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get_generic_seed() for the cases without /dev/random and AV_READ_TIME
Originally committed as revision 24102 to svn://svn.ffmpeg.org/ffmpeg/trunk
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@ -21,6 +21,7 @@
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#include <unistd.h>
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#include <fcntl.h>
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#include "timer.h"
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#include "time.h"
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#include "random_seed.h"
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#include "avutil.h"
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@ -37,6 +38,38 @@ static int read_random(uint32_t *dst, const char *file)
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return err;
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}
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static uint32_t get_generic_seed(void)
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{
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int last_t=0;
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int bits=0;
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uint64_t random=0;
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int i;
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int s=0;
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for(i=0;bits<64;i++){
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int t= clock()>>s;
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if(last_t && t != last_t){
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if(i<10000U && s<24){
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s++;
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i=t=0;
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}else{
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random= 2*random + (i&1);
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bits++;
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}
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}
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last_t= t;
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}
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#ifdef AV_READ_TIME
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random ^= AV_READ_TIME();
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#else
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random ^= clock();
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#endif
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random += random>>32;
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return random;
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}
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uint32_t av_get_random_seed(void)
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{
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uint32_t seed;
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@ -45,12 +78,7 @@ uint32_t av_get_random_seed(void)
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return seed;
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if (read_random(&seed, "/dev/random") == sizeof(seed))
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return seed;
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#ifdef AV_READ_TIME
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seed = AV_READ_TIME();
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#endif
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// XXX what to do ?
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return seed;
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return get_generic_seed();
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}
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#if LIBAVUTIL_VERSION_MAJOR < 51
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