Wed Jan 8 2020 09:49:47

Asterisk developer's documentation


format_ilbc.c
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1 /*
2  * Asterisk -- An open source telephony toolkit.
3  *
4  * Brian K. West <brian@bkw.org>
5  *
6  * Copyright (C) 1999 - 2005, Digium, Inc.
7  *
8  * Mark Spencer <markster@digium.com>
9  *
10  * See http://www.asterisk.org for more information about
11  * the Asterisk project. Please do not directly contact
12  * any of the maintainers of this project for assistance;
13  * the project provides a web site, mailing lists and IRC
14  * channels for your use.
15  *
16  * This program is free software, distributed under the terms of
17  * the GNU General Public License Version 2. See the LICENSE file
18  * at the top of the source tree.
19  */
20 
21 /*! \file
22  *
23  * \brief Save to raw, headerless iLBC data.
24  * \arg File name extension: ilbc
25  * \ingroup formats
26  */
27 
28 /*** MODULEINFO
29  <support_level>core</support_level>
30  ***/
31 
32 #include "asterisk.h"
33 
34 ASTERISK_FILE_VERSION(__FILE__, "$Revision: 364578 $")
35 
36 #include "asterisk/mod_format.h"
37 #include "asterisk/module.h"
38 #include "asterisk/endian.h"
39 
40 /* Some Ideas for this code came from makeg729e.c by Jeffrey Chilton */
41 
42 /* Portions of the conversion code are by guido@sienanet.it */
43 
44 #define ILBC_BUF_SIZE 50 /* One Real iLBC Frame */
45 #define ILBC_SAMPLES 240
46 
47 static struct ast_frame *ilbc_read(struct ast_filestream *s, int *whennext)
48 {
49  int res;
50  /* Send a frame from the file to the appropriate channel */
53  s->fr.mallocd = 0;
55  if ((res = fread(s->fr.data.ptr, 1, s->fr.datalen, s->f)) != s->fr.datalen) {
56  if (res)
57  ast_log(LOG_WARNING, "Short read (%d) (%s)!\n", res, strerror(errno));
58  return NULL;
59  }
60  *whennext = s->fr.samples = ILBC_SAMPLES;
61  return &s->fr;
62 }
63 
64 static int ilbc_write(struct ast_filestream *fs, struct ast_frame *f)
65 {
66  int res;
67  if (f->frametype != AST_FRAME_VOICE) {
68  ast_log(LOG_WARNING, "Asked to write non-voice frame!\n");
69  return -1;
70  }
71  if (f->subclass.codec != AST_FORMAT_ILBC) {
72  ast_log(LOG_WARNING, "Asked to write non-iLBC frame (%s)!\n", ast_getformatname(f->subclass.codec));
73  return -1;
74  }
75  if (f->datalen % 50) {
76  ast_log(LOG_WARNING, "Invalid data length, %d, should be multiple of 50\n", f->datalen);
77  return -1;
78  }
79  if ((res = fwrite(f->data.ptr, 1, f->datalen, fs->f)) != f->datalen) {
80  ast_log(LOG_WARNING, "Bad write (%d/50): %s\n", res, strerror(errno));
81  return -1;
82  }
83  return 0;
84 }
85 
86 static int ilbc_seek(struct ast_filestream *fs, off_t sample_offset, int whence)
87 {
88  long bytes;
89  off_t min,cur,max,offset=0;
90  min = 0;
91  cur = ftello(fs->f);
92  fseeko(fs->f, 0, SEEK_END);
93  max = ftello(fs->f);
94 
95  bytes = ILBC_BUF_SIZE * (sample_offset / ILBC_SAMPLES);
96  if (whence == SEEK_SET)
97  offset = bytes;
98  else if (whence == SEEK_CUR || whence == SEEK_FORCECUR)
99  offset = cur + bytes;
100  else if (whence == SEEK_END)
101  offset = max - bytes;
102  if (whence != SEEK_FORCECUR) {
103  offset = (offset > max)?max:offset;
104  }
105  /* protect against seeking beyond begining. */
106  offset = (offset < min)?min:offset;
107  if (fseeko(fs->f, offset, SEEK_SET) < 0)
108  return -1;
109  return 0;
110 }
111 
112 static int ilbc_trunc(struct ast_filestream *fs)
113 {
114  int fd;
115  off_t cur;
116 
117  if ((fd = fileno(fs->f)) < 0) {
118  ast_log(AST_LOG_WARNING, "Unable to determine file descriptor for iLBC filestream %p: %s\n", fs, strerror(errno));
119  return -1;
120  }
121  if ((cur = ftello(fs->f)) < 0) {
122  ast_log(AST_LOG_WARNING, "Unable to determine current position in iLBC filestream %p: %s\n", fs, strerror(errno));
