FFmpeg
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trasher.c
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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 
27 static uint32_t state;
28 static uint32_t ran(void)
29 {
30  return state = state * 1664525 + 1013904223;
31 }
32 
33 int 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 }