/* * Copyright (c) 2024 Michael Niedermayer <[email protected]> * * 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 * */ /** * @file * simple Pseudo Random Number Generator * * This is a implementation of SFC64, a 64-bit PRNG by Chris Doty-Humphrey. * * This Generator is much faster (0m1.872s) than 64bit KISS (0m3.823s) and PCG-XSH-RR-64/32 (0m2.700s) * And passes testu01 and practrand test suits. */ #ifndef AVUTIL_SFC64_H #define AVUTIL_SFC64_H #include <inttypes.h> FFSFC64; static inline uint64_t ff_sfc64_get(FFSFC64 *s) { … } /** * Return the previous random value, and step the generator backward. * * It is safe to take values before the first, but such values can be highly * correlated to the seeds. */ static inline uint64_t ff_sfc64_reverse_get(FFSFC64 *s) { … } /** * Initialize sfc64 with up to 3 seeds. * * @param rounds number of rounds mixing up state during init. Generally 8-18, larger numbers will help with bad quality seeds. * 12 is a good choice if all 3 seeds are equal * */ static inline void ff_sfc64_init(FFSFC64 *s, uint64_t seeda, uint64_t seedb, uint64_t seedc, int rounds) { … } #endif // AVUTIL_SFC64_H
Codebase Browser
chromium