ceph/src/boost/libs/context/doc/html/context/stack/pooled_fixedsize.html

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  24 </div>
  25 <div class="section">
  26 <div class="titlepage"><div><div><h3 class="title">
  27 <a name="context.stack.pooled_fixedsize"></a><a class="link" href="pooled_fixedsize.html" title="Class pooled_fixedsize_stack">Class <span class="emphasis"><em>pooled_fixedsize_stack</em></span></a>
  28 </h3></div></div></div>
  29 <p>
  30         <span class="bold"><strong>Boost.Context</strong></span> provides the class <span class="emphasis"><em>pooled_fixedsize_stack</em></span>
  31         which models the <span class="emphasis"><em>stack-allocator concept</em></span>. In contrast
  32         to <span class="emphasis"><em>protected_fixedsize_stack</em></span> it does not append a guard
  33         page at the end of each stack. The memory is managed internally by <a href="http://www.boost.org/doc/libs/release/libs/pool/doc/html/boost/pool.html" target="_top"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">pool</span><span class="special">&lt;&gt;</span></code></a>.
  34       </p>
  35 <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">context</span><span class="special">/</span><span class="identifier">pooled_fixedsize_stack</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
  36
  37 <span class="keyword">template</span><span class="special">&lt;</span> <span class="keyword">typename</span> <span class="identifier">traitsT</span> <span class="special">&gt;</span>
  38 <span class="keyword">struct</span> <span class="identifier">basic_pooled_fixedsize_stack</span> <span class="special">{</span>
  39     <span class="keyword">typedef</span> <span class="identifier">traitT</span>  <span class="identifier">traits_type</span><span class="special">;</span>
  40
  41     <span class="identifier">basic_pooled_fixedsize_stack</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">stack_size</span> <span class="special">=</span> <span class="identifier">traits_type</span><span class="special">::</span><span class="identifier">default_size</span><span class="special">(),</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">next_size</span> <span class="special">=</span> <span class="number">32</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">max_size</span> <span class="special">=</span> <span class="number">0</span><span class="special">);</span>
  42
  43     <span class="identifier">stack_context</span> <span class="identifier">allocate</span><span class="special">();</span>
  44
  45     <span class="keyword">void</span> <span class="identifier">deallocate</span><span class="special">(</span> <span class="identifier">stack_context</span> <span class="special">&amp;);</span>
  46 <span class="special">}</span>
  47
  48 <span class="keyword">typedef</span> <span class="identifier">basic_pooled_fixedsize_stack</span><span class="special">&lt;</span> <span class="identifier">stack_traits</span> <span class="special">&gt;</span> <span class="identifier">pooled_fixedsize_stack</span><span class="special">;</span>
  49 </pre>
  50 <h5>
  51 <a name="context.stack.pooled_fixedsize.h0"></a>
  52         <span><a name="context.stack.pooled_fixedsize._code__phrase_role__identifier__basic_pooled_fixedsize_stack__phrase__phrase_role__special_____phrase__phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__stack_size__phrase__phrase_role__special_____phrase___phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__next_size__phrase__phrase_role__special_____phrase___phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__max_size__phrase__phrase_role__special_____phrase___code_"></a></span><a class="link" href="pooled_fixedsize.html#context.stack.pooled_fixedsize._code__phrase_role__identifier__basic_pooled_fixedsize_stack__phrase__phrase_role__special_____phrase__phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__stack_size__phrase__phrase_role__special_____phrase___phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__next_size__phrase__phrase_role__special_____phrase___phrase_role__identifier__std__phrase__phrase_role__special______phrase__phrase_role__identifier__size_t__phrase___phrase_role__identifier__max_size__phrase__phrase_role__special_____phrase___code_"><code class="computeroutput"><span class="identifier">basic_pooled_fixedsize_stack</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span>
  53         <span class="identifier">stack_size</span><span class="special">,</span>
  54         <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">next_size</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">max_size</span><span class="special">)</span></code></a>
  55       </h5>
  56 <div class="variablelist">
  57 <p class="title"><b></b></p>
  58 <dl>
  59 <dt><span class="term">Preconditions:</span></dt>
  60 <dd><p>
  61               <code class="computeroutput"><span class="special">!</span> <span class="identifier">traits_type</span><span class="special">::</span><span class="identifier">is_unbounded</span><span class="special">()</span> <span class="special">&amp;&amp;</span>
  62               <span class="special">(</span> <span class="identifier">traits_type</span><span class="special">::</span><span class="identifier">maximum</span><span class="special">:</span><span class="identifier">size</span><span class="special">()</span> <span class="special">&gt;=</span> <span class="identifier">stack_size</span><span class="special">)</span></code>
  63               and <code class="computeroutput"><span class="number">0</span> <span class="special">&lt;</span>
  64               <span class="identifier">nest_size</span></code>.
