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97 lines
3.7 KiB
HTML
97 lines
3.7 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
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"http://www.w3.org/TR/html4/loose.dtd">
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<html>
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<head>
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<meta http-equiv="Content-Language" content="en-us">
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<meta http-equiv="Content-Type" content="text/html; charset=us-ascii">
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<link href="../pool.css" rel="stylesheet" type="text/css">
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<title>Simple Segregated Storage Implementation</title>
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</head>
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<body>
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<img src="../../../../boost.png" width="276" height="86" alt="C++ Boost">
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<h1 align="center">Simple Segregated Storage Implementation</h1>
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<h2>Dependencies</h2>
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<p>Includes the system headers <span class="code"><cstddef></span>
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and <span class="code"><functional></span>.</p>
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<h2>Protected Interface</h2>
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<h3>Synopsis</h3>
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<pre class="code">
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template <typename SizeType = std::size_t>
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class simple_segregated_storage
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{
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... // Public interface
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protected:
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void * first;
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static void * & nextof(void * const ptr);
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void * find_prev(void * ptr);
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};
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</pre>
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<h3 class="code">void * first;</h3>
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<p>This data member is the free list. It points to the first chunk in the
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free list, or is equal to 0 if the free list is empty.</p>
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<h3 class="code">static void * & nextof(void * const ptr);</h3>
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<p>This is a convenience function. It helps clean up code dealing with the
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free list by making it more readable. The return value is just <span class=
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"code">*ptr</span> cast to the appropriate type. <span class=
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"code">ptr</span> must not be 0.</p>
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<p>As an example, let us assume that we want to truncate the free list
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after the first chunk. That is, we want to set <span class=
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"code">*first</span> to 0; this will result in a free list with only one
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entry. The normal way to do this is to first cast <span class=
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"code">first</span> to a pointer to a pointer to void, and then dereference
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and assign (<span class="code">*static_cast<void **>(first) =
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0;</span>). This can be done more easily through the use of this
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convenience function (<span class="code">nextof(first) = 0;</span>).</p>
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<h3 class="code">void * find_prev(void * ptr);</h3>
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<p>Traverses the free list referred to by <span class="code">first</span>,
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and returns the pointer previous to where <span class="code">ptr</span>
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would go if it was in the free list. Returns 0 if <span class=
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"code">ptr</span> would go at the beginning of the free list (i.e., before
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<span class="code">first</span>).</p>
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<p>Note that this function finds the location previous to where
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<span class="code">ptr</span> <strong>would</strong> go <strong>if it
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was</strong> in the free list. It does <strong>not</strong> find the entry
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in the free list before <span class="code">ptr</span> (unless <span class=
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"code">ptr</span> is already in the free list). Specifically, <span class=
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"code">find_prev(0)</span> will return 0, <strong>not</strong> the last
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entry in the free list.</p>
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<h2><a href="../interfaces/simple_segregated_storage.html">Interface
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Description</a></h2>
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<hr>
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<p><a href="http://validator.w3.org/check?uri=referer"><img border="0" src=
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"http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01 Transitional"
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height="31" width="88"></a></p>
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<p>Revised
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<!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %B, %Y" startspan -->05
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December, 2006<!--webbot bot="Timestamp" endspan i-checksum="38516" --></p>
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<p><i>Copyright © 2000, 2001 Stephen Cleary (scleary AT jerviswebb DOT
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com)</i></p>
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<p><i>Distributed under the Boost Software License, Version 1.0. (See
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accompanying file <a href="../../../../LICENSE_1_0.txt">LICENSE_1_0.txt</a>
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or copy at <a href=
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"http://www.boost.org/LICENSE_1_0.txt">http://www.boost.org/LICENSE_1_0.txt</a>)</i></p>
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</body>
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</html>
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