ceph/src/boost/libs/icl/doc/html/boost_icl/implementation.html

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  25 <div class="section boost_icl_implementation" lang="en">
  26 <div class="titlepage"><div><div><h2 class="title" style="clear: both">
  27 <a name="boost_icl.implementation"></a><a class="link" href="implementation.html" title="Implementation">Implementation</a>
  28 </h2></div></div></div>
  29 <div class="toc"><dl>
  30 <dt><span class="section"><a href="implementation.html#boost_icl.implementation.iterative_size">Iterative size</a></span></dt>
  31 <dt><span class="section"><a href="implementation/complexity.html">Complexity</a></span></dt>
  32 <dt><span class="section"><a href="implementation/inplace_and_infix_operators.html">Inplace
  33       and infix operators</a></span></dt>
  34 </dl></div>
  35 <p>
  36       The <a class="link" href="interface.html" title="Interface">previous section</a> gave an overview
  37       over the interface of the <span class="bold"><strong>icl</strong></span> outlining <a class="link" href="interface.html#boost_icl.interface.class_templates" title="Class templates">class templates</a>, <a class="link" href="interface/associated_types.html" title="Associated Types">associated types</a> and
  38       polymorphic <a class="link" href="interface/function_synopsis.html" title="Function Synopsis">functions
  39       and operators</a>. In preparation to the <a class="link" href="function_reference.html" title="Function Reference">next
  40       section</a>, that describes the <span class="bold"><strong>icl's</strong></span> polymorphic
  41       functions in more detail together with <span class="emphasis"><em><span class="bold"><strong>complexity
  42       characteristics</strong></span></em></span>, this section summarizes some general
  43       information on implementation and performance.
  44     </p>
  45 <a name="boost_icl.implementation.stl_based_implementation"></a><h6>
  46 <a name="id1130357"></a>
  47       <a class="link" href="implementation.html#boost_icl.implementation.stl_based_implementation">STL based
  48       implementation</a>
  49     </h6>
  50 <p>
  51       The <span class="bold"><strong>implementation</strong></span> of the <span class="bold"><strong>icl's</strong></span>
  52       containers is based on <span class="bold"><strong>std::set</strong></span> and <span class="bold"><strong>std::map</strong></span>. So the underlying data structure of interval
  53       containers is a red black tree of intervals or interval value pairs. The element
  54       containers <a href="http://www.cplusplus.com/reference/stl/set/" target="_top"><code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">set</span></code>
  55       </a> and <code class="computeroutput"><a class="link" href="../boost/icl/map.html" title="Class template map">icl::map</a></code> are wrapper
  56       classes of <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">set</span></code> and <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">map</span></code>. Interval
  57       containers are then using <a href="http://www.cplusplus.com/reference/stl/set/" target="_top"><code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">sets</span></code></a>
  58       of intervals or <code class="computeroutput"><a class="link" href="../boost/icl/map.html" title="Class template map">icl::maps</a></code> of interval
  59       value pairs as implementing containers. So all the <span class="emphasis"><em><span class="bold"><strong>complexity
  60       characteristics</strong></span></em></span> of icl containers are based on and limited
  61       by the <span class="emphasis"><em><span class="bold"><strong>red-black tree implementation</strong></span></em></span>
  62       of the underlying std::AssociativeContainers.
