp>
|
||||
#ifndef BOOST_OBJECT_TYPE_TRAITS_HPP
|
||||
#include <boost/type_traits/object_traits.hpp>
|
||||
#endif
|
||||
#ifndef BOOST_SAME_TRAITS_HPP
|
||||
#include <boost/type_traits/same_traits.hpp>
|
||||
#endif
|
||||
#ifndef BOOST_CALL_TRAITS_HPP
|
||||
#include <boost/call_traits.hpp>
|
||||
@@ -29,6 +38,424 @@
|
||||
|
||||
namespace boost
|
||||
{
|
||||
#if defined(BOOST_MSVC6_MEMBER_TEMPLATES) || !defined(BOOST_NO_MEMBER_TEMPLATES)
|
||||
//
|
||||
// use member templates to emulate
|
||||
// partial specialisation. Note that due to
|
||||
// problems with overload resolution with VC6
|
||||
// each of the compressed_pair versions that follow
|
||||
// have one template single-argument constructor
|
||||
// in place of two specific constructors:
|
||||
//
|
||||
|
||||
template <class T1, class T2>
|
||||
class compressed_pair;
|
||||
|
||||
namespace detail{
|
||||
|
||||
template <class A, class T1, class T2>
|
||||
struct best_conversion_traits
|
||||
{
|
||||
typedef char one;
|
||||
typedef char (&two)[2];
|
||||
static A a;
|
||||
static one test(T1);
|
||||
static two test(T2);
|
||||
|
||||
enum { value = sizeof(test(a)) };
|
||||
};
|
||||
|
||||
template <int>
|
||||
struct init_one;
|
||||
|
||||
template <>
|
||||
struct init_one<1>
|
||||
{
|
||||
template <class A, class T1, class T2>
|
||||
static void init(const A& a, T1* p1, T2*)
|
||||
{
|
||||
*p1 = a;
|
||||
}
|
||||
};
|
||||
|
||||
template <>
|
||||
struct init_one<2>
|
||||
{
|
||||
template <class A, class T1, class T2>
|
||||
static void init(const A& a, T1*, T2* p2)
|
||||
{
|
||||
*p2 = a;
|
||||
}
|
||||
};
|
||||
|
||||
|
||||
// T1 != T2, both non-empty
|
||||
template <class T1, class T2>
|
||||
class compressed_pair_0
|
||||
{
|
||||
private:
|
||||
T1 _first;
|
||||
T2 _second;
|
||||
public:
|
||||
typedef T1 first_type;
|
||||
typedef T2 second_type;
|
||||
typedef typename call_traits<first_type>::param_type first_param_type;
|
||||
typedef typename call_traits<second_type>::param_type second_param_type;
|
||||
typedef typename call_traits<first_type>::reference first_reference;
|
||||
typedef typename call_traits<second_type>::reference second_reference;
|
||||
typedef typename call_traits<first_type>::const_reference first_const_reference;
|
||||
typedef typename call_traits<second_type>::const_reference second_const_reference;
|
||||
|
||||
compressed_pair_0() : _first(), _second() {}
|
||||
compressed_pair_0(first_param_type x, second_param_type y) : _first(x), _second(y) {}
|
||||
template <class A>
|
||||
explicit compressed_pair_0(const A& val)
|
||||
{
|
||||
init_one<best_conversion_traits<A, T1, T2>::value>::init(val, &_first, &_second);
|
||||
}
|
||||
compressed_pair_0(const ::boost::compressed_pair<T1,T2>& x)
|
||||
: _first(x.first()), _second(x.second()) {}
|
||||
|
||||
#if 0
|
||||
compressed_pair_0& operator=(const compressed_pair_0& x) {
|
||||
cout << "assigning compressed pair 0" << endl;
|
||||
_first = x._first;
|
||||
_second = x._second;
|
||||
cout << "finished assigning compressed pair 0" << endl;
|
||||
return *this;
|
||||
}
|
||||
#endif
|
||||
|
||||
first_reference first() { return _first; }
|
||||
first_const_reference first() const { return _first; }
|
||||
|
||||
second_reference second() { return _second; }
|
||||
second_const_reference second() const { return _second; }
|
||||
|
||||
void swap(compressed_pair_0& y)
|
||||
{
|
||||
using std::swap;
|
||||
swap(_first, y._first);
|
||||
swap(_second, y._second);
|
||||
}
|
||||
};
|
||||
|
||||
// T1 != T2, T2 empty
|
||||
template <class T1, class T2>
|
||||
class compressed_pair_1 : T2
|
||||
{
|
||||
private:
|
||||
T1 _first;
|
||||
public:
|
||||
typedef T1 first_type;
|
||||
typedef T2 second_type;
|
||||
typedef typename call_traits<first_type>::param_type first_param_type;
|
||||
typedef typename call_traits<second_type>::param_type second_param_type;
|
||||
typedef typename call_traits<first_type>::reference first_reference;
|
||||
typedef typename call_traits<second_type>::reference second_reference;
|
||||
typedef typename call_traits<first_type>::const_reference first_const_reference;
|
||||
typedef typename call_traits<second_type>::const_reference second_const_reference;
|
||||
|
||||
compressed_pair_1() : T2(), _first() {}
|
||||
compressed_pair_1(first_param_type x, second_param_type y) : T2(y), _first(x) {}
|
||||
|
||||
template <class A>
|
||||
explicit compressed_pair_1(const A& val)
|
||||
{
|
||||
init_one<best_conversion_traits<A, T1, T2>::value>::init(val, &_first, static_cast<T2*>(this));
|
||||
}
|
||||
|
||||
compressed_pair_1(const ::boost::compressed_pair<T1,T2>& x)
|
||||
: T2(x.second()), _first(x.first()) {}
|
||||
|
||||
#ifdef BOOST_MSVC
|
||||
// Total weirdness. If the assignment to _first is moved after
|
||||
// the call to the inherited operator=, then this breaks graph/test/graph.cpp
|
||||
// by way of iterator_adaptor.
|
||||
compressed_pair_1& operator=(const compressed_pair_1& x) {
|
||||
_first = x._first;
|
||||
T2::operator=(x);
|
||||
return *this;
|
||||
}
|
||||
#endif
|
||||
|
||||
first_reference first() { return _first; }
|
||||
first_const_reference first() const { return _first; }
|
||||
|
||||
second_reference second() { return *this; }
|
||||
second_const_reference second() const { return *this; }
|
||||
|
||||
void swap(compressed_pair_1& y)
|
||||
{
|
||||
// no need to swap empty base class:
|
||||
using std::swap;
|
||||
swap(_first, y._first);
|
||||
}
|
||||
};
|
||||
|
||||
// T1 != T2, T1 empty
|
||||
template <class T1, class T2>
|
||||
class compressed_pair_2 : T1
|
||||
{
|
||||
private:
|
||||
T2 _second;
|
||||
public:
|
||||
typedef T1 first_type;
|
||||
typedef T2 second_type;
|
||||
typedef typename call_traits<first_type>::param_type first_param_type;
|
||||
typedef typename call_traits<second_type>::param_type second_param_type;
|
||||
typedef typename call_traits<first_type>::reference first_reference;
|
||||
typedef typename call_traits<second_type>::reference second_reference;
|
||||
typedef typename call_traits<first_type>::const_reference first_const_reference;
|
||||
typedef typename call_traits<second_type>::const_reference second_const_reference;
|
||||
|
||||
compressed_pair_2() : T1(), _second() {}
|
||||
compressed_pair_2(first_param_type x, second_param_type y) : T1(x), _second(y) {}
|
||||
template <class A>
|
||||
explicit compressed_pair_2(const A& val)
|
||||
{
|
||||
init_one<best_conversion_traits<A, T1, T2>::value>::init(val, static_cast<T1*>(this), &_second);
|
||||
}
|
||||
compressed_pair_2(const ::boost::compressed_pair<T1,T2>& x)
|
||||
: T1(x.first()), _second(x.second()) {}
|
||||
|
||||
#if 0
|
||||
compressed_pair_2& operator=(const compressed_pair_2& x) {
|
||||
cout << "assigning compressed pair 2" << endl;
|
||||
T1::operator=(x);
|
||||
_second = x._second;
|
||||
cout << "finished assigning compressed pair 2" << endl;
|
||||
return *this;
|
||||
}
|
||||
#endif
|
||||
first_reference first() { return *this; }
|
||||
first_const_reference first() const { return *this; }
|
||||
|
||||
second_reference second() { return _second; }
|
||||
second_const_reference second() const { return _second; }
|
||||
|
||||
void swap(compressed_pair_2& y)
|
||||
{
|
||||
// no need to swap empty base class:
|
||||
using std::swap;
|
||||
swap(_second, y._second);
|
||||
}
|
||||
};
|
||||
|
||||
// T1 != T2, both empty
|
||||
template <class T1, class T2>
|
||||
class compressed_pair_3 : T1, T2
|
||||
{
|
||||
public:
|
||||
typedef T1 first_type;
|
||||
typedef T2 second_type;
|
||||
typedef typename call_traits<first_type>::param_type first_param_type;
|
||||
typedef typename call_traits<second_type>::param_type second_param_type;
|
||||
typedef typename call_traits<first_type>::reference first_reference;
|
||||
typedef typename call_traits<second_type>::reference second_reference;
|
||||
typedef typename call_traits<first_type>::const_reference first_const_reference;
|
||||
typedef typename call_traits<second_type>::const_reference second_const_reference;
|
||||
|
||||
compressed_pair_3() : T1(), T2() {}
|
||||
compressed_pair_3(first_param_type x, second_param_type y) : T1(x), T2(y) {}
|
||||
template <class A>
|
||||
explicit compressed_pair_3(const A& val)
|
||||
{
|
||||
init_one<best_conversion_traits<A, T1, T2>::value>::init(val, static_cast<T1*>(this), static_cast<T2*>(this));
|
||||
}
|
||||
compressed_pair_3(const ::boost::compressed_pair<T1,T2>& x)
|
||||
: T1(x.first()), T2(x.second()) {}
|
||||
|
||||
first_reference first() { return *this; }
|
||||
first_const_reference first() const { return *this; }
|
||||
|
||||
second_reference second() { return *this; }
|
||||
second_const_reference second() const { return *this; }
|
||||
|
||||
void swap(compressed_pair_3& y)
|
||||
{
|
||||
// no need to swap empty base classes:
|
||||
}
|
||||
};
|
||||
|
||||
// T1 == T2, and empty
|
||||
template <class T1, class T2>
|
||||
class compressed_pair_4 : T1
|
||||
{
|
||||
public:
|
||||
typedef T1 first_type;
|
||||
typedef T2 second_type;
|
||||
typedef typename call_traits<first_type>::param_type first_param_type;
|
||||
typedef typename call_traits<second_type>::param_type second_param_type;
|
||||
typedef typename call_traits<first_type>::reference first_reference;
|
||||
typedef typename call_traits<second_type>::reference second_reference;
|
||||
typedef typename call_traits<first_type>::const_reference first_const_reference;
|
||||
typedef typename call_traits<second_type>::const_reference second_const_reference;
|
||||
|
||||
compressed_pair_4() : T1() {}
|
||||
compressed_pair_4(first_param_type x, second_param_type) : T1(x) {}
|
||||
// only one single argument constructor since T1 == T2
|
||||
explicit compressed_pair_4(first_param_type x) : T1(x) {}
|
||||
compressed_pair_4(const ::boost::compressed_pair<T1,T2>& x)
|
||||
: T1(x.first()){}
|
||||
|
||||
first_reference first() { return *this; }
|
||||
first_const_reference first() const { return *this; }
|
||||
|
||||
second_reference second() { return *this; }
|
||||
second_const_reference second() const { return *this; }
|
||||
|
||||
void swap(compressed_pair_4& y)
|
||||
{
|
||||
// no need to swap empty base classes:
|
||||
}
|
||||
};
|
||||
|
||||
// T1 == T2, not empty
|
||||
template <class T1, class T2>
|
||||
class compressed_pair_5
|
||||
{
|
||||
private:
|
||||
T1 _first;
|
||||
T2 _second;
|
||||
public:
|
||||
typedef T1 first_type;
|
||||
typedef T2 second_type;
|
||||
typedef typename call_traits<first_type>::param_type first_param_type;
|
||||
typedef typename call_traits<second_type>::param_type second_param_type;
|
||||
typedef typename call_traits<first_type>::reference first_reference;
|
||||
typedef typename call_traits<second_type>::reference second_reference;
|
||||
typedef typename call_traits<first_type>::const_reference first_const_reference;
|
||||
typedef typename call_traits<second_type>::const_reference second_const_reference;
|
||||
|
||||
compressed_pair_5() : _first(), _second() {}
|
||||
compressed_pair_5(first_param_type x, second_param_type y) : _first(x), _second(y) {}
|
||||
// only one single argument constructor since T1 == T2
|
||||
explicit compressed_pair_5(first_param_type x) : _first(x), _second(x) {}
|
||||
compressed_pair_5(const ::boost::compressed_pair<T1,T2>& c)
|
||||
: _first(c.first()), _second(c.second()) {}
|
||||
|
||||
first_reference first() { return _first; }
|
||||
first_const_reference first() const { return _first; }
|
||||
|
||||
second_reference second() { return _second; }
|
||||
second_const_reference second() const { return _second; }
|
||||
|
||||
void swap(compressed_pair_5& y)
|
||||
{
|
||||
using std::swap;
|
||||
swap(_first, y._first);
|
||||
swap(_second, y._second);
|
||||
}
|
||||
};
|
||||
|
||||
template <bool e1, bool e2, bool same>
|
||||
struct compressed_pair_chooser
|
||||
{
|
||||
template <class T1, class T2>
|
||||
struct rebind
|
||||
{
|
||||
typedef compressed_pair_0<T1, T2> type;
|
||||
};
|
||||
};
|
||||
|
||||
template <>
|
||||
struct compressed_pair_chooser<false, true, false>
|
||||
{
|
||||
template <class T1, class T2>
|
||||
struct rebind
|
||||
{
|
||||
typedef compressed_pair_1<T1, T2> type;
|
||||
};
|
||||
};
|
||||
|
||||
template <>
|
||||
struct compressed_pair_chooser<true, false, false>
|
||||
{
|
||||
template <class T1, class T2>
|
||||
struct rebind
|
||||
{
|
||||
typedef compressed_pair_2<T1, T2> type;
|
||||
};
|
||||
};
|
||||
|
||||
template <>
|
||||
struct compressed_pair_chooser<true, true, false>
|
||||
{
|
||||
template <class T1, class T2>
|
||||
struct rebind
|
||||
{
|
||||
typedef compressed_pair_3<T1, T2> type;
|
||||
};
|
||||
};
|
||||
|
||||
template <>
|
||||
struct compressed_pair_chooser<true, true, true>
|
||||
{
|
||||
template <class T1, class T2>
|
||||
struct rebind
|
||||
{
|
||||
typedef compressed_pair_4<T1, T2> type;
|
||||
};
|
||||
};
|
||||
|
||||
template <>
|
||||
struct compressed_pair_chooser<false, false, true>
|
||||
{
|
||||
template <class T1, class T2>
|
||||
struct rebind
|
||||
{
|
||||
typedef compressed_pair_5<T1, T2> type;
|
||||
};
|
||||
};
|
||||
|
||||
template <class T1, class T2>
|
||||
struct compressed_pair_traits
|
||||
{
|
||||
private:
|
||||
typedef compressed_pair_chooser<is_empty<T1>::value, is_empty<T2>::value, is_same<T1,T2>::value> chooser;
|
||||
typedef typename chooser::template rebind<T1, T2> bound_type;
|
||||
public:
|
||||
typedef typename bound_type::type type;
|
||||
};
|
||||
|
||||
} // namespace detail
|
||||
|
||||
template <class T1, class T2>
|
||||
class compressed_pair : public detail::compressed_pair_traits<T1, T2>::type
|
||||
{
|
||||
private:
|
||||
typedef typename detail::compressed_pair_traits<T1, T2>::type base_type;
|
||||
public:
|
||||
typedef T1 first_type;
|
||||
typedef T2 second_type;
|
||||
typedef typename call_traits<first_type>::param_type first_param_type;
|
||||
typedef typename call_traits<second_type>::param_type second_param_type;
|
||||
typedef typename call_traits<first_type>::reference first_reference;
|
||||
typedef typename call_traits<second_type>::reference second_reference;
|
||||
typedef typename call_traits<first_type>::const_reference first_const_reference;
|
||||
typedef typename call_traits<second_type>::const_reference second_const_reference;
|
||||
|
||||
compressed_pair() : base_type() {}
|
||||
compressed_pair(first_param_type x, second_param_type y) : base_type(x, y) {}
|
||||
template <class A>
|
||||
explicit compressed_pair(const A& x) : base_type(x){}
|
||||
|
||||
first_reference first() { return base_type::first(); }
|
||||
first_const_reference first() const { return base_type::first(); }
|
||||
|
||||
second_reference second() { return base_type::second(); }
|
||||
second_const_reference second() const { return base_type::second(); }
|
||||
};
|
||||
|
||||
template <class T1, class T2>
|
||||
inline void swap(compressed_pair<T1, T2>& x, compressed_pair<T1, T2>& y)
|
||||
{
|
||||
x.swap(y);
|
||||
}
|
||||
|
||||
#else
|
||||
// no partial specialisation, no member templates:
|
||||
|
||||
template <class T1, class T2>
|
||||
class compressed_pair
|
||||
@@ -72,7 +499,11 @@ inline void swap(compressed_pair<T1, T2>& x, compressed_pair<T1, T2>& y)
|
||||
x.swap(y);
|
||||
}
|
||||
|
||||
#endif
|
||||
|
||||
} // boost
|
||||
|
||||
#endif // BOOST_OB_COMPRESSED_PAIR_HPP
|
||||
|
||||
|
||||
|
||||
|
@@ -15,6 +15,8 @@
|
||||
// See http://www.boost.org for most recent version including documentation.
|
||||
|
||||
// Revision History
|
||||
// 11 Feb 01 Fixed bugs in the iterator helpers which prevented explicitly
|
||||
// supplied arguments from actually being used (Dave Abrahams)
|
||||
// 04 Jul 00 Fixed NO_OPERATORS_IN_NAMESPACE bugs, major cleanup and
|
||||
// refactoring of compiler workarounds, additional documentation
|
||||
// (Alexy Gurtovoy and Mark Rodgers with some help and prompting from
|
||||
@@ -69,6 +71,10 @@
|
||||
#pragma set woff 1234
|
||||
#endif
|
||||
|
||||
#if defined(BOOST_MSVC)
|
||||
# pragma warning( disable : 4284 ) // complaint about return type of
|
||||
#endif // operator-> not begin a UDT
|
||||
|
||||
namespace boost {
|
||||
namespace detail {
|
||||
|
||||
@@ -510,7 +516,7 @@ struct forward_iterator_helper
|
||||
: equality_comparable<T
|
||||
, incrementable<T
|
||||
, dereferenceable<T,P
|
||||
, boost::iterator<std::forward_iterator_tag, V, D
|
||||
, boost::iterator<std::forward_iterator_tag,V,D,P,R
|
||||
> > > > {};
|
||||
|
||||
template <class T,
|
||||
@@ -523,7 +529,7 @@ struct bidirectional_iterator_helper
|
||||
, incrementable<T
|
||||
, decrementable<T
|
||||
, dereferenceable<T,P
|
||||
, boost::iterator<std::bidirectional_iterator_tag, V, D
|
||||
, boost::iterator<std::bidirectional_iterator_tag,V,D,P,R
|
||||
> > > > > {};
|
||||
|
||||
template <class T,
|
||||
@@ -540,7 +546,7 @@ struct random_access_iterator_helper
|
||||
, addable2<T,D
|
||||
, subtractable2<T,D
|
||||
, indexable<T,D,R
|
||||
, boost::iterator<std::random_access_iterator_tag, V, D
|
||||
, boost::iterator<std::random_access_iterator_tag,V,D,P,R
|
||||
> > > > > > > > >
|
||||
{
|
||||
#ifndef __BORLANDC__
|
||||
|
@@ -24,6 +24,7 @@
|
||||
|
||||
#include <boost/config.hpp>
|
||||
#include <cstddef> // for size_t
|
||||
#include <utility> // for std::pair
|
||||
|
||||
namespace boost
|
||||
{
|
||||
@@ -63,6 +64,32 @@ namespace boost
|
||||
const noncopyable& operator=( const noncopyable& );
|
||||
}; // noncopyable
|
||||
|
||||
// class tied -------------------------------------------------------//
|
||||
|
||||
// A helper for conveniently assigning the two values from a pair
|
||||
// into separate variables. The idea for this comes from Jaakko J<>rvi's
|
||||
// Binder/Lambda Library.
|
||||
|
||||
// Constributed by Jeremy Siek
|
||||
|
||||
template <class A, class B>
|
||||
class tied {
|
||||
public:
|
||||
inline tied(A& a, B& b) : _a(a), _b(b) { }
|
||||
template <class U, class V>
|
||||
inline tied& operator=(const std::pair<U,V>& p) {
|
||||
_a = p.first;
|
||||
_b = p.second;
|
||||
return *this;
|
||||
}
|
||||
protected:
|
||||
A& _a;
|
||||
B& _b;
|
||||
};
|
||||
|
||||
template <class A, class B>
|
||||
inline tied<A,B> tie(A& a, B& b) { return tied<A,B>(a, b); }
|
||||
|
||||
} // namespace boost
|
||||
|
||||
#endif // BOOST_UTILITY_HPP
|
||||
|
72
index.htm
72
index.htm
@@ -1,72 +0,0 @@
|
||||
<html>
|
||||
|
||||
<head>
|
||||
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
|
||||
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
|
||||
<meta name="ProgId" content="FrontPage.Editor.Document">
|
||||
<title>Boost Utility Library</title>
|
||||
</head>
|
||||
|
||||
<body bgcolor="#FFFFFF" text="#000000">
|
||||
|
||||
<table border="1" cellpadding="2" bgcolor="#007F7F">
|
||||
<tr>
|
||||
<td bgcolor="#FFFFFF"><img src="../../c++boost.gif" alt="c++boost.gif (8819 bytes)" width="277" height="86"></td>
|
||||
<td><a href="../../index.htm"><font color="#FFFFFF" size="4" face="Arial">Home</font></a></td>
|
||||
<td><a href="../../libraries.htm"><font color="#FFFFFF" size="4" face="Arial">Libraries</font></a></td>
|
||||
<td><a href="../../people.htm"><font color="#FFFFFF" size="4" face="Arial">People</font></a></td>
|
||||
<td><a href="../../more/faq.htm"><font color="#FFFFFF" size="4" face="Arial">FAQ</font></a></td>
|
||||
<td><a href="../../more/index.htm"><font color="#FFFFFF" size="4" face="Arial">More</font></a></td>
|
||||
</tr>
|
||||
</table>
|
||||
<h1>Boost Utility Library</h1>
|
||||
<table border="1" cellpadding="5">
|
||||
<tr>
|
||||
<td><b><i>Header</i></b></td>
|
||||
<td><b><i>Contents</i></b></td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><a href="../../boost/utility.hpp"><code>boost/utility.hpp<br>
|
||||
</code></a><a href="utility.htm">[Documentation]</a></td>
|
||||
<td>Class <b>noncopyable</b> plus <b>next()</b> and <b>prior()</b> template
|
||||
functions.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><a href="../../boost/cast.hpp"><code>boost/cast.hpp</code></a><br>
|
||||
<a href="cast.htm">[Documentation]</a></td>
|
||||
<td><b>polymorphic_cast</b>, <b>implicit_cast</b>, and <b>numeric_cast</b>
|
||||
function templates.
|
||||
<p><i>[Beta.]</i></p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><a href="../../boost/operators.hpp">boost/operators.hpp</a><br>
|
||||
<a href="operators.htm">[Documentation]</a></td>
|
||||
<td>Templates <b>equality_comparable</b>, <b>less_than_comparable</b>, <b>addable</b>,
|
||||
and the like ease the task of defining comparison and arithmetic
|
||||
operators, and iterators.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><a href="../../boost/detail/type_traits.hpp">boost/type_traits.hpp</a><br>
|
||||
[<a href="type_traits.htm">Documentation</a>]</td>
|
||||
<td>Template classes that describe the fundamental properties of a type. [<a href="c++_type_traits.htm">DDJ
|
||||
Article "C++ type traits"</a>]</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><a href="../../boost/detail/call_traits.hpp">boost/call_traits.hpp</a><br>
|
||||
[<a href="call_traits.htm">Documentation</a>]</td>
|
||||
<td>Template class call_traits<T>, that defines types used for passing
|
||||
parameters to and from a proceedure.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td><a href="../../boost/detail/compressed_pair.hpp">boost/compressed_pair.hpp</a><br>
|
||||
[<a href="compressed_pair.htm">Documentation</a>]</td>
|
||||
<td>Template class compressed_pait<T1, T2> which pairs two values
|
||||
using the empty member optimisation where appropriate.</td>
|
||||
</tr>
|
||||
</table>
|
||||
<p>Revised <!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %B %Y" startspan -->27 July 2000<!--webbot bot="Timestamp" endspan i-checksum="18770" --></p>
|
||||
|
||||
</body>
|
||||
|
||||
</html>
|
443
indirect_iterator.htm
Normal file
443
indirect_iterator.htm
Normal file
@@ -0,0 +1,443 @@
|
||||
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 3.2//EN">
|
||||
|
||||
<html>
|
||||
<head>
|
||||
<meta name="generator" content="HTML Tidy, see www.w3.org">
|
||||
<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
|
||||
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
|
||||
<meta name="ProgId" content="FrontPage.Editor.Document">
|
||||
|
||||
<title>Indirect Iterator Adaptor Documentation</title>
|
||||
</head>
|
||||
|
||||
<body bgcolor="#FFFFFF" text="#000000">
|
||||
|
||||
<img src="../../c++boost.gif" alt="c++boost.gif (8819 bytes)" align=
|
||||
"center" width="277" height="86">
|
||||
|
||||
<h1>Indirect Iterator Adaptor</h1>
|
||||
Defined in header <a href=
|
||||
"../../boost/iterator_adaptors.hpp">boost/iterator_adaptors.hpp</a>
|
||||
|
||||
<p>The indirect iterator adaptor augments an iterator by applying an
|
||||
<b>extra</b> dereference inside of <tt>operator*()</tt>. For example, this
|
||||
iterator makes it possible to view a container of pointers or
|
||||
smart-pointers (e.g. <tt>std::list<boost::shared_ptr<foo>
|
||||
></tt>) as if it were a container of the pointed-to type. The following
|
||||
<b>pseudo-code</b> shows the basic idea of the indirect iterator:
|
||||
|
||||
<blockquote>
|
||||
<pre>
|
||||
// inside a hypothetical indirect_iterator class...
|
||||
typedef std::iterator_traits<BaseIterator>::value_type Pointer;
|
||||
typedef std::iterator_traits<Pointer>::reference reference;
|
||||
|
||||
reference indirect_iterator::operator*() const {
|
||||
return **this->base_iterator;
|
||||
}
|
||||
</pre>
|
||||
</blockquote>
|
||||
|
||||
<h2>Synopsis</h2>
|
||||
|
||||
<blockquote>
|
||||
<pre>
|
||||
namespace boost {
|
||||
template <class BaseIterator,
|
||||
class Value, class Reference, class Category, class Pointer>
|
||||
struct indirect_iterator_generator;
|
||||
|
||||
template <class BaseIterator,
|
||||
class Value, class Reference, class ConstReference,
|
||||
class Category, class Pointer, class ConstPointer>
|
||||
struct indirect_iterator_pair_generator;
|
||||
|
||||
template <class BaseIterator>
|
||||
typename indirect_iterator_generator<BaseIterator>::type
|
||||
make_indirect_iterator(BaseIterator base)
|
||||
}
|
||||
</pre>
|
||||
</blockquote>
|
||||
<hr>
|
||||
|
||||
<h2><a name="indirect_iterator_generator">The Indirect Iterator Type
|
||||
Generator</a></h2>
|
||||
The <tt>indirect_iterator_generator</tt> template is a <a href=
|
||||
"../../more/generic_programming.html#type_generator">generator</a> of
|
||||
indirect iterator types. The main template parameter for this class is the
|
||||
<tt>BaseIterator</tt> type that is being wrapped. In most cases the type of
|
||||
the elements being pointed to can be deduced using
|
||||
<tt>std::iterator_traits</tt>, but in some situations the user may want to
|
||||
override this type, so there are also template parameters that allow a user
|
||||
to control the <tt>value_type</tt>, <tt>pointer</tt>, and
|
||||
<tt>reference</tt> types of the resulting iterators.
|
||||
|
||||
<blockquote>
|
||||
<pre>
|
||||
template <class BaseIterator,
|
||||
class Value, class Reference, class Pointer>
|
||||
class indirect_iterator_generator
|
||||
{
|
||||
public:
|
||||
typedef <tt><a href=
|
||||
"./iterator_adaptors.htm#iterator_adaptor">iterator_adaptor</a><...></tt> type; // the resulting indirect iterator type
|
||||
};
|
||||
</pre>
|
||||
</blockquote>
|
||||
|
||||
<h3>Example</h3>
|
||||
This example uses the <tt>indirect_iterator_generator</tt> to create
|
||||
indirect iterators which dereference the pointers stored in the
|
||||
<tt>pointers_to_chars</tt> array to access the <tt>char</tt>s in the
|
||||
<tt>characters</tt> array.
|
||||
|
||||
<blockquote>
|
||||
<pre>
|
||||
#include <boost/config.hpp>
|
||||
#include <vector>
|
||||
#include <iostream>
|
||||
#include <iterator>
|
||||
#include <boost/iterator_adaptors.hpp>
|
||||
|
||||
int main(int, char*[])
|
||||
{
|
||||
char characters[] = "abcdefg";
|
||||
const int N = sizeof(characters)/sizeof(char) - 1; // -1 since characters has a null char
|
||||
char* pointers_to_chars[N]; // at the end.
|
||||
for (int i = 0; i < N; ++i)
|
||||
pointers_to_chars[i] = &characters[i];
|
||||
|
||||
boost::indirect_iterator_generator<char**, char>::type
|
||||
indirect_first(pointers_to_chars), indirect_last(pointers_to_chars + N);
|
||||
|
||||
std::copy(indirect_first, indirect_last, std::ostream_iterator<char>(std::cout, ","));
|
||||
std::cout << std::endl;
|
||||
|
||||
// to be continued...
|
||||
</pre>
|
||||
</blockquote>
|
||||
|
||||
<h3>Template Parameters</h3>
|
||||
|
||||
<table border>
|
||||
<tr>
|
||||
<th>Parameter
|
||||
|
||||
<th>Description
|
||||
|
||||
<tr>
|
||||
<td><tt>BaseIterator</tt>
|
||||
|
||||
<td>The iterator type being wrapped. The <tt>value_type</tt>
|
||||
of the base iterator should itself be dereferenceable.
|
||||
The return type of the <tt>operator*</tt> for the
|
||||
<tt>value_type</tt> should match the <tt>Reference</tt> type.
|
||||
|
||||
<tr>
|
||||
<td><tt>Value</tt>
|
||||
|
||||
<td>The <tt>value_type</tt> of the resulting iterator, unless const. If
|
||||
Value is <tt>const X</tt>, a conforming compiler makes the
|
||||
<tt>value_type</tt> <tt><i>non-</i>const X</tt><a href=
|
||||
"iterator_adaptors.htm#1">[1]</a>. Note that if the default
|
||||
is used for <tt>Value</tt>, then there must be a valid specialization
|
||||
of <tt>iterator_traits</tt> for the value type of the base iterator.
|
||||
<br>
|
||||
<b>Default:</b> <tt>std::iterator_traits<<br>
|
||||
<20> std::iterator_traits<BaseIterator>::value_type
|
||||
>::value_type</tt><a href="#2">[2]</a>
|
||||
|
||||
<tr>
|
||||
<td><tt>Reference</tt>
|
||||
|
||||
<td>The <tt>reference</tt> type of the resulting iterator, and in
|
||||
particular, the result type of <tt>operator*()</tt>.<br>
|
||||
<b>Default:</b> <tt>Value&</tt>
|
||||
|
||||
<tr>
|
||||
<td><tt>Pointer</tt>
|
||||
|
||||
<td>The <tt>pointer</tt> type of the resulting iterator, and in
|
||||
particular, the result type of <tt>operator->()</tt>.<br>
|
||||
<b>Default:</b> <tt>Value*</tt>
|
||||
|
||||
<tr>
|
||||
<td><tt>Category</tt>
|
||||
<td>The <tt>iterator_category</tt> type for the resulting iterator.<br>
|
||||
<b>Default:</b>
|
||||
<tt>std::iterator_traits<BaseIterator>::iterator_category</tt>
|
||||
|
||||
</table>
|
||||
|
||||
<h3>Concept Model</h3>
|
||||
The indirect iterator will model whichever <a href=
|
||||
"http://www.sgi.com/tech/stl/Iterators.html">standard iterator
|
||||
concept category</a> is modeled by the base iterator. Thus, if the
|
||||
base iterator is a model of <a href=
|
||||
"http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random
|
||||
Access Iterator</a> then so is the resulting indirect iterator. If
|
||||
the base iterator models a more restrictive concept, the resulting
|
||||
indirect iterator will model the same concept <a href="#3">[3]</a>.