  65             </p></dd>
  66 <dt><span class="term">Effects:</span></dt>
  67 <dd><p>
  68               Allocates memory of at least <code class="computeroutput"><span class="identifier">stack_size</span></code>
  69               Bytes and stores a pointer to the stack and its actual size in <code class="computeroutput"><span class="identifier">sctx</span></code>. Depending on the architecture
  70               (the stack grows downwards/upwards) the stored address is the highest/lowest
  71               address of the stack. Argument <code class="computeroutput"><span class="identifier">next_size</span></code>
  72               determines the number of stacks to request from the system the first
  73               time that <code class="computeroutput"><span class="special">*</span><span class="keyword">this</span></code>
  74               needs to allocate system memory. The third argument <code class="computeroutput"><span class="identifier">max_size</span></code>
  75               controls how many memory might be allocated for stacks - a value of
  76               zero means no uper limit.
  77             </p></dd>
  78 </dl>
  79 </div>
  80 <h5>
  81 <a name="context.stack.pooled_fixedsize.h1"></a>
  82         <span><a name="context.stack.pooled_fixedsize._code__phrase_role__identifier__stack_context__phrase___phrase_role__identifier__allocate__phrase__phrase_role__special______phrase___code_"></a></span><a class="link" href="pooled_fixedsize.html#context.stack.pooled_fixedsize._code__phrase_role__identifier__stack_context__phrase___phrase_role__identifier__allocate__phrase__phrase_role__special______phrase___code_"><code class="computeroutput"><span class="identifier">stack_context</span> <span class="identifier">allocate</span><span class="special">()</span></code></a>
  83       </h5>
  84 <div class="variablelist">
  85 <p class="title"><b></b></p>
  86 <dl>
  87 <dt><span class="term">Preconditions:</span></dt>
  88 <dd><p>
  89               <code class="computeroutput"><span class="special">!</span> <span class="identifier">traits_type</span><span class="special">::</span><span class="identifier">is_unbounded</span><span class="special">()</span> <span class="special">&amp;&amp;</span>
  90               <span class="special">(</span> <span class="identifier">traits_type</span><span class="special">::</span><span class="identifier">maximum</span><span class="special">:</span><span class="identifier">size</span><span class="special">()</span> <span class="special">&gt;=</span> <span class="identifier">stack_size</span><span class="special">)</span></code>.
  91             </p></dd>
  92 <dt><span class="term">Effects:</span></dt>
  93 <dd><p>
  94               Allocates memory of at least <code class="computeroutput"><span class="identifier">stack_size</span></code>
  95               Bytes and stores a pointer to the stack and its actual size in <code class="computeroutput"><span class="identifier">sctx</span></code>. Depending on the architecture
  96               (the stack grows downwards/upwards) the stored address is the highest/lowest
  97               address of the stack.
  98             </p></dd>
  99 </dl>
 100 </div>
 101 <h5>
 102 <a name="context.stack.pooled_fixedsize.h2"></a>
 103         <span><a name="context.stack.pooled_fixedsize._code__phrase_role__keyword__void__phrase___phrase_role__identifier__deallocate__phrase__phrase_role__special_____phrase___phrase_role__identifier__stack_context__phrase___phrase_role__special___amp___phrase___phrase_role__identifier__sctx__phrase__phrase_role__special_____phrase___code_"></a></span><a class="link" href="pooled_fixedsize.html#context.stack.pooled_fixedsize._code__phrase_role__keyword__void__phrase___phrase_role__identifier__deallocate__phrase__phrase_role__special_____phrase___phrase_role__identifier__stack_context__phrase___phrase_role__special___amp___phrase___phrase_role__identifier__sctx__phrase__phrase_role__special_____phrase___code_"><code class="computeroutput"><span class="keyword">void</span> <span class="identifier">deallocate</span><span class="special">(</span> <span class="identifier">stack_context</span>
 104         <span class="special">&amp;</span> <span class="identifier">sctx</span><span class="special">)</span></code></a>
 105       </h5>
 106 <div class="variablelist">
 107 <p class="title"><b></b></p>
 108 <dl>
 109 <dt><span class="term">Preconditions:</span></dt>
 110 <dd><p>
 111               <code class="computeroutput"><span class="identifier">sctx</span><span class="special">.</span><span class="identifier">sp</span></code> is valid, <code class="computeroutput"><span class="special">!</span>
 112               <span class="identifier">traits_type</span><span class="special">::</span><span class="identifier">is_unbounded</span><span class="special">()</span>
 113               <span class="special">&amp;&amp;</span> <span class="special">(</span>
 114               <span class="identifier">traits_type</span><span class="special">::</span><span class="identifier">maximum</span><span class="special">:</span><span class="identifier">size</span><span class="special">()</span>
 115               <span class="special">&gt;=</span> <span class="identifier">sctx</span><span class="special">.</span><span class="identifier">size</span><span class="special">)</span></code>.
 116             </p></dd>
 117 <dt><span class="term">Effects:</span></dt>
 118 <dd><p>
 119               Deallocates the stack space.
 120             </p></dd>
 121 </dl>
 122 </div>
 123 </div>
 124 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 125 <td align="left"></td>
 126 <td align="right"><div class="copyright-footer">Copyright &#169; 2014 Oliver Kowalke<p>
 127         Distributed under the Boost Software License, Version 1.0. (See accompanying
 128         file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
 129       </p>
 130 </div></td>
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