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<a href="lfg_8h.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"> * Lagged Fibonacci PRNG</span>
<a name="l00003"></a>00003 <span class="comment"> * Copyright (c) 2008 Michael Niedermayer</span>
<a name="l00004"></a>00004 <span class="comment"> *</span>
<a name="l00005"></a>00005 <span class="comment"> * This file is part of FFmpeg.</span>
<a name="l00006"></a>00006 <span class="comment"> *</span>
<a name="l00007"></a>00007 <span class="comment"> * FFmpeg is free software; you can redistribute it and/or</span>
<a name="l00008"></a>00008 <span class="comment"> * modify it under the terms of the GNU Lesser General Public</span>
<a name="l00009"></a>00009 <span class="comment"> * License as published by the Free Software Foundation; either</span>
<a name="l00010"></a>00010 <span class="comment"> * version 2.1 of the License, or (at your option) any later version.</span>
<a name="l00011"></a>00011 <span class="comment"> *</span>
<a name="l00012"></a>00012 <span class="comment"> * FFmpeg is distributed in the hope that it will be useful,</span>
<a name="l00013"></a>00013 <span class="comment"> * but WITHOUT ANY WARRANTY; without even the implied warranty of</span>
<a name="l00014"></a>00014 <span class="comment"> * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU</span>
<a name="l00015"></a>00015 <span class="comment"> * Lesser General Public License for more details.</span>
<a name="l00016"></a>00016 <span class="comment"> *</span>
<a name="l00017"></a>00017 <span class="comment"> * You should have received a copy of the GNU Lesser General Public</span>
<a name="l00018"></a>00018 <span class="comment"> * License along with FFmpeg; if not, write to the Free Software</span>
<a name="l00019"></a>00019 <span class="comment"> * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA</span>
<a name="l00020"></a>00020 <span class="comment"> */</span>
<a name="l00021"></a>00021
<a name="l00022"></a>00022 <span class="preprocessor">#ifndef AVUTIL_LFG_H</span>
<a name="l00023"></a>00023 <span class="preprocessor"></span><span class="preprocessor">#define AVUTIL_LFG_H</span>
<a name="l00024"></a>00024 <span class="preprocessor"></span>
<a name="l00025"></a><a class="code" href="structAVLFG.html">00025</a> <span class="keyword">typedef</span> <span class="keyword">struct </span><a class="code" href="structAVLFG.html">AVLFG</a> {
<a name="l00026"></a><a class="code" href="structAVLFG.html#a9ddcde4642e40a41a3a945b24b4ce519">00026</a> <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> <a class="code" href="structAVLFG.html#a9ddcde4642e40a41a3a945b24b4ce519">state</a>[64];
<a name="l00027"></a><a class="code" href="structAVLFG.html#ae05dc3450a4c7e13f79d02812218a8f4">00027</a> <span class="keywordtype">int</span> <a class="code" href="structAVLFG.html#ae05dc3450a4c7e13f79d02812218a8f4">index</a>;
<a name="l00028"></a>00028 } <a class="code" href="structAVLFG.html">AVLFG</a>;
<a name="l00029"></a>00029
<a name="l00030"></a>00030 <span class="keywordtype">void</span> <a class="code" href="lfg_8h.html#a43003943a9712bf75f2aae140ee01ab3">av_lfg_init</a>(<a class="code" href="structAVLFG.html">AVLFG</a> *c, <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> seed);
<a name="l00031"></a>00031 <span class="comment"></span>
<a name="l00032"></a>00032 <span class="comment">/**</span>
<a name="l00033"></a>00033 <span class="comment"> * Get the next random unsigned 32-bit number using an ALFG.</span>
<a name="l00034"></a>00034 <span class="comment"> *</span>
<a name="l00035"></a>00035 <span class="comment"> * Please also consider a simple LCG like state= state*1664525+1013904223,</span>
<a name="l00036"></a>00036 <span class="comment"> * it may be good enough and faster for your specific use case.</span>
<a name="l00037"></a>00037 <span class="comment"> */</span>