|
||||
|
||||
<h3>Members</h3>
|
||||
The indirect iterator type implements the member functions and operators
|
||||
required of the <a href=
|
||||
"http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random Access
|
||||
Iterator</a> concept. In addition it has the following constructor:
|
||||
<pre>
|
||||
explicit indirect_iterator_generator::type(const BaseIterator& it)
|
||||
</pre>
|
||||
<br>
|
||||
<br>
|
||||
|
||||
<hr>
|
||||
|
||||
<p>
|
||||
|
||||
<h2><a name="indirect_iterator_pair_generator">The Indirect Iterator Pair
|
||||
Generator</a></h2>
|
||||
Sometimes a pair of <tt>const</tt>/non-<tt>const</tt> pair of iterators is
|
||||
needed, such as when implementing a container. The
|
||||
<tt>indirect_iterator_pair_generator</tt> class makes it more convenient to
|
||||
create this pair of iterator types.
|
||||
|
||||
<blockquote>
|
||||
<pre>
|
||||
template <class BaseIterator,
|
||||
class Value, class Pointer, class Reference,
|
||||
class ConstPointer, class ConstReference>
|
||||
class indirect_iterator_pair_generator
|
||||
{
|
||||
public:
|
||||
typedef <tt><a href=
|
||||
"./iterator_adaptors.htm#iterator_adaptor">iterator_adaptor</a><...></tt> iterator; // the mutable indirect iterator type
|
||||
typedef <tt><a href=
|
||||
"./iterator_adaptors.htm#iterator_adaptor">iterator_adaptor</a><...></tt> const_iterator; // the immutable indirect iterator type
|
||||
};
|
||||
</pre>
|
||||
</blockquote>
|
||||
|
||||
<h3>Example</h3>
|
||||
|
||||
<blockquote>
|
||||
<pre>
|
||||
// continuing from the last example...
|
||||
|
||||
typedef boost::indirect_iterator_pair_generator<char**,
|
||||
char, char*, char&, const char*, const char&> PairGen;
|
||||
|
||||
char mutable_characters[N];
|
||||
char* pointers_to_mutable_chars[N];
|
||||
for (int i = 0; i < N; ++i)
|
||||
pointers_to_mutable_chars[i] = &mutable_characters[i];
|
||||
|
||||
PairGen::iterator mutable_indirect_first(pointers_to_mutable_chars),
|
||||
mutable_indirect_last(pointers_to_mutable_chars + N);
|
||||
PairGen::const_iterator const_indirect_first(pointers_to_chars),
|
||||
const_indirect_last(pointers_to_chars + N);
|
||||
|
||||
std::transform(const_indirect_first, const_indirect_last,
|
||||
mutable_indirect_first, std::bind1st(std::plus<char>(), 1));
|
||||
|
||||
std::copy(mutable_indirect_first, mutable_indirect_last,
|
||||
std::ostream_iterator<char>(std::cout, ","));
|
||||
std::cout << std::endl;
|
||||
// to be continued...
|
||||
</pre>
|
||||
</blockquote>
|
||||
|
||||
<p>The output is:
|
||||
|
||||
<blockquote>
|
||||
<pre>
|
||||
b,c,d,e,f,g,h,
|
||||
</pre>
|
||||
</blockquote>
|
||||
|
||||
<h3>Template Parameters</h3>
|
||||
|
||||
<table border>
|
||||
<tr>
|
||||
<th>Parameter
|
||||
|
||||
<th>Description
|
||||
|
||||
<tr>
|
||||
<td><tt>BaseIterator</tt>
|
||||
|
||||
<td>The iterator type being wrapped. The <tt>value_type</tt> of the
|
||||
base iterator should itself be dereferenceable.
|
||||
The return type of the <tt>operator*</tt> for the
|
||||
<tt>value_type</tt> should match the <tt>Reference</tt> type.
|
||||
|
||||
<tr>
|
||||
<td><tt>Value</tt>
|
||||
|
||||
<td>The <tt>value_type</tt> of the resulting iterators.
|
||||
If Value is <tt>const X</tt>, a conforming compiler makes the
|
||||
<tt>value_type</tt> <tt><i>non-</i>const X</tt><a href=
|
||||
"iterator_adaptors.htm#1">[1]</a>. Note that if the default
|
||||
is used for <tt>Value</tt>, then there must be a valid
|
||||
specialization of <tt>iterator_traits</tt> for the value type
|
||||
of the base iterator.<br>
|
||||
|
||||
<b>Default:</b> <tt>std::iterator_traits<<br>
|
||||
<20> std::iterator_traits<BaseIterator>::value_type
|
||||
>::value_type</tt><a href="#2">[2]</a>
|
||||
|
||||
<tr>
|
||||
<td><tt>Reference</tt>
|
||||
|
||||
<td>The <tt>reference</tt> type of the resulting <tt>iterator</tt>, and
|
||||
in particular, the result type of its <tt>operator*()</tt>.<br>
|
||||
<b>Default:</b> <tt>Value&</tt>
|
||||
|
||||
<tr>
|
||||
<td><tt>Pointer</tt>
|
||||
|
||||
<td>The <tt>pointer</tt> type of the resulting <tt>iterator</tt>, and
|
||||
in particular, the result type of its <tt>operator->()</tt>.<br>
|
||||
<b>Default:</b> <tt>Value*</tt>
|
||||
|
||||
<tr>
|
||||
<td><tt>ConstReference</tt>
|
||||
|
||||
<td>The <tt>reference</tt> type of the resulting
|
||||
<tt>const_iterator</tt>, and in particular, the result type of its
|
||||
<tt>operator*()</tt>.<br>
|
||||
<b>Default:</b> <tt>const Value&</tt>
|
||||
|
||||
<tr>
|
||||
<td><tt>ConstPointer</tt>
|
||||
|
||||
<td>The <tt>pointer</tt> type of the resulting <tt>const_iterator</tt>,
|
||||
and in particular, the result type of its <tt>operator->()</tt>.<br>
|
||||
<b>Default:</b> <tt>const Value*</tt>
|
||||
|
||||
<tr>
|
||||
<td><tt>Category</tt>
|
||||
<td>The <tt>iterator_category</tt> type for the resulting iterator.<br>
|
||||
<b>Default:</b>
|
||||
<tt>std::iterator_traits<BaseIterator>::iterator_category</tt>
|
||||
</table>
|
||||
|
||||
<h3>Concept Model</h3>
|
||||
|
||||
The indirect iterators will model whichever <a href=
|
||||
"http://www.sgi.com/tech/stl/Iterators.html">standard iterator
|
||||
concept category</a> is modeled by the base iterator. Thus, if the
|
||||
base iterator is a model of <a href=
|
||||
"http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random
|
||||
Access Iterator</a> then so are the resulting indirect
|
||||
iterators. If the base iterator models a more restrictive concept,
|
||||
the resulting indirect iterators will model the same concept <a
|
||||
href="#3">[3]</a>.
|
||||
|
||||
|
||||
<h3>Members</h3>
|
||||
The resulting <tt>iterator</tt> and <tt>const_iterator</tt> types implement
|
||||
the member functions and operators required of the <a href=
|
||||
"http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random Access
|
||||
Iterator</a> concept. In addition they support the following constructors:
|
||||
|
||||
<blockquote>
|
||||
<pre>
|
||||
explicit indirect_iterator_pair_generator::iterator(const BaseIterator& it)
|
||||
explicit indirect_iterator_pair_generator::const_iterator(const BaseIterator& it)
|
||||
</pre>
|
||||
</blockquote>
|
||||
<br>
|
||||
<br>
|
||||
|
||||
<hr>
|
||||
|
||||
<p>
|
||||
|
||||
<h2><a name="make_indirect_iterator">The Indirect Iterator Object
|
||||
Generator</a></h2>
|
||||
The <tt>make_indirect_iterator()</tt> function provides a more convenient
|
||||
way to create indirect iterator objects. The function saves the user the
|
||||
trouble of explicitly writing out the iterator types.
|
||||
|
||||
<blockquote>
|
||||
<pre>
|
||||
template <class BaseIterator>
|
||||
typename indirect_iterator_generator<BaseIterator>::type
|
||||
make_indirect_iterator(BaseIterator base)
|
||||
</pre>
|
||||
</blockquote>
|
||||
|
||||
<h3>Example</h3>
|
||||
Here we again print the <tt>char</tt>s from the array <tt>characters</tt>
|
||||
by accessing them through the array of pointers <tt>pointer_to_chars</tt>,
|
||||
but this time we use the <tt>make_indirect_iterator()</tt> function which
|
||||
saves us some typing.
|
||||
|
||||
<blockquote>
|
||||
<pre>
|
||||
// continuing from the last example...
|
||||
|
||||
std::copy(boost::make_indirect_iterator(pointers_to_chars),
|
||||
boost::make_indirect_iterator(pointers_to_chars + N),
|
||||
std::ostream_iterator<char>(std::cout, ","));
|
||||
std::cout << std::endl;
|
||||
|
||||
return 0;
|
||||
}
|
||||
</pre>
|
||||
</blockquote>
|
||||
The output is:
|
||||
|
||||
<blockquote>
|
||||
<pre>
|
||||
a,b,c,d,e,f,g,
|
||||
</pre>
|
||||
</blockquote>
|
||||
<hr>
|
||||
|
||||
<h3>Notes</h3>
|
||||
|
||||
<p>
|
||||
|
||||
<p><a name="2">[2]</a> If your compiler does not support partial
|
||||
specialization and the base iterator or its <tt>value_type</tt> is a
|
||||
builtin pointer type, you will not be able to use the default for
|
||||
<tt>Value</tt> and will need to specify this type explicitly.
|
||||
|
||||
<p><a name="3">[3]</a>There is a caveat to which concept the
|
||||
indirect iterator can model. If the return type of the
|
||||
<tt>operator*</tt> for the base iterator's value type is not a
|
||||
true reference, then strickly speaking, the indirect iterator can
|
||||
not be a model of <a href=
|
||||
"http://www.sgi.com/tech/stl/ForwardIterator.html">Forward
|
||||
Iterator</a> or any of the concepts that refine it. In this case
|
||||
the <tt>Category</tt> for the indirect iterator should be
|
||||
specified as <tt>std::input_iterator_tag</tt>. However, even in
|
||||
this case, if the base iterator is a random access iterator, the
|
||||
resulting indirect iterator will still satisfy most of the
|
||||
requirements for <a href=
|
||||
"http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random
|
||||
Access Iterator</a>.
|
||||
|
||||
<hr>
|
||||
|
||||
<p>Revised
|
||||
<!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %b %Y" startspan -->28 Feb 2001<!--webbot bot="Timestamp" endspan i-checksum="14390" -->
|
||||
|
||||
|
||||
<p>© Copyright Jeremy Siek and David Abrahams 2001. Permission to
|
||||
copy, use, modify, sell and distribute this document is granted provided
|
||||
this copyright notice appears in all copies. This document is provided "as
|
||||
is" without express or implied warranty, and with no claim as to its
|
||||
suitability for any purpose.
|
||||
<!-- LocalWords: html charset alt gif hpp BaseIterator const namespace struct
|
||||
-->
|
||||
|
||||
<!-- LocalWords: ConstPointer ConstReference typename iostream int abcdefg
|
||||
-->
|
||||
<!-- LocalWords: sizeof PairGen pre Jeremy Siek David Abrahams
|
||||
-->
|
||||
|
||||
|
||||
</body>
|
||||
</html>
|
61
indirect_iterator_example.cpp
Normal file
61
indirect_iterator_example.cpp
Normal file
@@ -0,0 +1,61 @@
|
||||
// (C) Copyright Jeremy Siek 2000. Permission to copy, use, modify, sell and
|
||||
// distribute this software is granted provided this copyright notice appears
|
||||
// in all copies. This software is provided "as is" without express or implied
|
||||
// warranty, and with no claim as to its suitability for any purpose.
|
||||
|
||||
#include <boost/config.hpp>
|
||||
#include <vector>
|
||||
#include <iostream>
|
||||
#include <iterator>
|
||||
#include <functional>
|
||||
#include <boost/iterator_adaptors.hpp>
|
||||
|
||||
int main(int, char*[])
|
||||
{
|
||||
char characters[] = "abcdefg";
|
||||
const int N = sizeof(characters)/sizeof(char) - 1; // -1 since characters has a null char
|
||||
char* pointers_to_chars[N]; // at the end.
|
||||
for (int i = 0; i < N; ++i)
|
||||
pointers_to_chars[i] = &characters[i];
|
||||
|
||||
// Example of using indirect_iterator_generator
|
||||
|
||||
boost::indirect_iterator_generator<char**, char>::type
|
||||
indirect_first(pointers_to_chars), indirect_last(pointers_to_chars + N);
|
||||
|
||||
std::copy(indirect_first, indirect_last, std::ostream_iterator<char>(std::cout, ","));
|
||||
std::cout << std::endl;
|
||||
|
||||
|
||||
// Example of using indirect_iterator_pair_generator
|
||||
|
||||
typedef boost::indirect_iterator_pair_generator<char**,
|
||||
char, char*, char&, const char*, const char&> PairGen;
|
||||
|
||||
char mutable_characters[N];
|
||||
char* pointers_to_mutable_chars[N];
|
||||
for (int i = 0; i < N; ++i)
|
||||
pointers_to_mutable_chars[i] = &mutable_characters[i];
|
||||
|
||||
PairGen::iterator mutable_indirect_first(pointers_to_mutable_chars),
|
||||
mutable_indirect_last(pointers_to_mutable_chars + N);
|
||||
PairGen::const_iterator const_indirect_first(pointers_to_chars),
|
||||
const_indirect_last(pointers_to_chars + N);
|
||||
|
||||
std::transform(const_indirect_first, const_indirect_last,
|
||||
mutable_indirect_first, std::bind1st(std::plus<char>(), 1));
|
||||
|
||||
std::copy(mutable_indirect_first, mutable_indirect_last,
|
||||
std::ostream_iterator<char>(std::cout, ","));
|
||||
std::cout << std::endl;
|
||||
|
||||
|
||||
// Example of using make_indirect_iterator()
|
||||
|
||||
std::copy(boost::make_indirect_iterator(pointers_to_chars),
|
||||
boost::make_indirect_iterator(pointers_to_chars + N),
|
||||
std::ostream_iterator<char>(std::cout, ","));
|
||||
std::cout << std::endl;
|
||||
|
||||
return 0;
|
||||
}
|
151
indirect_iterator_test.cpp
Normal file
151
indirect_iterator_test.cpp
Normal file
@@ -0,0 +1,151 @@
|
||||
// (C) Copyright Jeremy Siek 1999. Permission to copy, use, modify,
|
||||
// sell and distribute this software is granted provided this
|
||||
// copyright notice appears in all copies. This software is provided
|
||||
// "as is" without express or implied warranty, and with no claim as
|
||||
// to its suitability for any purpose.
|
||||
|
||||
// Revision History
|
||||
// 08 Mar 2001 Jeremy Siek
|
||||
// Moved test of indirect iterator into its own file. It to
|
||||
// to be in iterator_adaptor_test.cpp.
|
||||
|
||||
#include <boost/config.hpp>
|
||||
#include <iostream>
|
||||
#include <algorithm>
|
||||
|
||||
#include <boost/iterator_adaptors.hpp>
|
||||
#include <boost/pending/iterator_tests.hpp>
|
||||
#include <boost/concept_archetype.hpp>
|
||||
#include <stdlib.h>
|
||||
#include <deque>
|
||||
#include <set>
|
||||
|
||||
struct my_iterator_tag : public std::random_access_iterator_tag { };
|
||||
|
||||
using boost::dummyT;
|
||||
|
||||
typedef std::deque<int> storage;
|
||||
typedef std::deque<int*> pointer_deque;
|
||||
typedef std::set<storage::iterator> iterator_set;
|
||||
|
||||
void more_indirect_iterator_tests()
|
||||
{
|
||||
// For some reason all heck breaks loose in the compiler under these conditions.
|
||||
#if !defined(BOOST_MSVC) || !defined(__STL_DEBUG)
|
||||
storage store(1000);
|
||||
std::generate(store.begin(), store.end(), rand);
|
||||
|
||||
pointer_deque ptr_deque;
|
||||
iterator_set iter_set;
|
||||
|
||||
for (storage::iterator p = store.begin(); p != store.end(); ++p)
|
||||
{
|
||||
ptr_deque.push_back(&*p);
|
||||
iter_set.insert(p);
|
||||
}
|
||||
|
||||
typedef boost::indirect_iterator_pair_generator<
|
||||
pointer_deque::iterator
|
||||
#ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
|
||||
, int
|
||||
#endif
|
||||
> IndirectDeque;
|
||||
|
||||
IndirectDeque::iterator db(ptr_deque.begin());
|
||||
IndirectDeque::iterator de(ptr_deque.end());
|
||||
assert(static_cast<std::size_t>(de - db) == store.size());
|
||||
assert(db + store.size() == de);
|
||||
IndirectDeque::const_iterator dci(db);
|
||||
assert(db == dci);
|
||||
assert(dci == db);
|
||||
assert(dci != de);
|
||||
assert(dci < de);
|
||||
assert(dci <= de);
|
||||
assert(de >= dci);
|
||||
assert(de > dci);
|
||||
dci = de;
|
||||
assert(dci == de);
|
||||
|
||||
boost::random_access_iterator_test(db + 1, store.size() - 1, boost::next(store.begin()));
|
||||
|
||||
*db = 999;
|
||||
assert(store.front() == 999);
|
||||
|
||||
// Borland C++ is getting very confused about the typedef's here
|
||||
|
||||
typedef boost::indirect_iterator_generator<
|
||||
iterator_set::iterator
|
||||
#ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
|
||||
, int
|
||||
#endif
|
||||
>::type indirect_set_iterator;
|
||||
|
||||
typedef boost::indirect_iterator_generator<
|
||||
iterator_set::iterator,
|
||||
const int
|
||||
>::type const_indirect_set_iterator;
|
||||
|
||||
indirect_set_iterator sb(iter_set.begin());
|
||||
indirect_set_iterator se(iter_set.end());
|
||||
const_indirect_set_iterator sci(iter_set.begin());
|
||||
assert(sci == sb);
|
||||
assert(sci != se);
|
||||
sci = se;
|
||||
assert(sci == se);
|
||||
|
||||
*boost::prior(se) = 888;
|
||||
assert(store.back() == 888);
|
||||
assert(std::equal(sb, se, store.begin()));
|
||||
|
||||
boost::bidirectional_iterator_test(boost::next(sb), store[1], store[2]);
|
||||
assert(std::equal(db, de, store.begin()));
|
||||
|
||||
#endif
|
||||
}
|
||||
|
||||
int
|
||||
main()
|
||||
{
|
||||
dummyT array[] = { dummyT(0), dummyT(1), dummyT(2),
|
||||
dummyT(3), dummyT(4), dummyT(5) };
|
||||
const int N = sizeof(array)/sizeof(dummyT);
|
||||
|
||||
// Test indirect_iterator_generator
|
||||
{
|
||||
dummyT* ptr[N];
|
||||
for (int k = 0; k < N; ++k)
|
||||
ptr[k] = array + k;
|
||||
|
||||
typedef boost::indirect_iterator_generator<dummyT**
|
||||
#ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
|
||||
, dummyT
|
||||
#endif
|
||||
>::type indirect_iterator;
|
||||
|
||||
typedef boost::indirect_iterator_generator<dummyT**, const dummyT>::type const_indirect_iterator;
|
||||
|
||||
indirect_iterator i(ptr);
|
||||
boost::random_access_iterator_test(i, N, array);
|
||||
|
||||
#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
|
||||
boost::random_access_iterator_test(boost::make_indirect_iterator(ptr), N, array);
|
||||
#endif
|
||||
|
||||
// check operator->
|
||||
assert((*i).m_x == i->foo());
|
||||
|
||||
const_indirect_iterator j(ptr);
|
||||
boost::random_access_iterator_test(j, N, array);
|
||||
|
||||
dummyT*const* const_ptr = ptr;
|
||||
|
||||
#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
|
||||
boost::random_access_iterator_test(boost::make_indirect_iterator(const_ptr), N, array);
|
||||
#endif
|
||||
boost::const_nonconst_iterator_test(i, ++j);
|
||||
|
||||
more_indirect_iterator_tests();
|
||||
}
|
||||
std::cout << "test successful " << std::endl;
|
||||
return 0;
|
||||
}
|
27
iter_adaptor_fail_expected1.cpp
Normal file
27
iter_adaptor_fail_expected1.cpp
Normal file
@@ -0,0 +1,27 @@
|
||||
// Test boost/pending/iterator_adaptors.hpp
|
||||
|
||||
// (C) Copyright Jeremy Siek 1999. Permission to copy, use, modify,
|
||||
// sell and distribute this software is granted provided this
|
||||
// copyright notice appears in all copies. This software is provided
|
||||
// "as is" without express or implied warranty, and with no claim as
|
||||
// to its suitability for any purpose.
|
||||
|
||||
// See http://www.boost.org for most recent version including documentation.
|
||||
|
||||
// Revision History
|
||||
// 21 Jan 01 Initial version (Jeremy Siek)
|
||||
|
||||
#include <boost/config.hpp>
|
||||
#include <list>
|
||||
#include <boost/pending/iterator_adaptors.hpp>
|
||||
|
||||
int main()
|
||||
{
|
||||
typedef boost::iterator_adaptor<std::list<int>::iterator,
|
||||
boost::default_iterator_policies,
|
||||
int,int&,int*,std::bidirectional_iterator_tag> adaptor_type;
|
||||
|
||||
adaptor_type i;
|
||||
i += 4;
|
||||
return 0;
|
||||
}
|
28
iter_adaptor_fail_expected2.cpp
Normal file
28
iter_adaptor_fail_expected2.cpp
Normal file
@@ -0,0 +1,28 @@
|
||||
// Test boost/pending/iterator_adaptors.hpp
|
||||
|
||||
// (C) Copyright Jeremy Siek 1999. Permission to copy, use, modify,
|
||||
// sell and distribute this software is granted provided this
|
||||
// copyright notice appears in all copies. This software is provided
|
||||
// "as is" without express or implied warranty, and with no claim as
|
||||
// to its suitability for any purpose.
|
||||
|
||||
// See http://www.boost.org for most recent version including documentation.
|
||||
|
||||
// Revision History
|
||||
// 21 Jan 01 Initial version (Jeremy Siek)
|
||||
|
||||
#include <boost/config.hpp>
|
||||
#include <iostream>
|
||||
#include <iterator>
|
||||
#include <boost/pending/iterator_adaptors.hpp>
|
||||
|
||||
int main()
|
||||
{
|
||||
typedef boost::iterator_adaptor<std::istream_iterator<int>,
|
||||
boost::default_iterator_policies,
|
||||
int,int&,int*,std::input_iterator_tag> adaptor_type;
|
||||
|
||||
adaptor_type iter;
|
||||
--iter;
|
||||
return 0;
|
||||
}
|
61
iter_traits_gen_test.cpp
Normal file
61
iter_traits_gen_test.cpp
Normal file
@@ -0,0 +1,61 @@
|
||||
// (C) Copyright Jeremy Siek 2000. Permission to copy, use, modify,
|
||||
// sell and distribute this software is granted provided this
|
||||
// copyright notice appears in all copies. This software is provided
|
||||
// "as is" without express or implied warranty, and with no claim as
|
||||
// to its suitability for any purpose.
|
||||
|
||||
// 8 Mar 2001 Jeremy Siek
|
||||
// Initial checkin.
|
||||
|
||||
#include <boost/iterator_adaptors.hpp>
|
||||
#include <boost/pending/iterator_tests.hpp>
|
||||
#include <boost/static_assert.hpp>
|
||||
|
||||
class bar { };
|
||||
void foo(bar) { }
|
||||
|
||||
int
|
||||
main()
|
||||
{
|
||||
using boost::dummyT;
|
||||
dummyT array[] = { dummyT(0), dummyT(1), dummyT(2),
|
||||
dummyT(3), dummyT(4), dummyT(5) };
|
||||
typedef boost::iterator_adaptor<dummyT*,
|
||||
boost::default_iterator_policies, dummyT> my_iter;
|
||||
my_iter mi(array);
|
||||
|
||||
{
|
||||
typedef boost::iterator_adaptor<my_iter, boost::default_iterator_policies,
|
||||
boost::iterator_traits_generator
|
||||
::reference<dummyT>
|
||||
::iterator_category<std::input_iterator_tag> > iter_type;
|
||||
|
||||
BOOST_STATIC_ASSERT((boost::is_same<iter_type::iterator_category*,
|
||||
std::input_iterator_tag*>::value));
|
||||
|
||||
BOOST_STATIC_ASSERT(( ! boost::is_convertible<iter_type::iterator_category*,
|
||||
std::forward_iterator_tag*>::value));
|
||||
|
||||
iter_type i(mi);
|
||||
boost::input_iterator_test(i, dummyT(0), dummyT(1));
|
||||
}
|
||||
{
|
||||
typedef boost::iterator_adaptor<dummyT*,
|
||||
boost::default_iterator_policies,
|
||||
boost::iterator_traits_generator
|
||||
::value_type<dummyT>
|
||||
::reference<const dummyT&>
|
||||
::pointer<const dummyT*>
|
||||
::iterator_category<std::forward_iterator_tag>
|
||||
::difference_type<std::ptrdiff_t> > adaptor_type;
|
||||
|
||||
adaptor_type i(array);
|
||||
|
||||
boost::input_iterator_test(i, dummyT(0), dummyT(1));
|
||||
int zero = 0;
|
||||
if (zero) // don't do this, just make sure it compiles
|
||||
assert((*i).m_x == i->foo());
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
47
iterator_adaptor_examples.cpp
Normal file
47
iterator_adaptor_examples.cpp
Normal file
@@ -0,0 +1,47 @@
|
||||
// (C) Copyright Jeremy Siek 2000. Permission to copy, use, modify, sell and
|
||||
// distribute this software is granted provided this copyright notice appears
|
||||
// in all copies. This software is provided "as is" without express or implied
|
||||
// warranty, and with no claim as to its suitability for any purpose.
|
||||
|
||||
|
||||
#include <functional>
|
||||
#include <algorithm>
|
||||
#include <iostream>
|
||||
#include <boost/pending/iterator_adaptors.hpp>
|
||||
#include <boost/pending/integer_range.hpp>
|
||||
|
||||
int
|
||||
main(int, char*[])
|
||||
{
|
||||
// This is a simple example of using the transform_iterators class to
|
||||
// generate iterators that multiply the value returned by dereferencing
|
||||
// the iterator. In this case we are multiplying by 2.
|
||||
// Would be cooler to use lambda library in this example.
|
||||
|
||||
int x[] = { 1, 2, 3, 4, 5, 6, 7, 8 };
|
||||
|
||||
typedef std::binder1st< std::multiplies<int> > Function;
|
||||
typedef boost::transform_iterator<Function, int*,
|
||||
boost::iterator<std::random_access_iterator_tag, int>
|
||||
>::type doubling_iterator;
|
||||
|
||||
doubling_iterator i(x, std::bind1st(std::multiplies<int>(), 2)),
|
||||
i_end(x + sizeof(x)/sizeof(int), std::bind1st(std::multiplies<int>(), 2));
|
||||
|
||||
std::cout << "multiplying the array by 2:" << std::endl;
|
||||
while (i != i_end)
|
||||
std::cout << *i++ << " ";
|
||||
std::cout << std::endl;
|
||||
|
||||
// Here is an example of counting from 0 to 5 using the integer_range class.
|
||||
|
||||
boost::integer_range<int> r(0,5);
|
||||
|
||||
std::cout << "counting to from 0 to 4:" << std::endl;
|
||||
std::copy(r.begin(), r.end(), std::ostream_iterator<int>(std::cout, " "));
|
||||
std::cout << std::endl;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
335
iterator_adaptor_test.cpp
Normal file
335
iterator_adaptor_test.cpp
Normal file
@@ -0,0 +1,335 @@
|
||||
// Test boost/iterator_adaptors.hpp
|
||||
|
||||
// (C) Copyright Jeremy Siek 1999. Permission to copy, use, modify,
|
||||
// sell and distribute this software is granted provided this
|
||||
// copyright notice appears in all copies. This software is provided
|
||||
// "as is" without express or implied warranty, and with no claim as
|
||||
// to its suitability for any purpose.
|
||||
|
||||
// See http://www.boost.org for most recent version including documentation.
|
||||
|
||||
// Revision History
|
||||
// 08 Mar 01 Moved indirect and transform tests to separate files.
|
||||
// (Jeremy Siek)
|
||||
// 19 Feb 01 Take adavantage of improved iterator_traits to do more tests
|
||||
// on MSVC. Hack around an MSVC-with-STLport internal compiler
|
||||
// error. (David Abrahams)
|
||||
// 11 Feb 01 Added test of operator-> for forward and input iterators.
|
||||
// (Jeremy Siek)
|
||||
// 11 Feb 01 Borland fixes (David Abrahams)
|
||||
// 10 Feb 01 Use new adaptors interface. (David Abrahams)
|
||||
// 10 Feb 01 Use new filter_ interface. (David Abrahams)
|
||||
// 09 Feb 01 Use new reverse_ and indirect_ interfaces. Replace
|
||||
// BOOST_NO_STD_ITERATOR_TRAITS with
|
||||
// BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION to prove we've
|
||||
// normalized to core compiler capabilities (David Abrahams)
|
||||
// 08 Feb 01 Use Jeremy's new make_reverse_iterator form; add more
|
||||
// comprehensive testing. Force-decay array function arguments to
|
||||
// pointers.
|
||||
// 07 Feb 01 Added tests for the make_xxx_iterator() helper functions.
|
||||
// (Jeremy Siek)
|
||||
// 07 Feb 01 Replaced use of xxx_pair_generator with xxx_generator where
|
||||
// possible (which was all but the projection iterator).
|
||||
// (Jeremy Siek)
|
||||
// 06 Feb 01 Removed now-defaulted template arguments where possible
|
||||
// Updated names to correspond to new generator naming convention.
|
||||
// Added a trivial test for make_transform_iterator().
|
||||
// Gave traits for const iterators a mutable value_type, per std.
|
||||
// Resurrected my original tests for indirect iterators.
|
||||
// (David Abrahams)
|
||||
// 04 Feb 01 Fix for compilers without standard iterator_traits
|
||||
// (David Abrahams)
|
||||
// 13 Jun 00 Added const version of the iterator tests (Jeremy Siek)
|
||||
// 12 Dec 99 Initial version with iterator operators (Jeremy Siek)
|
||||
|
||||
#include <boost/config.hpp>
|
||||
#include <iostream>
|
||||
|
||||
#include <algorithm>
|
||||
#include <functional>
|
||||
|
||||
#include <boost/iterator_adaptors.hpp>
|
||||
#include <boost/pending/iterator_tests.hpp>
|
||||
#include <boost/pending/integer_range.hpp>
|
||||
#include <boost/concept_archetype.hpp>
|
||||
#include <stdlib.h>
|
||||
#include <vector>
|
||||
#include <deque>
|
||||
#include <set>
|
||||
|
||||
struct my_iterator_tag : public std::random_access_iterator_tag { };
|
||||
|
||||
using boost::dummyT;
|
||||
|
||||
|
||||
struct mult_functor {
|
||||
typedef int result_type;
|
||||
typedef int argument_type;
|
||||
// Functors used with transform_iterator must be
|
||||
// DefaultConstructible, as the transform_iterator must be
|
||||
// DefaultConstructible to satisfy the requirements for
|
||||
// TrivialIterator.
|
||||
mult_functor() { }
|
||||
mult_functor(int aa) : a(aa) { }
|
||||
int operator()(int b) const { return a * b; }
|
||||
int a;
|
||||
};
|
||||
|
||||
template <class Pair>
|
||||
struct select1st_
|
||||
: public std::unary_function<Pair, typename Pair::first_type>
|
||||
{
|
||||
const typename Pair::first_type& operator()(const Pair& x) const {
|
||||
return x.first;
|
||||
}
|
||||
typename Pair::first_type& operator()(Pair& x) const {
|
||||
return x.first;
|
||||
}
|
||||
};
|
||||
|
||||
struct one_or_four {
|
||||
bool operator()(dummyT x) const {
|
||||
return x.foo() == 1 || x.foo() == 4;
|
||||
}
|
||||
};
|
||||
|
||||
typedef std::deque<int> storage;
|
||||
typedef std::deque<int*> pointer_deque;
|
||||
typedef std::set<storage::iterator> iterator_set;
|
||||
|
||||
int
|
||||
main()
|
||||
{
|
||||
dummyT array[] = { dummyT(0), dummyT(1), dummyT(2),
|
||||
dummyT(3), dummyT(4), dummyT(5) };
|
||||
const int N = sizeof(array)/sizeof(dummyT);
|
||||
|
||||
// sanity check, if this doesn't pass the test is buggy
|
||||
boost::random_access_iterator_test(array,N,array);
|
||||
|
||||
// Check that the policy concept checks and the default policy
|
||||
// implementation match up.
