ceph/src/boost/libs/flyweight/doc/reference/key_value.html

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  15 <h1><img src="../../../../boost.png" alt="Boost logo" align=
  16 "middle" width="277" height="86">Key-value flyweights reference</h1>
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  19 <code>flyweight</code> reference
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  30 <h2>Contents</h2>
  31
  32 <ul>
  33   <li><a href="#key_extractor">Key extractors</a></li>
  34   <li><a href="#key_value_fwd_synopsis">Header
  35     <code>"boost/flyweight/key_value_fwd.hpp"</code> synopsis</a>
  36   </li>
  37   <li><a href="#synopsis">Header
  38     <code>"boost/flyweight/key_value.hpp"</code> synopsis</a>
  39     <ul>
  40       <li><a href="#key_value_construct">Class template <code>key_value</code></a></li>
  41     </ul>
  42   </li>
  43 </ul>
  44
  45 <h2><a name="key_extractor">Key extractors</a></h2>
  46
  47 <p>
  48 Let <code>Key</code> be a type with some implicit equivalence relationship
  49 and <code>Value</code> a type constructible from <code>Key</code>.
  50 A <a href="http://www.sgi.com/tech/stl/DefaultConstructible.html"><code>Default
  51 Constructible</code></a> type <code>KeyFromValue</code> is said
  52 to be a key extractor from <code>Value</code> to <code>Key</code> if
  53 <ol>
  54   <li><code>kfv(cv)</code> is defined and have type <code>const Key&amp;</code>,</li>
  55   <li><code>kfv(cv)</code> is equivalent to <code>kfv(Value(cv))</code>,</li>
  56   <li><code>kfv(Value(k))</code> is equivalent to <code>k</code>,</li>
  57 </ol>
  58 for every <code>kfv</code> of type <code>const KeyFromValue</code>,
  59 <code>cv</code> of type <code>const Value</code> and
  60 <code>k</code> of type <code>Key</code>.
  61 </p>
  62
  63 <h2><a name="key_value_fwd_synopsis">Header
  64 <a href="../../../../boost/flyweight/key_value_fwd.hpp"><code>"boost/flyweight/key_value_fwd.hpp"</code></a> synopsis</a></h2>
  65
  66 <blockquote><pre>
  67 <span class=keyword>namespace</span> <span class=identifier>boost</span><span class=special>{</span>
  68
  69 <span class=keyword>namespace</span> <span class=identifier>flyweights</span><span class=special>{</span>
  70
  71 <span class=keyword>struct</span> <span class=identifier>no_key_from_value</span><span class=special>;</span>
  72
  73 <span class=keyword>template</span><span class=special>&lt;</span>
  74   <span class=keyword>typename</span> <span class=identifier>Key</span><span class=special>,</span><span class=keyword>typename</span> <span class=identifier>Value</span><span class=special>,</span>
  75   <span class=keyword>typename</span> <span class=identifier>KeyFromValue</span><span class=special>=</span><span class=identifier>no_key_from_value</span>
  76 <span class=special>&gt;</span>
  77 <span class=keyword>struct</span> <span class=identifier>key_value</span><span class=special>;</span>
  78
  79 <span class=special>}</span> <span class=comment>// namespace boost::flyweights</span>
  80
  81 <span class=special>}</span> <span class=comment>// namespace boost</span>
  82 </pre></blockquote>
  83
  84 <h2><a name="synopsis">Header
  85 <a href="../../../../boost/flyweight/key_value.hpp"><code>"boost/flyweight/key_value.hpp"</code></a> synopsis</a></h2>
  86
  87 <h3><a name="key_value_construct">Class template <code>key_value</code></a></h3>
  88
  89 <p>
  90 In <a href="flyweight.html#flyweight"><code>flyweight</code></a> instantiations
  91 of the form <code>flyweight&lt;T,...&gt;</code>, the associated
  92 <code>key_type</code> and <code>value_type</code> are both equal to <code>T</code>.
  93 Instantiations of the form <code>flyweight&lt;key_value&lt;Key,Value[,KeyFromValue]&gt;,...&gt;</code>
  94 allow to specify these types separately. <code>Key</code> and <code>Value</code>
  95 must be different types. When provided, <code>KeyFromValue</code>
  96 must be a <a href="#key_extractor"><code>Key Extractor</code></a> from
  97 <code>Value</code> to <code>Key</code>.
  98 </p>
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 113
 114 <p>Revised September 15th 2008</p>
 115
 116 <p>&copy; Copyright 2006-2008 Joaqu&iacute;n M L&oacute;pez Mu&ntilde;oz.
 117 Distributed under the Boost Software
 118 License, Version 1.0. (See accompanying file <a href="../../../../LICENSE_1_0.txt">
 119 LICENSE_1_0.txt</a> or copy at <a href="http://www.boost.org/LICENSE_1_0.txt">
 120 http://www.boost.org/LICENSE_1_0.txt</a>)
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