  63     </p>
  64 <div class="section boost_icl_implementation_iterative_size" lang="en">
  65 <div class="titlepage"><div><div><h3 class="title">
  66 <a name="boost_icl.implementation.iterative_size"></a><a class="link" href="implementation.html#boost_icl.implementation.iterative_size" title="Iterative size">Iterative size</a>
  67 </h3></div></div></div>
  68 <p>
  69         Throughout the documentation on complexity, big <span class="emphasis"><em>O</em></span> expressions
  70         like <span class="emphasis"><em>O(n)</em></span> or <span class="emphasis"><em>O(m log n)</em></span> refer to
  71         container sizes <span class="emphasis"><em>n</em></span> and <span class="emphasis"><em>m</em></span>. In this
  72         documentation these sizes <span class="emphasis"><em><span class="bold"><strong>do not</strong></span></em></span>
  73         denote to the familiar <code class="computeroutput"><span class="identifier">size</span></code>
  74         function that returns the <span class="emphasis"><em><span class="bold"><strong>number of elements</strong></span></em></span>
  75         of a container. Because for an interval container
  76 </p>
  77 <pre class="programlisting"><span class="identifier">interval_set</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&gt;</span> <span class="identifier">mono</span><span class="special">;</span>
  78 <span class="identifier">mono</span> <span class="special">+=</span> <span class="identifier">interval</span><span class="special">&lt;</span><span class="keyword">int</span><span class="special">&gt;::</span><span class="identifier">closed</span><span class="special">(</span><span class="number">1</span><span class="special">,</span><span class="number">5</span><span class="special">);</span> <span class="comment">// {[1 ... 5]}
  79 </span><span class="identifier">mono</span><span class="special">.</span><span class="identifier">size</span><span class="special">()</span>           <span class="special">==</span> <span class="number">5</span><span class="special">;</span>         <span class="comment">// true, 5 elements
  80 </span><span class="identifier">mono</span><span class="special">.</span><span class="identifier">interval_count</span><span class="special">()</span> <span class="special">==</span> <span class="number">1</span><span class="special">;</span>         <span class="comment">// true, only one interval
  81 </span></pre>
  82 <p>
  83       </p>
  84 <p>
  85         it's size and the number of contained intervals is usually different. To
  86         refer uniformly to a <span class="emphasis"><em>size</em></span> that matters for iteration,
  87         which is the decisive kind of size concerning algorithmic behavior there
  88         is a function
  89 </p>
  90 <pre class="programlisting"><span class="keyword">bool</span> <span class="identifier">T</span><span class="special">::</span><span class="identifier">iterative_size</span><span class="special">()</span><span class="keyword">const</span><span class="special">;</span> <span class="comment">// Number of entities that can be iterated over.
  91 </span></pre>
  92 <p>
  93         for all element and interval containers of the icl. So for complexity statements
  94         throughout the icl's documentation the sizes will be <code class="computeroutput"><span class="identifier">iterative_sizes</span></code>
  95         and big <span class="emphasis"><em>O</em></span> expressions like <span class="emphasis"><em>O(m log n)</em></span>
  96         will refer to sizes
  97 </p>
  98 <pre class="programlisting"><span class="identifier">n</span> <span class="special">=</span> <span class="identifier">y</span><span class="special">.</span><span class="identifier">iterative_size</span><span class="special">();</span>
  99 <span class="identifier">m</span> <span class="special">=</span> <span class="identifier">x</span><span class="special">.</span><span class="identifier">iterative_size</span><span class="special">();</span>
 100 </pre>
 101 <p>
 102         for containers <code class="computeroutput"><span class="identifier">y</span></code> and <code class="computeroutput"><span class="identifier">x</span></code>. Note that
 103 </p>
 104 <pre class="programlisting"><span class="identifier">iterative_size</span></pre>
 105 <p>
 106         refers to the primary entities, that we can iterate over. For interval containers
 107         these are intervals or segments.
 108 </p>
 109 <pre class="programlisting"><span class="identifier">Itervative_size</span></pre>
 110 <p>
 111         never refers to element iteration for interval containers.
 112       </p>
 113 </div>
 114 </div>
 115 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 116 <td align="left"></td>
 117 <td align="right"><div class="copyright-footer">Copyright &#169; 2007 -2010 Joachim Faulhaber<br>Copyright &#169; 1999 -2006 Cortex Software GmbH<p>
 118         Distributed under the Boost Software License, Version 1.0. (See accompanying
 119         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>)
 120       </p>
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