|
||||
boost::function_requires<
|
||||
boost::RandomAccessIteratorPoliciesConcept<
|
||||
boost::default_iterator_policies, int*,
|
||||
boost::iterator<std::random_access_iterator_tag, int, std::ptrdiff_t,
|
||||
int*, int&>
|
||||
> >();
|
||||
|
||||
// Test the iterator_adaptor
|
||||
{
|
||||
boost::iterator_adaptor<dummyT*, boost::default_iterator_policies, dummyT> i(array);
|
||||
boost::random_access_iterator_test(i, N, array);
|
||||
|
||||
boost::iterator_adaptor<const dummyT*, boost::default_iterator_policies, const dummyT> j(array);
|
||||
boost::random_access_iterator_test(j, N, array);
|
||||
boost::const_nonconst_iterator_test(i, ++j);
|
||||
}
|
||||
|
||||
// Test projection_iterator_pair_generator
|
||||
{
|
||||
typedef std::pair<dummyT,dummyT> Pair;
|
||||
Pair pair_array[N];
|
||||
for (int k = 0; k < N; ++k)
|
||||
pair_array[k].first = array[k];
|
||||
|
||||
typedef boost::projection_iterator_pair_generator<select1st_<Pair>,
|
||||
Pair*, const Pair*
|
||||
> Projection;
|
||||
|
||||
Projection::iterator i(pair_array);
|
||||
boost::random_access_iterator_test(i, N, array);
|
||||
|
||||
boost::random_access_iterator_test(boost::make_projection_iterator(pair_array, select1st_<Pair>()), N, array);
|
||||
boost::random_access_iterator_test(boost::make_projection_iterator< select1st_<Pair> >(pair_array), N, array);
|
||||
|
||||
Projection::const_iterator j(pair_array);
|
||||
boost::random_access_iterator_test(j, N, array);
|
||||
|
||||
boost::random_access_iterator_test(boost::make_const_projection_iterator(pair_array, select1st_<Pair>()), N, array);
|
||||
boost::random_access_iterator_test(boost::make_const_projection_iterator<select1st_<Pair> >(pair_array), N, array);
|
||||
|
||||
boost::const_nonconst_iterator_test(i, ++j);
|
||||
}
|
||||
|
||||
// Test reverse_iterator_generator
|
||||
{
|
||||
dummyT reversed[N];
|
||||
std::copy(array, array + N, reversed);
|
||||
std::reverse(reversed, reversed + N);
|
||||
|
||||
typedef boost::reverse_iterator_generator<dummyT*
|
||||
#ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
|
||||
, dummyT
|
||||
#endif
|
||||
>::type reverse_iterator;
|
||||
|
||||
reverse_iterator i(reversed + N);
|
||||
boost::random_access_iterator_test(i, N, array);
|
||||
|
||||
#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
|
||||
boost::random_access_iterator_test(boost::make_reverse_iterator(reversed + N), N, array);
|
||||
#endif
|
||||
|
||||
typedef boost::reverse_iterator_generator<const dummyT*
|
||||
#ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
|
||||
, const dummyT
|
||||
#endif
|
||||
>::type const_reverse_iterator;
|
||||
|
||||
const_reverse_iterator j(reversed + N);
|
||||
boost::random_access_iterator_test(j, N, array);
|
||||
|
||||
const dummyT* const_reversed = reversed;
|
||||
|
||||
#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
|
||||
boost::random_access_iterator_test(boost::make_reverse_iterator(const_reversed + N), N, array);
|
||||
#endif
|
||||
|
||||
boost::const_nonconst_iterator_test(i, ++j);
|
||||
}
|
||||
|
||||
// Test reverse_iterator_generator again, with traits fully deducible on all platforms
|
||||
{
|
||||
std::deque<dummyT> reversed_container;
|
||||
std::reverse_copy(array, array + N, std::back_inserter(reversed_container));
|
||||
const std::deque<dummyT>::iterator reversed = reversed_container.begin();
|
||||
|
||||
|
||||
typedef boost::reverse_iterator_generator<
|
||||
std::deque<dummyT>::iterator>::type reverse_iterator;
|
||||
typedef boost::reverse_iterator_generator<
|
||||
std::deque<dummyT>::const_iterator, const dummyT>::type const_reverse_iterator;
|
||||
|
||||
// MSVC/STLport gives an INTERNAL COMPILER ERROR when any computation
|
||||
// (e.g. "reversed + N") is used in the constructor below.
|
||||
const std::deque<dummyT>::iterator finish = reversed_container.end();
|
||||
reverse_iterator i(finish);
|
||||
|
||||
boost::random_access_iterator_test(i, N, array);
|
||||
boost::random_access_iterator_test(boost::make_reverse_iterator(reversed + N), N, array);
|
||||
|
||||
const_reverse_iterator j = reverse_iterator(finish);
|
||||
boost::random_access_iterator_test(j, N, array);
|
||||
|
||||
const std::deque<dummyT>::const_iterator const_reversed = reversed;
|
||||
boost::random_access_iterator_test(boost::make_reverse_iterator(const_reversed + N), N, array);
|
||||
|
||||
// Many compilers' builtin deque iterators don't interoperate well, though
|
||||
// STLport fixes that problem.
|
||||
#if defined(__SGI_STL_PORT) || !defined(__GNUC__) && !defined(__BORLANDC__) && !defined(BOOST_MSVC)
|
||||
boost::const_nonconst_iterator_test(i, ++j);
|
||||
#endif
|
||||
}
|
||||
|
||||
// Test integer_range's iterators
|
||||
{
|
||||
int int_array[] = { 0, 1, 2, 3, 4, 5 };
|
||||
boost::integer_range<int> r(0, 5);
|
||||
boost::random_access_iterator_test(r.begin(), r.size(), int_array);
|
||||
}
|
||||
|
||||
// Test filter iterator
|
||||
{
|
||||
// Using typedefs for filter_gen::type confused Borland terribly.
|
||||
typedef boost::detail::non_bidirectional_category<dummyT*>::type category;
|
||||
|
||||
typedef boost::filter_iterator_generator<one_or_four, dummyT*
|
||||
#ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
|
||||
, dummyT
|
||||
#endif
|
||||
>::type filter_iter;
|
||||
|
||||
#if defined(__BORLANDC__)
|
||||
// Borland is choking on accessing the policies_type explicitly
|
||||
// from the filter_iter.
|
||||
boost::forward_iterator_test(make_filter_iterator(array, array+N,
|
||||
one_or_four()),
|
||||
dummyT(1), dummyT(4));
|
||||
#else
|
||||
filter_iter i(array, filter_iter::policies_type(one_or_four(), array + N));
|
||||
boost::forward_iterator_test(i, dummyT(1), dummyT(4));
|
||||
#endif
|
||||
|
||||
#if !defined(__BORLANDC__)
|
||||
//
|
||||
enum { is_forward = boost::is_same<
|
||||
filter_iter::iterator_category,
|
||||
std::forward_iterator_tag>::value };
|
||||
BOOST_STATIC_ASSERT(is_forward);
|
||||
#endif
|
||||
|
||||
// On compilers not supporting partial specialization, we can do more type
|
||||
// deduction with deque iterators than with pointers... unless the library
|
||||
// is broken ;-(
|
||||
#if !defined(BOOST_MSVC) || defined(__SGI_STL_PORT)
|
||||
std::deque<dummyT> array2;
|
||||
std::copy(array+0, array+N, std::back_inserter(array2));
|
||||
boost::forward_iterator_test(
|
||||
boost::make_filter_iterator(array2.begin(), array2.end(), one_or_four()),
|
||||
dummyT(1), dummyT(4));
|
||||
|
||||
boost::forward_iterator_test(
|
||||
boost::make_filter_iterator<one_or_four>(array2.begin(), array2.end()),
|
||||
dummyT(1), dummyT(4));
|
||||
#endif
|
||||
|
||||
#if !defined(BOOST_MSVC) // This just freaks MSVC out completely
|
||||
boost::forward_iterator_test(
|
||||
boost::make_filter_iterator<one_or_four>(
|
||||
boost::make_reverse_iterator(array2.end()),
|
||||
boost::make_reverse_iterator(array2.begin())
|
||||
),
|
||||
dummyT(4), dummyT(1));
|
||||
#endif
|
||||
|
||||
#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
|
||||
boost::forward_iterator_test(
|
||||
boost::make_filter_iterator(array+0, array+N, one_or_four()),
|
||||
dummyT(1), dummyT(4));
|
||||
|
||||
boost::forward_iterator_test(
|
||||
boost::make_filter_iterator<one_or_four>(array, array + N),
|
||||
dummyT(1), dummyT(4));
|
||||
|
||||
#endif
|
||||
}
|
||||
|
||||
// check operator-> with a forward iterator
|
||||
{
|
||||
boost::forward_iterator_archetype<dummyT> forward_iter;
|
||||
#if defined(__BORLANDC__)
|
||||
typedef boost::iterator_adaptor<boost::forward_iterator_archetype<dummyT>,
|
||||
boost::default_iterator_policies,
|
||||
dummyT, const dummyT&, const dummyT*,
|
||||
std::forward_iterator_tag, std::ptrdiff_t> adaptor_type;
|
||||
#else
|
||||
typedef boost::iterator_adaptor<boost::forward_iterator_archetype<dummyT>,
|
||||
boost::default_iterator_policies,
|
||||
boost::iterator_traits_generator
|
||||
::value_type<dummyT>
|
||||
::reference<const dummyT&>
|
||||
::pointer<const dummyT*>
|
||||
::iterator_category<std::forward_iterator_tag>
|
||||
::difference_type<std::ptrdiff_t> > adaptor_type;
|
||||
#endif
|
||||
adaptor_type i(forward_iter);
|
||||
int zero = 0;
|
||||
if (zero) // don't do this, just make sure it compiles
|
||||
assert((*i).m_x == i->foo());
|
||||
}
|
||||
// check operator-> with an input iterator
|
||||
{
|
||||
boost::input_iterator_archetype<dummyT> input_iter;
|
||||
typedef boost::iterator_adaptor<boost::input_iterator_archetype<dummyT>,
|
||||
boost::default_iterator_policies,
|
||||
dummyT, const dummyT&, const dummyT*,
|
||||
std::input_iterator_tag, std::ptrdiff_t> adaptor_type;
|
||||
adaptor_type i(input_iter);
|
||||
int zero = 0;
|
||||
if (zero) // don't do this, just make sure it compiles
|
||||
assert((*i).m_x == i->foo());
|
||||
}
|
||||
std::cout << "test successful " << std::endl;
|
||||
return 0;
|
||||
}
|
863
iterator_adaptors.htm
Normal file
863
iterator_adaptors.htm
Normal file
@@ -0,0 +1,863 @@
|
||||
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
|
||||
|
||||
<html>
|
||||
<head>
|
||||
<meta name="generator" content="HTML Tidy, see www.w3.org">
|
||||
<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
|
||||
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
|
||||
<meta name="ProgId" content="FrontPage.Editor.Document">
|
||||
|
||||
<title>Boost Iterator Adaptor Library</title>
|
||||
</head>
|
||||
|
||||
<body bgcolor="#FFFFFF" text="#000000">
|
||||
|
||||
<img src="../../c++boost.gif" alt="c++boost.gif (8819 bytes)" align=
|
||||
"center" width="277" height="86">
|
||||
|
||||
<h1>Boost Iterator Adaptor Library</h1>
|
||||
|
||||
<h2>Introduction</h2>
|
||||
|
||||
<p>The Iterator Adaptor library allows you transform an arbitrary ``base''
|
||||
type into a standard-conforming iterator with the behaviors you choose.
|
||||
Doing so is especially easy if the ``base'' type is itself an iterator. The
|
||||
library also supplies several example <a href=
|
||||
"../../more/generic_programming.html#adaptors">adaptors</a> which apply
|
||||
specific useful behaviors to arbitrary base iterators.
|
||||
|
||||
<h2>Table of Contents</h2>
|
||||
|
||||
<ul>
|
||||
<li>
|
||||
Header <tt><a href=
|
||||
"../../boost/iterator_adaptors.hpp">boost/iterator_adaptors.hpp</a></tt>
|
||||
|
||||
|
||||
<ul>
|
||||
<li>
|
||||
Generalized Iterator Adaptor
|
||||
|
||||
<ul>
|
||||
<li>Class template <tt><a href=
|
||||
"#iterator_adaptor">iterator_adaptor</a></tt>
|
||||
|
||||
<li><a href="#template_parameters">Template Parameters</a>
|
||||
|
||||
<li><a href="#named_template_parameters">Named Template Parameters</a>
|
||||
|
||||
<li><a href="#policies">The Policies Class</a>
|
||||
|
||||
<li><a href="#additional_members">Additional Class Members</a>
|
||||
|
||||
<li><a href="#example">Example</a>
|
||||
|
||||
<li>(<tt>const</tt>/non-<tt>const</tt>) <a href=
|
||||
"#iterator_interactions">Iterator Interactions</a>
|
||||
|
||||
<li><a href="#challenge">Challenge</a>
|
||||
|
||||
<li><a href="#concept_model">Concept Model</a>
|
||||
|
||||
<li><a href="#declaration_synopsis">Declaration Synopsis</a>
|
||||
|
||||
<li><a href="#notes">Notes</a>
|
||||
</ul>
|
||||
|
||||
<li>
|
||||
<a name="specialized_adaptors">Specialized Iterator Adaptors</a>
|
||||
|
||||
<ul>
|
||||
<li><a href="indirect_iterator.htm">Indirect Iterator Adaptor</a>
|
||||
|
||||
<li><a href="reverse_iterator.htm">Reverse Iterator Adaptor</a>
|
||||
|
||||
<li><a href="transform_iterator.htm">Transform Iterator
|
||||
Adaptor</a>
|
||||
|
||||
<li><a href="projection_iterator.htm">Projection Iterator
|
||||
Adaptor</a>
|
||||
|
||||
<li><a href="filter_iterator.htm">Filter Iterator Adaptor</a>
|
||||
</ul>
|
||||
</ul>
|
||||
|
||||
<li>Header <tt><a href=
|
||||
"../../boost/counting_iterator.hpp">boost/counting_iterator.hpp</a></tt><br>
|
||||
|
||||
<a href="counting_iterator.htm">Counting Iterator Adaptor</a>
|
||||
|
||||
<li>Header <tt><a href=
|
||||
"../../boost/function_output_iterator.hpp">boost/function_output_iterator.hpp</a></tt><br>
|
||||
|
||||
<a href="function_output_iterator.htm">Function Output Iterator Adaptor</a>
|
||||
</ul>
|
||||
|
||||
<p><b><a href="http://www.boost.org/people/dave_abrahams.htm">Dave
|
||||
Abrahams</a></b> started the library, applying <a href=
|
||||
"../../more/generic_programming.html#policy">policy class</a> technique and
|
||||
handling const/non-const iterator interactions. He also contributed the
|
||||
<tt><a href="indirect_iterator.htm">indirect_</a></tt> and <tt><a href=
|
||||
"reverse_iterator.htm">reverse_</a></tt> iterator generators, and expanded
|
||||
<tt><a href="counting_iterator.htm">counting_iterator_generator</a></tt> to
|
||||
cover all incrementable types. He edited most of the documentation,
|
||||
sometimes heavily.<br>
|
||||
<b><a href="http://www.boost.org/people/jeremy_siek.htm">Jeremy
|
||||
Siek</a></b> contributed the <a href="transform_iterator.htm">transform
|
||||
iterator</a> adaptor, the integer-only version of <tt><a href=
|
||||
"counting_iterator.htm">counting_iterator_generator</a></tt>,
|
||||
the <a href="function_output_iterator.htm">function output iterator</a>
|
||||
adaptor, and most of the documentation.<br>
|
||||
<b><a href="http://www.boost.org/people/john_potter.htm">John
|
||||
Potter</a></b> contributed the <tt><a href=
|
||||
"projection_iterator.htm">projection_</a></tt> and <tt><a href=
|
||||
"filter_iterator.htm">filter_</a></tt> iterator generators and made some
|
||||
simplifications to the main <tt><a href=
|
||||
"#iterator_adaptor">iterator_adaptor</a></tt> template.<br>
|
||||
|
||||
|
||||
<h2><a name="iterator_adaptor">Class template</a>
|
||||
<tt>iterator_adaptor</tt></h2>
|
||||
Implementing standard conforming iterators is a non-trivial task. There are
|
||||
some fine points such as the interactions between an iterator and its
|
||||
corresponding const_iterator, and there are myriad operators that should be
|
||||
implemented but are easily forgotten or mishandled, such as
|
||||
<tt>operator->()</tt>. Using <tt>iterator_adaptor</tt>, you can easily
|
||||
implement an iterator class, and even more easily extend and <a href=
|
||||
"../../more/generic_programming.html#adaptors">adapt</a> existing iterator
|
||||
types. Moreover, it is easy to make a pair of interoperable <tt>const</tt>
|
||||
and <tt>non-const</tt> iterators.
|
||||
|
||||
<p><tt>iterator_adaptor</tt> is declared like this:
|
||||
<pre>
|
||||
template <class Base, class Policies,
|
||||
class ValueOrNamedParams = typename std::iterator_traits<Base>::value_type,
|
||||
class ReferenceOrNamedParams = <i>...(see below)</i>,
|
||||
class PointerOrNamedParams = <i>...(see below)</i>,
|
||||
class CategoryOrNamedParams = typename std::iterator_traits<Base>::iterator_category,
|
||||
class DistanceOrNamedParams = typename std::iterator_traits<Base>::difference_type>
|
||||
struct iterator_adaptor;
|
||||
</pre>
|
||||
|
||||
<h3><a name="template_parameters">Template Parameters</a></h3>
|
||||
|
||||
<p>Although <tt>iterator_adaptor</tt> takes seven template parameters,
|
||||
defaults have been carefully chosen to minimize the number of parameters
|
||||
you must supply in most cases, especially if <tt>BaseType</tt> is an
|
||||
iterator.
|
||||
|
||||
<table border="1" summary="iterator_adaptor template parameters">
|
||||
<tr>
|
||||
<th>Parameter
|
||||
|
||||
<th>Description
|
||||
|
||||
<tr>
|
||||
<td><tt>BaseType</tt>
|
||||
|
||||
<td>The type being wrapped.
|
||||
|
||||
<tr>
|
||||
<td><tt>Policies</tt>
|
||||
|
||||
<td>A <a href="../../more/generic_programming.html#policy">policy
|
||||
class</a> that supplies core functionality to the resulting iterator. A
|
||||
detailed description can be found <a href="#policies">below</a>.
|
||||
|
||||
<tr>
|
||||
<td><tt>Value</tt>
|
||||
|
||||
<td>The <tt>value_type</tt> of the resulting iterator, unless const. If
|
||||
Value is <tt>const X</tt> the
|
||||
<tt>value_type</tt> will be (<i>non-</i><tt>const</tt>) <tt>X</tt><a href=
|
||||
"#1">[1]</a>.<br>
|
||||
<b>Default:</b>
|
||||
<tt>std::iterator_traits<BaseType>::value_type</tt> <a href=
|
||||
"#2">[2]</a>
|
||||
|
||||
<tr>
|
||||
<td><tt>Reference</tt>
|
||||
|
||||
<td>The <tt>reference</tt> type of the resulting iterator, and in
|
||||
particular, the result type of <tt>operator*()</tt>.<br>
|
||||
<b>Default:</b> If <tt>Value</tt> is supplied, <tt>Value&</tt> is
|
||||
used. Otherwise
|
||||
<tt>std::iterator_traits<BaseType>::reference</tt> is used.
|
||||
|
||||
<tr>
|
||||
<td><tt>Pointer</tt>
|
||||
|
||||
<td>The <tt>pointer</tt> type of the resulting iterator, and in
|
||||
particular, the result type of <tt>operator->()</tt>.<br>
|
||||
<b>Default:</b> If <tt>Value</tt> was supplied, then <tt>Value*</tt>,
|
||||
otherwise <tt>std::iterator_traits<BaseType>::pointer</tt>.
|
||||
|
||||
<tr>
|
||||
<td><tt>Category</tt>
|
||||
|
||||
<td>The <tt>iterator_category</tt> type for the resulting iterator.<br>
|
||||
<b>Default:</b>
|
||||
<tt>std::iterator_traits<BaseType>::iterator_category</tt>
|
||||
|
||||
<tr>
|
||||
<td><tt>Distance</tt>
|
||||
|
||||
<td>The <tt>difference_type</tt> for the resulting iterator.<br>
|
||||
<b>Default:</b>
|
||||
<tt>std::iterator_traits<BaseType>::difference_type</tt>
|
||||
|
||||
<tr>
|
||||
<td><tt>NamedParams</tt>
|
||||
|
||||
<td>A list of named template parameters generated using the
|
||||
<a href="#iterator_traits_generator">
|
||||
<tt>iterator_traits_generator</tt></a> class (see below).
|
||||
</table>
|
||||
|
||||
<h3><a name="named_template_parameters">Named Template Parameters</a></h3>
|
||||
|
||||
With seven template parameters, providing arguments for
|
||||
<tt>iterator_adaptor</tt> in the correct order can be challenging.
|
||||
Also, often times one would like to specify the sixth or seventh
|
||||
template parameter, but use the defaults for the third through
|
||||
fifth. As a solution to these problems we provide a mechanism for
|
||||
naming the last five template parameters, and providing them in
|
||||
any order through the <tt>iterator_traits_generator</tt> class.
|
||||
|
||||
<blockquote>
|
||||
<pre>
|
||||
<a name="iterator_traits_generator">class iterator_traits_generator</a>
|
||||
{
|
||||
public:
|
||||
template <class Value>
|
||||
struct value_type : public <i>recursive magic</i> { };
|
||||
|
||||
template <class Reference>
|
||||
struct reference : public <i>recursive magic</i> { };
|
||||
|
||||
template <class Pointer>
|
||||
struct pointer : public <i>recursive magic</i> { };
|
||||
|
||||
template <class Distance>
|
||||
struct difference_type : public <i>recursive magic</i> { };
|
||||
|
||||
template <class Category>
|
||||
struct iterator_category : public <i>recursive magic</i> { };
|
||||
};
|
||||
</pre>
|
||||
</blockquote>
|
||||
|
||||
The <tt>iterator_traits_generator</tt> is used to create a list of
|
||||
of template arguments. For example, suppose you want to set the
|
||||
<tt>Reference</tt> and <tt>Category</tt> parameters, and use the
|
||||
defaults for the rest. Then you can use the traits generator as
|
||||
follows:
|
||||
|
||||
<blockquote>
|
||||
<pre>
|
||||
iterator_traits_generator::reference<foo>::category<std::input_iterator_tag>
|
||||
</pre>
|
||||
</blockquote>
|
||||
|
||||
This generated type can then be passed into the <tt>iterator_adaptor</tt>
|
||||
class to replace any of the last five parameters. If you use the traits
|
||||
generator in the <i>i</i>th parameter position, then the parameters <i>i</i>
|
||||
through 7 will use the types specified in the generator. For example, the
|
||||
following adapts <tt>foo_iterator</tt> to create an <a href=
|
||||
"http://www.sgi.com/tech/stl/InputIterator.html">InputIterator</a> with
|
||||
<tt>reference</tt> type <tt>foo</tt>, and whose other traits are determined
|
||||
according to the defaults described <a href="#template_parameters">above</a>.
|
||||
|
||||
<blockquote>
|
||||
<pre>
|
||||
iterator_adaptor<foo_iterator, foo_policies,
|
||||
iterator_traits_generator
|
||||
::reference<foo>
|
||||
::iterator_category<std::input_iterator_tag>
|
||||
>
|
||||
</pre>
|
||||
</blockquote>
|
||||
|
||||
|
||||
<h3><a name="policies">The Policies Class</a></h3>
|
||||
|
||||
<p>The main task in using <tt>iterator_adaptor</tt> is creating an
|
||||
appropriate <tt>Policies</tt> class. The <tt>Policies</tt> class will become
|
||||
the functional heart of the resulting iterator, supplying the core
|
||||
operations that determine its behavior. The <tt>iterator_adaptor</tt>
|
||||
template defines all of the operators required of a <a href=
|
||||
"http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random Access
|
||||
Iterator</a> by dispatching to a <tt>Policies</tt> object. Your
|
||||
<tt>Policies</tt> class must implement a subset of the core iterator
|
||||
operations below corresponding to the iterator categories you want it to
|
||||
support.<br>
|
||||
<br>
|
||||
|
||||
|
||||
<table border="1" summary="iterator_adaptor Policies operations">
|
||||
<caption>
|
||||
<b>Core Iterator Operations</b><br>
|
||||
<tt>T</tt>: adapted iterator type; <tt>p</tt>: object of type T; <tt>n</tt>: <tt>T::size_type</tt>; <tt>x</tt>: <tt>T::difference_type</tt>; <tt>p1</tt>, <tt>p2</tt>: iterators
|
||||
</caption>
|
||||
|
||||
<tr>
|
||||
<th>Operation
|
||||
|
||||
<th>Effects
|
||||
|
||||
<th>Implements Operations
|
||||
|
||||
<th>Required for Iterator Categories
|
||||
|
||||
<tr>
|
||||
<td><tt>dereference</tt>
|
||||
|
||||
<td>returns an element of the iterator's <tt>reference</tt> type
|
||||
|
||||
<td><tt>*p</tt>, <tt>p[n]</tt>
|
||||
|
||||
<td rowspan="3"><a href=
|
||||
"http://www.sgi.com/tech/stl/InputIterator.html">Input</a>/ <a href=
|
||||
"http://www.sgi.com/tech/stl/OutputIterator.html">Output</a>/ <a href=
|
||||
"http://www.sgi.com/tech/stl/ForwardIterator.html">Forward</a>/ <a
|
||||
href=
|
||||
"http://www.sgi.com/tech/stl/BidirectionalIterator.html">Bidirectional</a>/
|
||||
<a href="http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random
|
||||
Access</a>
|
||||
|
||||
<tr>
|
||||
<td><tt>equal</tt>
|
||||
|
||||
<td>tests the iterator for equality
|
||||
|
||||
<td><tt>p1 == p2</tt>, <tt>p1 != p2</tt>
|
||||
|
||||
<tr>
|
||||
<td><tt>increment</tt>
|
||||
|
||||
<td>increments the iterator
|
||||
|
||||
<td><tt>++p</tt>, <tt>p++</tt>
|
||||
|
||||
<tr>
|
||||
<td><tt>decrement</tt>
|
||||
|
||||
<td>decrements the iterator
|
||||
|
||||
<td><tt>--p</tt>, <tt>p--</tt>
|
||||
|
||||
<td><a href=
|
||||
"http://www.sgi.com/tech/stl/BidirectionalIterator.html">Bidirectional</a>/
|
||||
<a href="http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random
|
||||
Access</a>
|
||||
|
||||
<tr>
|
||||
<td><tt>less</tt>
|
||||
|
||||
<td>imposes a <a href=
|
||||
"http://www.sgi.com/tech/stl/StrictWeakOrdering.html">Strict Weak
|
||||
Ordering</a> relation on iterators
|
||||
|
||||
<td>
|
||||
<tt>p1 < p2</tt>,
|
||||
<tt>p1 <= p2</tt>,
|
||||
<tt>p1 > p2</tt>,
|
||||
<tt>p1 >= p2</tt>
|
||||
|
||||
<td rowspan="3"><a href=
|
||||
"http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random
|
||||
Access</a>
|
||||
|
||||
<tr>
|
||||
<td><tt>distance</tt>
|
||||
|
||||
<td>measures the distance between iterators
|
||||
|
||||
<td><tt>p1 - p2</tt>
|
||||
|
||||
<tr>
|
||||
<td><tt>advance</tt>
|
||||
|
||||
<td>adds an integer offset to iterators
|
||||
|
||||
<td>
|
||||
<tt>p + x</tt>,
|
||||
<tt>x + p</tt>,
|
||||
<tt>p += x</tt>,
|
||||
<tt>p - x</tt>,
|
||||
<tt>p -= x</tt>
|
||||
|
||||
</table>
|
||||
|
||||
<p>The library also supplies a "trivial" policy class,
|
||||
<tt>default_iterator_policies</tt>, which implements all seven of the core
|
||||
operations in the usual way. If you wish to create an iterator adaptor that
|
||||
only changes a few of the base type's behaviors, then you can derive your
|
||||
new policy class from <tt>default_iterator_policies</tt> to avoid retyping
|
||||
the usual behaviors. You should also look at
|
||||
<tt>default_iterator_policies</tt> as the ``boilerplate'' for your own
|
||||
policy classes, defining functions with the same interface. This is the
|
||||
definition of <tt>default_iterator_policies</tt>:<br>
|
||||
<br>
|
||||
|
||||
<blockquote>
|
||||
<pre>
|
||||
struct <a name="default_iterator_policies">default_iterator_policies</a>
|
||||
{
|
||||
template <class Reference, class BaseType>
|
||||
Reference dereference(type<Reference>, const BaseType& x) const
|
||||
{ return *x; }
|
||||
|
||||
template <class BaseType>
|
||||
static void increment(BaseType& x)
|
||||
{ ++x; }
|
||||
|
||||
template <class BaseType1, class BaseType2>
|
||||
bool equal(BaseType1& x, BaseType2& y) const
|
||||
{ return x == y; }
|
||||
|
||||
template <class BaseType>
|
||||
static void decrement(BaseType& x)
|
||||
{ --x; }
|
||||
|
||||
template <class BaseType, class DifferenceType>
|
||||
static void advance(BaseType& x, DifferenceType n)
|
||||
{ x += n; }
|
||||
|
||||
template <class Difference, class BaseType1, class BaseType2>
|
||||
Difference distance(type<Difference>, BaseType1& x, BaseType2& y) const
|
||||
{ return y - x; }
|
||||
|
||||
template <class BaseType1, class BaseType2>
|
||||
bool less(BaseType1& x, BaseType2& y) const
|
||||
{ return x < y; }
|
||||
};
|
||||
</pre>
|
||||
</blockquote>
|
||||
|
||||
<p>Template member functions are used throughout
|
||||
<tt>default_iterator_policies</tt> so that it can be employed with a wide
|
||||
range of iterators. If we had used concrete types above, we'd have tied the
|
||||
usefulness of <tt>default_iterator_policies</tt> to a particular range of
|
||||
adapted iterators. If you follow the same pattern with your
|
||||
<tt>Policies</tt> classes, you can use them to generate more specialized
|
||||
adaptors along the lines of <a href="#specialized_adaptors">those supplied by this library</a>.
|
||||
|
||||
<h3><a name="additional_members">Additional Members</a></h3>
|
||||
In addition to all of the member functions required of a <a href=
|
||||
"http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random Access
|
||||
Iterator</a>, the <tt>iterator_adaptor</tt> class template defines the
|
||||
following members. <br>
|
||||
<br>
|
||||
|
||||
|
||||
<table border="1" summary="additional iterator_adaptor members">
|
||||
<tr>
|
||||
<td><tt>explicit iterator_adaptor(const Base&, const Policies& =
|
||||
Policies())</tt>
|
||||
<br><br>
|
||||
Construct an adapted iterator from a base object and a policies
|
||||
object. As this constructor is <tt>explicit</tt>, it does not
|
||||
provide for implicit conversions from the <tt>Base</tt> type to
|
||||
the iterator adaptor.
|
||||
|
||||
<tr>
|
||||
<td><tt>template <class B, class V, class R, class P><br>
|
||||
iterator_adaptor(const
|
||||
iterator_adaptor<B,Policies,V,R,P,Category,Distance>&)</tt>
|
||||
<br><br>
|
||||
This constructor allows for conversion from non-<tt>const</tt> to
|
||||
constant adapted iterators. See <a href=
|
||||
"#iterator_interactions">below</a> for more details.<br>
|
||||
Requires: <tt>B</tt> is convertible to <tt>Base</tt>.
|
||||
|
||||
<tr>
|
||||
<td><tt>base_type base() const;</tt>
|
||||
<br><br>
|
||||
Return a copy of the base object.
|
||||
</table>
|
||||
|
||||
<h3><a name="example">Example</a></h3>
|
||||
|
||||
<p>It is often useful to automatically apply some function to the value
|
||||
returned by dereferencing an iterator. The <a href=
|
||||
"./transform_iterator.htm">transform iterator</a> makes it easy to create
|
||||
an iterator adaptor which does just that. Here we will show how easy it is
|
||||
to implement the transform iterator using the <tt>iterator_adaptor</tt>
|
||||
template.
|
||||
|
||||
<p>We want to be able to adapt a range of iterators and functions, so the
|
||||
policies class will have a template parameter for the function type and it
|
||||
will have a data member of that type. We know that the function takes one
|
||||
argument and that we'll need to be able to deduce the <tt>result_type</tt>
|
||||
of the function so we can use it for the adapted iterator's
|
||||
<tt>value_type</tt>. <a href=
|
||||
"http://www.sgi.com/Technology/STL/AdaptableUnaryFunction.html">AdaptableUnaryFunction</a>
|
||||
is the <a href="../../more/generic_programming.html#concept">Concept</a>
|
||||
that fulfills those requirements.
|
||||
|
||||
<p>To implement a transform iterator we will only change one of the base
|
||||
iterator's behaviors, so the <tt>transform_iterator_policies</tt> class can
|
||||
inherit the rest from <tt>default_iterator_policies</tt>. We will define
|
||||
the <tt>dereference()</tt> member function, which is used to implement
|
||||
<tt>operator*()</tt> of the adapted iterator. The implementation will
|
||||
dereference the base iterator and apply the function object. The
|
||||
<tt>type<Reference></tt> parameter is used to convey the appropriate
|
||||
return type. The complete code for <tt>transform_iterator_policies</tt>
|
||||
is:<br>
|
||||
<br>
|
||||
|
||||
|
||||
<blockquote>
|
||||
<pre>
|
||||
template <class AdaptableUnaryFunction>
|
||||
struct transform_iterator_policies : public default_iterator_policies
|
||||
{
|
||||
transform_iterator_policies() { }
|
||||
|
||||
transform_iterator_policies(const AdaptableUnaryFunction& f)
|
||||
: m_f(f) { }
|
||||
|
||||
template <class Reference, class BaseIterator>
|
||||
Reference dereference(type<Reference>, const BaseIterator& i) const
|
||||
{ return m_f(*i); }
|
||||
|
||||
AdaptableUnaryFunction m_f;
|
||||
};
|
||||
</pre>
|
||||
</blockquote>
|
||||
|
||||
<p>The next step is to use the <tt>iterator_adaptor</tt> template to
|
||||
construct the transform iterator type. The nicest way to package the
|
||||
construction of the transform iterator is to create a <a href=
|
||||
"../../more/generic_programming.html#type_generator">type generator</a>.
