/* * Implementation of non-cryptographic pseudo-random number * generator algorithm known as xoshiro. * * This file is part of mpv. * * mpv 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. * * mpv 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 mpv. If not, see <http://www.gnu.org/licenses/>. */#include <stdint.h>#include <libavutil/random_seed.h>#include "osdep/threads.h"#include "osdep/timer.h"#include "random.h"static uint64_t state[4];static mp_static_mutex state_mutex = MP_STATIC_MUTEX_INITIALIZER;static inline uint64_t rotl_u64(const uint64_t x, const int k){ return (x << k) | (x >> (64 - k));}static inline uint64_t splitmix64(uint64_t *const x){ uint64_t z = (*x += UINT64_C(0x9e3779b97f4a7c15)); z = (z ^ (z >> 30)) * UINT64_C(0xbf58476d1ce4e5b9); z = (z ^ (z >> 27)) * UINT64_C(0x94d049bb133111eb); return z ^ (z >> 31);}void mp_rand_seed(uint64_t seed){#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION seed = 42;#endif if (seed == 0) { uint8_t buf[sizeof(seed)]; if (av_random_bytes(buf, sizeof(buf)) < 0) { seed = mp_raw_time_ns(); } else { memcpy(&seed, buf, sizeof(seed)); } } mp_mutex_lock(&state_mutex); state[0] = seed; for (int i = 1; i < 4; i++) state[i] = splitmix64(&seed); mp_mutex_unlock(&state_mutex);}uint64_t mp_rand_next(void){ uint64_t result, t; mp_mutex_lock(&state_mutex); result = rotl_u64(state[1] * 5, 7) * 9; t = state[1] << 17; state[2] ^= state[0]; state[3] ^= state[1]; state[1] ^= state[2]; state[0] ^= state[3]; state[2] ^= t; state[3] = rotl_u64(state[3], 45); mp_mutex_unlock(&state_mutex); return result;}double mp_rand_next_double(void){ return (mp_rand_next() >> 11) * 0x1.0p-53;}
/*
* Implementation of non-cryptographic pseudo-random number
* generator algorithm known as xoshiro.
*
* This file is part of mpv.
*
* mpv 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.
*
* mpv 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 mpv. If not, see <http://www.gnu.org/licenses/>.
*/
#include <stdint.h>
#include <libavutil/random_seed.h>
#include "osdep/threads.h"
#include "osdep/timer.h"
#include "random.h"
static uint64_t state[4];
static mp_static_mutex state_mutex = MP_STATIC_MUTEX_INITIALIZER;
static inline uint64_t rotl_u64(const uint64_t x, const int k)
{
return (x << k) | (x >> (64 - k));
}
static inline uint64_t splitmix64(uint64_t *const x)
{
uint64_t z = (*x += UINT64_C(0x9e3779b97f4a7c15));
z = (z ^ (z >> 30)) * UINT64_C(0xbf58476d1ce4e5b9);
z = (z ^ (z >> 27)) * UINT64_C(0x94d049bb133111eb);
return z ^ (z >> 31);
}
void mp_rand_seed(uint64_t seed)
{
#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
seed = 42;
#endif
if (seed == 0) {
uint8_t buf[sizeof(seed)];
if (av_random_bytes(buf, sizeof(buf)) < 0) {
seed = mp_raw_time_ns();
} else {
memcpy(&seed, buf, sizeof(seed));
}
}
mp_mutex_lock(&state_mutex);
state[0] = seed;
for (int i = 1; i < 4; i++)
state[i] = splitmix64(&seed);
mp_mutex_unlock(&state_mutex);
}
uint64_t mp_rand_next(void)
{
uint64_t result, t;
mp_mutex_lock(&state_mutex);
result = rotl_u64(state[1] * 5, 7) * 9;
t = state[1] << 17;
state[2] ^= state[0];
state[3] ^= state[1];
state[1] ^= state[2];
state[0] ^= state[3];
state[2] ^= t;
state[3] = rotl_u64(state[3], 45);
mp_mutex_unlock(&state_mutex);
return result;
}
double mp_rand_next_double(void)
{
return (mp_rand_next() >> 11) * 0x1.0p-53;
}