<a name="l00038"></a><a class="code" href="lfg_8h.html#a58feb242e560adee0b7a16e11cce43e9">00038</a> <span class="keyword">static</span> <span class="keyword">inline</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> <a class="code" href="lfg_8h.html#a58feb242e560adee0b7a16e11cce43e9" title="Get the next random unsigned 32-bit number using an ALFG.">av_lfg_get</a>(<a class="code" href="structAVLFG.html">AVLFG</a> *c){
<a name="l00039"></a>00039 c-><a class="code" href="structAVLFG.html#a9ddcde4642e40a41a3a945b24b4ce519">state</a>[c-><a class="code" href="structAVLFG.html#ae05dc3450a4c7e13f79d02812218a8f4">index</a> & 63] = c-><a class="code" href="structAVLFG.html#a9ddcde4642e40a41a3a945b24b4ce519">state</a>[(c-><a class="code" href="structAVLFG.html#ae05dc3450a4c7e13f79d02812218a8f4">index</a>-24) & 63] + c-><a class="code" href="structAVLFG.html#a9ddcde4642e40a41a3a945b24b4ce519">state</a>[(c-><a class="code" href="structAVLFG.html#ae05dc3450a4c7e13f79d02812218a8f4">index</a>-55) & 63];
<a name="l00040"></a>00040 <span class="keywordflow">return</span> c-><a class="code" href="structAVLFG.html#a9ddcde4642e40a41a3a945b24b4ce519">state</a>[c-><a class="code" href="structAVLFG.html#ae05dc3450a4c7e13f79d02812218a8f4">index</a>++ & 63];
<a name="l00041"></a>00041 }
<a name="l00042"></a>00042 <span class="comment"></span>
<a name="l00043"></a>00043 <span class="comment">/**</span>
<a name="l00044"></a>00044 <span class="comment"> * Get the next random unsigned 32-bit number using a MLFG.</span>
<a name="l00045"></a>00045 <span class="comment"> *</span>
<a name="l00046"></a>00046 <span class="comment"> * Please also consider av_lfg_get() above, it is faster.</span>
<a name="l00047"></a>00047 <span class="comment"> */</span>
<a name="l00048"></a><a class="code" href="lfg_8h.html#a6f7ac2501d6740c557ceedf53588df0d">00048</a> <span class="keyword">static</span> <span class="keyword">inline</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> <a class="code" href="lfg_8h.html#a6f7ac2501d6740c557ceedf53588df0d" title="Get the next random unsigned 32-bit number using a MLFG.">av_mlfg_get</a>(<a class="code" href="structAVLFG.html">AVLFG</a> *c){
<a name="l00049"></a>00049 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> a= c-><a class="code" href="structAVLFG.html#a9ddcde4642e40a41a3a945b24b4ce519">state</a>[(c-><a class="code" href="structAVLFG.html#ae05dc3450a4c7e13f79d02812218a8f4">index</a>-55) & 63];
<a name="l00050"></a>00050 <span class="keywordtype">unsigned</span> <span class="keywordtype">int</span> b= c-><a class="code" href="structAVLFG.html#a9ddcde4642e40a41a3a945b24b4ce519">state</a>[(c-><a class="code" href="structAVLFG.html#ae05dc3450a4c7e13f79d02812218a8f4">index</a>-24) & 63];
<a name="l00051"></a>00051 <span class="keywordflow">return</span> c-><a class="code" href="structAVLFG.html#a9ddcde4642e40a41a3a945b24b4ce519">state</a>[c-><a class="code" href="structAVLFG.html#ae05dc3450a4c7e13f79d02812218a8f4">index</a>++ & 63] = 2*a*b+a+b;
<a name="l00052"></a>00052 }
<a name="l00053"></a>00053 <span class="comment"></span>
<a name="l00054"></a>00054 <span class="comment">/**</span>
<a name="l00055"></a>00055 <span class="comment"> * Get the next two numbers generated by a Box-Muller Gaussian</span>
<a name="l00056"></a>00056 <span class="comment"> * generator using the random numbers issued by lfg.</span>
<a name="l00057"></a>00057 <span class="comment"> *</span>
<a name="l00058"></a>00058 <span class="comment"> * @param out array where the two generated numbers are placed</span>
<a name="l00059"></a>00059 <span class="comment"> */</span>
<a name="l00060"></a>00060 <span class="keywordtype">void</span> <a class="code" href="lfg_8h.html#a64cbf8ac9c59912b4fddae8286eb8303" title="Get the next two numbers generated by a Box-Muller Gaussian generator using the random numbers issued...">av_bmg_get</a>(<a class="code" href="structAVLFG.html">AVLFG</a> *lfg, <span class="keywordtype">double</span> out[2]);
<a name="l00061"></a>00061
<a name="l00062"></a>00062 <span class="preprocessor">#endif </span><span class="comment">/* AVUTIL_LFG_H */</span>
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