|
||||
The first template parameter to the generator will be the type of the
|
||||
function object and the second will be the base iterator type. We use
|
||||
<tt>iterator_adaptor</tt> to define the transform iterator type as a nested
|
||||
<tt>typedef</tt> inside the <tt>transform_iterator_generator</tt> class.
|
||||
Because the function may return by-value, we must limit the
|
||||
<tt>iterator_category</tt> to <a href=
|
||||
"http://www.sgi.com/tech/stl/InputIterator.html">Input Iterator</a>, and
|
||||
the iterator's <tt>reference</tt> type cannot be a true reference (the
|
||||
standard allows this for input iterators), so in this case we can use few
|
||||
of <tt>iterator_adaptor</tt>'s default template arguments.<br>
|
||||
<br>
|
||||
|
||||
|
||||
<blockquote>
|
||||
<pre>
|
||||
template <class AdaptableUnaryFunction, class Iterator>
|
||||
struct transform_iterator_generator
|
||||
{
|
||||
typedef typename AdaptableUnaryFunction::result_type value_type;
|
||||
public:
|
||||
typedef iterator_adaptor<Iterator,
|
||||
transform_iterator_policies<AdaptableUnaryFunction>,
|
||||
value_type, value_type, value_type*, std::input_iterator_tag>
|
||||
type;
|
||||
};
|
||||
</pre>
|
||||
</blockquote>
|
||||
|
||||
<p>As a finishing touch, we will create an <a href=
|
||||
"../../more/generic_programming.html#object_generator">object generator</a>
|
||||
for the transform iterator. This is a function that makes it more
|
||||
convenient to create a transform iterator.<br>
|
||||
<br>
|
||||
|
||||
|
||||
<blockquote>
|
||||
<pre>
|
||||
template <class AdaptableUnaryFunction, class Iterator>
|
||||
typename transform_iterator_generator<AdaptableUnaryFunction,Iterator>::type
|
||||
make_transform_iterator(Iterator base,
|
||||
const AdaptableUnaryFunction& f = AdaptableUnaryFunction())
|
||||
{
|
||||
typedef typename transform_iterator_generator<AdaptableUnaryFunction,
|
||||
Iterator>::type result_t;
|
||||
return result_t(base, f);
|
||||
}
|
||||
</pre>
|
||||
</blockquote>
|
||||
|
||||
<p>Here is an example that shows how to use a transform iterator to iterate
|
||||
through a range of numbers, multiplying each of them by 2 and printing the
|
||||
result to standard output.<br>
|
||||
<br>
|
||||
|
||||
|
||||
<blockquote>
|
||||
<pre>
|
||||
#include <functional>
|
||||
#include <algorithm>
|
||||
#include <iostream>
|
||||
#include <boost/iterator_adaptors.hpp>
|
||||
|
||||
int main(int, char*[])
|
||||
{
|
||||
int x[] = { 1, 2, 3, 4, 5, 6, 7, 8 };
|
||||
const int N = sizeof(x)/sizeof(int);
|
||||
std::cout << "multiplying the array by 2:" << std::endl;
|
||||
std::copy(boost::make_transform_iterator(x, std::bind1st(std::multiplies<int>(), 2)),
|
||||
boost::make_transform_iterator(x + N, std::bind1st(std::multiplies<int>(), 2)),
|
||||
std::ostream_iterator<int>(std::cout, " "));
|
||||
std::cout << std::endl;
|
||||
return 0;
|
||||
}
|
||||
</pre>
|
||||
This output is:
|
||||
<pre>
|
||||
2 4 6 8 10 12 14 16
|
||||
</pre>
|
||||
</blockquote>
|
||||
|
||||
<h3><a name="iterator_interactions">Iterator Interactions</a></h3>
|
||||
|
||||
<p>C++ allows <tt>const</tt> and non-<tt>const</tt> pointers to interact in
|
||||
the following intuitive ways:
|
||||
|
||||
<ul>
|
||||
<li>a non-<tt>const</tt> pointer to <tt>T</tt> can be implicitly
|
||||
converted to a <tt>const</tt> pointer to <tt>T</tt>.
|
||||
|
||||
<li><tt>const</tt> and non-<tt>const</tt> pointers to <tt>T</tt> can be
|
||||
freely mixed in comparison expressions.
|
||||
|
||||
<li><tt>const</tt> and non-<tt>const</tt> pointers to <tt>T</tt> can be
|
||||
freely subtracted, in any order.
|
||||
</ul>
|
||||
|
||||
Getting user-defined iterators to work together that way is nontrivial (see
|
||||
<a href="reverse_iterator.htm#interactions">here</a> for an example of where
|
||||
the C++ standard got it wrong), but <tt>iterator_adaptor</tt> can make it
|
||||
easy. The rules are as follows:
|
||||
|
||||
<ul>
|
||||
<li><a name="interoperable">Adapted iterators that share the same <tt>Policies</tt>,
|
||||
<tt>Category</tt>, and <tt>Distance</tt> parameters are called
|
||||
<i>interoperable</i>.</a>
|
||||
|
||||
<li>An adapted iterator can be implicitly converted to any other adapted
|
||||
iterator with which it is interoperable, so long as the <tt>Base</tt>
|
||||
type of the source iterator can be converted to the <tt>Base</tt> type of
|
||||
the target iterator.
|
||||
|
||||
<li>Interoperable iterators can be freely mixed in comparison expressions
|
||||
so long as the <tt>Policies</tt> class has <tt>equal</tt> (and, for
|
||||
random access iterators, <tt>less</tt>) members that can accept both
|
||||
<tt>Base</tt> types in either order.
|
||||
|
||||
<li>Interoperable iterators can be freely mixed in subtraction
|
||||
expressions so long as the <tt>Policies</tt> class has a
|
||||
<tt>distance</tt> member that can accept both <tt>Base</tt> types in
|
||||
either order.
|
||||
</ul>
|
||||
|
||||
<h4>Example</h4>
|
||||
|
||||
<p>The <a href="projection_iterator.htm">Projection Iterator</a> adaptor is similar to the <a
|
||||
href="./transform_iterator.htm">transform iterator adaptor</a> in that
|
||||
its <tt>operator*()</tt> applies some function to the result of
|
||||
dereferencing the base iterator and then returns the result. The
|
||||
difference is that the function must return a reference to some
|
||||
existing object (for example, a data member within the
|
||||
<tt>value_type</tt> of the base iterator).
|
||||
|
||||
<p>
|
||||
The <a
|
||||
href="projection_iterator.htm#projection_iterator_pair_generator">projection_iterator_pair_generator</a> template
|
||||
is a special two-<a href="../../more/generic_programming.html#type_generator">type generator</a> for mutable and constant versions of a
|
||||
projection iterator. It is defined as follows:
|
||||
<blockquote>
|
||||
<pre>
|
||||
template <class AdaptableUnaryFunction, class Iterator, class ConstIterator>
|
||||
struct projection_iterator_pair_generator {
|
||||
typedef typename AdaptableUnaryFunction::result_type value_type;
|
||||
typedef projection_iterator_policies<AdaptableUnaryFunction> policies;
|
||||
public:
|
||||
typedef iterator_adaptor<Iterator,policies,value_type> iterator;
|
||||
typedef iterator_adaptor<ConstIterator,policies,value_type,
|
||||
const value_type&,const value_type*> const_iterator;
|
||||
};
|
||||
</pre>
|
||||
</blockquote>
|
||||
|
||||
<p>It is assumed that the <tt>Iterator</tt> and <tt>ConstIterator</tt> arguments are corresponding mutable
|
||||
and constant iterators. <ul>
|
||||
<li>
|
||||
Clearly, then, the
|
||||
<tt>projection_iterator_pair_generator</tt>'s <tt>iterator</tt> and
|
||||
<tt>const_iterator</tt> are <a href="#interoperable">interoperable</a>, since
|
||||
they share the same <tt>Policies</tt> and since <tt>Category</tt> and
|
||||
<tt>Distance</tt> as supplied by <tt>std::iterator_traits</tt> through the
|
||||
<a href="#template_parameters">default template parameters</a> to
|
||||
<tt>iterator_adaptor</tt> should be the same.
|
||||
|
||||
<li>Since <tt>Iterator</tt> can presumably be converted to
|
||||
<tt>ConstIterator</tt>, the projection <tt>iterator</tt> will be convertible to
|
||||
the projection <tt>const_iterator</tt>.
|
||||
|
||||
<li> Since <tt>projection_iterator_policies</tt> implements only the
|
||||
<tt>dereference</tt> operation, and inherits all other behaviors from <tt><a
|
||||
href="#default_iterator_policies">default_iterator_policies</a></tt>, which has
|
||||
fully-templatized <tt>equal</tt>, <tt>less</tt>, and <tt>distance</tt>
|
||||
operations, the <tt>iterator</tt> and <tt>const_iterator</tt> can be freely
|
||||
mixed in comparison and subtraction expressions.
|
||||
|
||||
</ul>
|
||||
|
||||
<h3><a name="challenge">Challenge</a></h3>
|
||||
|
||||
<p>There is an unlimited number of ways the <tt>iterator_adaptors</tt>
|
||||
class can be used to create iterators. One interesting exercise would be to
|
||||
re-implement the iterators of <tt>std::list</tt> and <tt>std::slist</tt>
|
||||
using <tt>iterator_adaptors</tt>, where the adapted <tt>Iterator</tt> types
|
||||
would be node pointers.
|
||||
|
||||
<h3><a name="concept_model">Concept Model</a></h3>
|
||||
Depending on the <tt>Base</tt> and <tt>Policies</tt> template parameters,
|
||||
an <tt>iterator_adaptor</tt> can be a <a href=
|
||||
"http://www.sgi.com/tech/stl/InputIterator.html">Input Iterator</a>, <a
|
||||
href="http://www.sgi.com/tech/stl/ForwardIterator.html">Forward
|
||||
Iterator</a>, <a href=
|
||||
"http://www.sgi.com/tech/stl/BidirectionalIterator.html">Bidirectional
|
||||
Iterator</a>, or <a href=
|
||||
"http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random Access
|
||||
Iterator</a>.
|
||||
|
||||
<h3><a name="declaration_synopsis">Declaration Synopsis</a></h3>
|
||||
<pre>
|
||||
template <class Base, class Policies,
|
||||
class Value = typename std::iterator_traits<Base>::value_type,
|
||||
class Reference = <i>...(see below)</i>,
|
||||
class Pointer = <i>...(see below)</i>,
|
||||
class Category = typename std::iterator_traits<Base>::iterator_category,
|
||||
class Distance = typename std::iterator_traits<Base>::difference_type
|
||||
>
|
||||
struct iterator_adaptor
|
||||
{
|
||||
typedef Distance difference_type;
|
||||
typedef typename boost::remove_const<Value>::type value_type;
|
||||
typedef Pointer pointer;
|
||||
typedef Reference reference;
|
||||
typedef Category iterator_category;
|
||||
typedef Base base_type;
|
||||
typedef Policies policies_type;
|
||||
|
||||
iterator_adaptor();
|
||||
explicit iterator_adaptor(const Base&, const Policies& = Policies());
|
||||
|
||||
base_type base() const;
|
||||
|
||||
template <class B, class V, class R, class P>
|
||||
iterator_adaptor(
|
||||
const iterator_adaptor<B,Policies,V,R,P,Category,Distance>&);
|
||||
|
||||
reference operator*() const;
|
||||
<i>operator_arrow_result_type</i> operator->() const; <a href=
|
||||
"#3">[3]</a>
|
||||
<i>value_type</i> operator[](difference_type n) const; <a href="#3">[4]</a>
|
||||
|
||||
iterator_adaptor& operator++();
|
||||
iterator_adaptor& operator++(int);
|
||||
iterator_adaptor& operator--();
|
||||
iterator_adaptor& operator--(int);
|
||||
|
||||
iterator_adaptor& operator+=(difference_type n);
|
||||
iterator_adaptor& operator-=(difference_type n);
|
||||
|
||||
iterator_adaptor& operator-(Distance x) const;
|
||||
};
|
||||
|
||||
template <class B, class P, class V, class R, class Ptr,
|
||||
class C, class D1, class D2>
|
||||
iterator_adaptor<B,P,V,R,Ptr,C,D1>
|
||||
operator+(iterator_adaptor<B,P,V,R,Ptr,C,D1>, D2);
|
||||
|
||||
template <class B, class P, class V, class R, class Ptr,
|
||||
class C, class D1, class D2>
|
||||
iterator_adaptor<B,P,V,R,P,C,D1>
|
||||
operator+(D2, iterator_adaptor<B,P,V,R,Ptr,C,D1> p);
|
||||
|
||||
template <class B1, class B2, class P, class V1, class V2,
|
||||
class R1, class R2, class P1, class P2, class C, class D>
|
||||
Distance operator-(const iterator_adaptor<B1,P,V1,R1,P1,C,D>&,
|
||||
const iterator_adaptor<B2,P,V2,R2,P2,C,D>&);
|
||||
|
||||
template <class B1, class B2, class P, class V1, class V2,
|
||||
class R1, class R2, class P1, class P2, class C, class D>
|
||||
bool operator==(const iterator_adaptor<B1,P,V1,R1,P1,C,D>&,
|
||||
const iterator_adaptor<B2,P,V2,R2,P2,C,D>&);
|
||||
|
||||
// and similarly for operators !=, <, <=, >=, >
|
||||
</pre>
|
||||
|
||||
<h3><a name="notes">Notes</a></h3>
|
||||
|
||||
<p><a name="1">[1]</a> The standard specifies that the <tt>value_type</tt>
|
||||
of <tt>const</tt> iterators to <tt>T</tt> (e.g. <tt>const T*</tt>) is
|
||||
<tt><i>non-</i>const T</tt>, while the <tt>pointer</tt> and
|
||||
<tt>reference</tt> types for all <a href=
|
||||
"http://www.sgi.com/tech/stl/ForwardIterator.html">Forward Iterators</a> are
|
||||
<tt>const T*</tt> and <tt>const T&</tt>, respectively. Stripping the
|
||||
<tt>const</tt>-ness of <tt>Value</tt> allows you to easily
|
||||
make a <tt>const</tt> iterator adaptor by supplying a <tt>const</tt> type
|
||||
for <tt>Value</tt>, and allowing the defaults for the <tt>Pointer</tt> and
|
||||
<tt>Reference</tt> parameters to take effect. Although compilers that don't
|
||||
support partial specialization won't strip <tt>const</tt> for you, having a
|
||||
<tt>const value_type</tt> is often harmless in practice.
|
||||
|
||||
<p><a name="2">[2]</a> If your compiler does not support partial
|
||||
specialization and the base iterator is a builtin pointer type, you
|
||||
will not be able to use the default for <tt>Value</tt> and will have to
|
||||
specify this type explicitly.
|
||||
|
||||
<p><a name="3">[3]</a> The result type for the <tt>operator->()</tt>
|
||||
depends on the category and value type of the iterator and is somewhat
|
||||
complicated to describe. But be assured, it works in a stardard conforming
|
||||
fashion, providing access to members of the objects pointed to by the
|
||||
iterator.
|
||||
|
||||
<p><a name="4">[4]</a> The result type of <tt>operator[]()</tt> is
|
||||
<tt>value_type</tt> instead of <tt>reference</tt> as might be expected.
|
||||
There are two reasons for this choice. First, the C++ standard only
|
||||
requires that the return type of an arbitrary <a href=
|
||||
"http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random Access
|
||||
Iterator</a>'s <tt>operator[]</tt>be ``convertible to T'' (Table 76), so
|
||||
when adapting an arbitrary base iterator we may not have a reference to
|
||||
return. Second, and more importantly, for certain kinds of iterators,
|
||||
returning a reference could cause serious memory problems due to the
|
||||
reference being bound to a temporary object whose lifetime ends inside of
|
||||
the <tt>operator[]</tt>.
|
||||
<hr>
|
||||
|
||||
<p>Revised
|
||||
<!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %b %Y" startspan -->09 Mar 2001<!--webbot bot="Timestamp" endspan i-checksum="14894" -->
|
||||
|
||||
|
||||
<p>© Copyright Dave Abrahams and Jeremy Siek 2001. Permission to copy,
|
||||
use, modify, sell and distribute this document is granted provided this
|
||||
copyright notice appears in all copies. This document is provided "as is"
|
||||
without express or implied warranty, and with no claim as to its
|
||||
suitability for any purpose.
|
||||
|
||||
</body>
|
||||
|
||||
<!-- LocalWords: HTML html charset alt gif abrahams htm const
|
||||
incrementable david abrahams
|
||||
-->
|
||||
|
||||
<!-- LocalWords: jeremy siek mishandled interoperable typename struct Iter iter src
|
||||
-->
|
||||
|
||||
<!-- LocalWords: int bool ForwardIterator BidirectionalIterator BaseIterator
|
||||
-->
|
||||
|
||||
<!-- LocalWords: RandomAccessIterator DifferenceType AdaptableUnaryFunction
|
||||
-->
|
||||
|
||||
<!-- LocalWords: iostream hpp sizeof InputIterator constness ConstIterator
|
||||
David Abrahams
|
||||
-->
|
||||
</html>
|
||||
|
210
iterator_traits_test.cpp
Normal file
210
iterator_traits_test.cpp
Normal file
@@ -0,0 +1,210 @@
|
||||
// (C) Copyright David Abrahams 2001. Permission to copy, use, modify,
|
||||
// sell and distribute this software is granted provided this
|
||||
// copyright notice appears in all copies. This software is provided
|
||||
// "as is" without express or implied warranty, and with no claim as
|
||||
// to its suitability for any purpose.
|
||||
|
||||
// See http://www.boost.org for most recent version including documentation.
|
||||
|
||||
// Revision History
|
||||
// 04 Mar 2001 Patches for Intel C++ (Dave Abrahams)
|
||||
// 19 Feb 2001 Take advantage of improved iterator_traits to do more tests
|
||||
// on MSVC. Reordered some #ifdefs for coherency.
|
||||
// (David Abrahams)
|
||||
// 13 Feb 2001 Test new VC6 workarounds (David Abrahams)
|
||||
// 11 Feb 2001 Final fixes for Borland (David Abrahams)
|
||||
// 11 Feb 2001 Some fixes for Borland get it closer on that compiler
|
||||
// (David Abrahams)
|
||||
// 07 Feb 2001 More comprehensive testing; factored out static tests for
|
||||
// better reuse (David Abrahams)
|
||||
// 21 Jan 2001 Quick fix to my_iterator, which wasn't returning a
|
||||
// reference type from operator* (David Abrahams)
|
||||
// 19 Jan 2001 Initial version with iterator operators (David Abrahams)
|
||||
|
||||
#include <boost/detail/iterator.hpp>
|
||||
#include <boost/type_traits.hpp>
|
||||
#include <boost/operators.hpp>
|
||||
#include <boost/static_assert.hpp>
|
||||
#include <iterator>
|
||||
#include <vector>
|
||||
#include <list>
|
||||
#include <cassert>
|
||||
#include <iostream>
|
||||
|
||||
// An iterator for which we can get traits.
|
||||
struct my_iterator1
|
||||
: boost::forward_iterator_helper<my_iterator1, char, long, const char*, const char&>
|
||||
{
|
||||
my_iterator1(const char* p) : m_p(p) {}
|
||||
|
||||
bool operator==(const my_iterator1& rhs) const
|
||||
{ return this->m_p == rhs.m_p; }
|
||||
|
||||
my_iterator1& operator++() { ++this->m_p; return *this; }
|
||||
const char& operator*() { return *m_p; }
|
||||
private:
|
||||
const char* m_p;
|
||||
};
|
||||
|
||||
// Used to prove that we don't require std::iterator<> in the hierarchy under
|
||||
// MSVC6, and that we can compute all the traits for a standard-conforming UDT
|
||||
// iterator.
|
||||
struct my_iterator2
|
||||
: boost::equality_comparable<my_iterator2
|
||||
, boost::incrementable<my_iterator2
|
||||
, boost::dereferenceable<my_iterator2,const char*> > >
|
||||
{
|
||||
typedef char value_type;
|
||||
typedef long difference_type;
|
||||
typedef const char* pointer;
|
||||
typedef const char& reference;
|
||||
typedef std::forward_iterator_tag iterator_category;
|
||||
|
||||
my_iterator2(const char* p) : m_p(p) {}
|
||||
|
||||
bool operator==(const my_iterator2& rhs) const
|
||||
{ return this->m_p == rhs.m_p; }
|
||||
|
||||
my_iterator2& operator++() { ++this->m_p; return *this; }
|
||||
const char& operator*() { return *m_p; }
|
||||
private:
|
||||
const char* m_p;
|
||||
};
|
||||
|
||||
// Used to prove that we're not overly confused by the existence of
|
||||
// std::iterator<> in the hierarchy under MSVC6 - we should find that
|
||||
// boost::detail::iterator_traits<my_iterator3>::difference_type is int.
|
||||
struct my_iterator3 : my_iterator1
|
||||
{
|
||||
typedef int difference_type;
|
||||
my_iterator3(const char* p) : my_iterator1(p) {}
|
||||
};
|
||||
|
||||
template <class Iterator,
|
||||
class value_type, class difference_type, class pointer, class reference, class category>
|
||||
struct non_portable_tests
|
||||
{
|
||||
// Unfortunately, the VC6 standard library doesn't supply these :(
|
||||
BOOST_STATIC_ASSERT((
|
||||
boost::is_same<
|
||||
typename boost::detail::iterator_traits<Iterator>::pointer,
|
||||
pointer
|
||||
>::value));
|
||||
|
||||
BOOST_STATIC_ASSERT((
|
||||
boost::is_same<
|
||||
typename boost::detail::iterator_traits<Iterator>::reference,
|
||||
reference
|
||||
>::value));
|
||||
};
|
||||
|
||||
template <class Iterator,
|
||||
class value_type, class difference_type, class pointer, class reference, class category>
|
||||
struct portable_tests
|
||||
{
|
||||
BOOST_STATIC_ASSERT((
|
||||
boost::is_same<
|
||||
typename boost::detail::iterator_traits<Iterator>::difference_type,
|
||||
difference_type
|
||||
>::value));
|
||||
|
||||
BOOST_STATIC_ASSERT((
|
||||
boost::is_same<
|
||||
typename boost::detail::iterator_traits<Iterator>::iterator_category,
|
||||
category
|
||||
>::value));
|
||||
};
|
||||
|
||||
// Test iterator_traits
|
||||
template <class Iterator,
|
||||
class value_type, class difference_type, class pointer, class reference, class category>
|
||||
struct input_iterator_test
|
||||
: portable_tests<Iterator,value_type,difference_type,pointer,reference,category>
|
||||
{
|
||||
BOOST_STATIC_ASSERT((
|
||||
boost::is_same<
|
||||
typename boost::detail::iterator_traits<Iterator>::value_type,
|
||||
value_type
|
||||
>::value));
|
||||
};
|
||||
|
||||
template <class Iterator,
|
||||
class value_type, class difference_type, class pointer, class reference, class category>
|
||||
struct non_pointer_test
|
||||
: input_iterator_test<Iterator,value_type,difference_type,pointer,reference,category>
|
||||
, non_portable_tests<Iterator,value_type,difference_type,pointer,reference,category>
|
||||
{
|
||||
};
|
||||
|
||||
template <class Iterator,
|
||||
class value_type, class difference_type, class pointer, class reference, class category>
|
||||
struct maybe_pointer_test
|
||||
: portable_tests<Iterator,value_type,difference_type,pointer,reference,category>
|
||||
#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
|
||||
, non_portable_tests<Iterator,value_type,difference_type,pointer,reference,category>
|
||||
#endif
|
||||
{
|
||||
};
|
||||
|
||||
input_iterator_test<std::istream_iterator<int>, int, std::ptrdiff_t, int*, int&, std::input_iterator_tag>
|
||||
istream_iterator_test;
|
||||
|
||||
//
|
||||
#if defined(__BORLANDC__) && !defined(__SGI_STL_PORT)
|
||||
typedef ::std::char_traits<char>::off_type distance;
|
||||
non_pointer_test<std::ostream_iterator<int>,int,
|
||||
distance,int*,int&,std::output_iterator_tag> ostream_iterator_test;
|
||||
#elif defined(BOOST_MSVC_STD_ITERATOR)
|
||||
non_pointer_test<std::ostream_iterator<int>,
|
||||
int, void, void, void, std::output_iterator_tag>
|
||||
ostream_iterator_test;
|
||||
#else
|
||||
non_pointer_test<std::ostream_iterator<int>,
|
||||
void, void, void, void, std::output_iterator_tag>
|
||||
ostream_iterator_test;
|
||||
#endif
|
||||
|
||||
|
||||
#ifdef __KCC
|
||||
typedef long std_list_diff_type;
|
||||
#else
|
||||
typedef std::ptrdiff_t std_list_diff_type;
|
||||
#endif
|
||||
non_pointer_test<std::list<int>::iterator, int, std_list_diff_type, int*, int&, std::bidirectional_iterator_tag>
|
||||
list_iterator_test;
|
||||
|
||||
maybe_pointer_test<std::vector<int>::iterator, int, std::ptrdiff_t, int*, int&, std::random_access_iterator_tag>
|
||||
vector_iterator_test;
|
||||
|
||||
maybe_pointer_test<int*, int, std::ptrdiff_t, int*, int&, std::random_access_iterator_tag>
|
||||
int_pointer_test;
|
||||
|
||||
non_pointer_test<my_iterator1, char, long, const char*, const char&, std::forward_iterator_tag>
|
||||
my_iterator1_test;
|
||||
|
||||
non_pointer_test<my_iterator2, char, long, const char*, const char&, std::forward_iterator_tag>
|
||||
my_iterator2_test;
|
||||
|
||||
non_pointer_test<my_iterator3, char, int, const char*, const char&, std::forward_iterator_tag>
|
||||
my_iterator3_test;
|
||||
|
||||
int main()
|
||||
{
|
||||
char chars[100];
|
||||
int ints[100];
|
||||
|
||||
for (std::ptrdiff_t length = 3; length < 100; length += length / 3)
|
||||
{
|
||||
std::list<int> l(length);
|
||||
assert(boost::detail::distance(l.begin(), l.end()) == length);
|
||||
|
||||
std::vector<int> v(length);
|
||||
assert(boost::detail::distance(v.begin(), v.end()) == length);
|
||||
|
||||
assert(boost::detail::distance(&ints[0], ints + length) == length);
|
||||
assert(boost::detail::distance(my_iterator1(chars), my_iterator1(chars + length)) == length);
|
||||
assert(boost::detail::distance(my_iterator2(chars), my_iterator2(chars + length)) == length);
|
||||
assert(boost::detail::distance(my_iterator3(chars), my_iterator3(chars + length)) == length);
|
||||
}
|
||||
return 0;
|
||||
}
|
393
numeric_traits_test.cpp
Normal file
393
numeric_traits_test.cpp
Normal file
@@ -0,0 +1,393 @@
|
||||
// (C) Copyright David Abrahams 2001. Permission to copy, use, modify,
|
||||
// sell and distribute this software is granted provided this
|
||||
// copyright notice appears in all copies. This software is provided
|
||||
// "as is" without express or implied warranty, and with no claim as
|
||||
// to its suitability for any purpose.
|
||||
|
||||
// See http://www.boost.org for most recent version including documentation.
|
||||
|
||||
// Revision History
|
||||
// 11 Feb 2001 Fixes for Borland (David Abrahams)
|
||||
// 23 Jan 2001 Added test for wchar_t (David Abrahams)
|
||||
// 23 Jan 2001 Now statically selecting a test for signed numbers to avoid
|
||||
// warnings with fancy compilers. Added commentary and
|
||||
// additional dumping of traits data for tested types (David
|
||||
// Abrahams).
|
||||
// 21 Jan 2001 Initial version (David Abrahams)
|
||||
|
||||
#include <boost/detail/numeric_traits.hpp>
|
||||
#include <cassert>
|
||||
#include <boost/type_traits.hpp>
|
||||
#include <boost/static_assert.hpp>
|
||||
#include <boost/cstdint.hpp>
|
||||
#include <boost/utility.hpp>
|
||||
#include <boost/lexical_cast.hpp>
|
||||
#include <climits>
|
||||
#include <typeinfo>
|
||||
#include <iostream>
|
||||
#include <string>
|
||||
#ifndef BOOST_NO_LIMITS
|
||||
# include <limits>
|
||||
#endif
|
||||
|
||||
// A macro for declaring class compile-time constants.
|
||||
#ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION
|
||||
# define DECLARE_CLASS_CONST(type, init) static const type init
|
||||
#else
|
||||
# define DECLARE_CLASS_CONST(type, init) enum { init }
|
||||
#endif
|
||||
|
||||
// =================================================================================
|
||||
// template class complement_traits<Number> --
|
||||
//
|
||||
// statically computes the max and min for 1s and 2s-complement binary
|
||||
// numbers. This helps on platforms without <limits> support. It also shows
|
||||
// an example of a recursive template that works with MSVC!
|
||||
//
|
||||
|
||||
template <unsigned size> struct complement; // forward
|
||||
|
||||
// The template complement, below, does all the real work, using "poor man's
|
||||
// partial specialization". We need complement_traits_aux<> so that MSVC doesn't
|
||||
// complain about undefined min/max as we're trying to recursively define them.
|
||||
template <class Number, unsigned size>
|
||||
struct complement_traits_aux
|
||||
{
|
||||
DECLARE_CLASS_CONST(Number, max = complement<size>::template traits<Number>::max);
|
||||
DECLARE_CLASS_CONST(Number, min = complement<size>::template traits<Number>::min);
|
||||
};
|
||||
|
||||
template <unsigned size>
|
||||
struct complement
|
||||
{
|
||||
template <class Number>
|
||||
struct traits
|
||||
{
|
||||
private:
|
||||
// indirection through complement_traits_aux neccessary to keep MSVC happy
|
||||
typedef complement_traits_aux<Number, size - 1> prev;
|
||||
public:
|
||||
DECLARE_CLASS_CONST(Number, max =
|
||||
Number(Number(prev::max) << CHAR_BIT)
|
||||
+ Number(UCHAR_MAX));
|
||||
|
||||
DECLARE_CLASS_CONST(Number, min = Number(Number(prev::min) << CHAR_BIT));
|
||||
};
|
||||
};
|
||||
|
||||
// Template class complement_base<> -- defines values for min and max for
|
||||
// complement<1>, at the deepest level of recursion. Uses "poor man's partial
|
||||
// specialization" again.
|
||||
template <bool is_signed> struct complement_base;
|
||||
|
||||
template <> struct complement_base<false>
|
||||
{
|
||||
template <class Number>
|
||||
struct values
|
||||
{
|
||||
DECLARE_CLASS_CONST(Number, min = 0);
|
||||
DECLARE_CLASS_CONST(Number, max = UCHAR_MAX);
|
||||
};
|
||||
};
|
||||
|
||||
template <> struct complement_base<true>
|
||||
{
|
||||
template <class Number>
|
||||
struct values
|
||||
{
|
||||
DECLARE_CLASS_CONST(Number, min = SCHAR_MIN);
|
||||
DECLARE_CLASS_CONST(Number, max = SCHAR_MAX);
|
||||
};
|
||||
};
|
||||
|
||||
// Base specialization of complement, puts an end to the recursion.
|
||||
template <>
|
||||
struct complement<1>
|
||||
{
|
||||
template <class Number>
|
||||
struct traits
|
||||
{
|
||||
DECLARE_CLASS_CONST(bool, is_signed = boost::detail::is_signed<Number>::value);
|
||||
DECLARE_CLASS_CONST(Number, min =
|
||||
complement_base<is_signed>::template values<Number>::min);
|
||||
DECLARE_CLASS_CONST(Number, max =
|
||||
complement_base<is_signed>::template values<Number>::max);
|
||||
};
|
||||
};
|
||||
|
||||
// Now here's the "pretty" template you're intended to actually use.
|
||||
// complement_traits<Number>::min, complement_traits<Number>::max are the
|
||||
// minimum and maximum values of Number if Number is a built-in integer type.
|
||||
template <class Number>
|
||||
struct complement_traits
|
||||
{
|
||||
DECLARE_CLASS_CONST(Number, max = (complement_traits_aux<Number, sizeof(Number)>::max));
|
||||
DECLARE_CLASS_CONST(Number, min = (complement_traits_aux<Number, sizeof(Number)>::min));
|
||||
};
|
||||
|
||||
// =================================================================================
|
||||
|
||||
// Support for streaming various numeric types in exactly the format I want. I
|
||||
// needed this in addition to all the assertions so that I could see exactly
|
||||
// what was going on.
|
||||
//
|
||||
// Numbers go through a 2-stage conversion process (by default, though, no real
|
||||
// conversion).
|
||||
//
|
||||
template <class T> struct stream_as {
|
||||
typedef T t1;
|
||||
typedef T t2;
|
||||
};
|
||||
|
||||
// char types first get converted to unsigned char, then to unsigned.
|
||||
template <> struct stream_as<char> {
|
||||
typedef unsigned char t1;
|
||||
typedef unsigned t2;
|
||||
};
|
||||
template <> struct stream_as<unsigned char> {
|
||||
typedef unsigned char t1; typedef unsigned t2;
|
||||
};
|
||||
template <> struct stream_as<signed char> {
|
||||
typedef unsigned char t1; typedef unsigned t2;
|
||||
};
|
||||
|
||||
#if defined(BOOST_MSVC) // No intmax streaming built-in
|
||||
|
||||
// On this platform, __int64 and __uint64 get streamed as strings
|
||||
template <> struct stream_as<boost::uintmax_t> {
|
||||
typedef std::string t1;
|
||||
typedef std::string t2;
|
||||
};
|
||||
|
||||
template <> struct stream_as<boost::intmax_t> {
|
||||
typedef std::string t1;
|
||||
typedef std::string t2;
|
||||
};
|
||||
#endif
|
||||
|
||||
// Standard promotion process for streaming
|
||||
template <class T> struct promote
|
||||
{
|
||||
static typename stream_as<T>::t1 from(T x) {
|
||||
typedef typename stream_as<T>::t1 t1;
|
||||
return t1(x);
|
||||
}
|
||||
};
|
||||
|
||||
#if defined(BOOST_MSVC) // No intmax streaming built-in
|
||||
|
||||
// On this platform, stream them as long/unsigned long if they fit.
