trasher.c
Go to the documentation of this file.
1 /*
2  * Copyright (c) 2007 Michael Niedermayer
3  *
4  * This file is part of Libav.
5  *
6  * Libav 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  * Libav 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 Libav; 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 
25 static uint32_t state;
26 static uint32_t ran(void){
27  return state= state*1664525+1013904223;
28 }
29 
30 int main(int argc, char** argv)
31 {
32  FILE *f;
33  int count, maxburst, length;
34 
35  if (argc < 5){
36  printf("USAGE: trasher <filename> <count> <maxburst> <seed>\n");
37  return 1;
38  }
39 
40  f= fopen(argv[1], "rb+");
41  if (!f){
42  perror(argv[1]);
43  return 2;
44  }
45  count= atoi(argv[2]);
46  maxburst= atoi(argv[3]);
47  state= atoi(argv[4]);
48 
49  fseek(f, 0, SEEK_END);
50  length= ftell(f);
51  fseek(f, 0, SEEK_SET);
52 
53  while(count--){
54  int burst= 1 + ran() * (uint64_t) (abs(maxburst)-1) / UINT32_MAX;
55  int pos= ran() * (uint64_t) length / UINT32_MAX;
56  fseek(f, pos, SEEK_SET);
57 
58  if(maxburst<0) burst= -maxburst;
59 
60  if(pos + burst > length)
61  continue;
62 
63  while(burst--){
64  int val= ran() * 256ULL / UINT32_MAX;
65 
66  if(maxburst<0) val=0;
67 
68  fwrite(&val, 1, 1, f);
69  }
70  }
71 
72  return 0;
73 }