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Diffstat (limited to 'contrib/ffmpeg/libavutil/random.c')
-rw-r--r-- | contrib/ffmpeg/libavutil/random.c | 104 |
1 files changed, 0 insertions, 104 deletions
diff --git a/contrib/ffmpeg/libavutil/random.c b/contrib/ffmpeg/libavutil/random.c deleted file mode 100644 index c3e71e699..000000000 --- a/contrib/ffmpeg/libavutil/random.c +++ /dev/null @@ -1,104 +0,0 @@ -/* - * Mersenne Twister Random Algorithm - * Copyright (c) 2006 Ryan Martell. - * Based on A C-program for MT19937, with initialization improved 2002/1/26. Coded by - * Takuji Nishimura and Makoto Matsumoto. - * - * This file is part of FFmpeg. - * - * FFmpeg is free software; you can redistribute it and/or - * modify it under the terms of the GNU Lesser General Public - * License as published by the Free Software Foundation; either - * version 2.1 of the License, or (at your option) any later version. - * - * FFmpeg is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * Lesser General Public License for more details. - * - * You should have received a copy of the GNU Lesser General Public - * License along with FFmpeg; if not, write to the Free Software - * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA - */ - - -/** -see http://en.wikipedia.org/wiki/Mersenne_twister for an explanation of this algorithm. -*/ -#include <stdio.h> -#include "random.h" - -//#define DEBUG - -#ifdef DEBUG -#include "common.h" -#include "log.h" -#endif - - -/* Period parameters */ -#define M 397 -#define A 0x9908b0df /* constant vector a */ -#define UPPER_MASK 0x80000000 /* most significant w-r bits */ -#define LOWER_MASK 0x7fffffff /* least significant r bits */ - -/** initializes mt[AV_RANDOM_N] with a seed */ -void av_init_random(unsigned int seed, AVRandomState *state) -{ - int index; - - /* - This differs from the wikipedia article. Source is from the Makoto - Makoto Matsumoto and Takuji Nishimura code, with the following comment: - */ - /* See Knuth TAOCP Vol2. 3rd Ed. P.106 for multiplier. */ - /* In the previous versions, MSBs of the seed affect */ - /* only MSBs of the array mt[]. */ - state->mt[0] = seed & 0xffffffff; - for (index = 1; index < AV_RANDOM_N; index++) { - unsigned int prev= state->mt[index - 1]; - state->mt[index] = (1812433253UL * (prev ^ (prev>>30)) + index) & 0xffffffff; - } - state->index= index; // will cause it to generate untempered numbers the first iteration -} - -/** generate AV_RANDOM_N words at one time (which will then be tempered later) (av_random calls this; you shouldn't) */ -void av_random_generate_untempered_numbers(AVRandomState *state) -{ - int kk; - unsigned int y; - - for (kk = 0; kk < AV_RANDOM_N - M; kk++) { - y = (state->mt[kk] & UPPER_MASK) | (state->mt[kk + 1] & LOWER_MASK); - state->mt[kk] = state->mt[kk + M] ^ (y >> 1) ^ ((y&1)*A); - } - for (; kk < AV_RANDOM_N - 1; kk++) { - y = (state->mt[kk] & UPPER_MASK) | (state->mt[kk + 1] & LOWER_MASK); - state->mt[kk] = state->mt[kk + (M - AV_RANDOM_N)] ^ (y >> 1) ^ ((y&1)*A); - } - y = (state->mt[AV_RANDOM_N - 1] & UPPER_MASK) | (state->mt[0] & LOWER_MASK); - state->mt[AV_RANDOM_N - 1] = state->mt[M - 1] ^ (y >> 1) ^ ((y&1)*A); - state->index = 0; -} - -#ifdef DEBUG -void av_benchmark_random(void) -{ - int x=0; - int i, j; - AVRandomState state; - - av_init_random(0xdeadbeef, &state); - for (j = 0; j < 100; j++) { - START_TIMER; - x+= av_random(&state); - STOP_TIMER("first call to av_random"); - for (i = 1; i < AV_RANDOM_N; i++) { - START_TIMER; - x+= av_random(&state); - STOP_TIMER("AV_RANDOM_N calls of av_random"); - } - } - av_log(NULL, AV_LOG_ERROR, "final value:%X\n", x); -} -#endif |