|
||||
// Otherwise, write a string.
|
||||
template <> struct promote<boost::uintmax_t> {
|
||||
std::string static from(const boost::uintmax_t x) {
|
||||
if (x > ULONG_MAX)
|
||||
return std::string("large unsigned value");
|
||||
else
|
||||
return boost::lexical_cast<std::string>((unsigned long)x);
|
||||
}
|
||||
};
|
||||
template <> struct promote<boost::intmax_t> {
|
||||
std::string static from(const boost::intmax_t x) {
|
||||
if (x > boost::intmax_t(ULONG_MAX))
|
||||
return std::string("large positive signed value");
|
||||
else if (x >= 0)
|
||||
return boost::lexical_cast<std::string>((unsigned long)x);
|
||||
|
||||
if (x < boost::intmax_t(LONG_MIN))
|
||||
return std::string("large negative signed value");
|
||||
else
|
||||
return boost::lexical_cast<std::string>((long)x);
|
||||
}
|
||||
};
|
||||
#endif
|
||||
|
||||
// This is the function which converts types to the form I want to stream them in.
|
||||
template <class T>
|
||||
typename stream_as<T>::t2 stream_number(T x)
|
||||
{
|
||||
return promote<T>::from(x);
|
||||
}
|
||||
// =================================================================================
|
||||
|
||||
//
|
||||
// Tests for built-in signed and unsigned types
|
||||
//
|
||||
|
||||
// Tag types for selecting tests
|
||||
struct unsigned_tag {};
|
||||
struct signed_tag {};
|
||||
|
||||
// Tests for unsigned numbers. The extra default Number parameter works around
|
||||
// an MSVC bug.
|
||||
template <class Number>
|
||||
void test_aux(unsigned_tag, Number* = 0)
|
||||
{
|
||||
typedef typename boost::detail::numeric_traits<Number>::difference_type difference_type;
|
||||
BOOST_STATIC_ASSERT(!boost::detail::is_signed<Number>::value);
|
||||
BOOST_STATIC_ASSERT(
|
||||
(sizeof(Number) < sizeof(boost::intmax_t))
|
||||
| (boost::is_same<difference_type, boost::intmax_t>::value));
|
||||
|
||||
// Force casting to Number here to work around the fact that it's an enum on MSVC
|
||||
BOOST_STATIC_ASSERT(Number(complement_traits<Number>::max) > Number(0));
|
||||
BOOST_STATIC_ASSERT(Number(complement_traits<Number>::min) == Number(0));
|
||||
|
||||
const Number max = complement_traits<Number>::max;
|
||||
const Number min = complement_traits<Number>::min;
|
||||
|
||||
const Number test_max = (sizeof(Number) < sizeof(boost::intmax_t))
|
||||
? max
|
||||
: max / 2 - 1;
|
||||
|
||||
std::cout << std::hex << "(unsigned) min = " << stream_number(min) << ", max = "
|
||||
<< stream_number(max) << "..." << std::flush;
|
||||
std::cout << "difference_type = " << typeid(difference_type).name() << "..."
|
||||
<< std::flush;
|
||||
|
||||
difference_type d1 = boost::detail::numeric_distance(Number(0), test_max);
|
||||
difference_type d2 = boost::detail::numeric_distance(test_max, Number(0));
|
||||
|
||||
std::cout << "0->" << stream_number(test_max) << "==" << std::dec << stream_number(d1) << "; "
|
||||
<< std::hex << stream_number(test_max) << "->0==" << std::dec << stream_number(d2) << "..." << std::flush;
|
||||
|
||||
assert(d1 == difference_type(test_max));
|
||||
assert(d2 == -difference_type(test_max));
|
||||
}
|
||||
|
||||
// Tests for signed numbers. The extra default Number parameter works around an
|
||||
// MSVC bug.
|
||||
struct out_of_range_tag {};
|
||||
struct in_range_tag {};
|
||||
|
||||
// This test morsel gets executed for numbers whose difference will always be
|
||||
// representable in intmax_t
|
||||
template <class Number>
|
||||
void signed_test(in_range_tag, Number* = 0)
|
||||
{
|
||||
BOOST_STATIC_ASSERT(boost::detail::is_signed<Number>::value);
|
||||
typedef typename boost::detail::numeric_traits<Number>::difference_type difference_type;
|
||||
const Number max = complement_traits<Number>::max;
|
||||
const Number min = complement_traits<Number>::min;
|
||||
|
||||
difference_type d1 = boost::detail::numeric_distance(min, max);
|
||||
difference_type d2 = boost::detail::numeric_distance(max, min);
|
||||
|
||||
std::cout << stream_number(min) << "->" << stream_number(max) << "==";
|
||||
std::cout << std::dec << stream_number(d1) << "; ";
|
||||
std::cout << std::hex << stream_number(max) << "->" << stream_number(min)
|
||||
<< "==" << std::dec << stream_number(d2) << "..." << std::flush;
|
||||
assert(d1 == difference_type(max) - difference_type(min));
|
||||
assert(d2 == difference_type(min) - difference_type(max));
|
||||
}
|
||||
|
||||
// This test morsel gets executed for numbers whose difference may exceed the
|
||||
// capacity of intmax_t.
|
||||
template <class Number>
|
||||
void signed_test(out_of_range_tag, Number* = 0)
|
||||
{
|
||||
BOOST_STATIC_ASSERT(boost::detail::is_signed<Number>::value);
|
||||
typedef typename boost::detail::numeric_traits<Number>::difference_type difference_type;
|
||||
const Number max = complement_traits<Number>::max;
|
||||
const Number min = complement_traits<Number>::min;
|
||||
|
||||
difference_type min_distance = complement_traits<difference_type>::min;
|
||||
difference_type max_distance = complement_traits<difference_type>::max;
|
||||
|
||||
const Number n1 = Number(min + max_distance);
|
||||
const Number n2 = Number(max + min_distance);
|
||||
difference_type d1 = boost::detail::numeric_distance(min, n1);
|
||||
difference_type d2 = boost::detail::numeric_distance(max, n2);
|
||||
|
||||
std::cout << stream_number(min) << "->" << stream_number(n1) << "==";
|
||||
std::cout << std::dec << stream_number(d1) << "; ";
|
||||
std::cout << std::hex << stream_number(max) << "->" << stream_number(n2)
|
||||
<< "==" << std::dec << stream_number(d2) << "..." << std::flush;
|
||||
assert(d1 == max_distance);
|
||||
assert(d2 == min_distance);
|
||||
}
|
||||
|
||||
template <class Number>
|
||||
void test_aux(signed_tag, Number* = 0)
|
||||
{
|
||||
typedef typename boost::detail::numeric_traits<Number>::difference_type difference_type;
|
||||
BOOST_STATIC_ASSERT(boost::detail::is_signed<Number>::value);
|
||||
BOOST_STATIC_ASSERT(
|
||||
(sizeof(Number) < sizeof(boost::intmax_t))
|
||||
| (boost::is_same<difference_type, Number>::value));
|
||||
|
||||
// Force casting to Number here to work around the fact that it's an enum on MSVC
|
||||
BOOST_STATIC_ASSERT(Number(complement_traits<Number>::max) > Number(0));
|
||||
BOOST_STATIC_ASSERT(Number(complement_traits<Number>::min) < Number(0));
|
||||
|
||||
const Number max = complement_traits<Number>::max;
|
||||
const Number min = complement_traits<Number>::min;
|
||||
|
||||
std::cout << std::hex << "min = " << stream_number(min) << ", max = "
|
||||
<< stream_number(max) << "..." << std::flush;
|
||||
std::cout << "difference_type = " << typeid(difference_type).name() << "..."
|
||||
<< std::flush;
|
||||
|
||||
typedef typename boost::detail::if_true<
|
||||
(sizeof(Number) < sizeof(boost::intmax_t))>
|
||||
::template then<
|
||||
in_range_tag,
|
||||
out_of_range_tag
|
||||
>::type
|
||||
range_tag;
|
||||
signed_test<Number>(range_tag());
|
||||
}
|
||||
|
||||
|
||||
// Test for all numbers. The extra default Number parameter works around an MSVC
|
||||
// bug.
|
||||
template <class Number>
|
||||
void test(Number* = 0)
|
||||
{
|
||||
std::cout << "testing " << typeid(Number).name() << ":\n"
|
||||
#ifndef BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS
|
||||
<< "is_signed: " << (std::numeric_limits<Number>::is_signed ? "true\n" : "false\n")
|
||||
<< "is_bounded: " << (std::numeric_limits<Number>::is_bounded ? "true\n" : "false\n")
|
||||
<< "digits: " << std::numeric_limits<Number>::digits << "\n"
|
||||
#endif
|
||||
<< "..." << std::flush;
|
||||
|
||||
// factoring out difference_type for the assert below confused Borland :(
|
||||
typedef boost::detail::is_signed<
|
||||
#ifndef BOOST_MSVC
|
||||
typename
|
||||
#endif
|
||||
boost::detail::numeric_traits<Number>::difference_type
|
||||
> is_signed;
|
||||
BOOST_STATIC_ASSERT(is_signed::value);
|
||||
|
||||
typedef typename boost::detail::if_true<
|
||||
boost::detail::is_signed<Number>::value
|
||||
>::template then<signed_tag, unsigned_tag>::type signedness;
|
||||
|
||||
test_aux<Number>(signedness());
|
||||
std::cout << "passed" << std::endl;
|
||||
}
|
||||
|
||||
int main()
|
||||
{
|
||||
test<char>();
|
||||
test<unsigned char>();
|
||||
test<signed char>();
|
||||
test<wchar_t>();
|
||||
test<short>();
|
||||
test<unsigned short>();
|
||||
test<int>();
|
||||
test<unsigned int>();
|
||||
test<long>();
|
||||
test<unsigned long>();
|
||||
#if defined(ULLONG_MAX) || defined(ULONG_LONG_MAX)
|
||||
test<long long>();
|
||||
test<unsigned long long>();
|
||||
#elif defined(BOOST_MSVC)
|
||||
// The problem of not having compile-time static class constants other than
|
||||
// enums prevents this from working, since values get truncated.
|
||||
// test<boost::uintmax_t>();
|
||||
// test<boost::intmax_t>();
|
||||
#endif
|
||||
return 0;
|
||||
}
|
@@ -11,8 +11,8 @@
|
||||
|
||||
<h1><img src="../../c++boost.gif" alt="c++boost.gif (8819 bytes)" align="center" width="277" height="86">Header
|
||||
<a href="../../boost/operators.hpp">boost/operators.hpp</a></h1>
|
||||
<p>Header <a href="file:///c:/boost/site/boost/operators.hpp">boost/operators.hpp</a>
|
||||
supplies (in namespace boost) several sets of templates:</p>
|
||||
<p>Header <a href="../../boost/operators.hpp">boost/operators.hpp</a> supplies
|
||||
(in namespace boost) several sets of templates:</p>
|
||||
<ul>
|
||||
<li><a href="#Arithmetic">Arithmetic operators</a>.
|
||||
<li><a href="#deref and helpers">Dereference operators and iterator helpers.</a></li>
|
||||
@@ -43,10 +43,10 @@ additional operators, such as operator>, <=, >=, and +. <a href="
|
||||
forms</a> of the templates are also provided to allow interaction with other
|
||||
types.</p>
|
||||
<p><a href="http://www.boost.org/people/dave_abrahams.htm">Dave Abrahams</a>
|
||||
started the library and contributed the arithmetic operators in <a href="file:///c:/boost/site/boost/operators.hpp">boost/operators.hpp</a>.<br>
|
||||
started the library and contributed the arithmetic operators in <a href="../../boost/operators.hpp">boost/operators.hpp</a>.<br>
|
||||
<a href="http://www.boost.org/people/jeremy_siek.htm">Jeremy Siek</a>
|
||||
contributed the <a href="#deref and helpers">dereference operators and iterator
|
||||
helpers</a> in <a href="file:///c:/boost/site/boost/operators.hpp">boost/operators.hpp</a>.<br>
|
||||
helpers</a> in <a href="../../boost/operators.hpp">boost/operators.hpp</a>.<br>
|
||||
<a href="http://www.boost.org/people/aleksey_gurtovoy.htm">Aleksey Gurtovoy</a>
|
||||
contributed the code to support <a href="#chaining">base class chaining</a>
|
||||
while remaining backward-compatible with old versions of the library.<br>
|
||||
@@ -60,7 +60,7 @@ x >= y,</code> and <code>x <= y</code>. Moreover, unless your class has
|
||||
really surprising behavior, some of these related operators can be defined in
|
||||
terms of others (e.g. <code>x >= y <b><=></b> !(x < y)</code>).
|
||||
Replicating this boilerplate for multiple classes is both tedious and
|
||||
error-prone. The <a href="file:///c:/boost/site/boost/operators.hpp">boost/operators.hpp</a>
|
||||
error-prone. The <a href="../../boost/operators.hpp">boost/operators.hpp</a>
|
||||
templates help by generating operators for you at namespace scope based on other
|
||||
operators you've defined in your class.</p>
|
||||
<a name="two_arg">
|
||||
@@ -585,8 +585,7 @@ complicated than the old one, we think it's worth it to make the library more
|
||||
useful in real world. Alexy Gurtovoy contributed the code which supports the new
|
||||
usage idiom while allowing the library remain backward-compatible.</p>
|
||||
<hr>
|
||||
<p>Revised <!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %b %Y" startspan -->03 Aug 2000<!--webbot bot="Timestamp" endspan i-checksum="14750" -->
|
||||
</p>
|
||||
<p>Revised <!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %b %Y" startspan -->28 Sep 2000<!--webbot bot="Timestamp" endspan i-checksum="14938" --></p>
|
||||
<p><EFBFBD> Copyright David Abrahams and Beman Dawes 1999-2000. Permission to copy,
|
||||
use, modify, sell and distribute this document is granted provided this
|
||||
copyright notice appears in all copies. This document is provided "as
|
||||
|
391
projection_iterator.htm
Normal file
391
projection_iterator.htm
Normal file
@@ -0,0 +1,391 @@
|
||||
<html>
|
||||
|
||||
<head>
|
||||
<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
|
||||
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
|
||||
<meta name="ProgId" content="FrontPage.Editor.Document">
|
||||
<title>Projection Iterator Adaptor Documentation</title>
|
||||
</head>
|
||||
|
||||
<body bgcolor="#FFFFFF" text="#000000">
|
||||
|
||||
<img src="../../c++boost.gif" alt="c++boost.gif (8819 bytes)"
|
||||
align="center" width="277" height="86">
|
||||
|
||||
<h1>Projection Iterator Adaptor</h1>
|
||||
|
||||
Defined in header
|
||||
<a href="../../boost/iterator_adaptors.hpp">boost/iterator_adaptors.hpp</a>
|
||||
|
||||
<p>
|
||||
The projection iterator adaptor is similar to the <a
|
||||
href="./transform_iterator.htm">transform iterator adaptor</a> in that
|
||||
its <tt>operator*()</tt> applies some function to the result of
|
||||
dereferencing the base iterator and then returns the result. The
|
||||
difference is that the function must return a reference to some
|
||||
existing object (for example, a data member within the
|
||||
<tt>value_type</tt> of the base iterator). The following
|
||||
<b>pseudo-code</b> gives the basic idea. The data member <tt>p</tt> is
|
||||
the function object.
|
||||
|
||||
<pre>
|
||||
reference projection_iterator::operator*() const {
|
||||
return this->p(*this->base_iterator);
|
||||
}
|
||||
</pre>
|
||||
|
||||
<h2>Synopsis</h2>
|
||||
|
||||
<pre>
|
||||
namespace boost {
|
||||
template <class <a href="http://www.sgi.com/tech/stl/AdaptableUnaryFunction.html">AdaptableUnaryFunction</a>, class BaseIterator>
|
||||
struct projection_iterator_generator;
|
||||
|
||||
template <class <a href="http://www.sgi.com/tech/stl/AdaptableUnaryFunction.html">AdaptableUnaryFunction</a>,
|
||||
class BaseIterator, class ConstBaseIterator>
|
||||
struct projection_iterator_pair_generator;
|
||||
|
||||
template <class <a href="http://www.sgi.com/tech/stl/AdaptableUnaryFunction.html">AdaptableUnaryFunction</a>, class BaseIterator>
|
||||
typename projection_iterator_generator<AdaptableUnaryFunction, BaseIterator>::type
|
||||
make_projection_iterator(BaseIterator base,
|
||||
const AdaptableUnaryFunction& p = AdaptableUnaryFunction())
|
||||
|
||||
template <class <a href="http://www.sgi.com/tech/stl/AdaptableUnaryFunction.html">AdaptableUnaryFunction</a>, class ConstBaseIterator>
|
||||
typename projection_iterator_generator<AdaptableUnaryFunction, ConstBaseIterator>::type
|
||||
make_const_projection_iterator(ConstBaseIterator base,
|
||||
const AdaptableUnaryFunction& p = AdaptableUnaryFunction())
|
||||
}
|
||||
</pre>
|
||||
|
||||
<hr>
|
||||
|
||||
<h2><a name="projection_iterator_generator">The Projection Iterator Type
|
||||
Generator</a></h2>
|
||||
|
||||
The class <tt>projection_iterator_generator</tt> is a helper class
|
||||
whose purpose is to construct an projection iterator type. The main
|
||||
template parameter for this class is the <a
|
||||
href="http://www.sgi.com/tech/stl/AdaptableUnaryFunction.html"><tt>AdaptableUnaryFunction</tt></a>
|
||||
function object type and the <tt>BaseIterator</tt> type that is being
|
||||
wrapped.
|
||||
|
||||
<pre>
|
||||
template <class <a href="http://www.sgi.com/tech/stl/AdaptableUnaryFunction.html">AdaptableUnaryFunction</a>, class BaseIterator>
|
||||
class projection_iterator_generator
|
||||
{
|
||||
public:
|
||||
typedef <tt><a href="./iterator_adaptors.htm#iterator_adaptor">iterator_adaptor</a><...></tt> type; // the resulting projection iterator type
|
||||
};
|
||||
</pre>
|
||||
|
||||
<h3>Example</h3>
|
||||
|
||||
In the following example we have a list of personnel records. Each
|
||||
record has an employee's name and ID number. We want to be able to
|
||||
traverse through the list accessing either the name or the ID numbers
|
||||
of the employees using the projection iterator so we create the
|
||||
function object classes <tt>select_name</tt> and
|
||||
<tt>select_ID</tt>. We then use the
|
||||
<tt>projection_iterator_generator</tt> class to create a projection
|
||||
iterator and use it to print out the names of the employees.
|
||||
|
||||
<pre>
|
||||
#include <boost/config.hpp>
|
||||
#include <list>
|
||||
#include <iostream>
|
||||
#include <iterator>
|
||||
#include <algorithm>
|
||||
#include <string>
|
||||
#include <boost/iterator_adaptors.hpp>
|
||||
|
||||
struct personnel_record {
|
||||
personnel_record(std::string n, int id) : m_name(n), m_ID(id) { }
|
||||
std::string m_name;
|
||||
int m_ID;
|
||||
};
|
||||
|
||||
struct select_name {
|
||||
typedef personnel_record argument_type;
|
||||
typedef std::string result_type;
|
||||
const std::string& operator()(const personnel_record& r) const {
|
||||
return r.m_name;
|
||||
}
|
||||
std::string& operator()(personnel_record& r) const {
|
||||
return r.m_name;
|
||||
}
|
||||
};
|
||||
|
||||
struct select_ID {
|
||||
typedef personnel_record argument_type;
|
||||
typedef int result_type;
|
||||
const int& operator()(const personnel_record& r) const {
|
||||
return r.m_ID;
|
||||
}
|
||||
int& operator()(personnel_record& r) const {
|
||||
return r.m_ID;
|
||||
}
|
||||
};
|
||||
|
||||
int main(int, char*[])
|
||||
{
|
||||
std::list<personnel_record> personnel_list;
|
||||
|
||||
personnel_list.push_back(personnel_record("Barney", 13423));
|
||||
personnel_list.push_back(personnel_record("Fred", 12343));
|
||||
personnel_list.push_back(personnel_record("Wilma", 62454));
|
||||
personnel_list.push_back(personnel_record("Betty", 20490));
|
||||
|
||||
// Example of using projection_iterator_generator
|
||||
// to print out the names in the personnel list.
|
||||
|
||||
boost::projection_iterator_generator<select_name,
|
||||
std::list<personnel_record>::iterator>::type
|
||||
personnel_first(personnel_list.begin()),
|
||||
personnel_last(personnel_list.end());
|
||||
|
||||
std::copy(personnel_first, personnel_last,
|
||||
std::ostream_iterator<std::string>(std::cout, "\n"));
|
||||
std::cout << std::endl;
|
||||
|
||||
// to be continued...
|
||||
</pre>
|
||||
The output for this part is:
|
||||
<pre>
|
||||
Barney
|
||||
Fred
|
||||
Wilma
|
||||
Betty
|
||||
</pre>
|
||||
|
||||
<h3>Template Parameters</h3>
|
||||
|
||||
<Table border>
|
||||
<TR>
|
||||
<TH>Parameter</TH><TH>Description</TH>
|
||||
</TR>
|
||||
|
||||
<TR>
|
||||
<TD><a href="http://www.sgi.com/tech/stl/AdaptableUnaryFunction.html"><tt>AdaptableUnaryFunction</tt></a></TD>
|
||||
<TD>The type of the function object. The <tt>argument_type</tt> of the
|
||||
function must match the value type of the base iterator. The function
|
||||
should return a reference to the function's <tt>result_type</tt>.
|
||||
The <tt>result_type</tt> will be the resulting iterator's <tt>value_type</tt>.
|
||||
</TD>
|
||||
</TD>
|
||||
|
||||
<TR>
|
||||
<TD><tt>BaseIterator</tt></TD>
|
||||
<TD>The iterator type being wrapped.</TD>
|
||||
</TD>
|
||||
</TR>
|
||||
|
||||
</Table>
|
||||
|
||||
<h3>Model of</h3>
|
||||
|
||||
If the base iterator is a model of <a
|
||||
href="http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random
|
||||
Access Iterator</a> then so is the resulting projection iterator. If
|
||||
the base iterator supports less functionality than this the resulting
|
||||
projection iterator will also support less functionality.
|
||||
|
||||
<h3>Members</h3>
|
||||
|
||||
The projection iterator type implements the member functions and
|
||||
operators required of the <a
|
||||
href="http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random
|
||||
Access Iterator</a> concept.
|
||||
In addition it has the following constructor:
|
||||
|
||||
<pre>
|
||||
projection_iterator_generator::type(const BaseIterator& it,
|
||||
const AdaptableUnaryFunction& p = AdaptableUnaryFunction())
|
||||
</pre>
|
||||
|
||||
<p>
|
||||
<hr>
|
||||
<p>
|
||||
|
||||
<h2><a name="projection_iterator_pair_generator">The Projection Iterator Pair
|
||||
Generator</a></h2>
|
||||
|
||||
Sometimes a mutable/const pair of iterator types is needed, such as
|
||||
when implementing a container type. The
|
||||
<tt>projection_iterator_pair_generator</tt> class makes it more
|
||||
convenient to create this pair of iterator types.
|
||||
|
||||
<pre>
|
||||
template <class <a href="http://www.sgi.com/tech/stl/AdaptableUnaryFunction.html">AdaptableUnaryFunction</a>, class BaseIterator, class ConstBaseIterator>
|
||||
class projection_iterator_pair_generator
|
||||
{
|
||||
public:
|
||||
typedef <tt><a href="./iterator_adaptors.htm#iterator_adaptor">iterator_adaptor</a><...></tt> iterator; // the mutable projection iterator type
|
||||
typedef <tt><a href="./iterator_adaptors.htm#iterator_adaptor">iterator_adaptor</a><...></tt> const_iterator; // the immutable projection iterator type
|
||||
};
|
||||
</pre>
|
||||
|
||||
<h3>Example</h3>
|
||||
|
||||
In this part of the example we use the
|
||||
<tt>projection_iterator_pair_generator</tt> to create a mutable/const
|
||||
pair of projection iterators that access the ID numbers of the
|
||||
personnel. We use the mutable iterator to re-index the ID numbers from
|
||||
zero. We then use the constant iterator to print the ID numbers out.
|
||||
|
||||
<pre>
|
||||
// continuing from the last example...
|
||||
|
||||
typedef boost::projection_iterator_pair_generator<select_ID,
|
||||
std::list<personnel_record>::iterator,
|
||||
std::list<personnel_record>::const_iterator> PairGen;
|
||||
|
||||
PairGen::iterator ID_first(personnel_list.begin()),
|
||||
ID_last(personnel_list.end());
|
||||
|
||||
int new_id = 0;
|
||||
while (ID_first != ID_last) {
|
||||
*ID_first = new_id++;
|
||||
++ID_first;
|
||||
}
|
||||
|
||||
PairGen::const_iterator const_ID_first(personnel_list.begin()),
|
||||
const_ID_last(personnel_list.end());
|
||||
|
||||
std::copy(const_ID_first, const_ID_last,
|
||||
std::ostream_iterator<int>(std::cout, " "));
|
||||
std::cout << std::endl;
|
||||
std::cout << std::endl;
|
||||
|
||||
// to be continued...
|
||||
</pre>
|
||||
The output is:
|
||||
<pre>
|
||||
0 1 2 3
|
||||
</pre>
|
||||
|
||||
<h3>Template Parameters</h3>
|
||||
|
||||
<Table border>
|
||||
<TR>
|
||||
<TH>Parameter</TH><TH>Description</TH>
|
||||
</TR>
|
||||
|
||||
<TR>
|
||||
<TD><a href="http://www.sgi.com/tech/stl/AdaptableUnaryFunction.html"><tt>AdaptableUnaryFunction</tt></a></TD>
|
||||
<TD>The type of the function object. The <tt>argument_type</tt> of the
|
||||
function must match the value type of the base iterator. The function
|
||||
should return a true reference to the function's <tt>result_type</tt>.
|
||||
The <tt>result_type</tt> will be the resulting iterator's <tt>value_type</tt>.
|
||||
</TD>
|
||||
</TD>
|
||||
|
||||
<TR>
|
||||
<TD><tt>BaseIterator</tt></TD>
|
||||
<TD>The mutable iterator type being wrapped.</TD>
|
||||
</TD>
|
||||
</TR>
|
||||
|
||||
<TR>
|
||||
<TD><tt>ConstBaseIterator</tt></TD>
|
||||
<TD>The constant iterator type being wrapped.</TD>
|
||||
</TD>
|
||||
</TR>
|
||||
|
||||
</Table>
|
||||
|
||||
<h3>Model of</h3>
|
||||
|
||||
If the base iterator types model the <a
|
||||
href="http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random
|
||||
Access Iterator</a> then so do the resulting projection iterator
|
||||
types. If the base iterators support less functionality the
|
||||
resulting projection iterator types will also support less
|
||||
functionality. The resulting <tt>iterator</tt> type is mutable, and
|
||||
the resulting <tt>const_iterator</tt> type is constant.
|
||||
|
||||
<h3>Members</h3>
|
||||
|
||||
The resulting <tt>iterator</tt> and <tt>const_iterator</tt> types
|
||||
implements the member functions and operators required of the <a
|
||||
href="http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random
|
||||
Access Iterator</a> concept. In addition they support the following
|
||||
constructors:
|
||||
|
||||
<pre>
|
||||
projection_iterator_pair_generator::iterator(const BaseIterator& it,
|
||||
const AdaptableUnaryFunction& p = AdaptableUnaryFunction())</pre>
|
||||
|
||||
<pre>
|
||||
projection_iterator_pair_generator::const_iterator(const BaseIterator& it,
|
||||
const AdaptableUnaryFunction& p = AdaptableUnaryFunction())
|
||||
</pre>
|
||||
|
||||
<p>
|
||||
<hr>
|
||||
<p>
|
||||
|
||||
<h2><a name="make_projection_iterator">The Projection Iterator Object Generators</a></h2>
|
||||
|
||||
The <tt>make_projection_iterator()</tt> and
|
||||
<tt>make_const_projection_iterator()</tt> functions provide a more
|
||||
convenient way to create projection iterator objects. The functions
|
||||
save the user the trouble of explicitly writing out the iterator
|
||||
types.
|
||||
|
||||
<pre>
|
||||
template <class <a href="http://www.sgi.com/tech/stl/AdaptableUnaryFunction.html">AdaptableUnaryFunction</a>, class BaseIterator>
|
||||
typename projection_iterator_generator<AdaptableUnaryFunction, BaseIterator>::type
|
||||
make_projection_iterator(BaseIterator base,
|
||||
const AdaptableUnaryFunction& p = AdaptableUnaryFunction())
|
||||
|
||||
template <class <a href="http://www.sgi.com/tech/stl/AdaptableUnaryFunction.html">AdaptableUnaryFunction</a>, class ConstBaseIterator>
|
||||
typename projection_iterator_generator<AdaptableUnaryFunction, ConstBaseIterator>::type
|
||||
make_const_projection_iterator(ConstBaseIterator base,
|
||||
const AdaptableUnaryFunction& p = AdaptableUnaryFunction())
|
||||
</pre>
|
||||
|
||||
|
||||
<h3>Example</h3>
|
||||
|
||||
In this part of the example, we again print out the names of the
|
||||
personnel, but this time we use the
|
||||
<tt>make_const_projection_iterator()</tt> function to save some typing.
|
||||
|
||||
<pre>
|
||||
// continuing from the last example...
|
||||
|
||||
std::copy
|
||||
(boost::make_const_projection_iterator<select_name>(personnel_list.begin()),
|
||||
boost::make_const_projection_iterator<select_name>(personnel_list.end()),
|
||||
std::ostream_iterator<std::string>(std::cout, "\n"));
|
||||
|
||||
return 0;
|
||||
}
|
||||
</pre>
|
||||
The output is:
|
||||
<pre>
|
||||
Barney
|
||||
Fred
|
||||
Wilma
|
||||
Betty
|
||||
</pre>
|
||||
|
||||
<hr>
|
||||
<p>Revised <!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %b %Y" startspan -->28 Feb 2001<!--webbot bot="Timestamp" endspan i-checksum="14390" --></p>
|
||||
<p><EFBFBD> Copyright Jeremy Siek 2000. Permission to copy, use,
|
||||
modify, sell and distribute this document is granted provided this copyright
|
||||
notice appears in all copies. This document is provided "as is"
|
||||
without express or implied warranty, and with no claim as to its suitability for
|
||||
any purpose.</p>
|
||||
|
||||
</body>
|
||||
|
||||
</html>
|
||||
<!-- LocalWords: html charset alt gif hpp BaseIterator const namespace struct
|
||||
-->
|
||||
<!-- LocalWords: ConstPointer ConstReference typename iostream int abcdefg
|
||||
-->
|
||||
<!-- LocalWords: sizeof PairGen pre Siek htm AdaptableUnaryFunction
|
||||
-->
|
||||
<!-- LocalWords: ConstBaseIterator
|
||||
-->
|
96
projection_iterator_example.cpp
Normal file
96
projection_iterator_example.cpp
Normal file
@@ -0,0 +1,96 @@
|
||||
// (C) Copyright Jeremy Siek 2000. Permission to copy, use, modify, sell and
|
||||
// distribute this software is granted provided this copyright notice appears
|
||||
// in all copies. This software is provided "as is" without express or implied
|
||||
// warranty, and with no claim as to its suitability for any purpose.
|
||||
|
||||
#include <boost/config.hpp>
|
||||
#include <list>
|
||||
#include <iostream>
|
||||
#include <iterator>
|
||||
#include <algorithm>
|
||||
#include <string>
|
||||
#include <boost/iterator_adaptors.hpp>
|
||||
|
||||
struct personnel_record {
|
||||
personnel_record(std::string n, int id) : m_name(n), m_ID(id) { }
|
||||
std::string m_name;
|
||||
int m_ID;
|
||||
};
|
||||
|
||||
struct select_name {
|
||||
typedef personnel_record argument_type;
|
||||
typedef std::string result_type;
|
||||
const std::string& operator()(const personnel_record& r) const {
|
||||
return r.m_name;
|
||||
}
|
||||
std::string& operator()(personnel_record& r) const {
|
||||
return r.m_name;
|
||||
}
|
||||
};
|
||||
|
||||
struct select_ID {
|
||||
typedef personnel_record argument_type;
|
||||
typedef int result_type;
|
||||
const int& operator()(const personnel_record& r) const {
|
||||
return r.m_ID;
|
||||
}
|
||||
int& operator()(personnel_record& r) const {
|
||||
return r.m_ID;
|
||||
}
|
||||
};
|
||||
|
||||
int main(int, char*[])
|
||||
{
|
||||
std::list<personnel_record> personnel_list;
|
||||
|
||||
personnel_list.push_back(personnel_record("Barney", 13423));
|
||||
personnel_list.push_back(personnel_record("Fred", 12343));
|
||||
personnel_list.push_back(personnel_record("Wilma", 62454));
|
||||
personnel_list.push_back(personnel_record("Betty", 20490));
|
||||
|
||||
// Example of using projection_iterator_generator
|
||||
// to print out the names in the personnel list.
