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Author SHA1 Message Date
nobody a388ce5da4 This commit was manufactured by cvs2svn to create tag
'Version_1_30_0'.

[SVN r18026]
2003-03-20 02:53:48 +00:00
Terje Slettebø 6e077f97fc BOOST_MSVC<=1200 fix from Terje
[SVN r18019]
2003-03-19 21:25:45 +00:00
Beman Dawes d9eed4150b BOOST_MSVC<=1200 fix from Terje
[SVN r18002]
2003-03-19 12:14:32 +00:00
Dave Abrahams 62014cf4b6 Commit Terje's changes
[SVN r17982]
2003-03-18 23:55:14 +00:00
Terje Slettebø aad1bfda73 Updated Changes section
[SVN r17922]
2003-03-14 20:32:51 +00:00
Terje Slettebø 3f452717cf no message
[SVN r17921]
2003-03-14 20:17:47 +00:00
Beman Dawes b06d9f5639 overloading fix + less permissive wide character support
[SVN r17893]
2003-03-13 17:27:06 +00:00
Beman Dawes 1b796221b4 BOOST_NO_STD_WSTRING
[SVN r17872]
2003-03-13 00:36:13 +00:00
Beman Dawes 027afb3a87 update from Kevlin and Terje
[SVN r17861]
2003-03-12 21:33:16 +00:00
nobody 07cb73a96c This commit was manufactured by cvs2svn to create branch 'RC_1_30_0'.
[SVN r17693]
2003-03-01 19:43:06 +00:00
10 changed files with 139 additions and 352 deletions
+103 -155
View File
@@ -1,85 +1,64 @@
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<body bgcolor="#FFFFFF" text="#000000">
<h1><img src="../../c++boost.gif" alt="c++boost.gif (8819 bytes)" align=
"middle" width="277" height="86">Header <a href=
"../../boost/cast.hpp">boost/cast.hpp</a></h1>
<body bgcolor="#FFFFFF" text="#000000">
<h2><a name="Cast Functions">Cast Functions</a></h2>
<h1><img src="../../c++boost.gif" alt="c++boost.gif (8819 bytes)" align="middle" width="277" height="86">Header
<a href="../../boost/cast.hpp">boost/cast.hpp</a></h1>
<p>The header <a href="../../boost/cast.hpp">boost/cast.hpp</a> 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> function templates designed to
complement the C++ built-in casts.</p>
<h2><a name="Cast Functions">Cast Functions</a></h2>
<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>The header <a href="../../boost/cast.hpp">boost/cast.hpp</a>
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> function templates designed
to complement the C++ built-in casts.</p>
<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.</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 throwing form of <b>dynamic_cast</b>, which
works on references, can be used on pointers through the ugly expression
&amp;<code>dynamic_cast&lt;T&amp;&gt;(*p)</code>, which causes undefined
behavior if <code>p</code> is <code>0</code>. The <b>polymorphic_cast</b>
template performs a <b>dynamic_cast</b> on a pointer, 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&lt;Derived&gt;(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 (ODR) if NDEBUG is
inconsistently defined across translation units. [See ISO Std 3.2]</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>
namespace boost {
<p>The program <a href="cast_test.cpp">cast_test.cpp</a> can be used to
verify these function templates work as expected.</p>
<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.</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&lt;Derived&gt;(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 (ODR) if NDEBUG is inconsistently
defined across translation units. [See ISO Std 3.2]</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>namespace boost {
template &lt;class Derived, class Base&gt;
inline Derived polymorphic_cast(Base* x);
@@ -91,15 +70,11 @@ inline Derived polymorphic_downcast(Base* x);
// Effects: assert( dynamic_cast&lt;Derived&gt;(x) == x );
// Returns: static_cast&lt;Derived&gt;(x)
}
</pre>
</blockquote>
<h3>polymorphic_downcast example</h3>
<blockquote>
<pre>
#include &lt;boost/cast.hpp&gt;
}</pre>
</blockquote>
<h3>polymorphic_downcast example</h3>
<blockquote>
<pre>#include &lt;boost/cast.hpp&gt;
...
class Fruit { public: virtual ~Fruit(){}; ... };
class Banana : public Fruit { ... };
@@ -107,40 +82,26 @@ class Banana : public Fruit { ... };
void f( Fruit * fruit ) {
// ... logic which leads us to believe it is a Banana
Banana * banana = boost::polymorphic_downcast&lt;Banana*&gt;(fruit);
...
