1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
|
/*
This file is part of libextractor.
Copyright (C) 2012 Christian Grothoff
libextractor is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published
by the Free Software Foundation; either version 3, or (at your
option) any later version.
libextractor is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with libextractor; see the file COPYING. If not, write to the
Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
Boston, MA 02110-1301, USA.
*/
/**
* @file plugins/mp4_extractor.c
* @brief plugin to support MP4 files
* @author Christian Grothoff
*/
#include "platform.h"
#include "extractor.h"
#include <mp4v2/mp4v2.h>
/**
* Callback invoked by libmp4v2 to open the file.
* We cheated and passed our extractor context as
* the filename (fingers crossed) and will simply
* return it again to make it the handle.
*
* @param name "filename" to open
* @param open mode, only reading allowed
* @return NULL if the file is not opened for reading
*/
static void*
open_cb (const char *name,
MP4FileMode mode)
{
void *ecp;
if (FILEMODE_READ != mode)
return NULL;
if (1 != sscanf (name, "%p", &ecp))
return NULL;
return ecp;
}
/**
* Seek callback for libmp4v2.
*
* @param handle the 'struct EXTRACTOR_ExtractContext'
* @param pos target seek position (relative or absolute?)
* @return true on failure, false on success
*/
static int
seek_cb (void *handle,
int64_t pos)
{
struct EXTRACTOR_ExtractContext *ec = handle;
fprintf (stderr, "Seek: %lld!\n", (long long) pos);
if (-1 ==
ec->seek (ec->cls,
pos,
SEEK_CUR))
return true; /* failure */
return false;
}
/**
* Read callback for libmp4v2.
*
* @param handle the 'struct EXTRACTOR_ExtractContext'
* @param buffer where to write data read
* @param size desired number of bytes to read
* @param nin where to write number of bytes read
* @param maxChunkSize some chunk size (ignored)
* @return true on failure, false on success
*/
static int
read_cb (void *handle,
void *buffer,
int64_t size,
int64_t *nin,
int64_t maxChunkSize)
{
struct EXTRACTOR_ExtractContext *ec = handle;
void *buf;
ssize_t ret;
fprintf (stderr, "read!\n");
*nin = 0;
if (-1 ==
(ret = ec->read (ec->cls,
&buf,
size)))
return true; /* failure */
memcpy (buffer, buf, ret);
*nin = ret;
return false; /* success */
}
/**
* Write callback for libmp4v2.
*
* @param handle the 'struct EXTRACTOR_ExtractContext'
* @param buffer data to write
* @param size desired number of bytes to write
* @param nin where to write number of bytes written
* @param maxChunkSize some chunk size (ignored)
* @return true on failure (always fails)
*/
static int
write_cb (void *handle,
const void *buffer,
int64_t size,
int64_t *nout,
int64_t maxChunkSize)
{
fprintf (stderr, "Write!?\n");
return true; /* failure */
}
/**
* Write callback for libmp4v2. Does nothing.
*
* @param handle the 'struct EXTRACTOR_ExtractContext'
* @return false on success (always succeeds)
*/
static int
close_cb (void *handle)
{
fprintf (stderr, "Close!\n");
return false; /* success */
}
#if 0
/**
* Wrapper to replace 'stat64' call by libmp4v2.
*/
int
stat_cb (const char * path,
struct stat64 * buf)
{
void *ecp;
struct EXTRACTOR_ExtractContext *ec;
fprintf (stderr, "stat!\n");
if (1 != sscanf (path, "%p", &ecp))
{
errno = EINVAL;
return -1;
}
ec = ecp;
memset (buf, 0, sizeof (struct stat));
buf->st_size = ec->get_size (ec->cls);
return 0;
}
#endif
/**
* Main entry method for the MP4 extraction plugin.
*
* @param ec extraction context provided to the plugin
*/
void
EXTRACTOR_mp4_extract_method (struct EXTRACTOR_ExtractContext *ec)
{
MP4FileProvider fp;
MP4FileHandle mp4;
const MP4Tags *tags;
char ecp[128];
if (1)
return; /* plugin is known not to work yet;
see issue 138 filed against MP4v2 lib */
snprintf (ecp, sizeof (ecp), "%p", ec);
fp.open = &open_cb;
fp.seek = &seek_cb;
fp.read = &read_cb;
fp.write = &write_cb;
fp.close = &close_cb;
if (NULL == (mp4 = MP4ReadProvider (ecp,
&fp)))
return;
tags = MP4TagsAlloc ();
if (MP4TagsFetch (tags, mp4))
{
fprintf (stderr, "got tags!\n");
}
MP4Close (mp4, 0);
}
/* end of mp4_extractor.c */
|