|
||||
|
||||
boost::projection_iterator_generator<select_name,
|
||||
std::list<personnel_record>::iterator>::type
|
||||
personnel_first(personnel_list.begin()),
|
||||
personnel_last(personnel_list.end());
|
||||
|
||||
std::copy(personnel_first, personnel_last,
|
||||
std::ostream_iterator<std::string>(std::cout, "\n"));
|
||||
std::cout << std::endl;
|
||||
|
||||
// Example of using projection_iterator_pair_generator
|
||||
// to assign new ID numbers to the personnel.
|
||||
|
||||
typedef boost::projection_iterator_pair_generator<select_ID,
|
||||
std::list<personnel_record>::iterator,
|
||||
std::list<personnel_record>::const_iterator> PairGen;
|
||||
|
||||
PairGen::iterator ID_first(personnel_list.begin()),
|
||||
ID_last(personnel_list.end());
|
||||
|
||||
int new_id = 0;
|
||||
while (ID_first != ID_last) {
|
||||
*ID_first = new_id++;
|
||||
++ID_first;
|
||||
}
|
||||
|
||||
PairGen::const_iterator const_ID_first(personnel_list.begin()),
|
||||
const_ID_last(personnel_list.end());
|
||||
|
||||
std::copy(const_ID_first, const_ID_last,
|
||||
std::ostream_iterator<int>(std::cout, " "));
|
||||
std::cout << std::endl;
|
||||
std::cout << std::endl;
|
||||
|
||||
// Example of using make_const_projection_iterator()
|
||||
// to print out the names in the personnel list again.
|
||||
|
||||
std::copy
|
||||
(boost::make_const_projection_iterator<select_name>(personnel_list.begin()),
|
||||
boost::make_const_projection_iterator<select_name>(personnel_list.end()),
|
||||
std::ostream_iterator<std::string>(std::cout, "\n"));
|
||||
|
||||
return 0;
|
||||
}
|
331
reverse_iterator.htm
Normal file
331
reverse_iterator.htm
Normal file
@@ -0,0 +1,331 @@
|
||||
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 3.2//EN">
|
||||
|
||||
<html>
|
||||
<head>
|
||||
<meta name="generator" content="HTML Tidy, see www.w3.org">
|
||||
<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
|
||||
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
|
||||
<meta name="ProgId" content="FrontPage.Editor.Document">
|
||||
|
||||
<title>Reverse Iterator Adaptor Documentation</title>
|
||||
</head>
|
||||
|
||||
<body bgcolor="#FFFFFF" text="#000000">
|
||||
<img src="../../c++boost.gif" alt="c++boost.gif (8819 bytes)" align=
|
||||
"center" width="277" height="86">
|
||||
|
||||
<h1>Reverse Iterator Adaptor</h1>
|
||||
Defined in header <a href=
|
||||
"../../boost/iterator_adaptors.hpp">boost/iterator_adaptors.hpp</a>
|
||||
|
||||
<p>The reverse iterator adaptor flips the direction of a base iterator's
|
||||
motion. Invoking <tt>operator++()</tt> moves the base iterator backward and
|
||||
invoking <tt>operator--()</tt> moves the base iterator forward. The Boost
|
||||
reverse iterator adaptor is better to use than the
|
||||
<tt>std::reverse_iterator</tt> class in situations where pairs of
|
||||
mutable/constant iterators are needed (e.g., in containers) because
|
||||
comparisons and conversions between the mutable and const versions are
|
||||
implemented correctly.
|
||||
|
||||
<h2>Synopsis</h2>
|
||||
<pre>
|
||||
namespace boost {
|
||||
template <class <a href=
|
||||
"http://www.sgi.com/tech/stl/BidirectionalIterator.html">BidirectionalIterator</a>,
|
||||
class Value, class Reference, class Pointer, class Category, class Distance>
|
||||
struct reverse_iterator_generator;
|
||||
|
||||
template <class <a href=
|
||||
"http://www.sgi.com/tech/stl/BidirectionalIterator.html">BidirectionalIterator</a>>
|
||||
typename reverse_iterator_generator<BidirectionalIterator>::type
|
||||
make_reverse_iterator(BidirectionalIterator base)
|
||||
}
|
||||
</pre>
|
||||
<hr>
|
||||
|
||||
<h2><a name="reverse_iterator_generator">The Reverse Iterator Type
|
||||
Generator</a></h2>
|
||||
The <tt>reverse_iterator_generator</tt> template is a <a href=
|
||||
"../../more/generic_programming.html#type_generator">generator</a> of
|
||||
reverse iterator types. The main template parameter for this class is the
|
||||
base <tt>BidirectionalIterator</tt> type that is being adapted. In most
|
||||
cases the associated types of the base iterator can be deduced using
|
||||
<tt>std::iterator_traits</tt>, but in some situations the user may want to
|
||||
override these types, so there are also template parameters for the base
|
||||
iterator's associated types.
|
||||
|
||||
<blockquote>
|
||||
<pre>
|
||||
template <class <a href=
|
||||
"http://www.sgi.com/tech/stl/BidirectionalIterator.html">BidirectionalIterator</a>,
|
||||
class Value, class Reference, class Pointer, class Category, class Distance>
|
||||
class reverse_iterator_generator
|
||||
{
|
||||
public:
|
||||
typedef <tt><a href=
|
||||
"./iterator_adaptors.htm#iterator_adaptor">iterator_adaptor</a><...></tt> type; // the resulting reverse iterator type
|
||||
};
|
||||
</pre>
|
||||
</blockquote>
|
||||
|
||||
<h3>Example</h3>
|
||||
In this example we sort a sequence of letters and then output the sequence
|
||||
in descending order using reverse iterators.
|
||||
|
||||
<blockquote>
|
||||
<pre>
|
||||
#include <boost/config.hpp>
|
||||
#include <iostream>
|
||||
#include <algorithm>
|
||||
#include <boost/iterator_adaptors.hpp>
|
||||
|
||||
int main(int, char*[])
|
||||
{
|
||||
char letters[] = "hello world!";
|
||||
const int N = sizeof(letters)/sizeof(char) - 1;
|
||||
std::cout << "original sequence of letters:\t"
|
||||
<< letters << std::endl;
|
||||
|
||||
std::sort(letters, letters + N);
|
||||
|
||||
// Use reverse_iterator_generator to print a sequence
|
||||
// of letters in reverse order.
|
||||
|
||||
boost::reverse_iterator_generator<char*>::type
|
||||
reverse_letters_first(letters + N),
|
||||
reverse_letters_last(letters);
|
||||
|
||||
std::cout << "letters in descending order:\t";
|
||||
std::copy(reverse_letters_first, reverse_letters_last,
|
||||
std::ostream_iterator<char>(std::cout));
|
||||
std::cout << std::endl;
|
||||
|
||||
// to be continued...
|
||||
</pre>
|
||||
</blockquote>
|
||||
The output is:
|
||||
|
||||
<blockquote>
|
||||
<pre>
|
||||
original sequence of letters: hello world!
|
||||
letters in descending order: wroolllhed!
|
||||
</pre>
|
||||
</blockquote>
|
||||
|
||||
<h3>Template Parameters</h3>
|
||||
|
||||
<table border>
|
||||
<tr>
|
||||
<th>Parameter
|
||||
|
||||
<th>Description
|
||||
|
||||
<tr>
|
||||
<td><tt><a href=
|
||||
"http://www.sgi.com/tech/stl/BidirectionalIterator.html">BidirectionalIterator</a></tt>
|
||||
|
||||
|
||||
<td>The iterator type being wrapped.
|
||||
|
||||
<tr>
|
||||
<td><tt>Value</tt>
|
||||
|
||||
<td>The value-type of the base iterator and the resulting reverse
|
||||
iterator.<br>
|
||||
<b>Default:</b><tt>std::iterator_traits<BidirectionalIterator>::value_type</tt>
|
||||
|
||||
|
||||
<tr>
|
||||
<td><tt>Reference</tt>
|
||||
|
||||
<td>The <tt>reference</tt> type of the resulting iterator, and in
|
||||
particular, the result type of <tt>operator*()</tt>.<br>
|
||||
<b>Default:</b> If <tt>Value</tt> is supplied, <tt>Value&</tt> is
|
||||
used. Otherwise
|
||||
<tt>std::iterator_traits<BidirectionalIterator>::reference</tt>
|
||||
is used.
|
||||
|
||||
<tr>
|
||||
<td><tt>Pointer</tt>
|
||||
|
||||
<td>The <tt>pointer</tt> type of the resulting iterator, and in
|
||||
particular, the result type of <tt>operator->()</tt>.<br>
|
||||
<b>Default:</b> If <tt>Value</tt> was supplied, then <tt>Value*</tt>,
|
||||
otherwise
|
||||
<tt>std::iterator_traits<BidirectionalIterator>::pointer</tt>.
|
||||
|
||||
<tr>
|
||||
<td><tt>Category</tt>
|
||||
|
||||
<td>The <tt>iterator_category</tt> type for the resulting iterator.<br>
|
||||
<b>Default:</b>
|
||||
<tt>std::iterator_traits<BidirectionalIterator>::iterator_category</tt>
|
||||
|
||||
|
||||
<tr>
|
||||
<td><tt>Distance</tt>
|
||||
|
||||
<td>The <tt>difference_type</tt> for the resulting iterator.<br>
|
||||
<b>Default:</b>
|
||||
<tt>std::iterator_traits<BidirectionalIterator&gt::difference_type</tt>
|
||||
|
||||
</table>
|
||||
|
||||
<h3>Concept Model</h3>
|
||||
The indirect iterator will model whichever <a href=
|
||||
"http://www.sgi.com/tech/stl/Iterators.html">standard iterator concept
|
||||
category</a> is modeled by the base iterator. Thus, if the base iterator is
|
||||
a model of <a href=
|
||||
"http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random Access
|
||||
Iterator</a> then so is the resulting indirect iterator. If the base
|
||||
iterator models a more restrictive concept, the resulting indirect iterator
|
||||
will model the same concept. The base iterator must be at least a <a href=
|
||||
"http://www.sgi.com/tech/stl/BidirectionalIterator.html">Bidirectional
|
||||
Iterator</a>
|
||||
|
||||
<h3>Members</h3>
|
||||
The reverse iterator type implements the member functions and operators
|
||||
required of the <a href=
|
||||
"http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random Access
|
||||
Iterator</a> concept. In addition it has the following constructor:
|
||||
|
||||
<blockquote>
|
||||
<pre>
|
||||
reverse_iterator_generator::type(const BidirectionalIterator& it)
|
||||
</pre>
|
||||
</blockquote>
|
||||
|
||||
|
||||
<br>
|
||||
<br>
|
||||
|
||||
<hr>
|
||||
|
||||
<p>
|
||||
|
||||
<h2><a name="make_reverse_iterator">The Reverse Iterator Object
|
||||
Generator</a></h2>
|
||||
The <tt>make_reverse_iterator()</tt> function provides a more convenient
|
||||
way to create reverse iterator objects. The function saves the user the
|
||||
trouble of explicitly writing out the iterator types.
|
||||
|
||||
<blockquote>
|
||||
<pre>
|
||||
template <class BidirectionalIterator>
|
||||
typename reverse_iterator_generator<BidirectionalIterator>::type
|
||||
make_reverse_iterator(BidirectionalIterator base);
|
||||
</pre>
|
||||
</blockquote>
|
||||
|
||||
<h3>Example</h3>
|
||||
In this part of the example we use <tt>make_reverse_iterator()</tt> to
|
||||
print the sequence of letters in reverse-reverse order, which is the
|
||||
original order.
|
||||
|
||||
<blockquote>
|
||||
<pre>
|
||||
// continuing from the previous example...
|
||||
|
||||
std::cout << "letters in ascending order:\t";
|
||||
std::copy(boost::make_reverse_iterator(reverse_letters_last),
|
||||
boost::make_reverse_iterator(reverse_letters_first),
|
||||
std::ostream_iterator<char>(std::cout));
|
||||
std::cout << std::endl;
|
||||
|
||||
return 0;
|
||||
}
|
||||
</pre>
|
||||
</blockquote>
|
||||
The output is:
|
||||
|
||||
<blockquote>
|
||||
<pre>
|
||||
letters in ascending order: !dehllloorw
|
||||
</pre>
|
||||
</blockquote>
|
||||
<hr>
|
||||
|
||||
<h2><a name="interactions">Constant/Mutable Iterator Interactions</a></h2>
|
||||
|
||||
<p>One failing of the standard <tt><a
|
||||
href="http://www.sgi.com/tech/stl/ReverseIterator.html">reverse_iterator</a></tt>
|
||||
adaptor is that it doesn't properly support interactions between adapted
|
||||
<tt>const</tt> and non-<tt>const</tt> iterators. For example:
|
||||
<blockquote>
|
||||
<pre>
|
||||
#include <vector>
|
||||
|
||||
template <class T> void convert(T x) {}
|
||||
|
||||
// Test interactions of a matched pair of random access iterators
|
||||
template <class Iterator, class ConstIterator>
|
||||
void test_interactions(Iterator i, ConstIterator ci)
|
||||
{
|
||||
bool eq = i == ci; // comparisons
|
||||
bool ne = i != ci;
|
||||
bool lt = i < ci;
|
||||
bool le = i <= ci;
|
||||
bool gt = i > ci;
|
||||
bool ge = i >= ci;
|
||||
std::size_t distance = i - ci; // difference
|
||||
ci = i; // assignment
|
||||
ConstIterator ci2(i); // construction
|
||||
convert<ConstIterator>(i); // implicit conversion
|
||||
}
|
||||
|
||||
void f()
|
||||
{
|
||||
typedef std::vector<int> vec;
|
||||
vec v;
|
||||
const vec& cv;
|
||||
|
||||
test_interactions(v.begin(), cv.begin()); // <font color="#007F00">OK</font>
|
||||
test_interactions(v.rbegin(), cv.rbegin()); // <font color="#FF0000">ERRORS ON EVERY TEST!!</font>
|
||||
</pre>
|
||||
</blockquote>
|
||||
Reverse iterators created with <tt>boost::reverse_iterator_generator</tt> don't have this problem, though:
|
||||
<blockquote>
|
||||
<pre>
|
||||
typedef boost::reverse_iterator_generator<vec::iterator>::type ri;
|
||||
typedef boost::reverse_iterator_generator<vec::const_iterator>::type cri;
|
||||
test_interactions(ri(v.begin()), cri(cv.begin())); // <font color="#007F00">OK!!</font>
|
||||
</pre>
|
||||
</blockquote>
|
||||
Or, more simply,
|
||||
<blockquote>
|
||||
<pre>
|
||||
test_interactions(
|
||||
boost::make_reverse_iterator(v.begin()),
|
||||
boost::make_reverse_iterator(cv.begin())); // <font color="#007F00">OK!!</font>
|
||||
}
|
||||
</pre>
|
||||
</blockquote>
|
||||
|
||||
<p>If you are wondering why there is no
|
||||
<tt>reverse_iterator_pair_generator</tt> in the manner of <tt><a
|
||||
href="projection_iterator.htm#projection_iterator_pair_generator">projection_iterator_pair_generator</a></tt>,
|
||||
the answer is simple: we tried it, but found that in practice it took
|
||||
<i>more</i> typing to use <tt>reverse_iterator_pair_generator</tt> than to
|
||||
simply use <tt>reverse_iterator_generator</tt> twice!<br><br>
|
||||
|
||||
<hr>
|
||||
|
||||
|
||||
<p>Revised
|
||||
<!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %b %Y" startspan -->28 Feb 2001<!--webbot bot="Timestamp" endspan i-checksum="14390" -->
|
||||
|
||||
|
||||
<p>© Copyright Jeremy Siek 2000. Permission to copy, use, modify, sell
|
||||
and distribute this document is granted provided this copyright notice
|
||||
appears in all copies. This document is provided "as is" without express or
|
||||
implied warranty, and with no claim as to its suitability for any purpose.
|
||||
<!-- LocalWords: html charset alt gif hpp BidirectionalIterator const namespace struct
|
||||
-->
|
||||
|
||||
<!-- LocalWords: ConstPointer ConstReference typename iostream int abcdefg
|
||||
-->
|
||||
<!-- LocalWords: sizeof PairGen pre Siek wroolllhed dehllloorw
|
||||
-->
|
||||
</body>
|
||||
</html>
|
||||
|
42
reverse_iterator_example.cpp
Normal file
42
reverse_iterator_example.cpp
Normal file
@@ -0,0 +1,42 @@
|
||||
// (C) Copyright Jeremy Siek 2000. Permission to copy, use, modify, sell and
|
||||
// distribute this software is granted provided this copyright notice appears
|
||||
// in all copies. This software is provided "as is" without express or implied
|
||||
// warranty, and with no claim as to its suitability for any purpose.
|
||||
|
||||
#include <boost/config.hpp>
|
||||
#include <iostream>
|
||||
#include <algorithm>
|
||||
#include <boost/iterator_adaptors.hpp>
|
||||
|
||||
int main(int, char*[])
|
||||
{
|
||||
char letters[] = "hello world!";
|
||||
const int N = sizeof(letters)/sizeof(char) - 1;
|
||||
std::cout << "original sequence of letters:\t"
|
||||
<< letters << std::endl;
|
||||
|
||||
std::sort(letters, letters + N);
|
||||
|
||||
// Use reverse_iterator_generator to print a sequence
|
||||
// of letters in reverse order.
|
||||
|
||||
boost::reverse_iterator_generator<char*>::type
|
||||
reverse_letters_first(letters + N),
|
||||
reverse_letters_last(letters);
|
||||
|
||||
std::cout << "letters in descending order:\t";
|
||||
std::copy(reverse_letters_first, reverse_letters_last,
|
||||
std::ostream_iterator<char>(std::cout));
|
||||
std::cout << std::endl;
|
||||
|
||||
// Use make_reverse_iterator() to print the sequence
|
||||
// of letters in reverse-reverse order.
|
||||
|
||||
std::cout << "letters in ascending order:\t";
|
||||
std::copy(boost::make_reverse_iterator(reverse_letters_last),
|
||||
boost::make_reverse_iterator(reverse_letters_first),
|
||||
std::ostream_iterator<char>(std::cout));
|
||||
std::cout << std::endl;
|
||||
|
||||
return 0;
|
||||
}
|
137
tie.html
Normal file
137
tie.html
Normal file
@@ -0,0 +1,137 @@
|
||||
<HTML>
|
||||
<!--
|
||||
-- Copyright (c) Jeremy Siek, Lie-Quan Lee, and Andrew Lumsdaine 2000
|
||||
--
|
||||
-- Permission to use, copy, modify, distribute and sell this software
|
||||
-- and its documentation for any purpose is hereby granted without fee,
|
||||
-- provided that the above copyright notice appears in all copies and
|
||||
-- that both that copyright notice and this permission notice appear
|
||||
-- in supporting documentation. We make no
|
||||
-- representations about the suitability of this software for any
|
||||
-- purpose. It is provided "as is" without express or implied warranty.
|
||||
-->
|
||||
<Head>
|
||||
<Title>Boost Tie</Title>
|
||||
<BODY BGCOLOR="#ffffff" LINK="#0000ee" TEXT="#000000" VLINK="#551a8b"
|
||||
ALINK="#ff0000">
|
||||
<IMG SRC="../../c++boost.gif"
|
||||
ALT="C++ Boost" width="277" height="86">
|
||||
|
||||
<BR Clear>
|
||||
|
||||
<H1><A NAME="sec:tie"></A>
|
||||
<TT>tie</TT>
|
||||
</H1>
|
||||
|
||||
<P>
|
||||
<PRE>
|
||||
template <class A, class B>
|
||||
tied<A,B> tie(A& a, B& b);
|
||||
</PRE>
|
||||
|
||||
<P>
|
||||
This is a utility function that makes it more convenient to work with
|
||||
a function which returns a std::pair<>. The effect of the <TT>tie()</TT>
|
||||
function is to allow the assignment of the two values of the pair to
|
||||
two separate variables. The idea for this comes from Jaakko
|
||||
Järvi's Binders [<A
|
||||
HREF="../graph/doc/bibliography.html#jaakko_tuple_assign">1</A>].
|
||||
|
||||
<P>
|
||||
|
||||
<H3>Where Defined</H3>
|
||||
|
||||
<P>
|
||||
<a href="../../boost/utility.hpp"><TT>boost/utility.hpp</TT></a>
|
||||
|
||||
<P>
|
||||
|
||||
<H3>Example</H3>
|
||||
|
||||
<P>
|
||||
An example of using the <TT>tie()</TT> function with the
|
||||
<TT>vertices()</TT> function, which returns a pair of
|
||||
type <TT>std::pair<vertex_iterator,vertex_iterator></TT>. The
|
||||
pair of iterators is assigned to the iterator variables <TT>i</TT> and
|
||||
<TT>end</TT>.
|
||||
|
||||
<P>
|
||||
<PRE>
|
||||
graph_traits< adjacency_list<> >::vertex_iterator i, end;
|
||||
for(tie(i,end) = vertices(G); i != end; ++i)
|
||||
// ...
|
||||
</PRE>
|
||||
|
||||
<P>
|
||||
Here is another example that uses <TT>tie()</TT> for handling operations with <a
|
||||
href="http://www.sgi.com/Technology/STL/set.html"><TT>std::set</TT></a>.
|
||||
|
||||
<P>
|
||||
<PRE>
|
||||
#include <set>
|
||||
#include <algorithm>
|
||||
#include <iostream>
|
||||
#include <boost/utility.hpp>
|
||||
|
||||
int
|
||||
main(int, char*[])
|
||||
{
|
||||
{
|
||||
typedef std::set<int> SetT;
|
||||
SetT::iterator i, end;
|
||||
bool inserted;
|
||||
|
||||
int vals[5] = { 5, 2, 4, 9, 1 };
|
||||
SetT s(vals, vals + 5);
|
||||
|
||||
// Using tie() with a return value of pair<iterator,bool>
|
||||
|
||||
int new_vals[2] = { 3, 9 };
|
||||
|
||||
for (int k = 0; k < 2; ++k) {
|
||||
boost::tie(i,inserted) = s.insert(new_vals[k]);
|
||||
if (!inserted)
|
||||
std::cout << *i << " was already in the set." << std::endl;
|
||||
else
|
||||
std::cout << *i << " successfully inserted." << std::endl;
|
||||
}
|
||||
}
|
||||
{
|
||||
int* i, *end;
|
||||
int vals[6] = { 5, 2, 4, 4, 9, 1 };
|
||||
std::sort(vals, vals + 6);
|
||||
|
||||
// Using tie() with a return value of pair<iterator,iterator>
|
||||
|
||||
boost::tie(i,end) = std::equal_range(vals, vals + 6, 4);
|
||||
std::cout << "There were " << std::distance(i,end)
|
||||
<< " occurrences of " << *i << "." << std::endl;
|
||||
// Footnote: of course one would normally just use std::count()
|
||||
// to get this information, but that would spoil the example :)
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
</PRE>
|
||||
The output is:
|
||||
<PRE>
|
||||
3 successfully inserted.
|
||||
9 was already in the set.
|
||||
There were 2 occurrences of 4.
|
||||
</PRE>
|
||||
|
||||
<br>
|
||||
<HR>
|
||||
<TABLE>
|
||||
<TR valign=top>
|
||||
<TD nowrap>Copyright © 2000</TD><TD>
|
||||
<A HREF=http://www.boost.org/people/jeremy_siek.htm>Jeremy Siek</A>,
|
||||
Univ.of Notre Dame (<A
|
||||
HREF="mailto:jsiek@lsc.nd.edu">jsiek@lsc.nd.edu</A>)<br>
|
||||
<A HREF=http://www.lsc.nd.edu/~llee1>Lie-Quan Lee</A>, Univ.of Notre Dame (<A HREF="mailto:llee1@lsc.nd.edu">llee1@lsc.nd.edu</A>)<br>
|
||||
<A HREF=http://www.lsc.nd.edu/~lums>Andrew Lumsdaine</A>,
|
||||
Univ.of Notre Dame (<A
|
||||
HREF="mailto:lums@lsc.nd.edu">lums@lsc.nd.edu</A>)
|
||||
</TD></TR></TABLE>
|
||||
|
||||
</BODY>
|
||||
</HTML>
|
61
tie_example.cpp
Normal file
61
tie_example.cpp
Normal file
@@ -0,0 +1,61 @@
|
||||
// (C) Copyright Jeremy Siek 2000. Permission to copy, use, modify,
|
||||
// sell and distribute this software is granted provided this
|
||||
// copyright notice appears in all copies. This software is provided
|
||||
// "as is" without express or implied warranty, and with no claim as
|
||||
// to its suitability for any purpose.
|
||||
//
|
||||
// This is an example demonstrating how to use the tie() function.
|
||||
// The purpose of tie() is to make it easiery to deal with std::pair
|
||||
// return values.
|
||||
//
|
||||
// Contributed by Jeremy Siek
|
||||
//
|
||||
// Sample output
|
||||
//
|
||||
// 3 successfully inserted.
|
||||
// 9 was already in the set.
|
||||
// There were 2 occurances of 4.
|
||||
|
||||
#include <set>
|
||||
#include <algorithm>
|
||||
#include <iostream>
|
||||
#include <boost/utility.hpp>
|
||||
|
||||
int
|
||||
main(int, char*[])
|
||||
{
|
||||
{
|
||||
typedef std::set<int> SetT;
|
||||
SetT::iterator i, end;
|
||||
bool inserted;
|
||||
|
||||
int vals[5] = { 5, 2, 4, 9, 1 };
|
||||
SetT s(vals, vals + 5);
|
||||
|
||||
// Using tie() with a return value of pair<iterator,bool>
|
||||
|
||||
int new_vals[2] = { 3, 9 };
|
||||
|
||||
for (int k = 0; k < 2; ++k) {
|
||||
boost::tie(i,inserted) = s.insert(new_vals[k]);
|
||||
if (!inserted)
|
||||
std::cout << *i << " was already in the set." << std::endl;
|
||||
else
|
||||
std::cout << *i << " successfully inserted." << std::endl;
|
||||
}
|
||||
}
|
||||
{
|
||||
int* i, *end;
|
||||
int vals[6] = { 5, 2, 4, 4, 9, 1 };
|
||||
std::sort(vals, vals + 6);
|
||||
|
||||
// Using tie() with a return value of pair<iterator,iterator>
|
||||
|
||||
boost::tie(i,end) = std::equal_range(vals, vals + 6, 4);
|
||||
std::cout << "There were " << std::distance(i,end)
|
||||
<< " occurances of " << *i << "." << std::endl;
|
||||
// Footnote: of course one would normally just use std::count()
|
||||
// to get this information, but that would spoil the example :)
|
||||
}
|
||||
return 0;
|
||||
}
|
215
transform_iterator.htm
Normal file
215
transform_iterator.htm
Normal file
@@ -0,0 +1,215 @@
|
||||
<html>
|
||||
|
||||
<head>
|
||||
<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
|
||||
<meta name="GENERATOR" content="Microsoft FrontPage 4.0">
|
||||
<meta name="ProgId" content="FrontPage.Editor.Document">
|
||||
<title>Transform Iterator Adaptor Documentation</title>
|
||||
</head>
|
||||
|
||||
<body bgcolor="#FFFFFF" text="#000000">
|
||||
|
||||
<img src="../../c++boost.gif" alt="c++boost.gif (8819 bytes)"
|
||||
align="center" width="277" height="86">
|
||||
|
||||
<h1>Transform Iterator Adaptor</h1>
|
||||
|
||||
Defined in header
|
||||
<a href="../../boost/iterator_adaptors.hpp">boost/iterator_adaptors.hpp</a>
|
||||
|
||||
<p>
|
||||
The transform iterator adaptor augments an iterator by applying some
|
||||
function object to the result of dereferencing the iterator. Another
|
||||
words, the <tt>operator*</tt> of the transform iterator first
|
||||
dereferences the base iterator, passes the result of this to the
|
||||
function object, and then returns the result. The following
|
||||
<b>pseudo-code</b> shows the basic idea:
|
||||
|
||||
<pre>
|
||||
value_type transform_iterator::operator*() const {
|
||||
return this->f(*this->base_iterator);
|
||||
}
|
||||
</pre>
|
||||
|
||||
All of the other operators of the transform iterator behave in the
|
||||
same fashion as those of the base iterator.
|
||||
|
||||
|
||||
<h2>Synopsis</h2>
|
||||
|
||||
<pre>
|
||||
namespace boost {
|
||||
template <class <a href="http://www.sgi.com/tech/stl/AdaptableUnaryFunction.html">AdaptableUnaryFunction</a>, class BaseIterator>
|
||||
class transform_iterator_generator;
|
||||
|
||||
template <class <a href="http://www.sgi.com/tech/stl/AdaptableUnaryFunction.html">AdaptableUnaryFunction</a>, class BaseIterator>
|
||||
typename transform_iterator_generator<AdaptableUnaryFunction,Iterator>::type
|
||||
make_transform_iterator(BaseIterator base, const AdaptableUnaryFunction& f = AdaptableUnaryFunction());
|
||||
}
|
||||
</pre>
|
||||
|
||||
<hr>
|
||||
|
||||
<h2><a name="transform_iterator_generator">The Transform Iterator Type
|
||||
Generator</a></h2>
|
||||
|
||||
The class <tt>transform_iterator_generator</tt> is a helper class whose
|
||||
purpose is to construct a transform iterator type. The template
|
||||
parameters for this class are the <tt>AdaptableUnaryFunction</tt> function object
|
||||
type and the <tt>BaseIterator</tt> type that is being wrapped.
|
||||
|
||||
<pre>
|
||||
template <class AdaptableUnaryFunction, class Iterator>
|
||||
class transform_iterator_generator
|
||||
{
|
||||
public:
|
||||
typedef <a href="./iterator_adaptors.htm#iterator_adaptor">iterator_adaptor</a><...> type;
|
||||
};
|
||||
</pre>
|
||||
|
||||
<h3>Example</h3>
|
||||
|
||||
<p>
|
||||
The following is an example of how to use the
|
||||
<tt>transform_iterator_generator</tt> class to iterate through a range of
|
||||
numbers, multiplying each of them by 2 when they are dereferenced.
|
||||
|
||||
<p>
|
||||
<PRE>
|
||||
#include <functional>
|
||||
#include <iostream>
|
||||
#include <boost/iterator_adaptors.hpp>
|
||||
|
||||
int
|
||||
main(int, char*[])
|
||||
{
|
||||
int x[] = { 1, 2, 3, 4, 5, 6, 7, 8 };
|
||||
|
||||
typedef std::binder1st< std::multiplies<int> > Function;
|
||||
typedef boost::transform_iterator_generator<Function, int*>::type doubling_iterator;
|
||||
|
||||
doubling_iterator i(x, std::bind1st(std::multiplies<int>(), 2)),
|
||||
i_end(x + sizeof(x)/sizeof(int), std::bind1st(std::multiplies<int>(), 2));
|
||||
|
||||
std::cout << "multiplying the array by 2:" << std::endl;
|
||||
while (i != i_end)
|
||||
std::cout << *i++ << " ";
|
||||
std::cout << std::endl;
|
||||
|
||||
// to be continued...
|
||||
</PRE>
|
||||
The output from this part is:
|
||||
<pre>
|
||||
2 4 6 8 10 12 14 16
|
||||
</pre>
|
||||
|
||||
<h3>Template Parameters</h3>
|
||||
|
||||
<Table border>
|
||||
<TR>
|
||||
<TH>Parameter</TH><TH>Description</TH>
|
||||
</TR>
|
||||
|
||||
<TR>
|
||||
<TD><a href="http://www.sgi.com/tech/stl/AdaptableUnaryFunction.html"><tt>AdaptableUnaryFunction</tt></a></TD>
|
||||
<TD>The function object that transforms each element in the iterator
|
||||
range. The <tt>argument_type</tt> of the function object must match
|
||||
the value type of the base iterator. The <tt>result_type</tt> of the
|
||||
function object will be the resulting iterator's
|
||||
<tt>value_type</tt>. If you want the resulting iterator to behave as
|
||||
an iterator, the result of the function should be solely a function of
|
||||
its argument.</TD>
|
||||
</TR>
|
||||
|
||||
<TR>
|
||||
<TD><tt>BaseIterator</tt></TD>
|
||||
<TD>The iterator type being wrapped. This type must at least be a model
|
||||
of the <a href="http://www.sgi.com/tech/stl/InputIterator">InputIterator</a> concept.</TD>
|
||||
</TR>
|
||||
|
||||
</Table>
|
||||
|
||||
<h3>Model of</h3>
|
||||
|
||||
The transform iterator adaptor (the type
|
||||
<tt>transform_iterator_generator<...>::type</tt>) is a model of <a
|
||||
href="http://www.sgi.com/tech/stl/InputIterator.html">Input Iterator</a><a href="#1">[1]</a>.
|
||||
|
||||
|
||||
<h3>Members</h3>
|
||||
|
||||
The transform iterator type implements the member functions and
|
||||
operators required of the <a
|
||||
href="http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random Access Iterator</a>
|
||||
concept, except that the <tt>reference</tt> type is the same as the <tt>value_type</tt>
|
||||
so <tt>operator*()</tt> returns by-value. In addition it has the following constructor:
|
||||
|
||||
<pre>
|
||||
transform_iterator_generator::type(const BaseIterator& it,
|
||||
const AdaptableUnaryFunction& f = AdaptableUnaryFunction())
|
||||
</pre>
|
||||
|
||||
<p>
|
||||
<hr>
|
||||
<p>
|
||||
|
||||
|
||||
<h2><a name="make_transform_iterator">The Transform Iterator Object Generator</a></h2>
|
||||
|
||||
<pre>
|
||||
template <class AdaptableUnaryFunction, class BaseIterator>
|
||||
typename transform_iterator_generator<AdaptableUnaryFunction,BaseIterator>::type
|
||||
make_transform_iterator(BaseIterator base,
|
||||
const AdaptableUnaryFunction& f = AdaptableUnaryFunction());
|
||||
</pre>
|
||||
|
||||
This function provides a convenient way to create transform iterators.
