From 47cf98efcb88320f45b22a10677f434c51ea4e66 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sat, 6 Mar 2010 01:31:17 +0000 Subject: Make trasher use a well defined random number generator and allow the seed to be specified on the cmd line. Originally committed as revision 22228 to svn://svn.ffmpeg.org/ffmpeg/trunk --- tools/trasher.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-) (limited to 'tools') diff --git a/tools/trasher.c b/tools/trasher.c index c7a0c7aa6a..12214f50ea 100644 --- a/tools/trasher.c +++ b/tools/trasher.c @@ -24,13 +24,18 @@ #include #include +static uint32_t state; +static uint32_t ran(void){ + return state= state*1664525+1013904223; +} + int main(int argc, char** argv) { FILE *f; int count, maxburst, length; - if (argc < 4){ - printf("USAGE: trasher \n"); + if (argc < 5){ + printf("USAGE: trasher \n"); return 1; } @@ -41,16 +46,15 @@ int main(int argc, char** argv) } count= atoi(argv[2]); maxburst= atoi(argv[3]); - - srandom (time (0)); + state= atoi(argv[4]); fseek(f, 0, SEEK_END); length= ftell(f); fseek(f, 0, SEEK_SET); while(count--){ - int burst= 1 + random() * (uint64_t) (abs(maxburst)-1) / RAND_MAX; - int pos= random() * (uint64_t) length / RAND_MAX; + int burst= 1 + ran() * (uint64_t) (abs(maxburst)-1) / UINT32_MAX; + int pos= ran() * (uint64_t) length / UINT32_MAX; fseek(f, pos, SEEK_SET); if(maxburst<0) burst= -maxburst; @@ -59,7 +63,7 @@ int main(int argc, char** argv) continue; while(burst--){ - int val= random() * 256ULL / RAND_MAX; + int val= ran() * 256ULL / UINT32_MAX; if(maxburst<0) val=0; -- cgit v1.2.3