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2ba45a60 DM |
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 | } |