yading@11: /*
yading@11:  * Copyright (c) 2007 Michael Niedermayer
yading@11:  *
yading@11:  * This file is part of FFmpeg.
yading@11:  *
yading@11:  * FFmpeg is free software; you can redistribute it and/or
yading@11:  * modify it under the terms of the GNU Lesser General Public
yading@11:  * License as published by the Free Software Foundation; either
yading@11:  * version 2.1 of the License, or (at your option) any later version.
yading@11:  *
yading@11:  * FFmpeg is distributed in the hope that it will be useful,
yading@11:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@11:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@11:  * Lesser General Public License for more details.
yading@11:  *
yading@11:  * You should have received a copy of the GNU Lesser General Public
yading@11:  * License along with FFmpeg; if not, write to the Free Software
yading@11:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@11:  */
yading@11: 
yading@11: #include <stdio.h>
yading@11: #include <stdlib.h>
yading@11: #include <inttypes.h>
yading@11: #include <errno.h>
yading@11: #include <string.h>
yading@11: 
yading@11: static uint32_t state;
yading@11: static uint32_t ran(void)
yading@11: {
yading@11:     return state = state * 1664525 + 1013904223;
yading@11: }
yading@11: 
yading@11: int main(int argc, char **argv)
yading@11: {
yading@11:     FILE *f;
yading@11:     int count, maxburst, length;
yading@11: 
yading@11:     if (argc < 5) {
yading@11:         printf("USAGE: trasher <filename> <count> <maxburst> <seed>\n");
yading@11:         return 1;
yading@11:     }
yading@11: 
yading@11:     f = fopen(argv[1], "rb+");
yading@11:     if (!f) {
yading@11:         perror(argv[1]);
yading@11:         return 2;
yading@11:     }
yading@11:     count    = atoi(argv[2]);
yading@11:     maxburst = atoi(argv[3]);
yading@11:     state    = atoi(argv[4]);
yading@11: 
yading@11:     fseek(f, 0, SEEK_END);
yading@11:     length = ftell(f);
yading@11:     fseek(f, 0, SEEK_SET);
yading@11: 
yading@11:     while (count--) {
yading@11:         int burst = 1 + ran() * (uint64_t) (abs(maxburst) - 1) / UINT32_MAX;
yading@11:         int pos   = ran() * (uint64_t) length / UINT32_MAX;
yading@11:         if (fseek(f, pos, SEEK_SET) < 0) {
yading@11:             fprintf(stderr, "seek failed\n");
yading@11:             return 1;
yading@11:         }
yading@11: 
yading@11:         if (maxburst < 0)
yading@11:             burst = -maxburst;
yading@11: 
yading@11:         if (pos + burst > length)
yading@11:             continue;
yading@11: 
yading@11:         while (burst--) {
yading@11:             int val = ran() * 256ULL / UINT32_MAX;
yading@11: 
yading@11:             if (maxburst < 0)
yading@11:                 val = 0;
yading@11: 
yading@11:             fwrite(&val, 1, 1, f);
yading@11:         }
yading@11:     }
yading@11: 
yading@11:     return 0;
yading@11: }