1 /*
2
3 File: file_amr.c
4
5 Copyright (C) 2008 Christophe GRENIER <grenier@cgsecurity.org>
6
7 This software is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or
10 (at your option) any later version.
11
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License along
18 with this program; if not, write the Free Software Foundation, Inc., 51
19 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
20
21 */
22
23 #ifdef HAVE_CONFIG_H
24 #include <config.h>
25 #endif
26 #ifdef HAVE_STRING_H
27 #include <string.h>
28 #endif
29 #include <stdio.h>
30 #include "types.h"
31 #include "filegen.h"
32 #include "log.h"
33
34 static void register_header_check_amr(file_stat_t *file_stat);
35 static int header_check_amr(const unsigned char *buffer, const unsigned int buffer_size, const unsigned int safe_header_only, const file_recovery_t *file_recovery, file_recovery_t *file_recovery_new);
36
37 const file_hint_t file_hint_amr= {
38 .extension="amr",
39 .description="Adaptive Multi-Rate",
40 .max_filesize=PHOTOREC_MAX_FILE_SIZE,
41 .recover=1,
42 .enable_by_default=1,
43 .register_header_check=®ister_header_check_amr
44 };
45
data_check_amr(const unsigned char * buffer,const unsigned int buffer_size,file_recovery_t * file_recovery)46 static data_check_t data_check_amr(const unsigned char *buffer, const unsigned int buffer_size, file_recovery_t *file_recovery)
47 {
48 while(file_recovery->calculated_file_size + buffer_size/2 >= file_recovery->file_size &&
49 file_recovery->calculated_file_size + 4 < file_recovery->file_size + buffer_size/2)
50 {
51 const unsigned int i=file_recovery->calculated_file_size - file_recovery->file_size + buffer_size/2;
52 #ifdef DEBUG_AMR
53 log_info("data_check_amr %04x %02x %u\n", file_recovery->calculated_file_size, buffer[i], (buffer[i]>>1)&7);
54 #endif
55 if((buffer[i]&0x83)!=0)
56 return DC_STOP;
57 if(buffer[i]==0 && buffer[i+1]==0 && buffer[i+2]==0 && buffer[i+3]==0)
58 return DC_STOP;
59 switch((buffer[i]>>3)&0x7)
60 {
61 case 0: file_recovery->calculated_file_size+=13; break;
62 case 1: file_recovery->calculated_file_size+=14; break;
63 case 2: file_recovery->calculated_file_size+=16; break;
64 case 3: file_recovery->calculated_file_size+=18; break;
65 case 4: file_recovery->calculated_file_size+=20; break;
66 case 5: file_recovery->calculated_file_size+=21; break;
67 case 6: file_recovery->calculated_file_size+=27; break;
68 case 7: file_recovery->calculated_file_size+=32; break;
69 }
70 }
71 return DC_CONTINUE;
72 }
73
header_check_amr(const unsigned char * buffer,const unsigned int buffer_size,const unsigned int safe_header_only,const file_recovery_t * file_recovery,file_recovery_t * file_recovery_new)74 static int header_check_amr(const unsigned char *buffer, const unsigned int buffer_size, const unsigned int safe_header_only, const file_recovery_t *file_recovery, file_recovery_t *file_recovery_new)
75 {
76 if((buffer[6]&0x83)!=0)
77 return 0;
78 if(buffer[6]==0 && buffer[6+1]==0 && buffer[6+2]==0 && buffer[6+3]==0)
79 return 0;
80 reset_file_recovery(file_recovery_new);
81 file_recovery_new->calculated_file_size=6;
82 file_recovery_new->data_check=&data_check_amr;
83 file_recovery_new->file_check=&file_check_size;
84 file_recovery_new->extension=file_hint_amr.extension;
85 return 1;
86 }
87
88 /* AMR file format is described in
89 * http://developer.nokia.com/community/wiki/AMR_format
90 * ftp://ftp.rfc-editor.org/in-notes/rfc3267.txt */
91
register_header_check_amr(file_stat_t * file_stat)92 static void register_header_check_amr(file_stat_t *file_stat)
93 {
94 static const unsigned char amr_header[6]= {'#','!','A','M','R','\n'};
95 register_header_check(0, amr_header,sizeof(amr_header), &header_check_amr, file_stat);
96 }
97