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improvements to the spec

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[SVN r21604]
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Jeremy Siek
2004-01-11 17:46:42 +00:00
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doc/reverse_iterator.html
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@ -3,13 +3,13 @@
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta name="generator" content="Docutils 0.3.1: http://docutils.sourceforge.net/" />
<meta name="generator" content="Docutils 0.3.0: http://docutils.sourceforge.net/" />
<title>Reverse Iterator</title>
<meta name="author" content="David Abrahams, Jeremy Siek, Thomas Witt" />
<meta name="organization" content="Boost Consulting, Indiana University Open Systems Lab, University of Hanover Institute for Transport Railway Operation and Construction" />
<meta name="date" content="2003-09-14" />
<meta name="copyright" content="Copyright David Abrahams, Jeremy Siek, and Thomas Witt 2003. All rights reserved" />
<link rel="stylesheet" href="../../../rst.css" type="text/css" />
<link rel="stylesheet" href="default.css" type="text/css" />
</head>
<body>
<div class="document" id="reverse-iterator">
@ -47,15 +47,19 @@ invoking <tt class="literal"><span class="pre">operator--()</span></tt> moves th
<div class="contents topic" id="table-of-contents">
<p class="topic-title"><a name="table-of-contents">Table of Contents</a></p>
<ul class="simple">
<li><a class="reference" href="#reverse-iterator-requirements" id="id1" name="id1"><tt class="literal"><span class="pre">reverse_iterator</span></tt> requirements</a></li>
<li><a class="reference" href="#reverse-iterator-synopsis" id="id1" name="id1"><tt class="literal"><span class="pre">reverse_iterator</span></tt> synopsis</a></li>
<li><a class="reference" href="#reverse-iterator-requirements" id="id2" name="id2"><tt class="literal"><span class="pre">reverse_iterator</span></tt> requirements</a></li>
<li><a class="reference" href="#reverse-iterator-models" id="id3" name="id3"><tt class="literal"><span class="pre">reverse_iterator</span></tt> models</a></li>
<li><a class="reference" href="#reverse-iterator-operations" id="id4" name="id4"><tt class="literal"><span class="pre">reverse_iterator</span></tt> operations</a></li>
<li><a class="reference" href="#example" id="id5" name="id5">Example</a></li>
</ul>
</div>
<div class="section" id="reverse-iterator-synopsis">
<h1><a class="toc-backref" href="#id1" name="reverse-iterator-synopsis"><tt class="literal"><span class="pre">reverse_iterator</span></tt> synopsis</a></h1>
<pre class="literal-block">
template &lt;class Iterator&gt;
class reverse_iterator :
public iterator_adaptor&lt; reverse_iterator&lt;Iterator&gt;, Iterator &gt;
class reverse_iterator
{
friend class iterator_core_access;
public:
reverse_iterator() {}
explicit reverse_iterator(Iterator x) ;
@ -65,33 +69,49 @@ public:
reverse_iterator&lt;OtherIterator&gt; const&amp; r
, typename enable_if_convertible&lt;OtherIterator, Iterator&gt;::type* = 0 // exposition
);
private: // as-if specification
typename reverse_iterator::reference dereference() const { return *prior(this-&gt;base()); }
void increment() { --this-&gt;base_reference(); }
void decrement() { ++this-&gt;base_reference(); }
void advance(typename reverse_iterator::difference_type n)
{
this-&gt;base_reference() += -n;
}
template &lt;class OtherIterator&gt;
typename reverse_iterator::difference_type
distance_to(reverse_iterator&lt;OtherIterator&gt; const&amp; y) const
{
return this-&gt;base_reference() - y.base();
}
reference operator*() const;
reverse_iterator&amp; operator++();
private:
Iterator current; // exposition
};
</pre>
</div>
<div class="section" id="reverse-iterator-requirements">
<h1><a class="toc-backref" href="#id1" name="reverse-iterator-requirements"><tt class="literal"><span class="pre">reverse_iterator</span></tt> requirements</a></h1>
<h1><a class="toc-backref" href="#id2" name="reverse-iterator-requirements"><tt class="literal"><span class="pre">reverse_iterator</span></tt> requirements</a></h1>
<p>The base <tt class="literal"><span class="pre">Iterator</span></tt> must be a model of Bidirectional Traversal
Iterator. The resulting <tt class="literal"><span class="pre">reverse_iterator</span></tt> will be a model of the
most refined standard traversal and access concepts that are modeled
by <tt class="literal"><span class="pre">Iterator</span></tt>.</p>
Iterator and Readable Iterator.</p>
</div>
<div class="section" id="reverse-iterator-models">
<h1><a class="toc-backref" href="#id3" name="reverse-iterator-models"><tt class="literal"><span class="pre">reverse_iterator</span></tt> models</a></h1>
