diff options
Diffstat (limited to 'libavutil/random_seed.c')
| -rw-r--r-- | libavutil/random_seed.c | 59 |
1 files changed, 38 insertions, 21 deletions
diff --git a/libavutil/random_seed.c b/libavutil/random_seed.c index 6a8666cca6..d56280d838 100644 --- a/libavutil/random_seed.c +++ b/libavutil/random_seed.c @@ -22,8 +22,15 @@ #include <fcntl.h> #include <math.h> #include <time.h> +#include <string.h> #include "timer.h" #include "random_seed.h" +#include "sha.h" +#include "intreadwrite.h" + +#ifndef TEST +#define TEST 0 +#endif static int read_random(uint32_t *dst, const char *file) { @@ -40,34 +47,44 @@ static int read_random(uint32_t *dst, const char *file) static uint32_t get_generic_seed(void) { + uint8_t tmp[av_sha_size]; + struct AVSHA *sha = (void*)tmp; clock_t last_t = 0; - int bits = 0; - uint64_t random = 0; - unsigned i; - float s = 0.000000000001; + static uint64_t i = 0; + static uint32_t buffer[512] = {0}; + unsigned char digest[32]; + uint64_t last_i = i; - for (i = 0; bits < 64; i++) { + if(TEST){ + memset(buffer, 0, sizeof(buffer)); + last_i = i = 0; + }else{ +#ifdef AV_READ_TIME + buffer[13] ^= AV_READ_TIME(); + buffer[41] ^= AV_READ_TIME()>>32; +#endif + } + + for (;;) { clock_t t = clock(); - if (last_t && fabs(t - last_t) > s || t == (clock_t) -1) { - if (i < 10000 && s < (1 << 24)) { - s += s; - i = t = 0; - } else { - random = 2 * random + (i & 1); - bits++; - } + + if(last_t == t){ + buffer[i&511]++; + }else{ + buffer[++i&511]+= (t-last_t) % 3294638521U; + if(last_i && i-last_i > 4 || i-last_i > 64 || TEST && i-last_i > 8) + break; } last_t = t; } -#ifdef AV_READ_TIME - random ^= AV_READ_TIME(); -#else - random ^= clock(); -#endif - random += random >> 32; + if(TEST) + buffer[0] = buffer[1] = 0; - return random; + av_sha_init(sha, 160); + av_sha_update(sha, (uint8_t*)buffer, sizeof(buffer)); + av_sha_final(sha, digest); + return AV_RB32(digest) + AV_RB32(digest+32); } uint32_t av_get_random_seed(void) @@ -81,7 +98,7 @@ uint32_t av_get_random_seed(void) return get_generic_seed(); } -#ifdef TEST +#if TEST #undef printf #define N 256 #include <stdio.h> |