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| <title>Simple Segregated Storage Implementation</title> |
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| <h1 align="center">Simple Segregated Storage Implementation</h1> |
| |
| <h2>Dependencies</h2> |
| |
| <p>Includes the system headers <span class="code"><cstddef></span> |
| and <span class="code"><functional></span>.</p> |
| |
| <h2>Protected Interface</h2> |
| |
| <h3>Synopsis</h3> |
| <pre class="code"> |
| template <typename SizeType = std::size_t> |
| class simple_segregated_storage |
| { |
| ... // Public interface |
| |
| protected: |
| void * first; |
| static void * & nextof(void * const ptr); |
| void * find_prev(void * ptr); |
| }; |
| </pre> |
| |
| <h3 class="code">void * first;</h3> |
| |
| <p>This data member is the free list. It points to the first chunk in the |
| free list, or is equal to 0 if the free list is empty.</p> |
| |
| <h3 class="code">static void * & nextof(void * const ptr);</h3> |
| |
| <p>This is a convenience function. It helps clean up code dealing with the |
| free list by making it more readable. The return value is just <span class= |
| "code">*ptr</span> cast to the appropriate type. <span class= |
| "code">ptr</span> must not be 0.</p> |
| |
| <p>As an example, let us assume that we want to truncate the free list |
| after the first chunk. That is, we want to set <span class= |
| "code">*first</span> to 0; this will result in a free list with only one |
| entry. The normal way to do this is to first cast <span class= |
| "code">first</span> to a pointer to a pointer to void, and then dereference |
| and assign (<span class="code">*static_cast<void **>(first) = |
| 0;</span>). This can be done more easily through the use of this |
| convenience function (<span class="code">nextof(first) = 0;</span>).</p> |
| |
| <h3 class="code">void * find_prev(void * ptr);</h3> |
| |
| <p>Traverses the free list referred to by <span class="code">first</span>, |
| and returns the pointer previous to where <span class="code">ptr</span> |
| would go if it was in the free list. Returns 0 if <span class= |
| "code">ptr</span> would go at the beginning of the free list (i.e., before |
| <span class="code">first</span>).</p> |
| |
| <p>Note that this function finds the location previous to where |
| <span class="code">ptr</span> <strong>would</strong> go <strong>if it |
| was</strong> in the free list. It does <strong>not</strong> find the entry |
| in the free list before <span class="code">ptr</span> (unless <span class= |
| "code">ptr</span> is already in the free list). Specifically, <span class= |
| "code">find_prev(0)</span> will return 0, <strong>not</strong> the last |
| entry in the free list.</p> |
| |
| <h2><a href="../interfaces/simple_segregated_storage.html">Interface |
| Description</a></h2> |
| <hr> |
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| |
| <p>Revised |
| <!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %B, %Y" startspan -->05 |
| December, 2006<!--webbot bot="Timestamp" endspan i-checksum="38516" --></p> |
| |
| <p><i>Copyright © 2000, 2001 Stephen Cleary (scleary AT jerviswebb DOT |
| com)</i></p> |
| |
| <p><i>Distributed under the Boost Software License, Version 1.0. (See |
| accompanying file <a href="../../../../LICENSE_1_0.txt">LICENSE_1_0.txt</a> |
| or copy at <a href= |
| "http://www.boost.org/LICENSE_1_0.txt">http://www.boost.org/LICENSE_1_0.txt</a>)</i></p> |
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