<p><tt class="literal"><span class="pre">reverse_iterator</span></tt> models Bidirectional Traversal Iterator and
Readable Iterator. In addition, <tt class="literal"><span class="pre">reverse_iterator</span></tt> models the same
standard iterator access concepts (if any) that the <tt class="literal"><span class="pre">Iterator</span></tt>
argument models. Also, <tt class="literal"><span class="pre">reverse_iterator</span></tt> models concepts
according to the following table.</p>
<table border class="table">
<colgroup>
<col width="35%" />
<col width="65%" />
</colgroup>
<thead valign="bottom">
<tr><th>If <tt class="literal"><span class="pre">Iterator</span></tt> models</th>
<th>then <tt class="literal"><span class="pre">reverse_iterator</span></tt> models</th>
</tr>
</thead>
<tbody valign="top">
<tr><td>Bidirectional Iterator</td>
<td>Bidirectional Iterator, Readable Lvalue Iterator,
Bidirectional Traversal Iterator</td>
</tr>
<tr><td>Mutable Bidirectional Iterator</td>
<td>Mutable Bidirectional Iterator, Writable Lvalue Iterator,
Bidirectional Traversal Iterator</td>
</tr>
</tbody>
</table>
</div>
<div class="section" id="reverse-iterator-operations">
<h1><a class="toc-backref" href="#id4" name="reverse-iterator-operations"><tt class="literal"><span class="pre">reverse_iterator</span></tt> operations</a></h1>
<p><tt class="literal"><span class="pre">reverse_iterator();</span></tt></p>
<table class="field-list" frame="void" rules="none">
<col class="field-name" />
@ -99,8 +119,8 @@ by <tt class="literal"><span class="pre">Iterator</span></tt>.</p>
<tbody valign="top">
<tr class="field"><th class="field-name">Requires:</th><td class="field-body"><tt class="literal"><span class="pre">Iterator</span></tt> must be Default Constructible.</td>
</tr>
<tr class="field"><th class="field-name">Returns:</th><td class="field-body">An instance of <tt class="literal"><span class="pre">reverse_iterator</span></tt> with a
default constructed base object.</td>
<tr class="field"><th class="field-name">Returns:</th><td class="field-body">An instance of <tt class="literal"><span class="pre">reverse_iterator</span></tt> with <tt class="literal"><span class="pre">current</span></tt>
default constructed.</td>
</tr>
</tbody>
</table>
@ -110,7 +130,7 @@ default constructed base object.</td>
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Returns:</th><td class="field-body">An instance of <tt class="literal"><span class="pre">reverse_iterator</span></tt> with a
base object copy constructed from <tt class="literal"><span class="pre">x</span></tt>.</td>
<tt class="literal"><span class="pre">current</span></tt> constructed from <tt class="literal"><span class="pre">x</span></tt>.</td>
</tr>
</tbody>
</table>
@ -131,13 +151,57 @@ reverse_iterator(
</tr>
</tbody>
</table>
<p><tt class="literal"><span class="pre">reference</span> <span class="pre">operator*()</span> <span class="pre">const;</span></tt></p>
<table class="field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Effects:</th><td class="field-body"></td>
</tr>
</tbody>
</table>
<pre class="literal-block">
Iterator tmp = current;
return *--tmp;
</pre>
<p><tt class="literal"><span class="pre">reverse_iterator&amp;</span> <span class="pre">operator++();</span></tt></p>
<table class="field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Effects:</th><td class="field-body"><tt class="literal"><span class="pre">--current</span></tt></td>
</tr>
<tr class="field"><th class="field-name">Returns:</th><td class="field-body"><tt class="literal"><span class="pre">*this</span></tt></td>
</tr>
</tbody>
</table>
</div>
<div class="section" id="example">
<h1><a class="toc-backref" href="#id5" name="example">Example</a></h1>
<p>The following example prints an array of characters in reverse order
using <tt class="literal"><span class="pre">reverse_iterator</span></tt>.</p>
<pre class="literal-block">
char letters_[] = &quot;hello world!&quot;;
const int N = sizeof(letters_)/sizeof(char) - 1;
typedef char* base_iterator;
base_iterator letters(letters_);
std::cout &lt;&lt; &quot;original sequence of letters:\t&quot; &lt;&lt; letters_ &lt;&lt; std::endl;
boost::reverse_iterator&lt;base_iterator&gt;
reverse_letters_first(letters + N),
reverse_letters_last(letters);
std::cout &lt;&lt; &quot;sequence in reverse order:\t&quot;;
std::copy(reverse_letters_first, reverse_letters_last,
std::ostream_iterator&lt;char&gt;(std::cout));
std::cout &lt;&lt; std::endl;
</pre>
<p>The output is:</p>
<pre class="literal-block">
original sequence of letters: hello world!
sequence in reverse order: !dlrow olleh
</pre>
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