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rt-thread
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<h1>lib/memb.c</h1><a href="a00120.html">Go to the documentation of this file.</a><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">/*</span>
<a name="l00002"></a>00002 <span class="comment"> * Copyright (c) 2004, Swedish Institute of Computer Science.</span>
<a name="l00003"></a>00003 <span class="comment"> * All rights reserved.</span>
<a name="l00004"></a>00004 <span class="comment"> *</span>
<a name="l00005"></a>00005 <span class="comment"> * Redistribution and use in source and binary forms, with or without</span>
<a name="l00006"></a>00006 <span class="comment"> * modification, are permitted provided that the following conditions</span>
<a name="l00007"></a>00007 <span class="comment"> * are met:</span>
<a name="l00008"></a>00008 <span class="comment"> * 1. Redistributions of source code must retain the above copyright</span>
<a name="l00009"></a>00009 <span class="comment"> *    notice, this list of conditions and the following disclaimer.</span>
<a name="l00010"></a>00010 <span class="comment"> * 2. Redistributions in binary form must reproduce the above copyright</span>
<a name="l00011"></a>00011 <span class="comment"> *    notice, this list of conditions and the following disclaimer in the</span>
<a name="l00012"></a>00012 <span class="comment"> *    documentation and/or other materials provided with the distribution.</span>
<a name="l00013"></a>00013 <span class="comment"> * 3. Neither the name of the Institute nor the names of its contributors</span>
<a name="l00014"></a>00014 <span class="comment"> *    may be used to endorse or promote products derived from this software</span>
<a name="l00015"></a>00015 <span class="comment"> *    without specific prior written permission.</span>
<a name="l00016"></a>00016 <span class="comment"> *</span>
<a name="l00017"></a>00017 <span class="comment"> * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND</span>
<a name="l00018"></a>00018 <span class="comment"> * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE</span>
<a name="l00019"></a>00019 <span class="comment"> * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE</span>
<a name="l00020"></a>00020 <span class="comment"> * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE</span>
<a name="l00021"></a>00021 <span class="comment"> * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL</span>
<a name="l00022"></a>00022 <span class="comment"> * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS</span>
<a name="l00023"></a>00023 <span class="comment"> * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)</span>
<a name="l00024"></a>00024 <span class="comment"> * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT</span>
<a name="l00025"></a>00025 <span class="comment"> * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY</span>
<a name="l00026"></a>00026 <span class="comment"> * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF</span>
<a name="l00027"></a>00027 <span class="comment"> * SUCH DAMAGE.</span>
<a name="l00028"></a>00028 <span class="comment"> *</span>
<a name="l00029"></a>00029 <span class="comment"> * This file is part of the uIP TCP/IP stack</span>
<a name="l00030"></a>00030 <span class="comment"> *</span>
<a name="l00031"></a>00031 <span class="comment"> * Author: Adam Dunkels &lt;adam@sics.se&gt;</span>
<a name="l00032"></a>00032 <span class="comment"> *</span>
<a name="l00033"></a>00033 <span class="comment"> * $Id: memb.c,v 1.1 2006/06/12 08:21:43 adam Exp $</span>
<a name="l00034"></a>00034 <span class="comment"> */</span>
<a name="l00035"></a>00035 <span class="comment"></span>
<a name="l00036"></a>00036 <span class="comment">/**</span>
<a name="l00037"></a>00037 <span class="comment"> * \addtogroup memb</span>
<a name="l00038"></a>00038 <span class="comment"> * @{</span>
<a name="l00039"></a>00039 <span class="comment"> */</span>
<a name="l00040"></a>00040 <span class="comment"></span>
<a name="l00041"></a>00041 <span class="comment"> /**</span>
<a name="l00042"></a>00042 <span class="comment"> * \file</span>
<a name="l00043"></a>00043 <span class="comment"> * Memory block allocation routines.</span>
<a name="l00044"></a>00044 <span class="comment"> * \author Adam Dunkels &lt;adam@sics.se&gt;</span>
<a name="l00045"></a>00045 <span class="comment"> */</span>
<a name="l00046"></a>00046 <span class="preprocessor">#include &lt;string.h&gt;</span>
<a name="l00047"></a>00047 
<a name="l00048"></a>00048 <span class="preprocessor">#include "<a class="code" href="a00121.html">memb.h</a>"</span>
<a name="l00049"></a>00049 
<a name="l00050"></a>00050 <span class="comment">/*---------------------------------------------------------------------------*/</span>
<a name="l00051"></a>00051 <span class="keywordtype">void</span>
<a name="l00052"></a><a class="code" href="a00159.html#gd58a6c7e62ae59bf7a016ded12ca2910">00052</a> <a class="code" href="a00159.html#gd58a6c7e62ae59bf7a016ded12ca2910">memb_init</a>(<span class="keyword">struct</span> <a class="code" href="a00081.html">memb_blocks</a> *m)
<a name="l00053"></a>00053 {
<a name="l00054"></a>00054   memset(m-&gt;<a class="code" href="a00081.html#5595902fd42d874e35a70206fad8f6d0">count</a>, 0, m-&gt;<a class="code" href="a00081.html#164124d48fe85bc98d9a300382a5245d">num</a>);
