diff options
author | Sven Gothel <[email protected]> | 2023-02-23 22:10:17 +0100 |
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committer | Sven Gothel <[email protected]> | 2023-02-23 22:10:17 +0100 |
commit | 55a3e7e548bbc3333318ee55dbab39f016b8d5f6 (patch) | |
tree | a754d6d621532328c15095619180c0ef4556aabc /make/stub_includes/ffmpeg/v0600/libavutil/lfg.h | |
parent | dc48fb0f101dfefd3f4fb23f585d14de7fa9a6fe (diff) |
FFMPEGMediaPlayer: Replace old FFmpeg header w/ FFmpeg version 4.3, 5.1 and 6.0 (major version counts for binary compatibility)
Diffstat (limited to 'make/stub_includes/ffmpeg/v0600/libavutil/lfg.h')
-rw-r--r-- | make/stub_includes/ffmpeg/v0600/libavutil/lfg.h | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/make/stub_includes/ffmpeg/v0600/libavutil/lfg.h b/make/stub_includes/ffmpeg/v0600/libavutil/lfg.h new file mode 100644 index 000000000..e75a986f1 --- /dev/null +++ b/make/stub_includes/ffmpeg/v0600/libavutil/lfg.h @@ -0,0 +1,81 @@ +/* + * Lagged Fibonacci PRNG + * Copyright (c) 2008 Michael Niedermayer + * + * 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 + */ + +#ifndef AVUTIL_LFG_H +#define AVUTIL_LFG_H + +#include <stdint.h> + +/** + * Context structure for the Lagged Fibonacci PRNG. + * The exact layout, types and content of this struct may change and should + * not be accessed directly. Only its `sizeof()` is guaranteed to stay the same + * to allow easy instanciation. + */ +typedef struct AVLFG { + unsigned int state[64]; + int index; +} AVLFG; + +void av_lfg_init(AVLFG *c, unsigned int seed); + +/** + * Seed the state of the ALFG using binary data. + * + * @return 0 on success, negative value (AVERROR) on failure. + */ +int av_lfg_init_from_data(AVLFG *c, const uint8_t *data, unsigned int length); + +/** + * Get the next random unsigned 32-bit number using an ALFG. + * + * Please also consider a simple LCG like state= state*1664525+1013904223, + * it may be good enough and faster for your specific use case. + */ +static inline unsigned int av_lfg_get(AVLFG *c){ + unsigned a = c->state[c->index & 63] = c->state[(c->index-24) & 63] + c->state[(c->index-55) & 63]; + c->index += 1U; + return a; +} + +/** + * Get the next random unsigned 32-bit number using a MLFG. + * + * Please also consider av_lfg_get() above, it is faster. + */ +static inline unsigned int av_mlfg_get(AVLFG *c){ + unsigned int a= c->state[(c->index-55) & 63]; + unsigned int b= c->state[(c->index-24) & 63]; + a = c->state[c->index & 63] = 2*a*b+a+b; + c->index += 1U; + return a; +} + +/** + * Get the next two numbers generated by a Box-Muller Gaussian + * generator using the random numbers issued by lfg. + * + * @param lfg pointer to the contex structure + * @param out array where the two generated numbers are placed + */ +void av_bmg_get(AVLFG *lfg, double out[2]); + +#endif /* AVUTIL_LFG_H */ |