diff options
| author | Michael Niedermayer <michael@niedermayer.cc> | 2016-12-22 03:59:03 +0100 |
|---|---|---|
| committer | Michael Niedermayer <michael@niedermayer.cc> | 2017-02-08 21:17:50 +0100 |
| commit | 02073b5ab1a0b9d0fdca083337a825bca8d7f30b (patch) | |
| tree | a8ac8214a14661bf73c55041c52ed5d2501b664d /libavutil | |
| parent | 1825f7670a8863419ffb10f6a6bb4b4b44c876dc (diff) | |
| download | ffmpeg-02073b5ab1a0b9d0fdca083337a825bca8d7f30b.tar.gz | |
avutil/random_seed: Improve get_generic_seed() with higher precission clock()
Tested-by: Thomas Turner <thomastdt@googlemail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit da73d95bad4736c5e0a6b4b1a811f4dd4525bb4c)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
Diffstat (limited to 'libavutil')
| -rw-r--r-- | libavutil/random_seed.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/libavutil/random_seed.c b/libavutil/random_seed.c index 5af8e9e524..bbc4596581 100644 --- a/libavutil/random_seed.c +++ b/libavutil/random_seed.c @@ -67,6 +67,7 @@ static uint32_t get_generic_seed(void) uint8_t tmp[120]; struct AVSHA *sha = (void*)tmp; clock_t last_t = 0; + clock_t last_td = 0; static uint64_t i = 0; static uint32_t buffer[512] = { 0 }; unsigned char digest[20]; @@ -86,11 +87,12 @@ static uint32_t get_generic_seed(void) for (;;) { clock_t t = clock(); - - if (last_t == t) { - buffer[i & 511]++; + if (last_t + 2*last_td + 1 >= t) { + last_td = t - last_t; + buffer[i & 511] = 1664525*buffer[i & 511] + 1013904223 + (last_td % 3294638521U); } else { - buffer[++i & 511] += (t - last_t) % 3294638521U; + last_td = t - last_t; + buffer[++i & 511] += last_td % 3294638521U; if (last_i && i - last_i > 4 || i - last_i > 64 || TEST && i - last_i > 8) break; } |