<a name="l00055"></a>00055   memset(m-&gt;<a class="code" href="a00081.html#b5801722740492e69bcc73687476009f">mem</a>, 0, m-&gt;<a class="code" href="a00081.html#b42c7af6114fde5d21206a2e18a7d3ee">size</a> * m-&gt;<a class="code" href="a00081.html#164124d48fe85bc98d9a300382a5245d">num</a>);
<a name="l00056"></a>00056 }
<a name="l00057"></a>00057 <span class="comment">/*---------------------------------------------------------------------------*/</span>
<a name="l00058"></a>00058 <span class="keywordtype">void</span> *
<a name="l00059"></a><a class="code" href="a00159.html#gfe5e93119035e14cc485760a176249ba">00059</a> <a class="code" href="a00159.html#gfe5e93119035e14cc485760a176249ba">memb_alloc</a>(<span class="keyword">struct</span> <a class="code" href="a00081.html">memb_blocks</a> *m)
<a name="l00060"></a>00060 {
<a name="l00061"></a>00061   <span class="keywordtype">int</span> i;
<a name="l00062"></a>00062 
<a name="l00063"></a>00063   <span class="keywordflow">for</span>(i = 0; i &lt; m-&gt;<a class="code" href="a00081.html#164124d48fe85bc98d9a300382a5245d">num</a>; ++i) {
<a name="l00064"></a>00064     <span class="keywordflow">if</span>(m-&gt;<a class="code" href="a00081.html#5595902fd42d874e35a70206fad8f6d0">count</a>[i] == 0) {
<a name="l00065"></a>00065       <span class="comment">/* If this block was unused, we increase the reference count to</span>
<a name="l00066"></a>00066 <span class="comment">         indicate that it now is used and return a pointer to the</span>
<a name="l00067"></a>00067 <span class="comment">         memory block. */</span>
<a name="l00068"></a>00068       ++(m-&gt;<a class="code" href="a00081.html#5595902fd42d874e35a70206fad8f6d0">count</a>[i]);
<a name="l00069"></a>00069       return (<span class="keywordtype">void</span> *)((<span class="keywordtype">char</span> *)m-&gt;<a class="code" href="a00081.html#b5801722740492e69bcc73687476009f">mem</a> + (i * m-&gt;<a class="code" href="a00081.html#b42c7af6114fde5d21206a2e18a7d3ee">size</a>));
<a name="l00070"></a>00070     }
<a name="l00071"></a>00071   }
<a name="l00072"></a>00072 
<a name="l00073"></a>00073   <span class="comment">/* No free block was found, so we return NULL to indicate failure to</span>
<a name="l00074"></a>00074 <span class="comment">     allocate block. */</span>
<a name="l00075"></a>00075   <span class="keywordflow">return</span> <a class="code" href="a00160.html#g070d2ce7b6bb7e5c05602aa8c308d0c4">NULL</a>;
<a name="l00076"></a>00076 }
<a name="l00077"></a>00077 <span class="comment">/*---------------------------------------------------------------------------*/</span>
<a name="l00078"></a>00078 <span class="keywordtype">char</span>
<a name="l00079"></a><a class="code" href="a00159.html#gceb952d27de8125d5146ac0bee325b8f">00079</a> <a class="code" href="a00159.html#gceb952d27de8125d5146ac0bee325b8f">memb_free</a>(<span class="keyword">struct</span> <a class="code" href="a00081.html">memb_blocks</a> *m, <span class="keywordtype">void</span> *ptr)
<a name="l00080"></a>00080 {
<a name="l00081"></a>00081   <span class="keywordtype">int</span> i;
<a name="l00082"></a>00082   <span class="keywordtype">char</span> *ptr2;
<a name="l00083"></a>00083 
<a name="l00084"></a>00084   <span class="comment">/* Walk through the list of blocks and try to find the block to</span>
<a name="l00085"></a>00085 <span class="comment">     which the pointer "ptr" points to. */</span>
<a name="l00086"></a>00086   ptr2 = (<span class="keywordtype">char</span> *)m-&gt;<a class="code" href="a00081.html#b5801722740492e69bcc73687476009f">mem</a>;
<a name="l00087"></a>00087   <span class="keywordflow">for</span>(i = 0; i &lt; m-&gt;num; ++i) {
<a name="l00088"></a>00088     
<a name="l00089"></a>00089     <span class="keywordflow">if</span>(ptr2 == (<span class="keywordtype">char</span> *)ptr) {
<a name="l00090"></a>00090       <span class="comment">/* We've found to block to which "ptr" points so we decrease the</span>
<a name="l00091"></a>00091 <span class="comment">         reference count and return the new value of it. */</span>
<a name="l00092"></a>00092       <span class="keywordflow">if</span>(m-&gt;<a class="code" href="a00081.html#5595902fd42d874e35a70206fad8f6d0">count</a>[i] &gt; 0) {
<a name="l00093"></a>00093         <span class="comment">/* Make sure that we don't deallocate free memory. */</span>
<a name="l00094"></a>00094         --(m-&gt;<a class="code" href="a00081.html#5595902fd42d874e35a70206fad8f6d0">count</a>[i]);
<a name="l00095"></a>00095       }
<a name="l00096"></a>00096       <span class="keywordflow">return</span> m-&gt;<a class="code" href="a00081.html#5595902fd42d874e35a70206fad8f6d0">count</a>[i];
<a name="l00097"></a>00097     }
<a name="l00098"></a>00098     ptr2 += m-&gt;<a class="code" href="a00081.html#b42c7af6114fde5d21206a2e18a7d3ee">size</a>;
<a name="l00099"></a>00099   }
<a name="l00100"></a>00100   <span class="keywordflow">return</span> -1;
<a name="l00101"></a>00101 }
<a name="l00102"></a>00102 <span class="comment">/*---------------------------------------------------------------------------*/</span>
<a name="l00103"></a>00103 <span class="comment"></span>
<a name="l00104"></a>00104 <span class="comment">/** @} */</span>
</pre></div><hr size="1"><address style="align: right;"><small>Generated on Mon Jun 12 10:23:01 2006 for uIP 1.0 by&nbsp;
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