1 /* 2 * Lagged Fibonacci PRNG 3 * Copyright (c) 2008 Michael Niedermayer 4 * 5 * This file is part of FFmpeg. 6 * 7 * FFmpeg is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU Lesser General Public 9 * License as published by the Free Software Foundation; either 10 * version 2.1 of the License, or (at your option) any later version. 11 * 12 * FFmpeg is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 15 * Lesser General Public License for more details. 16 * 17 * You should have received a copy of the GNU Lesser General Public 18 * License along with FFmpeg; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 */ 21 22 module ffmpeg.libavutil.lfg; 23 24 extern (C): 25 import ffmpeg; @nogc nothrow: 26 27 struct AVLFG 28 { 29 uint[64] state; 30 int index; 31 } 32 33 void av_lfg_init (AVLFG* c, uint seed); 34 35 /** 36 * Seed the state of the ALFG using binary data. 37 * 38 * Return value: 0 on success, negative value (AVERROR) on failure. 39 */ 40 int av_lfg_init_from_data (AVLFG* c, const(ubyte)* data, uint length); 41 42 /** 43 * Get the next random unsigned 32-bit number using an ALFG. 44 * 45 * Please also consider a simple LCG like state= state*1664525+1013904223, 46 * it may be good enough and faster for your specific use case. 47 */ 48 uint av_lfg_get (AVLFG* c); 49 50 /** 51 * Get the next random unsigned 32-bit number using a MLFG. 52 * 53 * Please also consider av_lfg_get() above, it is faster. 54 */ 55 uint av_mlfg_get (AVLFG* c); 56 57 /** 58 * Get the next two numbers generated by a Box-Muller Gaussian 59 * generator using the random numbers issued by lfg. 60 * 61 * @param out array where the two generated numbers are placed 62 */ 63 void av_bmg_get (AVLFG* lfg, ref double[2] out_); 64 65 /* AVUTIL_LFG_H */