</pre>
</blockquote>
<h3><a name="numeric_cast">numeric_cast</a></h3>
<p>A <b>static_cast</b> or implicit conversion will not detect failure to
preserve range for numeric casts. The <b>numeric_cast</b> function
templates 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 [ISO Std
20.1.3].</li>
<li>Both argument and result types are Numeric, defined by
<code>std::numeric_limits&lt;&gt;::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>
namespace boost {
...</pre>
</blockquote>
<h3><a name="numeric_cast">numeric_cast</a></h3>
<p>A <b>static_cast</b> or implicit conversion will not
detect failure to preserve range for numeric casts. The <b>numeric_cast</b> function
templates 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 [ISO Std 20.1.3].</li>
<li>Both argument and result types are Numeric, defined by <code>std::numeric_limits&lt;&gt;::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>namespace boost {
class bad_numeric_cast : public std::bad_cast {...};
@@ -151,15 +112,11 @@ template&lt;typename Target, typename Source&gt;
// overflow, as determined by std::numeric_limits
// Returns: static_cast&lt;Target&gt;(arg)
}
</pre>
</blockquote>
<h3>numeric_cast example</h3>
<blockquote>
<pre>
#include &lt;boost/cast.hpp&gt;
}</pre>
</blockquote>
<h3>numeric_cast example</h3>
<blockquote>
<pre>#include &lt;boost/cast.hpp&gt;
using namespace boost::cast;
void ariane(double vx)
@@ -167,36 +124,27 @@ void ariane(double vx)
...
unsigned short dx = numeric_cast&lt;unsigned short&gt;(vx);
...
}
</pre>
</blockquote>
}</pre>
</blockquote>
<h3>numeric_cast rationale</h3>
<p>The form of the throws condition is specified so that != is not a required
operation.</p>
<h3>History</h3>
<p><b>polymorphic_cast</b> was suggested by Bjarne Stroustrup in &quot;The C++
Programming Language&quot;.<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>
<hr>
<p>Revised <!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %B, %Y" startspan
-->06 January, 2001<!--webbot bot="Timestamp" endspan i-checksum="38320"
--></p>
<p>© 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 &quot;as is&quot; without express or
implied warranty, and with no claim as to its suitability for any purpose.</p>
<h3>numeric_cast rationale</h3>
</body>
<p>The form of the throws condition is specified so that != is not a
required operation.</p>
<h3>History</h3>
<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>
<hr>
<p>Revised
<!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %B, %Y" startspan
-->06 January, 2001
<!--webbot bot="Timestamp" endspan i-checksum="38320"
--></p>
<p>&copy; 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>
+1 -1
View File
@@ -175,7 +175,7 @@ namespace boost
# ifdef LONGLONG_MIN
return LONGLONG_MIN;
# else
return -( 9223372036854775807LL )-1; // hope this is portable
return -9223372036854775808LL; // hope this is portable
# endif
}
};
-36
View File
@@ -1,36 +0,0 @@
// Copyright David Abrahams 2003. 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.
