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/*
* Copyright (c) 2007 Michael Niedermayer
*
* This file is part of FFmpeg.
*
* FFmpeg 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.
*
* FFmpeg 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 FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <stdio.h>
#include <stdlib.h>
#include <inttypes.h>
#include <errno.h>
#include <string.h>
static uint32_t state;
static uint32_t ran(void)
{
return state = state * 1664525 + 1013904223;
}
static void checked_seek(FILE *stream, int64_t offset, int whence)
{
offset = fseek(stream, offset, whence);
if (offset < 0) {
fprintf(stderr, "seek failed\n");
exit(1);
}
}
int main(int argc, char **argv)
{
FILE *f;
int count, maxburst, length;
if (argc < 5) {
printf("USAGE: trasher <filename> <count> <maxburst> <seed>\n");
return 1;
}
f = fopen(argv[1], "rb+");
if (!f) {
perror(argv[1]);
return 2;
}
count = atoi(argv[2]);
maxburst = atoi(argv[3]);
state = atoi(argv[4]);
checked_seek(f, 0, SEEK_END);
length = ftell(f);
checked_seek(f, 0, SEEK_SET);
while (count--) {
int burst = 1 + ran() * (uint64_t) (abs(maxburst) - 1) / UINT32_MAX;
int pos = ran() * (uint64_t) length / UINT32_MAX;
checked_seek(f, pos, SEEK_SET);
if (maxburst < 0)
burst = -maxburst;
if (pos + burst > length)
continue;
while (burst--) {
int val = ran() * 256ULL / UINT32_MAX;
if (maxburst < 0)
val = 0;
fwrite(&val, 1, 1, f);
}
}
return 0;
}