1/*
2 * Copyright (c) 2007 Michael Niedermayer
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21#include <stdio.h>
22#include <stdlib.h>
23#include <inttypes.h>
24#include <errno.h>
25#include <string.h>
26
27static uint32_t state;
28static uint32_t ran(void)
29{
30    return state = state * 1664525 + 1013904223;
31}
32
33int main(int argc, char **argv)
34{
35    FILE *f;
36    int count, maxburst, length;
37
38    if (argc < 5) {
39        printf("USAGE: trasher <filename> <count> <maxburst> <seed>\n");
40        return 1;
41    }
42
43    f = fopen(argv[1], "rb+");
44    if (!f) {
45        perror(argv[1]);
46        return 2;
47    }
48    count    = atoi(argv[2]);
49    maxburst = atoi(argv[3]);
50    state    = atoi(argv[4]);
51
52    fseek(f, 0, SEEK_END);
53    length = ftell(f);
54    fseek(f, 0, SEEK_SET);
55
56    while (count--) {
57        int burst = 1 + ran() * (uint64_t) (abs(maxburst) - 1) / UINT32_MAX;
58        int pos   = ran() * (uint64_t) length / UINT32_MAX;
59        if (fseek(f, pos, SEEK_SET) < 0) {
60            fprintf(stderr, "seek failed\n");
61            return 1;
62        }
63
64        if (maxburst < 0)
65            burst = -maxburst;
66
67        if (pos + burst > length)
68            continue;
69
70        while (burst--) {
71            int val = ran() * 256ULL / UINT32_MAX;
72
73            if (maxburst < 0)
74                val = 0;
75
76            fwrite(&val, 1, 1, f);
77        }
78    }
79
80    return 0;
81}
82