|
||||
|
||||
<h3>Example</h3>
|
||||
|
||||
Continuing from the previous example, we use the <tt>make_transform_iterator()</tt>
|
||||
function to add four to each element of the array.
|
||||
|
||||
<pre>
|
||||
std::cout << "adding 4 to each element in the array:" << std::endl;
|
||||
|
||||
std::copy(boost::make_transform_iterator(x, std::bind1st(std::plus<int>(), 4)),
|
||||
boost::make_transform_iterator(x + N, std::bind1st(std::plus<int>(), 4)),
|
||||
std::ostream_iterator<int>(std::cout, " "));
|
||||
std::cout << std::endl;
|
||||
|
||||
return 0;
|
||||
}
|
||||
</pre>
|
||||
The output from this part is:
|
||||
<pre>
|
||||
5 6 7 8 9 10 11 12
|
||||
</pre>
|
||||
|
||||
<h3>Notes</h3>
|
||||
|
||||
|
||||
<a name="1">[1]</a> If the base iterator is a model of <a
|
||||
href="http://www.sgi.com/tech/stl/RandomAccessIterator.html">Random Access Iterator</a>
|
||||
then the transform iterator will also suppport most of the
|
||||
functionality required by the Random Access Iterator concept. However, a
|
||||
transform iterator can never completely satisfy the requirements for
|
||||
<a
|
||||
href="http://www.sgi.com/tech/stl/ForwardIterator.html">Forward Iterator</a>
|
||||
(or of any concepts that refine Forward Iterator, which includes
|
||||
Random Access Iterator and Bidirectional Iterator) since the <tt>operator*</tt> of the transform
|
||||
iterator always returns by-value.
|
||||
|
||||
|
||||
|
||||
<hr>
|
||||
<p>Revised <!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %b %Y" startspan -->09 Mar 2001<!--webbot bot="Timestamp" endspan i-checksum="14894" --></p>
|
||||
<p><EFBFBD> Copyright Jeremy Siek 2000. Permission to copy, use,
|
||||
modify, sell and distribute this document is granted provided this copyright
|
||||
notice appears in all copies. This document is provided "as is"
|
||||
without express or implied warranty, and with no claim as to its suitability for
|
||||
any purpose.</p>
|
||||
|
||||
</body>
|
||||
|
||||
</html>
|
44
transform_iterator_example.cpp
Normal file
44
transform_iterator_example.cpp
Normal file
@@ -0,0 +1,44 @@
|
||||
// (C) Copyright Jeremy Siek 2000. Permission to copy, use, modify, sell and
|
||||
// distribute this software is granted provided this copyright notice appears
|
||||
// in all copies. This software is provided "as is" without express or implied
|
||||
// warranty, and with no claim as to its suitability for any purpose.
|
||||
|
||||
|
||||
#include <functional>
|
||||
#include <algorithm>
|
||||
#include <iostream>
|
||||
#include <boost/iterator_adaptors.hpp>
|
||||
|
||||
int
|
||||
main(int, char*[])
|
||||
{
|
||||
// This is a simple example of using the transform_iterators class to
|
||||
// generate iterators that multiply the value returned by dereferencing
|
||||
// the iterator. In this case we are multiplying by 2.
|
||||
// Would be cooler to use lambda library in this example.
|
||||
|
||||
int x[] = { 1, 2, 3, 4, 5, 6, 7, 8 };
|
||||
const int N = sizeof(x)/sizeof(int);
|
||||
|
||||
typedef std::binder1st< std::multiplies<int> > Function;
|
||||
typedef boost::transform_iterator_generator<Function, int*>::type doubling_iterator;
|
||||
|
||||
doubling_iterator i(x, std::bind1st(std::multiplies<int>(), 2)),
|
||||
i_end(x + N, std::bind1st(std::multiplies<int>(), 2));
|
||||
|
||||
std::cout << "multiplying the array by 2:" << std::endl;
|
||||
while (i != i_end)
|
||||
std::cout << *i++ << " ";
|
||||
std::cout << std::endl;
|
||||
|
||||
std::cout << "adding 4 to each element in the array:" << std::endl;
|
||||
|
||||
std::copy(boost::make_transform_iterator(x, std::bind1st(std::plus<int>(), 4)),
|
||||
boost::make_transform_iterator(x + N, std::bind1st(std::plus<int>(), 4)),
|
||||
std::ostream_iterator<int>(std::cout, " "));
|
||||
std::cout << std::endl;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
54
transform_iterator_test.cpp
Normal file
54
transform_iterator_test.cpp
Normal file
@@ -0,0 +1,54 @@
|
||||
// (C) Copyright Jeremy Siek 1999. Permission to copy, use, modify,
|
||||
// sell and distribute this software is granted provided this
|
||||
// copyright notice appears in all copies. This software is provided
|
||||
// "as is" without express or implied warranty, and with no claim as
|
||||
// to its suitability for any purpose.
|
||||
|
||||
// Revision History
|
||||
// 08 Mar 2001 Jeremy Siek
|
||||
// Moved test of transform iterator into its own file. It to
|
||||
// to be in iterator_adaptor_test.cpp.
|
||||
|
||||
#include <boost/config.hpp>
|
||||
#include <iostream>
|
||||
#include <algorithm>
|
||||
#include <boost/iterator_adaptors.hpp>
|
||||
#include <boost/pending/iterator_tests.hpp>
|
||||
|
||||
struct mult_functor {
|
||||
typedef int result_type;
|
||||
typedef int argument_type;
|
||||
// Functors used with transform_iterator must be
|
||||
// DefaultConstructible, as the transform_iterator must be
|
||||
// DefaultConstructible to satisfy the requirements for
|
||||
// TrivialIterator.
|
||||
mult_functor() { }
|
||||
mult_functor(int aa) : a(aa) { }
|
||||
int operator()(int b) const { return a * b; }
|
||||
int a;
|
||||
};
|
||||
|
||||
int
|
||||
main()
|
||||
{
|
||||
const int N = 10;
|
||||
|
||||
// Borland is getting confused about typedef's and constructors here
|
||||
|
||||
// Test transform_iterator
|
||||
{
|
||||
int x[N], y[N];
|
||||
for (int k = 0; k < N; ++k)
|
||||
x[k] = k;
|
||||
std::copy(x, x + N, y);
|
||||
|
||||
for (int k2 = 0; k2 < N; ++k2)
|
||||
x[k2] = x[k2] * 2;
|
||||
|
||||
boost::transform_iterator_generator<mult_functor, int*>::type i(y, mult_functor(2));
|
||||
boost::input_iterator_test(i, x[0], x[1]);
|
||||
boost::input_iterator_test(boost::make_transform_iterator(&y[0], mult_functor(2)), x[0], x[1]);
|
||||
}
|
||||
std::cout << "test successful " << std::endl;
|
||||
return 0;
|
||||
}
|
626
type_traits.htm
626
type_traits.htm
@@ -1,626 +0,0 @@
|
||||
<html>
|
||||
|
||||
<head>
|
||||
<meta http-equiv="Content-Type"
|
||||
content="text/html; charset=iso-8859-1">
|
||||
<meta name="Template"
|
||||
content="C:\PROGRAM FILES\MICROSOFT OFFICE\OFFICE\html.dot">
|
||||
<meta name="GENERATOR" content="Microsoft FrontPage Express 2.0">
|
||||
<title>Type Traits</title>
|
||||
</head>
|
||||
|
||||
<body bgcolor="#FFFFFF" link="#0000FF" vlink="#800080">
|
||||
|
||||
<h1><img src="../../c++boost.gif" width="276" height="86">Header
|
||||
<<a href="../../boost/detail/type_traits.hpp">boost/type_traits.hpp</a>></h1>
|
||||
|
||||
<p>The contents of <boost/type_traits.hpp> are declared in
|
||||
namespace boost.</p>
|
||||
|
||||
<p>The file <<a href="../../boost/detail/type_traits.hpp">boost/type_traits.hpp</a>>
|
||||
contains various template classes that describe the fundamental
|
||||
properties of a type; each class represents a single type
|
||||
property or a single type transformation. This documentation is
|
||||
divided up into the following sections:</p>
|
||||
|
||||
<pre><a href="#fop">Fundamental type operations</a>
|
||||
<a href="#fp">Fundamental type properties</a>
|
||||
<a href="#misc">Miscellaneous</a>
|
||||
<code> </code><a href="#cv">cv-Qualifiers</a>
|
||||
<code> </code><a href="#ft">Fundamental Types</a>
|
||||
<code> </code><a href="#ct">Compound Types</a>
|
||||
<code> </code><a href="#ot">Object/Scalar Types</a>
|
||||
<a href="#cs">Compiler Support Information</a>
|
||||
<a href="#ec">Example Code</a></pre>
|
||||
|
||||
<h2><a name="fop"></a>Fundamental type operations</h2>
|
||||
|
||||
<p>Usage: "class_name<T>::type" performs
|
||||
indicated transformation on type T.</p>
|
||||
|
||||
<table border="1" cellpadding="7" cellspacing="1" width="100%">
|
||||
<tr>
|
||||
<td valign="top" width="45%"><p align="center">Expression.</p>
|
||||
</td>
|
||||
<td valign="top" width="45%"><p align="center">Description.</p>
|
||||
</td>
|
||||
<td valign="top" width="33%"><p align="center">Compiler.</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>remove_volatile<T>::type</code></td>
|
||||
<td valign="top" width="45%">Creates a type the same as T
|
||||
but with any top level volatile qualifier removed. For
|
||||
example "volatile int" would become "int".</td>
|
||||
<td valign="top" width="33%"><p align="center">P</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>remove_const<T>::type</code></td>
|
||||
<td valign="top" width="45%">Creates a type the same as T
|
||||
but with any top level const qualifier removed. For
|
||||
example "const int" would become "int".</td>
|
||||
<td valign="top" width="33%"><p align="center">P</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>remove_cv<T>::type</code></td>
|
||||
<td valign="top" width="45%">Creates a type the same as T
|
||||
but with any top level cv-qualifiers removed. For example
|
||||
"const int" would become "int", and
|
||||
"volatile double" would become "double".</td>
|
||||
<td valign="top" width="33%"><p align="center">P</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>remove_reference<T>::type</code></td>
|
||||
<td valign="top" width="45%">If T is a reference type
|
||||
then removes the reference, otherwise leaves T unchanged.
|
||||
For example "int&" becomes "int"
|
||||
but "int*" remains unchanged.</td>
|
||||
<td valign="top" width="33%"><p align="center">P</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>add_reference<T>::type</code></td>
|
||||
<td valign="top" width="45%">If T is a reference type
|
||||
then leaves T unchanged, otherwise converts T to a
|
||||
reference type. For example "int&" remains
|
||||
unchanged, but "double" becomes "double&".</td>
|
||||
<td valign="top" width="33%"><p align="center">P</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>remove_bounds<T>::type</code></td>
|
||||
<td valign="top" width="45%">If T is an array type then
|
||||
removes the top level array qualifier from T, otherwise
|
||||
leaves T unchanged. For example "int[2][3]"
|
||||
becomes "int[3]".</td>
|
||||
<td valign="top" width="33%"><p align="center">P</p>
|
||||
</td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<p> </p>
|
||||
|
||||
<h2><a name="fp"></a>Fundamental type properties</h2>
|
||||
|
||||
<p>Usage: "class_name<T>::value" is true if
|
||||
indicated property is true, false otherwise. (Note that class_name<T>::value
|
||||
is always defined as a compile time constant).</p>
|
||||
|
||||
<h3><a name="misc"></a>Miscellaneous</h3>
|
||||
|
||||
<table border="1" cellspacing="1" width="100%">
|
||||
<tr>
|
||||
<td width="37%"><p align="center">Expression</p>
|
||||
</td>
|
||||
<td width="36%"><p align="center">Description</p>
|
||||
</td>
|
||||
<td width="27%"><p align="center">Compiler</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td width="37%"><div align="center"><center><pre><code>is_same<T,U>::value</code></pre>
|
||||
</center></div></td>
|
||||
<td width="36%"><p align="center">True if T and U are the
|
||||
same type.</p>
|
||||
</td>
|
||||
<td width="27%"><p align="center">P</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td width="37%"><div align="center"><center><pre>is_convertible<T,U>::value</pre>
|
||||
</center></div></td>
|
||||
<td width="36%"><p align="center">True if type T is
|
||||
convertible to type U.</p>
|
||||
</td>
|
||||
<td width="27%"> </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td width="37%"><div align="center"><center><pre>alignment_of<T>::value</pre>
|
||||
</center></div></td>
|
||||
<td width="36%"><p align="center">An integral value
|
||||
representing the minimum alignment requirements of type T
|
||||
(strictly speaking defines a multiple of the type's
|
||||
alignment requirement; for all compilers tested so far
|
||||
however it does return the actual alignment).</p>
|
||||
</td>
|
||||
<td width="27%"> </td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<p> </p>
|
||||
|
||||
<h3><a name="cv"></a>cv-Qualifiers</h3>
|
||||
|
||||
<p>The following classes determine what cv-qualifiers are present
|
||||
on a type (see 3.93).</p>
|
||||
|
||||
<table border="1" cellpadding="7" cellspacing="1" width="100%">
|
||||
<tr>
|
||||
<td valign="top" width="37%"><p align="center">Expression.</p>
|
||||
</td>
|
||||
<td valign="top" width="37%"><p align="center">Description.</p>
|
||||
</td>
|
||||
<td valign="top" width="27%"><p align="center">Compiler.</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="37%"><code>is_const<T>::value</code></td>
|
||||
<td valign="top" width="37%">True if type T is top-level
|
||||
const qualified.</td>
|
||||
<td valign="top" width="27%"><p align="center">P</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="37%"><code>is_volatile<T>::value</code></td>
|
||||
<td valign="top" width="37%">True if type T is top-level
|
||||
volatile qualified.</td>
|
||||
<td valign="top" width="27%"><p align="center">P</p>
|
||||
</td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<p> </p>
|
||||
|
||||
<h3><a name="ft"></a>Fundamental Types</h3>
|
||||
|
||||
<p>The following will only ever be true for cv-unqualified types;
|
||||
these are closely based on the section 3.9 of the C++ Standard.</p>
|
||||
|
||||
<table border="1" cellpadding="7" cellspacing="1" width="100%">
|
||||
<tr>
|
||||
<td valign="top" width="45%"><p align="center">Expression.</p>
|
||||
</td>
|
||||
<td valign="top" width="45%"><p align="center">Description.</p>
|
||||
</td>
|
||||
<td valign="top" width="33%"><p align="center">Compiler.</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_void<T>::value</code></td>
|
||||
<td valign="top" width="45%">True only if T is void.</td>
|
||||
<td valign="top" width="33%"> </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_standard_unsigned_integral<T>::value</code></td>
|
||||
<td valign="top" width="45%">True only if T is one of the
|
||||
standard unsigned integral types (3.9.1 p3) - unsigned
|
||||
char, unsigned short, unsigned int, and unsigned long.</td>
|
||||
<td valign="top" width="33%"> </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_standard_signed_integral<T>::value</code></td>
|
||||
<td valign="top" width="45%">True only if T is one of the
|
||||
standard signed integral types (3.9.1 p2) - signed char,
|
||||
short, int, and long.</td>
|
||||
<td valign="top" width="33%"> </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_standard_integral<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if T is a standard
|
||||
integral type(3.9.1 p7) - T is either char, wchar_t, bool
|
||||
or either is_standard_signed_integral<T>::value or
|
||||
is_standard_integral<T>::value is true.</td>
|
||||
<td valign="top" width="33%"> </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_standard_float<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if T is one of the
|
||||
standard floating point types(3.9.1 p8) - float, double
|
||||
or long double.</td>
|
||||
<td valign="top" width="33%"> </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_standard_arithmetic<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if T is a standard
|
||||
arithmetic type(3.9.1 p8) - implies is_standard_integral
|
||||
or is_standard_float is true.</td>
|
||||
<td valign="top" width="33%"> </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_standard_fundamental<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if T is a standard
|
||||
arithmetic type or if T is void.</td>
|
||||
<td valign="top" width="33%"> </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_extension_unsigned_integral<T>::value</code></td>
|
||||
<td valign="top" width="45%">True for compiler specific
|
||||
unsigned integral types.</td>
|
||||
<td valign="top" width="33%"> </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_extension_signed_integral<T>>:value</code></td>
|
||||
<td valign="top" width="45%">True for compiler specific
|
||||
signed integral types.</td>
|
||||
<td valign="top" width="33%"> </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_extension_integral<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if either is_extension_unsigned_integral<T>::value
|
||||
or is_extension_signed_integral<T>::value is true.</td>
|
||||
<td valign="top" width="33%"> </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_extension_float<T>::value</code></td>
|
||||
<td valign="top" width="45%">True for compiler specific
|
||||
floating point types.</td>
|
||||
<td valign="top" width="33%"> </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_extension_arithmetic<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if either is_extension_integral<T>::value
|
||||
or is_extension_float<T>::value are true.</td>
|
||||
<td valign="top" width="33%"> </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code> is_extension_fundamental<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if either is_extension_arithmetic<T>::value
|
||||
or is_void<T>::value are true.</td>
|
||||
<td valign="top" width="33%"> </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code> is_unsigned_integral<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if either is_standard_unsigned_integral<T>::value
|
||||
or is_extention_unsigned_integral<T>::value are
|
||||
true.</td>
|
||||
<td valign="top" width="33%"> </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_signed_integral<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if either is_standard_signed_integral<T>::value
|
||||
or is_extention_signed_integral<T>>::value are
|
||||
true.</td>
|
||||
<td valign="top" width="33%"> </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_integral<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if either is_standard_integral<T>::value
|
||||
or is_extention_integral<T>::value are true.</td>
|
||||
<td valign="top" width="33%"> </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_float<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if either is_standard_float<T>::value
|
||||
or is_extention_float<T>::value are true.</td>
|
||||
<td valign="top" width="33%"> </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_arithmetic<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if either is_integral<T>::value
|
||||
or is_float<T>::value are true.</td>
|
||||
<td valign="top" width="33%"> </td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_fundamental<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if either is_arithmetic<T>::value
|
||||
or is_void<T>::value are true.</td>
|
||||
<td valign="top" width="33%"> </td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<p> </p>
|
||||
|
||||
<h3><a name="ct"></a>Compound Types</h3>
|
||||
|
||||
<p>The following will only ever be true for cv-unqualified types,
|
||||
as defined by the Standard. </p>
|
||||
|
||||
<table border="1" cellpadding="7" cellspacing="1" width="100%">
|
||||
<tr>
|
||||
<td valign="top" width="45%"><p align="center">Expression</p>
|
||||
</td>
|
||||
<td valign="top" width="45%"><p align="center">Description</p>
|
||||
</td>
|
||||
<td valign="top" width="33%"><p align="center">Compiler</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_array<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if T is an array type.</td>
|
||||
<td valign="top" width="33%"><p align="center">P</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_pointer<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if T is a regular
|
||||
pointer type - including function pointers - but
|
||||
excluding pointers to member functions (3.9.2 p1 and 8.3.1).</td>
|
||||
<td valign="top" width="33%"><p align="center">P</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_member_pointer<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if T is a pointer to a
|
||||
non-static class member (3.9.2 p1 and 8.3.1).</td>
|
||||
<td valign="top" width="33%"><p align="center">P</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_reference<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if T is a reference
|
||||
type (3.9.2 p1 and 8.3.2).</td>
|
||||
<td valign="top" width="33%"><p align="center">P</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_class<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if T is a class or
|
||||
struct type.</td>
|
||||
<td valign="top" width="33%"><p align="center">PD</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_union<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if T is a union type.</td>
|
||||
<td valign="top" width="33%"><p align="center">C</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_enum<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if T is an enumerator
|
||||
type.</td>
|
||||
<td valign="top" width="33%"><p align="center">C</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_compound<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if T is any of the
|
||||
above compound types.</td>
|
||||
<td valign="top" width="33%"><p align="center">PD</p>
|
||||
</td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<p> </p>
|
||||
|
||||
<h3><a name="ot"></a>Object/Scalar Types</h3>
|
||||
|
||||
<p>The following ignore any top level cv-qualifiers: if <code>class_name<T>::value</code>
|
||||
is true then <code>class_name<cv-qualified-T>::value</code>
|
||||
will also be true.</p>
|
||||
|
||||
<table border="1" cellpadding="7" cellspacing="1" width="100%">
|
||||
<tr>
|
||||
<td valign="top" width="45%"><p align="center">Expression</p>
|
||||
</td>
|
||||
<td valign="top" width="45%"><p align="center">Description</p>
|
||||
</td>
|
||||
<td valign="top" width="33%"><p align="center">Compiler</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_object<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if T is not a reference
|
||||
type, or a (possibly cv-qualified) void type.</td>
|
||||
<td valign="top" width="33%"><p align="center">P</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_standard_scalar<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if T is a standard
|
||||
arithmetic type, an enumerated type, a pointer or a
|
||||
member pointer.</td>
|
||||
<td valign="top" width="33%"><p align="center">PD</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_extension_scalar<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if T is an extentions
|
||||
arithmetic type, an enumerated type, a pointer or a
|
||||
member pointer.</td>
|
||||
<td valign="top" width="33%"><p align="center">PD</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_scalar<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if T is an arithmetic
|
||||
type, an enumerated type, a pointer or a member pointer.</td>
|
||||
<td valign="top" width="33%"><p align="center">PD</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_POD<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if T is a "Plain
|
||||
Old Data" type (see 3.9 p2&p3). Note that
|
||||
although this requires compiler support to be correct in
|
||||
all cases, if T is a scalar or an array of scalars then
|
||||
we can correctly define T as a POD.</td>
|
||||
<td valign="top" width="33%"><p align="center">PC</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>is_empty<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if T is an empty struct
|
||||
or class. If the compiler implements the "zero sized
|
||||
empty base classes" optimisation, then is_empty will
|
||||
correctly guess whether T is empty. Relies upon is_class
|
||||
to determine whether T is a class type. Screens out enum
|
||||
types by using is_convertible<T,int>, this means
|
||||
that empty classes that overload operator int(), will not
|
||||
be classified as empty.</td>
|
||||
<td valign="top" width="33%"><p align="center">PCD</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>has_trivial_constructor<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if T has a trivial
|
||||
default constructor - that is T() is equivalent to memset.</td>
|
||||
<td valign="top" width="33%"><p align="center">PC</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>has_trivial_copy<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if T has a trivial copy
|
||||
constructor - that is T(const T&) is equivalent to
|
||||
memcpy.</td>
|
||||
<td valign="top" width="33%"><p align="center">PC</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>has_trivial_assign<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if T has a trivial
|
||||
assignment operator - that is if T::operator=(const T&)
|
||||
is equivalent to memcpy.</td>
|
||||
<td valign="top" width="33%"><p align="center">PC</p>
|
||||
</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="45%"><code>has_trivial_destructor<T>::value</code></td>
|
||||
<td valign="top" width="45%">True if T has a trivial
|
||||
destructor - that is if T::~T() has no effect.</td>
|
||||
<td valign="top" width="33%"><p align="center">PC</p>
|
||||
</td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<p> </p>
|
||||
|
||||
<h2><a name="cs"></a>Compiler Support Information</h2>
|
||||
|
||||
<p>The legends used in the tables above have the following
|
||||
meanings:</p>
|
||||
|
||||
<table border="0" cellpadding="7" cellspacing="0" width="480">
|
||||
<tr>
|
||||
<td valign="top" width="50%"><p align="center">P</p>
|
||||
</td>
|
||||
<td valign="top" width="90%">Denotes that the class
|
||||
requires support for partial specialisation of class
|
||||
templates to work correctly.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="50%"><p align="center">C</p>
|
||||
</td>
|
||||
<td valign="top" width="90%">Denotes that direct compiler
|
||||
support for that traits class is required.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="50%"><p align="center">D</p>
|
||||
</td>
|
||||
<td valign="top" width="90%">Denotes that the traits
|
||||
class is dependent upon a class that requires direct
|
||||
compiler support.</td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<p> </p>
|
||||
|
||||
<p>For those classes that are marked with a D or C, if compiler
|
||||
support is not provided, this type trait may return "false"
|
||||
when the correct value is actually "true". The single
|
||||
exception to this rule is "is_class", which attempts to
|
||||
guess whether or not T is really a class, and may return "true"
|
||||
when the correct value is actually "false". This can
|
||||
happen if: T is a union, T is an enum, or T is a compiler-supplied
|
||||
scalar type that is not specialised for in these type traits.</p>
|
||||
|
||||
<p><i>If there is no compiler support</i>, to ensure that these
|
||||
traits <i>always</i> return the correct values, specialise 'is_enum'
|
||||
for each user-defined enumeration type, 'is_union' for each user-defined
|
||||
union type, 'is_empty' for each user-defined empty composite type,
|
||||
and 'is_POD' for each user-defined POD type. The 'has_*' traits
|
||||
should also be specialized if the user-defined type has those
|
||||
traits and is <i>not</i> a POD.</p>
|
||||
|
||||
<p>The following rules are automatically enforced:</p>
|
||||
|
||||
<p>is_enum implies is_POD</p>
|
||||
|
||||
<p>is_POD implies has_*</p>
|
||||
|
||||
<p>This means, for example, if you have an empty POD-struct, just
|
||||
specialize is_empty and is_POD, which will cause all the has_* to
|
||||
also return true.</p>
|
||||
|
||||
<h2><a name="ec"></a>Example code</h2>
|
||||
|
||||
<p>Type-traits comes with two sample programs: <a
|
||||
href="type_traits_test.cpp">type_traits_test.cpp</a> tests the
|
||||
type traits classes - mostly this is a test of your compiler's
|
||||
support for the concepts used in the type traits implementation,
|
||||
while <a href="algo_opt_examples.cpp">algo_opt_examples.cpp</a>
|
||||
uses the type traits classes to "optimise" some
|
||||
familiar standard library algorithms.</p>
|
||||
|
||||
<p>There are four algorithm examples in algo_opt_examples.cpp:</p>
|
||||
|
||||
<table border="0" cellpadding="7" cellspacing="0" width="638">
|
||||
<tr>
|
||||
<td valign="top" width="50%"><pre>opt::copy</pre>
|
||||
</td>
|
||||
<td valign="top" width="50%">If the copy operation can be
|
||||
performed using memcpy then does so, otherwise uses a
|
||||
regular element by element copy (<i>c.f.</i> std::copy).</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="50%"><pre>opt::fill</pre>
|
||||
</td>
|
||||
<td valign="top" width="50%">If the fill operation can be
|
||||
performed by memset, then does so, otherwise uses a
|
||||
regular element by element assign. Also uses call_traits
|
||||
to optimise how the parameters can be passed (<i>c.f.</i>
|
||||
std::fill).</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="50%"><pre>opt::destroy_array</pre>
|
||||
</td>
|
||||
<td valign="top" width="50%">If the type in the array has
|
||||
a trivial destructor then does nothing, otherwise calls
|
||||
destructors for all elements in the array - this
|
||||
algorithm is the reverse of std::uninitialized_copy / std::uninitialized_fill.</td>
|
||||
</tr>
|
||||
<tr>
|
||||
<td valign="top" width="50%"><pre>opt::iter_swap</pre>
|
||||
</td>
|
||||
<td valign="top" width="50%">Determines whether the
|
||||
iterator is a proxy-iterator: if it is then does a "slow
|
||||
and safe" swap, otherwise calls std::swap on the
|
||||
assumption that std::swap may be specialised for the
|
||||
iterated type.</td>
|
||||
</tr>
|
||||
</table>
|
||||
|
||||
<p> </p>
|
||||
|
||||
<hr>
|
||||
|
||||
<p>Revised 08<sup>th</sup> March 2000</p>
|
||||
|
||||
<p><EFBFBD> Copyright boost.org 2000. Permission to copy, use, modify,
|
||||
sell and distribute this document is granted provided this
|
||||
copyright notice appears in all copies. This document is provided
|
||||
"as is" without express or implied warranty, and with
|
||||
no claim as to its suitability for any purpose.</p>
|
||||
|
||||
<p>Based on contributions by Steve Cleary, Beman Dawes, Howard
|
||||
Hinnant and John Maddock.</p>
|
||||
|
||||
<p>Maintained by <a href="mailto:John_Maddock@compuserve.com">John
|
||||
Maddock</a>, the latest version of this file can be found at <a
|
||||
href="http://www.boost.org/">www.boost.org</a>, and the boost
|
||||
discussion list at <a href="http://www.egroups.com/list/boost">www.egroups.com/list/boost</a>.</p>
|
||||
</body>
|
||||
</html>
|
@@ -1,595 +0,0 @@
|
||||
// (C) Copyright Steve Cleary, Beman Dawes, Howard Hinnant & John Maddock 2000.
|
||||
// Permission to copy, use, modify, sell and
|
||||
// distribute this software is granted provided this copyright notice appears
|
||||
// in all copies. This software is provided "as is" without express or implied
|
||||
// warranty, and with no claim as to its suitability for any purpose.
|
||||
|
||||
// standalone test program for <boost/type_traits.hpp>
|
||||
|
||||
/* Release notes:
|
||||
31st July 2000:
|
||||
Added extra tests for is_empty, is_convertible, alignment_of.
|
||||
23rd July 2000:
|
||||
Removed all call_traits tests to call_traits_test.cpp
|
||||
Removed all compressed_pair tests to compressed_pair_tests.cpp
|
||||
Improved tests macros
|
||||
Tidied up specialistions of type_types classes for test cases.
|
||||
*/
|
||||
|
||||
#include <iostream>
|
||||
#include <typeinfo>
|
||||
|
||||
#include <boost/type_traits.hpp>
|
||||
#include "type_traits_test.hpp"
|
||||
|
||||
using namespace boost;
|
||||
|
||||
// Since there is no compiler support, we should specialize:
|
||||
// is_enum for all enumerations (is_enum implies is_POD)
|
||||
// is_union for all unions
|
||||
// is_empty for all empty composites
|
||||
// is_POD for all PODs (except enums) (is_POD implies has_*)
|
||||
// has_* for any UDT that has that trait and is not POD
|
||||
|
||||
enum enum_UDT{ one, two, three };
|
||||
struct UDT
|
||||
{
|
||||
UDT();
|
||||
~UDT();
|
||||
UDT(const UDT&);
|
||||
UDT& operator=(const UDT&);
|
||||
int i;
|
||||
|
||||
void f1();
|
||||
int f2();
|
||||
int f3(int);
|
||||
int f4(int, float);
|
||||
};
|
||||
|
||||
struct POD_UDT { int x; };
|
||||
struct empty_UDT{ ~empty_UDT(){}; };
|
||||
struct empty_POD_UDT{};
|
||||
union union_UDT
|
||||
{
|
||||
int x;
|
||||
double y;
|
||||
~union_UDT();
|
||||
};
|
||||
union POD_union_UDT
|
||||
{
|
||||
int x;
|
||||
double y;
|
||||
};
|
||||
union empty_union_UDT
|
||||
{
|
||||
~empty_union_UDT();
|
||||
};
|
||||
union empty_POD_union_UDT{};
|
||||
#ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION
|
||||
namespace boost {
|
||||
template <> struct is_enum<enum_UDT>
|
||||
{ static const bool value = true; };
|
||||
template <> struct is_POD<POD_UDT>
|
||||
{ static const bool value = true; };
|
||||
// this type is not POD, so we have to specialize the has_* individually
|
||||
template <> struct has_trivial_constructor<empty_UDT>
|
||||
{ static const bool value = true; };
|
||||
template <> struct has_trivial_copy<empty_UDT>
|
||||
{ static const bool value = true; };
|
||||
template <> struct has_trivial_assign<empty_UDT>
|
||||
{ static const bool value = true; };
|
||||
template <> struct is_POD<empty_POD_UDT>
|
||||
{ static const bool value = true; };
|
||||
template <> struct is_union<union_UDT>
|
||||
{ static const bool value = true; };
|
||||
template <> struct is_union<POD_union_UDT>
|
||||
{ static const bool value = true; };
|
||||
template <> struct is_POD<POD_union_UDT>
|
||||
{ static const bool value = true; };
|
||||
template <> struct is_union<empty_union_UDT>
|
||||
{ static const bool value = true; };
|
||||
// this type is not POD, so we have to specialize the has_* individually
|
||||
template <> struct has_trivial_constructor<empty_union_UDT>
|
||||
{ static const bool value = true; };
|
||||
template <> struct has_trivial_copy<empty_union_UDT>
|
||||
{ static const bool value = true; };
|
||||
template <> struct has_trivial_assign<empty_union_UDT>
|
||||
{ static const bool value = true; };
|
||||
template <> struct is_union<empty_POD_union_UDT>
|
||||
{ static const bool value = true; };
|
||||
template <> struct is_POD<empty_POD_union_UDT>
|
||||
{ static const bool value = true; };
|
||||
}
|
||||
#else
|
||||
namespace boost {
|
||||
template <> struct is_enum<enum_UDT>
|
||||
{ enum{ value = true }; };
|
||||
template <> struct is_POD<POD_UDT>
|
||||
{ enum{ value = true }; };
|
||||
// this type is not POD, so we have to specialize the has_* individually
|
||||
template <> struct has_trivial_constructor<empty_UDT>
|
||||
{ enum{ value = true }; };
|
||||
template <> struct has_trivial_copy<empty_UDT>
|
||||
{ enum{ value = true }; };
|
||||
template <> struct has_trivial_assign<empty_UDT>
|
||||
{ enum{ value = true }; };
|
||||
template <> struct is_POD<empty_POD_UDT>
|
||||
{ enum{ value = true }; };
|
||||
template <> struct is_union<union_UDT>
|
||||
{ enum{ value = true }; };
|
||||
template <> struct is_union<POD_union_UDT>
|
||||
{ enum{ value = true }; };
|
||||
template <> struct is_POD<POD_union_UDT>
|
||||
{ enum{ value = true }; };
|
||||
template <> struct is_union<empty_union_UDT>
|
||||
{ enum{ value = true }; };
|
||||
// this type is not POD, so we have to specialize the has_* individually
|
||||
template <> struct has_trivial_constructor<empty_union_UDT>
|
||||
{ enum{ value = true }; };
|
||||
template <> struct has_trivial_copy<empty_union_UDT>
|
||||
{ enum{ value = true }; };
|
||||
template <> struct has_trivial_assign<empty_union_UDT>
|
||||
{ enum{ value = true }; };
|
||||
template <> struct is_union<empty_POD_union_UDT>
|
||||
{ enum{ value = true }; };
|
||||
template <> struct is_POD<empty_POD_union_UDT>
|
||||
{ enum{ value = true }; };
|
||||
}
|
||||
#endif
|
||||
|
||||
class Base { };
|
||||
|
||||
class Deriverd : public Base { };
|
||||
|
||||
class NonDerived { };
|
||||
|
||||
enum enum1
|
||||
{
|
||||
one_,two_
|
||||
};
|
||||
|
||||
enum enum2
|
||||
{
|
||||
three_,four_
|
||||
};
|
||||
|
||||
struct VB
|
||||
{
|
||||
virtual ~VB(){};
|
||||
};
|
||||
|
||||
struct VD : VB
|
||||
{
|
||||
~VD(){};
|
||||
};
|
||||
|
||||
|
||||
// Steve: All comments that I (Steve Cleary) have added below are prefixed with
|
||||
// "Steve:" The failures that BCB4 has on the tests are due to Borland's
|
||||
// not considering cv-qual's as a part of the type -- they are considered
|
||||
// compiler hints only. These failures should be fixed before long.
