WSJT-X/boost/libs/iterator/doc/BidirectionalTraversal.html

77 lines
3.4 KiB
HTML

<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<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 0.5: http://docutils.sourceforge.net/" />
<title>Bidirectional Traversal Concept</title>
<link rel="stylesheet" href="../../../rst.css" type="text/css" />
</head>
<body>
<div class="document" id="bidirectional-traversal-concept">
<h1 class="title">Bidirectional Traversal Concept</h1>
<!-- Copyright David Abrahams 2006. Distributed under the Boost -->
<!-- Software License, Version 1.0. (See accompanying -->
<!-- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) -->
<p>A class or built-in type <tt class="docutils literal"><span class="pre">X</span></tt> models the <em>Bidirectional Traversal</em>
concept if, in addition to <tt class="docutils literal"><span class="pre">X</span></tt> meeting the requirements of Forward
Traversal Iterator, the following expressions are valid and respect
the stated semantics.</p>
<table border="1" class="docutils">
<colgroup>
<col width="38%" />
<col width="37%" />
<col width="25%" />
</colgroup>
<thead valign="bottom">
<tr><th class="head" colspan="3">Bidirectional Traversal Iterator Requirements (in addition to Forward Traversal
Iterator)</th>
</tr>
<tr><th class="head">Expression</th>
<th class="head">Return Type</th>
<th class="head">Assertion/Semantics /
Pre-/Post-condition</th>
</tr>
</thead>
<tbody valign="top">
<tr><td><tt class="docutils literal"><span class="pre">--r</span></tt></td>
<td><tt class="docutils literal"><span class="pre">X&amp;</span></tt></td>
<td>pre: there exists
<tt class="docutils literal"><span class="pre">s</span></tt> such that <tt class="docutils literal"><span class="pre">r</span>
<span class="pre">==</span> <span class="pre">++s</span></tt>. post:
<tt class="docutils literal"><span class="pre">s</span></tt> is
dereferenceable.
<tt class="docutils literal"><span class="pre">--(++r)</span> <span class="pre">==</span> <span class="pre">r</span></tt>.
<tt class="docutils literal"><span class="pre">--r</span> <span class="pre">==</span> <span class="pre">--s</span></tt>
implies <tt class="docutils literal"><span class="pre">r</span> <span class="pre">==</span>
<span class="pre">s</span></tt>. <tt class="docutils literal"><span class="pre">&amp;r</span> <span class="pre">==</span> <span class="pre">&amp;--r</span></tt>.</td>
</tr>
<tr><td><tt class="docutils literal"><span class="pre">r--</span></tt></td>
<td>convertible to <tt class="docutils literal"><span class="pre">const</span> <span class="pre">X&amp;</span></tt></td>
<td><pre class="first last literal-block">
{
X tmp = r;
--r;
return tmp;
}
</pre>
</td>
</tr>
<tr><td><tt class="docutils literal"><span class="pre">iterator_traversal&lt;X&gt;::type</span></tt></td>
<td>Convertible to
<tt class="docutils literal"><span class="pre">bidirectional_traversal_tag</span></tt></td>
<td>&nbsp;</td>
</tr>
</tbody>
</table>
</div>
<div class="footer">
<hr class="footer" />
<a class="reference external" href="BidirectionalTraversal.rst">View document source</a>.
Generated by <a class="reference external" href="http://docutils.sourceforge.net/">Docutils</a> from <a class="reference external" href="http://docutils.sourceforge.net/rst.html">reStructuredText</a> source.
</div>
</body>
</html>