123  return -1;
124  }
125  /* Truncate file to current length */
126  return ftruncate(fd, cur);
127 }
128 
129 static off_t ilbc_tell(struct ast_filestream *fs)
130 {
131  off_t offset = ftello(fs->f);
132  return (offset/ILBC_BUF_SIZE)*ILBC_SAMPLES;
133 }
134 
135 static const struct ast_format ilbc_f = {
136  .name = "iLBC",
137  .exts = "ilbc",
138  .format = AST_FORMAT_ILBC,
139  .write = ilbc_write,
140  .seek = ilbc_seek,
141  .trunc = ilbc_trunc,
142  .tell = ilbc_tell,
143  .read = ilbc_read,
144  .buf_size = ILBC_BUF_SIZE + AST_FRIENDLY_OFFSET,
145 };
146 
147 static int load_module(void)
148 {
149  if (ast_format_register(&ilbc_f))
152 }
153 
154 static int unload_module(void)
155 {
156  return ast_format_unregister(ilbc_f.name);
157 }
158 
160  .load = load_module,
161  .unload = unload_module,
162  .load_pri = AST_MODPRI_APP_DEPEND
163 );
union ast_frame_subclass subclass
Definition: frame.h:146
Asterisk main include file. File version handling, generic pbx functions.
#define ast_format_register(f)
Definition: mod_format.h:131
int offset
Definition: frame.h:156
void * ptr
Definition: frame.h:160
#define LOG_WARNING
Definition: logger.h:144
#define AST_LOG_WARNING
Definition: logger.h:149
static int unload_module(void)
Definition: format_ilbc.c:154
#define ILBC_SAMPLES
Definition: format_ilbc.c:45
Each supported file format is described by the following structure.
Definition: mod_format.h:43
#define AST_MODULE_INFO(keystr, flags_to_set, desc, fields...)
Definition: module.h:374
format_t codec
Definition: frame.h:137
#define AST_FRAME_SET_BUFFER(fr, _base, _ofs, _datalen)
Definition: frame.h:183
#define AST_FRIENDLY_OFFSET
Offset into a frame&#39;s data buffer.
Definition: frame.h:204
Asterisk architecture endianess compatibility definitions.
int datalen
Definition: frame.h:148
struct ast_frame fr
Definition: mod_format.h:117
int ast_format_unregister(const char *name)
Unregisters a file format.
Definition: file.c:104
char * ast_getformatname(format_t format)
Get the name of a format.
Definition: frame.c:578
char name[80]
Definition: mod_format.h:44
#define ILBC_BUF_SIZE
Definition: format_ilbc.c:44
void ast_log(int level, const char *file, int line, const char *function, const char *fmt,...)
Used for sending a log message This is the standard logger function. Probably the only way you will i...
Definition: logger.c:1207
int errno
#define SEEK_FORCECUR
Definition: file.h:50
static int load_module(void)
Definition: format_ilbc.c:147
static off_t ilbc_tell(struct ast_filestream *fs)
Definition: format_ilbc.c:129
static struct ast_format f[]
Definition: format_g726.c:181
static int ilbc_write(struct ast_filestream *fs, struct ast_frame *f)
Definition: format_ilbc.c:64
int mallocd
Definition: frame.h:152
This structure is allocated by file.c in one chunk, together with buf_size and desc_size bytes of mem...
Definition: mod_format.h:100
Data structure associated with a single frame of data.
Definition: frame.h:142
static int ilbc_trunc(struct ast_filestream *fs)
Definition: format_ilbc.c:112
enum ast_frame_type frametype
Definition: frame.h:144
#define ASTERISK_GPL_KEY
The text the key() function should return.
Definition: module.h:38
Asterisk module definitions.
union ast_frame::@172 data
#define AST_FORMAT_ILBC
Definition: frame.h:262
static int ilbc_seek(struct ast_filestream *fs, off_t sample_offset, int whence)
Definition: format_ilbc.c:86
static struct ast_frame * ilbc_read(struct ast_filestream *s, int *whennext)
Definition: format_ilbc.c:47
#define ASTERISK_FILE_VERSION(file, version)
Register/unregister a source code file with the core.
Definition: asterisk.h:180
int samples
Definition: frame.h:150
static struct ast_format ilbc_f
Definition: format_ilbc.c:135