|
||||
|
||||
int main()
|
||||
{
|
||||
std::cout << "Checking type operations..." << std::endl << std::endl;
|
||||
|
||||
// cv-qualifiers applied to reference types should have no effect
|
||||
// declare these here for later use with is_reference and remove_reference:
|
||||
typedef int& r_type;
|
||||
typedef const r_type cr_type;
|
||||
|
||||
type_test(int, remove_reference<int>::type)
|
||||
type_test(const int, remove_reference<const int>::type)
|
||||
type_test(int, remove_reference<int&>::type)
|
||||
type_test(const int, remove_reference<const int&>::type)
|
||||
type_test(volatile int, remove_reference<volatile int&>::type)
|
||||
type_test(int, remove_reference<cr_type>::type)
|
||||
|
||||
type_test(int, remove_const<const int>::type)
|
||||
// Steve: fails on BCB4
|
||||
type_test(volatile int, remove_const<volatile int>::type)
|
||||
// Steve: fails on BCB4
|
||||
type_test(volatile int, remove_const<const volatile int>::type)
|
||||
type_test(int, remove_const<int>::type)
|
||||
type_test(int*, remove_const<int* const>::type)
|
||||
type_test(int, remove_volatile<volatile int>::type)
|
||||
// Steve: fails on BCB4
|
||||
type_test(const int, remove_volatile<const int>::type)
|
||||
// Steve: fails on BCB4
|
||||
type_test(const int, remove_volatile<const volatile int>::type)
|
||||
type_test(int, remove_volatile<int>::type)
|
||||
type_test(int*, remove_volatile<int* volatile>::type)
|
||||
type_test(int, remove_cv<volatile int>::type)
|
||||
type_test(int, remove_cv<const int>::type)
|
||||
type_test(int, remove_cv<const volatile int>::type)
|
||||
type_test(int, remove_cv<int>::type)
|
||||
type_test(int*, remove_cv<int* volatile>::type)
|
||||
type_test(int*, remove_cv<int* const>::type)
|
||||
type_test(int*, remove_cv<int* const volatile>::type)
|
||||
type_test(const int *, remove_cv<const int * const>::type)
|
||||
type_test(int, remove_bounds<int>::type)
|
||||
type_test(int*, remove_bounds<int*>::type)
|
||||
type_test(int, remove_bounds<int[3]>::type)
|
||||
type_test(int[3], remove_bounds<int[2][3]>::type)
|
||||
|
||||
std::cout << std::endl << "Checking type properties..." << std::endl << std::endl;
|
||||
|
||||
value_test(true, (is_same<int, int>::value))
|
||||
value_test(false, (is_same<int, const int>::value))
|
||||
value_test(false, (is_same<int, int&>::value))
|
||||
value_test(false, (is_same<int*, const int*>::value))
|
||||
value_test(false, (is_same<int*, int*const>::value))
|
||||
value_test(false, (is_same<int, int[2]>::value))
|
||||
|
||||
value_test(false, is_const<int>::value)
|
||||
value_test(true, is_const<const int>::value)
|
||||
value_test(false, is_const<volatile int>::value)
|
||||
value_test(true, is_const<const volatile int>::value)
|
||||
|
||||
value_test(false, is_volatile<int>::value)
|
||||
value_test(false, is_volatile<const int>::value)
|
||||
value_test(true, is_volatile<volatile int>::value)
|
||||
value_test(true, is_volatile<const volatile int>::value)
|
||||
|
||||
value_test(true, is_void<void>::value)
|
||||
// Steve: fails on BCB4
|
||||
// JM: but looks as though it should according to [3.9.3p1]?
|
||||
//value_test(false, is_void<const void>::value)
|
||||
value_test(false, is_void<int>::value)
|
||||
|
||||
value_test(false, is_standard_unsigned_integral<UDT>::value)
|
||||
value_test(false, is_standard_unsigned_integral<void>::value)
|
||||
value_test(false, is_standard_unsigned_integral<bool>::value)
|
||||
value_test(false, is_standard_unsigned_integral<char>::value)
|
||||
value_test(false, is_standard_unsigned_integral<signed char>::value)
|
||||
value_test(true, is_standard_unsigned_integral<unsigned char>::value)
|
||||
value_test(false, is_standard_unsigned_integral<wchar_t>::value)
|
||||
value_test(false, is_standard_unsigned_integral<short>::value)
|
||||
value_test(true, is_standard_unsigned_integral<unsigned short>::value)
|
||||
value_test(false, is_standard_unsigned_integral<int>::value)
|
||||
value_test(true, is_standard_unsigned_integral<unsigned int>::value)
|
||||
value_test(false, is_standard_unsigned_integral<long>::value)
|
||||
value_test(true, is_standard_unsigned_integral<unsigned long>::value)
|
||||
value_test(false, is_standard_unsigned_integral<float>::value)
|
||||
value_test(false, is_standard_unsigned_integral<double>::value)
|
||||
value_test(false, is_standard_unsigned_integral<long double>::value)
|
||||
#ifdef ULLONG_MAX
|
||||
value_test(false, is_standard_unsigned_integral<long long>::value)
|
||||
value_test(false, is_standard_unsigned_integral<unsigned long long>::value)
|
||||
#endif
|
||||
#if defined(__BORLANDC__) || defined(_MSC_VER)
|
||||
value_test(false, is_standard_unsigned_integral<__int64>::value)
|
||||
value_test(false, is_standard_unsigned_integral<unsigned __int64>::value)
|
||||
#endif
|
||||
|
||||
value_test(false, is_standard_signed_integral<UDT>::value)
|
||||
value_test(false, is_standard_signed_integral<void>::value)
|
||||
value_test(false, is_standard_signed_integral<bool>::value)
|
||||
value_test(false, is_standard_signed_integral<char>::value)
|
||||
value_test(true, is_standard_signed_integral<signed char>::value)
|
||||
value_test(false, is_standard_signed_integral<unsigned char>::value)
|
||||
value_test(false, is_standard_signed_integral<wchar_t>::value)
|
||||
value_test(true, is_standard_signed_integral<short>::value)
|
||||
value_test(false, is_standard_signed_integral<unsigned short>::value)
|
||||
value_test(true, is_standard_signed_integral<int>::value)
|
||||
value_test(false, is_standard_signed_integral<unsigned int>::value)
|
||||
value_test(true, is_standard_signed_integral<long>::value)
|
||||
value_test(false, is_standard_signed_integral<unsigned long>::value)
|
||||
value_test(false, is_standard_signed_integral<float>::value)
|
||||
value_test(false, is_standard_signed_integral<double>::value)
|
||||
value_test(false, is_standard_signed_integral<long double>::value)
|
||||
#ifdef ULLONG_MAX
|
||||
value_test(false, is_standard_signed_integral<long long>::value)
|
||||
value_test(false, is_standard_signed_integral<unsigned long long>::value)
|
||||
#endif
|
||||
#if defined(__BORLANDC__) || defined(_MSC_VER)
|
||||
value_test(false, is_standard_signed_integral<__int64>::value)
|
||||
value_test(false, is_standard_signed_integral<unsigned __int64>::value)
|
||||
#endif
|
||||
|
||||
value_test(false, is_standard_arithmetic<UDT>::value)
|
||||
value_test(false, is_standard_arithmetic<void>::value)
|
||||
value_test(true, is_standard_arithmetic<bool>::value)
|
||||
value_test(true, is_standard_arithmetic<char>::value)
|
||||
value_test(true, is_standard_arithmetic<signed char>::value)
|
||||
value_test(true, is_standard_arithmetic<unsigned char>::value)
|
||||
value_test(true, is_standard_arithmetic<wchar_t>::value)
|
||||
value_test(true, is_standard_arithmetic<short>::value)
|
||||
value_test(true, is_standard_arithmetic<unsigned short>::value)
|
||||
value_test(true, is_standard_arithmetic<int>::value)
|
||||
value_test(true, is_standard_arithmetic<unsigned int>::value)
|
||||
value_test(true, is_standard_arithmetic<long>::value)
|
||||
value_test(true, is_standard_arithmetic<unsigned long>::value)
|
||||
value_test(true, is_standard_arithmetic<float>::value)
|
||||
value_test(true, is_standard_arithmetic<double>::value)
|
||||
value_test(true, is_standard_arithmetic<long double>::value)
|
||||
#ifdef ULLONG_MAX
|
||||
value_test(false, is_standard_arithmetic<long long>::value)
|
||||
value_test(false, is_standard_arithmetic<unsigned long long>::value)
|
||||
#endif
|
||||
#if defined(__BORLANDC__) || defined(_MSC_VER)
|
||||
value_test(false, is_standard_arithmetic<__int64>::value)
|
||||
value_test(false, is_standard_arithmetic<unsigned __int64>::value)
|
||||
#endif
|
||||
|
||||
value_test(false, is_standard_fundamental<UDT>::value)
|
||||
value_test(true, is_standard_fundamental<void>::value)
|
||||
value_test(true, is_standard_fundamental<bool>::value)
|
||||
value_test(true, is_standard_fundamental<char>::value)
|
||||
value_test(true, is_standard_fundamental<signed char>::value)
|
||||
value_test(true, is_standard_fundamental<unsigned char>::value)
|
||||
value_test(true, is_standard_fundamental<wchar_t>::value)
|
||||
value_test(true, is_standard_fundamental<short>::value)
|
||||
value_test(true, is_standard_fundamental<unsigned short>::value)
|
||||
value_test(true, is_standard_fundamental<int>::value)
|
||||
value_test(true, is_standard_fundamental<unsigned int>::value)
|
||||
value_test(true, is_standard_fundamental<long>::value)
|
||||
value_test(true, is_standard_fundamental<unsigned long>::value)
|
||||
value_test(true, is_standard_fundamental<float>::value)
|
||||
value_test(true, is_standard_fundamental<double>::value)
|
||||
value_test(true, is_standard_fundamental<long double>::value)
|
||||
#ifdef ULLONG_MAX
|
||||
value_test(false, is_standard_fundamental<long long>::value)
|
||||
value_test(false, is_standard_fundamental<unsigned long long>::value)
|
||||
#endif
|
||||
#if defined(__BORLANDC__) || defined(_MSC_VER)
|
||||
value_test(false, is_standard_fundamental<__int64>::value)
|
||||
value_test(false, is_standard_fundamental<unsigned __int64>::value)
|
||||
#endif
|
||||
|
||||
value_test(false, is_arithmetic<UDT>::value)
|
||||
value_test(true, is_arithmetic<char>::value)
|
||||
value_test(true, is_arithmetic<signed char>::value)
|
||||
value_test(true, is_arithmetic<unsigned char>::value)
|
||||
value_test(true, is_arithmetic<wchar_t>::value)
|
||||
value_test(true, is_arithmetic<short>::value)
|
||||
value_test(true, is_arithmetic<unsigned short>::value)
|
||||
value_test(true, is_arithmetic<int>::value)
|
||||
value_test(true, is_arithmetic<unsigned int>::value)
|
||||
value_test(true, is_arithmetic<long>::value)
|
||||
value_test(true, is_arithmetic<unsigned long>::value)
|
||||
value_test(true, is_arithmetic<float>::value)
|
||||
value_test(true, is_arithmetic<double>::value)
|
||||
value_test(true, is_arithmetic<long double>::value)
|
||||
value_test(true, is_arithmetic<bool>::value)
|
||||
#ifdef ULLONG_MAX
|
||||
value_test(true, is_arithmetic<long long>::value)
|
||||
value_test(true, is_arithmetic<unsigned long long>::value)
|
||||
#endif
|
||||
#if defined(__BORLANDC__) || defined(_MSC_VER)
|
||||
value_test(true, is_arithmetic<__int64>::value)
|
||||
value_test(true, is_arithmetic<unsigned __int64>::value)
|
||||
#endif
|
||||
|
||||
value_test(false, is_array<int>::value)
|
||||
value_test(false, is_array<int*>::value)
|
||||
value_test(true, is_array<int[2]>::value)
|
||||
value_test(true, is_array<int[2][3]>::value)
|
||||
value_test(true, is_array<UDT[2]>::value)
|
||||
|
||||
typedef void(*f1)();
|
||||
typedef int(*f2)(int);
|
||||
typedef int(*f3)(int, bool);
|
||||
typedef void (UDT::*mf1)();
|
||||
typedef int (UDT::*mf2)();
|
||||
typedef int (UDT::*mf3)(int);
|
||||
typedef int (UDT::*mf4)(int, float);
|
||||
|
||||
value_test(false, is_pointer<int>::value)
|
||||
value_test(false, is_pointer<int&>::value)
|
||||
value_test(true, is_pointer<int*>::value)
|
||||
// Steve: was 'true', should be 'false', via 3.9.2p3, 3.9.3p1
|
||||
value_test(false, is_pointer<int*const>::value)
|
||||
// Steve: was 'true', should be 'false', via 3.9.2p3, 3.9.3p1
|
||||
value_test(false, is_pointer<int*volatile>::value)
|
||||
// Steve: was 'true', should be 'false', via 3.9.2p3, 3.9.3p1
|
||||
value_test(false, is_pointer<int*const volatile>::value)
|
||||
value_test(true, is_pointer<f1>::value)
|
||||
value_test(true, is_pointer<f2>::value)
|
||||
value_test(true, is_pointer<f3>::value)
|
||||
// Steve: was 'true', should be 'false', via 3.9.2p3
|
||||
value_test(false, is_pointer<mf1>::value)
|
||||
// Steve: was 'true', should be 'false', via 3.9.2p3
|
||||
value_test(false, is_pointer<mf2>::value)
|
||||
// Steve: was 'true', should be 'false', via 3.9.2p3
|
||||
value_test(false, is_pointer<mf3>::value)
|
||||
// Steve: was 'true', should be 'false', via 3.9.2p3
|
||||
value_test(false, is_pointer<mf4>::value)
|
||||
|
||||
value_test(false, is_reference<bool>::value)
|
||||
value_test(true, is_reference<int&>::value)
|
||||
value_test(true, is_reference<const int&>::value)
|
||||
value_test(true, is_reference<volatile int &>::value)
|
||||
value_test(true, is_reference<r_type>::value)
|
||||
value_test(true, is_reference<cr_type>::value)
|
||||
|
||||
value_test(false, is_class<int>::value)
|
||||
value_test(false, is_class<const int>::value)
|
||||
value_test(false, is_class<volatile int>::value)
|
||||
value_test(false, is_class<int*>::value)
|
||||
value_test(false, is_class<int* const>::value)
|
||||
value_test(false, is_class<int[2]>::value)
|
||||
value_test(false, is_class<int&>::value)
|
||||
value_test(false, is_class<mf4>::value)
|
||||
value_test(false, is_class<f1>::value)
|
||||
value_test(false, is_class<enum_UDT>::value)
|
||||
value_test(true, is_class<UDT>::value)
|
||||
value_test(true, is_class<UDT const>::value)
|
||||
value_test(true, is_class<UDT volatile>::value)
|
||||
value_test(true, is_class<empty_UDT>::value)
|
||||
value_test(true, is_class<std::iostream>::value)
|
||||
value_test(false, is_class<UDT*>::value)
|
||||
value_test(false, is_class<UDT[2]>::value)
|
||||
value_test(false, is_class<UDT&>::value)
|
||||
|
||||
value_test(true, is_object<int>::value)
|
||||
value_test(true, is_object<UDT>::value)
|
||||
value_test(false, is_object<int&>::value)
|
||||
value_test(false, is_object<void>::value)
|
||||
value_test(true, is_standard_scalar<int>::value)
|
||||
value_test(true, is_extension_scalar<void*>::value)
|
||||
|
||||
value_test(false, is_enum<int>::value)
|
||||
value_test(true, is_enum<enum_UDT>::value)
|
||||
|
||||
value_test(false, is_member_pointer<f1>::value)
|
||||
value_test(false, is_member_pointer<f2>::value)
|
||||
value_test(false, is_member_pointer<f3>::value)
|
||||
value_test(true, is_member_pointer<mf1>::value)
|
||||
value_test(true, is_member_pointer<mf2>::value)
|
||||
value_test(true, is_member_pointer<mf3>::value)
|
||||
value_test(true, is_member_pointer<mf4>::value)
|
||||
|
||||
value_test(false, is_empty<int>::value)
|
||||
value_test(false, is_empty<int*>::value)
|
||||
value_test(false, is_empty<int&>::value)
|
||||
#ifdef __MWERKS__
|
||||
// apparent compiler bug causes this to fail to compile:
|
||||
value_fail(false, is_empty<int[2]>::value)
|
||||
#else
|
||||
value_test(false, is_empty<int[2]>::value)
|
||||
#endif
|
||||
value_test(false, is_empty<f1>::value)
|
||||
value_test(false, is_empty<mf1>::value)
|
||||
value_test(false, is_empty<UDT>::value)
|
||||
value_test(true, is_empty<empty_UDT>::value)
|
||||
value_test(true, is_empty<empty_POD_UDT>::value)
|
||||
value_test(true, is_empty<empty_union_UDT>::value)
|
||||
value_test(false, is_empty<enum_UDT>::value)
|
||||
|
||||
value_test(true, has_trivial_constructor<int>::value)
|
||||
value_test(true, has_trivial_constructor<int*>::value)
|
||||
value_test(true, has_trivial_constructor<int*const>::value)
|
||||
value_test(true, has_trivial_constructor<const int>::value)
|
||||
value_test(true, has_trivial_constructor<volatile int>::value)
|
||||
value_test(true, has_trivial_constructor<int[2]>::value)
|
||||
value_test(true, has_trivial_constructor<int[3][2]>::value)
|
||||
value_test(true, has_trivial_constructor<int[2][4][5][6][3]>::value)
|
||||
value_test(true, has_trivial_constructor<f1>::value)
|
||||
value_test(true, has_trivial_constructor<mf2>::value)
|
||||
value_test(false, has_trivial_constructor<UDT>::value)
|
||||
value_test(true, has_trivial_constructor<empty_UDT>::value)
|
||||
value_test(true, has_trivial_constructor<enum_UDT>::value)
|
||||
|
||||
value_test(true, has_trivial_copy<int>::value)
|
||||
value_test(true, has_trivial_copy<int*>::value)
|
||||
value_test(true, has_trivial_copy<int*const>::value)
|
||||
value_test(true, has_trivial_copy<const int>::value)
|
||||
// Steve: was 'false' -- should be 'true' via 3.9p3, 3.9p10
|
||||
value_test(true, has_trivial_copy<volatile int>::value)
|
||||
value_test(true, has_trivial_copy<int[2]>::value)
|
||||
value_test(true, has_trivial_copy<int[3][2]>::value)
|
||||
value_test(true, has_trivial_copy<int[2][4][5][6][3]>::value)
|
||||
value_test(true, has_trivial_copy<f1>::value)
|
||||
value_test(true, has_trivial_copy<mf2>::value)
|
||||
value_test(false, has_trivial_copy<UDT>::value)
|
||||
value_test(true, has_trivial_copy<empty_UDT>::value)
|
||||
value_test(true, has_trivial_copy<enum_UDT>::value)
|
||||
|
||||
value_test(true, has_trivial_assign<int>::value)
|
||||
value_test(true, has_trivial_assign<int*>::value)
|
||||
value_test(true, has_trivial_assign<int*const>::value)
|
||||
value_test(true, has_trivial_assign<const int>::value)
|
||||
// Steve: was 'false' -- should be 'true' via 3.9p3, 3.9p10
|
||||
value_test(true, has_trivial_assign<volatile int>::value)
|
||||
value_test(true, has_trivial_assign<int[2]>::value)
|
||||
value_test(true, has_trivial_assign<int[3][2]>::value)
|
||||
value_test(true, has_trivial_assign<int[2][4][5][6][3]>::value)
|
||||
value_test(true, has_trivial_assign<f1>::value)
|
||||
value_test(true, has_trivial_assign<mf2>::value)
|
||||
value_test(false, has_trivial_assign<UDT>::value)
|
||||
value_test(true, has_trivial_assign<empty_UDT>::value)
|
||||
value_test(true, has_trivial_assign<enum_UDT>::value)
|
||||
|
||||
value_test(true, has_trivial_destructor<int>::value)
|
||||
value_test(true, has_trivial_destructor<int*>::value)
|
||||
value_test(true, has_trivial_destructor<int*const>::value)
|
||||
value_test(true, has_trivial_destructor<const int>::value)
|
||||
value_test(true, has_trivial_destructor<volatile int>::value)
|
||||
value_test(true, has_trivial_destructor<int[2]>::value)
|
||||
value_test(true, has_trivial_destructor<int[3][2]>::value)
|
||||
value_test(true, has_trivial_destructor<int[2][4][5][6][3]>::value)
|
||||
value_test(true, has_trivial_destructor<f1>::value)
|
||||
value_test(true, has_trivial_destructor<mf2>::value)
|
||||
value_test(false, has_trivial_destructor<UDT>::value)
|
||||
value_test(false, has_trivial_destructor<empty_UDT>::value)
|
||||
value_test(true, has_trivial_destructor<enum_UDT>::value)
|
||||
|
||||
value_test(true, is_POD<int>::value)
|
||||
value_test(true, is_POD<int*>::value)
|
||||
// Steve: was 'true', should be 'false', via 3.9p10
|
||||
value_test(false, is_POD<int&>::value)
|
||||
value_test(true, is_POD<int*const>::value)
|
||||
value_test(true, is_POD<const int>::value)
|
||||
// Steve: was 'false', should be 'true', via 3.9p10
|
||||
value_test(true, is_POD<volatile int>::value)
|
||||
// Steve: was 'true', should be 'false', via 3.9p10
|
||||
value_test(false, is_POD<const int&>::value)
|
||||
value_test(true, is_POD<int[2]>::value)
|
||||
value_test(true, is_POD<int[3][2]>::value)
|
||||
value_test(true, is_POD<int[2][4][5][6][3]>::value)
|
||||
value_test(true, is_POD<f1>::value)
|
||||
value_test(true, is_POD<mf2>::value)
|
||||
value_test(false, is_POD<UDT>::value)
|
||||
value_test(false, is_POD<empty_UDT>::value)
|
||||
value_test(true, is_POD<enum_UDT>::value)
|
||||
|
||||
value_test(true, (boost::is_convertible<Deriverd,Base>::value));
|
||||
value_test(true, (boost::is_convertible<Deriverd,Deriverd>::value));
|
||||
value_test(true, (boost::is_convertible<Base,Base>::value));
|
||||
value_test(false, (boost::is_convertible<Base,Deriverd>::value));
|
||||
value_test(true, (boost::is_convertible<Deriverd,Deriverd>::value));
|
||||
value_test(false, (boost::is_convertible<NonDerived,Base>::value));
|
||||
//value_test(false, (boost::is_convertible<boost::noncopyable, boost::noncopyable>::value));
|
||||
value_test(true, (boost::is_convertible<float,int>::value));
|
||||
#if defined(BOOST_MSVC6_MEMBER_TEMPLATES) || !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
|
||||
value_test(false, (boost::is_convertible<float,void>::value));
|
||||
value_test(false, (boost::is_convertible<void,float>::value));
|
||||
value_test(true, (boost::is_convertible<void,void>::value));
|
||||
#endif
|
||||
value_test(true, (boost::is_convertible<enum1, int>::value));
|
||||
value_test(true, (boost::is_convertible<Deriverd*, Base*>::value));
|
||||
value_test(false, (boost::is_convertible<Base*, Deriverd*>::value));
|
||||
value_test(true, (boost::is_convertible<Deriverd&, Base&>::value));
|
||||
value_test(false, (boost::is_convertible<Base&, Deriverd&>::value));
|
||||
value_test(true, (boost::is_convertible<const Deriverd*, const Base*>::value));
|
||||
value_test(false, (boost::is_convertible<const Base*, const Deriverd*>::value));
|
||||
value_test(true, (boost::is_convertible<const Deriverd&, const Base&>::value));
|
||||
value_test(false, (boost::is_convertible<const Base&, const Deriverd&>::value));
|
||||
|
||||
value_test(false, (boost::is_convertible<const int *, int*>::value));
|
||||
value_test(false, (boost::is_convertible<const int&, int&>::value));
|
||||
value_test(false, (boost::is_convertible<int*, int[2]>::value));
|
||||
value_test(false, (boost::is_convertible<const int*, int[3]>::value));
|
||||
value_test(true, (boost::is_convertible<const int&, int>::value));
|
||||
value_test(true, (boost::is_convertible<int(&)[4], const int*>::value));
|
||||
value_test(true, (boost::is_convertible<int(&)(int), int(*)(int)>::value));
|
||||
value_test(true, (boost::is_convertible<int *, const int*>::value));
|
||||
value_test(true, (boost::is_convertible<int&, const int&>::value));
|
||||
value_test(true, (boost::is_convertible<int[2], int*>::value));
|
||||
value_test(true, (boost::is_convertible<int[2], const int*>::value));
|
||||
value_test(false, (boost::is_convertible<const int[2], int*>::value));
|
||||
|
||||
align_test(int);
|
||||
align_test(char);
|
||||
align_test(double);
|
||||
align_test(int[4]);
|
||||
align_test(int(*)(int));
|
||||
#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
|
||||
align_test(char&);
|
||||
align_test(char (&)(int));
|
||||
align_test(char(&)[4]);
|
||||
#endif
|
||||
align_test(int*);
|
||||
//align_test(const int);
|
||||
align_test(VB);
|
||||
align_test(VD);
|
||||
|
||||
std::cout << std::endl << test_count << " tests completed (" << failures << " failures)... press any key to exit";
|
||||
std::cin.get();
|
||||
return failures;
|
||||
}
|
||||
|
||||
|
||||
|
||||
|
@@ -1,106 +0,0 @@
|
||||
// boost::compressed_pair test program
|
||||
|
||||
// (C) Copyright John Maddock 2000. Permission to copy, use, modify, sell and
|
||||
// distribute this software is granted provided this copyright notice appears
|
||||
// in all copies. This software is provided "as is" without express or implied
|
||||
// warranty, and with no claim as to its suitability for any purpose.
|
||||
|
||||
// common test code for type_traits_test.cpp/call_traits_test.cpp/compressed_pair_test.cpp
|
||||
|
||||
|
||||
#ifndef BOOST_TYPE_TRAITS_TEST_HPP
|
||||
#define BOOST_TYPE_TRAITS_TEST_HPP
|
||||
|
||||
//
|
||||
// this one is here just to suppress warnings:
|
||||
//
|
||||
template <class T>
|
||||
bool do_compare(T i, T j)
|
||||
{
|
||||
return i == j;
|
||||
}
|
||||
|
||||
//
|
||||
// this one is to verify that a constant is indeed a
|
||||
// constant-integral-expression:
|
||||
//
|
||||
template <int>
|
||||
struct ct_checker
|
||||
{
|
||||
};
|
||||
|
||||
#define BOOST_DO_JOIN( X, Y ) BOOST_DO_JOIN2(X,Y)
|
||||
#define BOOST_DO_JOIN2(X, Y) X ## Y
|
||||
#define BOOST_JOIN( X, Y ) BOOST_DO_JOIN( X, Y )
|
||||
|
||||
|
||||
#define value_test(v, x) ++test_count;\
|
||||
typedef ct_checker<(x)> BOOST_JOIN(this_is_a_compile_time_check_, __LINE__);\
|
||||
if(!do_compare((int)v,(int)x)){++failures; std::cout << "checking value of " << #x << "...failed" << std::endl;}
|
||||
#define value_fail(v, x) ++test_count; ++failures; std::cout << "checking value of " << #x << "...failed" << std::endl;
|
||||
|
||||
#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
|
||||
#define type_test(v, x) ++test_count;\
|
||||
if(do_compare(boost::is_same<v, x>::value, false)){\
|
||||
++failures; \
|
||||
std::cout << "checking type of " << #x << "...failed" << std::endl; \
|
||||
std::cout << " expected type was " << #v << std::endl; \
|
||||
std::cout << " " << typeid(boost::is_same<v, x>).name() << "::value is false" << std::endl; }
|
||||
#else
|
||||
#define type_test(v, x) ++test_count;\
|
||||
if(typeid(v) != typeid(x)){\
|
||||
++failures; \
|
||||
std::cout << "checking type of " << #x << "...failed" << std::endl; \
|
||||
std::cout << " expected type was " << #v << std::endl; \
|
||||
std::cout << " " << "typeid(" #v ") != typeid(" #x ")" << std::endl; }
|
||||
#endif
|
||||
|
||||
template <class T>
|
||||
struct test_align
|
||||
{
|
||||
struct padded
|
||||
{
|
||||
char c;
|
||||
T t;
|
||||
};
|
||||
static void do_it()
|
||||
{
|
||||
padded p;
|
||||
unsigned a = reinterpret_cast<char*>(&(p.t)) - reinterpret_cast<char*>(&p);
|
||||
value_test(a, boost::alignment_of<T>::value);
|
||||
}
|
||||
};
|
||||
#ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
|
||||
template <class T>
|
||||
struct test_align<T&>
|
||||
{
|
||||
static void do_it()
|
||||
{
|
||||
//
|
||||
// we can't do the usual test because we can't take the address
|
||||
// of a reference, so check that the result is the same as for a
|
||||
// pointer type instead:
|
||||
value_test(boost::alignment_of<T*>::value, boost::alignment_of<T&>::value);
|
||||
}
|
||||
};
|
||||
#endif
|
||||
|
||||
#define align_test(T) test_align<T>::do_it()
|
||||
|
||||
//
|
||||
// define tests here
|
||||
unsigned failures = 0;
|
||||
unsigned test_count = 0;
|
||||
|
||||
//
|
||||
// turn off some warnings:
|
||||
#ifdef __BORLANDC__
|
||||
#pragma option -w-8004
|
||||
#endif
|
||||
|
||||
#ifdef BOOST_MSVC
|
||||
#pragma warning (disable: 4018)
|
||||
#endif
|
||||
|
||||
|
||||
#endif // BOOST_TYPE_TRAITS_TEST_HPP
|
@@ -16,10 +16,11 @@
|
||||
<h2>Contents</h2>
|
||||
|
||||
<ul>
|
||||
<li>Template functions <a href="#functions next">next() and prior()</a></li>
|
||||
<li>Function templates <a href="#functions next">next() and prior()</a></li>
|
||||
<li>Class <a href="#Class noncopyable">noncopyable</a></li>
|
||||
<li>Function template <a href="tie.html">tie()</a> and supporting class tied.</li>
|
||||
</ul>
|
||||
<h2>Template <a name="functions next">functions next</a>() and prior()</h2>
|
||||
<h2> <a name="functions next">Function</a> templates next() and prior()</h2>
|
||||
|
||||
<p>Certain data types, such as the C++ Standard Library's forward and
|
||||
bidirectional iterators, do not provide addition and subtraction via operator+()
|
||||
@@ -80,7 +81,7 @@ CodeWarrior 5.0, and Microsoft Visual C++ 6.0 sp 3.</p>
|
||||
<pre>// inside one of your own headers ...
|
||||
#include <boost/utility.hpp>
|
||||
|
||||
class ResourceLadenFileSystem : noncopyable {
|
||||
class ResourceLadenFileSystem : boost::noncopyable {
|
||||
...</pre>
|
||||
</blockquote>
|
||||
|
||||
@@ -92,7 +93,7 @@ destructor declarations. He says "Probably this concern is misplaced, becau
|
||||
noncopyable will be used mostly for classes which own resources and thus have non-trivial destruction semantics."</p>
|
||||
<hr>
|
||||
<p>Revised <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan
|
||||
-->26 January, 2000<!--webbot bot="Timestamp" endspan i-checksum="38194"
|
||||
-->28 February, 2001<!--webbot bot="Timestamp" endspan i-checksum="40412"
|
||||
-->
|
||||
</p>
|
||||
<p><EFBFBD> Copyright boost.org 1999. Permission to copy, use, modify, sell and
|
||||
|
Reference in New Issue
Block a user