#ifndef IMPLICIT_CAST_DWA200356_HPP
# define IMPLICIT_CAST_DWA200356_HPP
# include <boost/mpl/identity.hpp>
namespace boost {
// implementation originally suggested by C. Green in
// http://lists.boost.org/MailArchives/boost/msg00886.php
// The use of identity creates a non-deduced form, so that the
// explicit template argument must be supplied
template <typename T>
inline T implicit_cast (typename mpl::identity<T>::type x) {
return x;
}
// incomplete return type now is here
//template <typename T>
//void implicit_cast (...);
// Macro for when you need a constant expression (Gennaro Prota)
#define BOOST_IMPLICIT_CAST(dst_type, expr) \
( sizeof( implicit_cast<dst_type>(expr) ) \
, \
static_cast<dst_type>(expr) \
)
} // namespace boost
#endif // IMPLICIT_CAST_DWA200356_HPP
+33 -31
View File
@@ -18,7 +18,6 @@
#include <typeinfo>
#include <boost/config.hpp>
#include <boost/limits.hpp>
#include <boost/throw_exception.hpp>
#include <boost/type_traits/is_pointer.hpp>
#ifdef BOOST_NO_STRINGSTREAM
@@ -30,47 +29,51 @@
#if defined(BOOST_NO_STRINGSTREAM) || \
defined(BOOST_NO_STD_WSTRING) || \
defined(BOOST_NO_STD_LOCALE) || \
defined(BOOST_NO_INTRINSIC_WCHAR_T)
defined(BOOST_NO_CWCHAR) || \
defined(BOOST_MSVC) && (BOOST_MSVC <= 1200)
#define DISABLE_WIDE_CHAR_SUPPORT
#endif
#ifdef BOOST_NO_INTRINSIC_WCHAR_T
#include <cwchar>
#endif
namespace boost
{
// exception used to indicate runtime lexical_cast failure
class bad_lexical_cast : public std::bad_cast
{
public:
bad_lexical_cast() :
source(&typeid(void)), target(&typeid(void))
{
}
bad_lexical_cast(
const std::type_info &s,
const std::type_info &t) :
source(&s), target(&t)
{
}
const std::type_info &source_type() const
{
return *source;
}
const std::type_info &target_type() const
{
return *target;
}
virtual const char *what() const throw()
{
return "bad lexical cast: "
"source type value could not be interpreted as target";
}
virtual ~bad_lexical_cast() throw()
{
}
private:
const std::type_info *source;
const std::type_info *target;
};
namespace detail // actual underlying concrete exception type
{
template<typename Target, typename Source>
class no_lexical_conversion : public bad_lexical_cast
{
public:
no_lexical_conversion()
: description(
std::string() + "bad lexical cast: " +
"source type value could not be interpreted as target, Target=" +
typeid(Target).name() + ", Source=" + typeid(Source).name())
{
}
virtual ~no_lexical_conversion() throw()
{
}
virtual const char *what() const throw()
{
return description.c_str();
}
private:
const std::string description; // static initialization fails on MSVC6
};
}
namespace detail // selectors for choosing stream character type
{
template<typename Type>
@@ -141,7 +144,7 @@ namespace boost
}
bool operator<<(const Source &input)
{
return !(stream << input).fail();
return stream << input;
}
template<typename InputStreamable>
bool operator>>(InputStreamable &output)
@@ -187,7 +190,7 @@ namespace boost
Target result;
if(!(interpreter << arg && interpreter >> result))
throw_exception(bad_lexical_cast(typeid(Target), typeid(Source)));
throw detail::no_lexical_conversion<Target, Source>();
return result;
}
}
@@ -202,4 +205,3 @@ namespace boost
#undef DISABLE_WIDE_CHAR_SUPPORT
#endif
View File
+2 -14
View File
@@ -25,7 +25,8 @@
#if defined(BOOST_NO_STRINGSTREAM) || \
defined(BOOST_NO_STD_WSTRING) || \
defined(BOOST_NO_STD_LOCALE) || \
defined(BOOST_NO_INTRINSIC_WCHAR_T)
defined(BOOST_NO_CWCHAR) || \
defined(BOOST_MSVC) && (BOOST_MSVC <= 1200)
#define DISABLE_WIDE_CHAR_SUPPORT
#endif
@@ -36,7 +37,6 @@ void test_conversion_to_int();
void test_conversion_to_double();
void test_conversion_to_bool();
void test_conversion_to_string();
void test_conversion_from_to_wchar_t_alias();
void test_conversion_to_pointer();
void test_conversion_from_wchar_t();
void test_conversion_to_wchar_t();
@@ -51,7 +51,6 @@ unit_test_framework::test_suite *init_unit_test_suite(int, char **)
