diff options
Diffstat (limited to 'tools/descramble.c')
-rw-r--r-- | tools/descramble.c | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/tools/descramble.c b/tools/descramble.c new file mode 100644 index 0000000000..d9a4bf59d9 --- /dev/null +++ b/tools/descramble.c | |||
@@ -0,0 +1,83 @@ | |||
1 | /*************************************************************************** | ||
2 | * __________ __ ___. | ||
3 | * Open \______ \ ____ ____ | | _\_ |__ _______ ___ | ||
4 | * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / | ||
5 | * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < | ||
6 | * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ | ||
7 | * \/ \/ \/ \/ \/ | ||
8 | * $Id$ | ||
9 | * | ||
10 | * Copyright (C) 2002 by Björn Stenberg | ||
11 | * | ||
12 | * All files in this archive are subject to the GNU General Public License. | ||
13 | * See the file COPYING in the source tree root for full license agreement. | ||
14 | * | ||
15 | * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY | ||
16 | * KIND, either express or implied. | ||
17 | * | ||
18 | ****************************************************************************/ | ||
19 | |||
20 | #include <stdio.h> | ||
21 | #include <stdlib.h> | ||
22 | |||
23 | int main (int argc, char** argv) | ||
24 | { | ||
25 | unsigned long length,i,slen; | ||
26 | unsigned char *inbuf,*outbuf; | ||
27 | FILE* file; | ||
28 | |||
29 | if (argc < 3) { | ||
30 | printf("usage: %s <input file> <output file>\n",argv[0]); | ||
31 | return -1; | ||
32 | } | ||
33 | |||
34 | /* open file and check size */ | ||
35 | file = fopen(argv[1],"rb"); | ||
36 | if (!file) { | ||
37 | perror(argv[1]); | ||
38 | return -1; | ||
39 | } | ||
40 | fseek(file,0,SEEK_END); | ||
41 | length = ftell(file) - 6; /* skip 6-byte header */ | ||
42 | fseek(file,6,SEEK_SET); | ||
43 | inbuf = malloc(length); | ||
44 | outbuf = malloc(length); | ||
45 | if ( !inbuf || !outbuf ) { | ||
46 | printf("out of memory!\n"); | ||
47 | return -1; | ||
48 | } | ||
49 | |||
50 | /* read file */ | ||
51 | i=fread(inbuf,1,length,file); | ||
52 | if ( !i ) { | ||
53 | perror(argv[1]); | ||
54 | return -1; | ||
55 | } | ||
56 | fclose(file); | ||
57 | |||
58 | /* descramble */ | ||
59 | slen = length/4; | ||
60 | for (i = 0; i < length; i++) { | ||
61 | unsigned long addr = ((i % slen) << 2) + i/slen; | ||
62 | unsigned char data = inbuf[i]; | ||
63 | data = ~((data >> 1) | ((data << 7) & 0x80)); /* poor man's ROR */ | ||
64 | outbuf[addr] = data; | ||
65 | } | ||
66 | |||
67 | /* write file */ | ||
68 | file = fopen(argv[2],"wb"); | ||
69 | if ( !file ) { | ||
70 | perror(argv[2]); | ||
71 | return -1; | ||
72 | } | ||
73 | if ( !fwrite(outbuf,length,1,file) ) { | ||
74 | perror(argv[2]); | ||
75 | return -1; | ||
76 | } | ||
77 | fclose(file); | ||
78 | |||
79 | free(inbuf); | ||
80 | free(outbuf); | ||
81 | |||
82 | return 0; | ||
83 | } | ||