ceph/src/boost/libs/iterator/doc/iterator_archetypes.html

   1 <?xml version="1.0" encoding="utf-8" ?>
   2 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
   3 <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
   4 <head>
   5 <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
   6 <meta name="generator" content="Docutils 0.5: http://docutils.sourceforge.net/" />
   7 <title>Iterator Archetype</title>
   8 <meta name="author" content="David Abrahams, Jeremy Siek, Thomas Witt" />
   9 <meta name="organization" content="Boost Consulting, Indiana University Open Systems Lab, Zephyr Associates, Inc." />
  10 <meta name="date" content="2006-09-11" />
  11 <meta name="copyright" content="Copyright David Abrahams, Jeremy Siek, and Thomas Witt 2004." />
  12 <link rel="stylesheet" href="../../../rst.css" type="text/css" />
  13 </head>
  14 <body>
  15 <div class="document" id="iterator-archetype">
  16 <h1 class="title">Iterator Archetype</h1>
  17 <table class="docinfo" frame="void" rules="none">
  18 <col class="docinfo-name" />
  19 <col class="docinfo-content" />
  20 <tbody valign="top">
  21 <tr><th class="docinfo-name">Author:</th>
  22 <td>David Abrahams, Jeremy Siek, Thomas Witt</td></tr>
  23 <tr><th class="docinfo-name">Contact:</th>
  24 <td><a class="first reference external" href="mailto:dave&#64;boost-consulting.com">dave&#64;boost-consulting.com</a>, <a class="reference external" href="mailto:jsiek&#64;osl.iu.edu">jsiek&#64;osl.iu.edu</a>, <a class="last reference external" href="mailto:witt&#64;styleadvisor.com">witt&#64;styleadvisor.com</a></td></tr>
  25 <tr><th class="docinfo-name">Organization:</th>
  26 <td><a class="first reference external" href="http://www.boost-consulting.com">Boost Consulting</a>, Indiana University <a class="reference external" href="http://www.osl.iu.edu">Open Systems
  27 Lab</a>, <a class="last reference external" href="http://www.styleadvisor.com">Zephyr Associates, Inc.</a></td></tr>
  28 <tr><th class="docinfo-name">Date:</th>
  29 <td>2006-09-11</td></tr>
  30 <tr><th class="docinfo-name">Copyright:</th>
  31 <td>Copyright David Abrahams, Jeremy Siek, and Thomas Witt 2004.</td></tr>
  32 </tbody>
  33 </table>
  34 <!-- Distributed under the Boost -->
  35 <!-- Software License, Version 1.0. (See accompanying -->
  36 <!-- file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) -->
  37 <table class="docutils field-list" frame="void" rules="none">
  38 <col class="field-name" />
  39 <col class="field-body" />
  40 <tbody valign="top">
  41 <tr class="field"><th class="field-name">abstract:</th><td class="field-body">The <tt class="docutils literal"><span class="pre">iterator_archetype</span></tt> class constructs a minimal implementation of
  42 one of the iterator access concepts and one of the iterator traversal concepts.
  43 This is used for doing a compile-time check to see if a the type requirements
  44 of a template are really enough to cover the implementation of the template.
  45 For further information see the documentation for the <a class="reference external" href="../../concept_check/index.html"><tt class="docutils literal"><span class="pre">boost::concept_check</span></tt></a> library.</td>
  46 </tr>
  47 </tbody>
  48 </table>
  49 <div class="contents topic" id="table-of-contents">
  50 <p class="topic-title first">Table of Contents</p>
  51 <ul class="simple">
  52 <li><a class="reference internal" href="#reference" id="id1">Reference</a><ul>
  53 <li><a class="reference internal" href="#iterator-archetype-synopsis" id="id2"><tt class="docutils literal"><span class="pre">iterator_archetype</span></tt> Synopsis</a></li>
  54 <li><a class="reference internal" href="#access-category-tags" id="id3"><tt class="docutils literal"><span class="pre">Access</span> <span class="pre">Category</span> <span class="pre">Tags</span></tt></a></li>
  55 <li><a class="reference internal" href="#iterator-archetype-requirements" id="id4"><tt class="docutils literal"><span class="pre">iterator_archetype</span></tt> Requirements</a></li>
  56 <li><a class="reference internal" href="#iterator-archetype-models" id="id5"><tt class="docutils literal"><span class="pre">iterator_archetype</span></tt> Models</a></li>
  57 <li><a class="reference internal" href="#traits" id="id6"><tt class="docutils literal"><span class="pre">Traits</span></tt></a></li>
  58 </ul>
  59 </li>
  60 </ul>
  61 </div>
  62 <div class="section" id="reference">
  63 <h1><a class="toc-backref" href="#id1">Reference</a></h1>
  64 <div class="section" id="iterator-archetype-synopsis">
  65 <h2><a class="toc-backref" href="#id2"><tt class="docutils literal"><span class="pre">iterator_archetype</span></tt> Synopsis</a></h2>
  66 <pre class="literal-block">
  67 namespace iterator_archetypes
  68 {
  69     // Access categories
  70
  71     typedef /*implementation  defined*/ readable_iterator_t;
  72     typedef /*implementation  defined*/ writable_iterator_t;
  73     typedef /*implementation  defined*/ readable_writable_iterator_t;
  74     typedef /*implementation  defined*/ readable_lvalue_iterator_t;
  75     typedef /*implementation  defined*/ writable_lvalue_iterator_t;
  76
  77 }
  78
  79 template &lt;
  80     class Value
  81   , class AccessCategory
  82   , class TraversalCategory
  83 &gt;
  84 class iterator_archetype
  85 {
  86     typedef /* see below */ value_type;