suite->add(BOOST_TEST_CASE(test_conversion_to_int));
suite->add(BOOST_TEST_CASE(test_conversion_to_double));
suite->add(BOOST_TEST_CASE(test_conversion_to_bool));
suite->add(BOOST_TEST_CASE(test_conversion_from_to_wchar_t_alias));
suite->add(BOOST_TEST_CASE(test_conversion_to_pointer));
suite->add(BOOST_TEST_CASE(test_conversion_to_string));
#ifndef DISABLE_WIDE_CHAR_SUPPORT
@@ -181,17 +180,6 @@ void test_conversion_to_string()
BOOST_CHECK_EQUAL("", lexical_cast<std::string>(std::string("")));
}
void test_conversion_from_to_wchar_t_alias()
{
BOOST_CHECK_EQUAL(123u, lexical_cast<unsigned short>("123"));
BOOST_CHECK_EQUAL(123u, lexical_cast<unsigned int>("123"));
BOOST_CHECK_EQUAL(123u, lexical_cast<unsigned long>("123"));
BOOST_CHECK_EQUAL(std::string("123"),
lexical_cast<std::string>(static_cast<unsigned short>(123)));
BOOST_CHECK_EQUAL(std::string("123"), lexical_cast<std::string>(123u));
BOOST_CHECK_EQUAL(std::string("123"), lexical_cast<std::string>(123ul));
}
void test_conversion_to_pointer()
{
BOOST_CHECK_THROW(lexical_cast<char *>("Test"), boost::bad_lexical_cast);
-33
View File
@@ -1,33 +0,0 @@
# Signals library
# Copyright (C) 2001-2003 Douglas Gregor
# Permission to copy, use, sell and distribute this software is granted
# provided this copyright notice appears in all copies. Permission to modify
# the code and to distribute modified code is granted provided this copyright
# notice appears in all copies, and a notice that the code was modified is
# included with the copyright notice. This software is provided "as is"
# without express or implied warranty, and with no claim as to its suitability
# for any purpose.
# For more information, see http://www.boost.org/
# Testing Jamfile autogenerated from XML source
subproject libs/conversion/test ;
# bring in rules for testing
import testing ;
# Make tests run by default.
DEPENDS all : test ;
{
test-suite conversion
: [ run implicit_cast.cpp ]
[ compile-fail implicit_cast_fail.cpp ]
[ run ../cast_test.cpp ]
[ run ../lexical_cast_test.cpp ]
;
}
-25
View File
@@ -1,25 +0,0 @@
# Signals library
# Copyright (C) 2001-2003 Douglas Gregor
# Permission to copy, use, sell and distribute this software is granted
# provided this copyright notice appears in all copies. Permission to modify
# the code and to distribute modified code is granted provided this copyright
# notice appears in all copies, and a notice that the code was modified is
# included with the copyright notice. This software is provided "as is"
# without express or implied warranty, and with no claim as to its suitability
# for any purpose.
# For more information, see http://www.boost.org/
# bring in rules for testing
import testing ;
test-suite conversion
: [ run implicit_cast.cpp ]
[ compile-fail implicit_cast_fail.cpp ]
[ run ../cast_test.cpp ]
[ run ../lexical_cast_test.cpp ]
;
-34
View File
@@ -1,34 +0,0 @@
// Copyright David Abrahams 2003. 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/implicit_cast.hpp>
#include <cassert>
#include <boost/type.hpp>
using boost::implicit_cast;
using boost::type;
template <class T>
type<T> check_return(T) { return type<T>(); }
struct foo
{
foo(char const*) {}
operator long() const { return 0; }
};
typedef type<long> long_type;
typedef type<foo> foo_type;
int main()
{
type<long> x = check_return(boost::implicit_cast<long>(1));
assert(boost::implicit_cast<long>(1) == 1L);
type<foo> f = check_return(boost::implicit_cast<foo>("hello"));
type<long> z = check_return(boost::implicit_cast<long>(foo("hello")));
return 0;
}
-23
View File
@@ -1,23 +0,0 @@
// Copyright David Abrahams 2003. 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/implicit_cast.hpp>
#include <boost/type.hpp>
#define BOOST_INCLUDE_MAIN
#include <boost/test/test_tools.hpp>
using boost::implicit_cast;
struct foo
{
explicit foo(char const*) {}
};
int test_main(int, char*[])
{
foo x = implicit_cast<foo>("foobar");
}