  87     typedef /* see below */ reference;
  88     typedef /* see below */ pointer;
  89     typedef /* see below */ difference_type;
  90     typedef /* see below */ iterator_category;
  91 };
  92 </pre>
  93 </div>
  94 <div class="section" id="access-category-tags">
  95 <h2><a class="toc-backref" href="#id3"><tt class="docutils literal"><span class="pre">Access</span> <span class="pre">Category</span> <span class="pre">Tags</span></tt></a></h2>
  96 <p>The access category types provided correspond to the following
  97 standard iterator access concept combinations:</p>
  98 <pre class="literal-block">
  99 readable_iterator_t :=
 100
 101   Readable Iterator
 102
 103 writable_iterator_t :=
 104
 105   Writeable Iterator
 106
 107 readable_writable_iterator_t :=
 108
 109   Readable Iterator &amp; Writeable Iterator &amp; Swappable Iterator
 110
 111 readable_lvalue_iterator_t :=
 112
 113   Readable Iterator &amp; Lvalue Iterator
 114
 115 writeable_lvalue_iterator_t :=
 116
 117   Readable Iterator &amp; Writeable Iterator &amp; Swappable Iterator &amp; Lvalue Iterator
 118 </pre>
 119 </div>
 120 <div class="section" id="iterator-archetype-requirements">
 121 <h2><a class="toc-backref" href="#id4"><tt class="docutils literal"><span class="pre">iterator_archetype</span></tt> Requirements</a></h2>
 122 <p>The <tt class="docutils literal"><span class="pre">AccessCategory</span></tt> argument must be one of the predefined access
 123 category tags. The <tt class="docutils literal"><span class="pre">TraversalCategory</span></tt> must be one of the standard
 124 traversal tags. The <tt class="docutils literal"><span class="pre">Value</span></tt> type must satisfy the requirements of
 125 the iterator concept specified by <tt class="docutils literal"><span class="pre">AccessCategory</span></tt> and
 126 <tt class="docutils literal"><span class="pre">TraversalCategory</span></tt> as implied by the nested traits types.</p>
 127 </div>
 128 <div class="section" id="iterator-archetype-models">
 129 <h2><a class="toc-backref" href="#id5"><tt class="docutils literal"><span class="pre">iterator_archetype</span></tt> Models</a></h2>
 130 <p><tt class="docutils literal"><span class="pre">iterator_archetype</span></tt> models the iterator concepts specified by the
 131 <tt class="docutils literal"><span class="pre">AccessCategory</span></tt> and <tt class="docutils literal"><span class="pre">TraversalCategory</span></tt>
 132 arguments. <tt class="docutils literal"><span class="pre">iterator_archetype</span></tt> does not model any other access
 133 concepts or any more derived traversal concepts.</p>
 134 </div>
 135 <div class="section" id="traits">
 136 <h2><a class="toc-backref" href="#id6"><tt class="docutils literal"><span class="pre">Traits</span></tt></a></h2>
 137 <p>The nested trait types are defined as follows:</p>
 138 <pre class="literal-block">
 139 if (AccessCategory == readable_iterator_t)
 140
 141   value_type = Value
 142   reference  = Value
 143   pointer    = Value*
 144
 145 else if (AccessCategory == writable_iterator_t)
 146
 147   value_type = void
 148   reference  = void
 149   pointer    = void
 150
 151 else if (AccessCategory == readable_writable_iterator_t)
 152
 153   value_type = Value
 154
 155   reference :=
 156
 157     A type X that is convertible to Value for which the following
 158     expression is valid. Given an object x of type X and v of type
 159     Value.
 160
 161     x = v
 162
 163   pointer    = Value*
 164
 165 else if (AccessCategory == readable_lvalue_iterator_t)
 166
 167   value_type = Value
 168   reference  = Value const&amp;
 169   pointer    = Value const*
 170
 171 else if (AccessCategory == writable_lvalue_iterator_t)
 172
 173   value_type = Value
 174   reference  = Value&amp;
 175   pointer    = Value*
 176
 177 if ( TraversalCategory is convertible to forward_traversal_tag )
 178
 179   difference_type := ptrdiff_t
 180
 181 else
 182
 183   difference_type := unspecified type
 184
 185
 186 iterator_category :=
 187
 188   A type X satisfying the following two constraints:
 189
 190      1. X is convertible to X1, and not to any more-derived
 191         type, where X1 is defined by:
 192
 193           if (reference is a reference type
 194               &amp;&amp; TraversalCategory is convertible to forward_traversal_tag)
 195           {
 196               if (TraversalCategory is convertible to random_access_traversal_tag)
 197                   X1 = random_access_iterator_tag
 198               else if (TraversalCategory is convertible to bidirectional_traversal_tag)
 199                   X1 = bidirectional_iterator_tag
 200               else
 201                   X1 = forward_iterator_tag
 202           }
 203           else
 204           {
 205               if (TraversalCategory is convertible to single_pass_traversal_tag
 206                   &amp;&amp; reference != void)
 207                   X1 = input_iterator_tag
 208               else
 209                   X1 = output_iterator_tag
 210           }
 211
 212      2. X is convertible to TraversalCategory
 213 </pre>
 214 </div>
 215 </div>
 216 </div>
 217 <div class="footer">
 218 <hr class="footer" />
 219 <a class="reference external" href="iterator_archetypes.rst">View document source</a>.
 220 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.
 221
 222 </div>
 223 </body>
 224 </html>