Asterisk - The Open Source Telephony Project  GIT-master-44aef04
mod_format.h
Go to the documentation of this file.
1 /*
2  * Asterisk -- An open source telephony toolkit.
3  *
4  * Copyright (C) 1999 - 2006, Digium, Inc.
5  *
6  * Mark Spencer <markster@digium.com>
7  *
8  * See http://www.asterisk.org for more information about
9  * the Asterisk project. Please do not directly contact
10  * any of the maintainers of this project for assistance;
11  * the project provides a web site, mailing lists and IRC
12  * channels for your use.
13  *
14  * This program is free software, distributed under the terms of
15  * the GNU General Public License Version 2. See the LICENSE file
16  * at the top of the source tree.
17  */
18 
19 /*! \file
20  * \brief Header for providers of file and format handling routines.
21  * Clients of these routines should include "asterisk/file.h" instead.
22  */
23 
24 #ifndef _ASTERISK_MOD_FORMAT_H
25 #define _ASTERISK_MOD_FORMAT_H
26 
27 #include "asterisk/file.h"
28 #include "asterisk/frame.h"
29 
30 #if defined(__cplusplus) || defined(c_plusplus)
31 extern "C" {
32 #endif
33 
34 /*! \brief
35  * Each supported file format is described by the following structure.
36  *
37  * Not all are necessary, the support routine implement default
38  * values for some of them.
39  * A handler typically fills a structure initializing the desired
40  * fields, and then calls ast_format_def_register() with the (readonly)
41  * structure as an argument.
42  */
44  char name[80]; /*!< Name of format */
45  char exts[80]; /*!< Extensions (separated by | if more than one)
46  * this format can read. First is assumed for writing (e.g. .mp3) */
47  char mime_types[80]; /*!< MIME Types related to the format (separated by | if more than one)*/
48  struct ast_format *format; /*!< Format of frames it uses/provides (one only) */
49  /*!
50  * \brief Prepare an input stream for playback.
51  * \return 0 on success, -1 on error.
52  * The FILE is already open (in s->f) so this function only needs to perform
53  * any applicable validity checks on the file. If none is required, the
54  * function can be omitted.
55  */
56  int (*open)(struct ast_filestream *s);
57  /*!
58  * \brief Prepare a stream for output, and comment it appropriately if applicable.
59  * \return 0 on success, -1 on error.
60  * Same as the open, the FILE is already open so the function just needs to
61  * prepare any header and other fields, if any.
62  * The function can be omitted if nothing is needed.
63  */
64  int (*rewrite)(struct ast_filestream *s, const char *comment);
65  /*! Write a frame to a channel */
66  int (*write)(struct ast_filestream *, struct ast_frame *);
67  /*! seek num samples into file, whence - like a normal seek but with offset in samples */
68  int (*seek)(struct ast_filestream *, off_t, int);
69  int (*trunc)(struct ast_filestream *fs); /*!< trunc file to current position */
70  off_t (*tell)(struct ast_filestream *fs); /*!< tell current position */
71  /*! Read the next frame from the filestream (if available) and report
72  * when to get next frame (in samples)
73  */
74  struct ast_frame * (*read)(struct ast_filestream *, int *whennext);
75  /*! Do any closing actions, if any. The descriptor and structure are closed
76  * and destroyed by the generic routines, so they must not be done here. */
77  void (*close)(struct ast_filestream *);
78  char * (*getcomment)(struct ast_filestream *); /*!< Retrieve file comment */
79 
81 
82  /*!
83  * If the handler needs a buffer (for read, typically)
84  * and/or a private descriptor, put here the
85  * required size (in bytes) and the support routine will allocate them
86  * for you, pointed by s->buf and s->private, respectively.
87  * When allocating a buffer, remember to leave AST_FRIENDLY_OFFSET
88  * spare bytes at the bginning.
89  */
90  int buf_size; /*!< size of frame buffer, if any, aligned to 8 bytes. */
91  int desc_size; /*!< size of private descriptor, if any */
92 
93  struct ast_module *module;
94 };
95 
96 /*! \brief
97  * This structure is allocated by file.c in one chunk,
98  * together with buf_size and desc_size bytes of memory
99  * to be used for private purposes (e.g. buffers etc.)
100  */
102  /*! Everybody reserves a block of AST_RESERVED_POINTERS pointers for us */
103  struct ast_format_def *fmt; /* need to write to the lock and usecnt */
104  int flags;
105  mode_t mode;
107  char *filename;
109  /*! Video file stream */
111  /*! Transparently translate from another format -- just once */
113  struct ast_tranlator_pvt *tr;
117  FILE *f;
118  /*!
119  * \brief frame produced by read, typically
120  * \note This frame holds a fr.subclass.format ref.
121  */
122  struct ast_frame fr;
123  char *buf; /*!< buffer pointed to by ast_frame; */
124  void *_private; /*!< pointer to private buffer */
125  const char *orig_chan_name;
127 };
128 
129 /*!
130  * \brief Register a new file format capability.
131  * Adds a format to Asterisk's format abilities.
132  * \retval 0 on success
133  * \retval -1 on failure
134  */
135 int __ast_format_def_register(const struct ast_format_def *f, struct ast_module *mod);
136 #define ast_format_def_register(f) __ast_format_def_register(f, AST_MODULE_SELF)
137 
138 /*!
139  * \brief Unregisters a file format
140  * \param name the name of the format you wish to unregister
141  * Unregisters a format based on the name of the format.
142  * \retval 0 on success
143  * \retval -1 on failure to unregister
144  */
145 int ast_format_def_unregister(const char *name);
146 
147 #if defined(__cplusplus) || defined(c_plusplus)
148 }
149 #endif
150 
151 #endif /* _ASTERISK_MOD_FORMAT_H */
char exts[80]
Definition: mod_format.h:45
Main Channel structure associated with a channel.
void(* close)(struct ast_filestream *)
Definition: mod_format.h:77
Definition of a media format.
Definition: format.c:43
char * realfilename
Definition: mod_format.h:108
Generic File Format Support. Should be included by clients of the file handling routines. File service providers should instead include mod_format.h.
struct ast_tranlator_pvt * tr
Definition: mod_format.h:113
Each supported file format is described by the following structure.
Definition: mod_format.h:43
int(* seek)(struct ast_filestream *, off_t, int)
Definition: mod_format.h:68
char * write_buffer
Definition: mod_format.h:126
int(* open)(struct ast_filestream *s)
Prepare an input stream for playback.
Definition: mod_format.h:56
int ast_format_def_unregister(const char *name)
Unregisters a file format.
Definition: file.c:162
int __ast_format_def_register(const struct ast_format_def *f, struct ast_module *mod)
Register a new file format capability. Adds a format to Asterisk&#39;s format abilities.
Definition: file.c:124
struct ast_module * module
Definition: mod_format.h:93
char * open_filename
Definition: mod_format.h:106
struct ast_format_def * fmt
Definition: mod_format.h:103
Asterisk internal frame definitions.
const char * orig_chan_name
Definition: mod_format.h:125
struct ast_format * format
Definition: mod_format.h:48
void * _private
Definition: mod_format.h:124
Default structure for translators, with the basic fields and buffers, all allocated as part of the sa...
Definition: translate.h:213
int(* rewrite)(struct ast_filestream *s, const char *comment)
Prepare a stream for output, and comment it appropriately if applicable.
Definition: mod_format.h:64
struct ast_channel * owner
Definition: mod_format.h:116
#define comment
Definition: ael_lex.c:976
char mime_types[80]
Definition: mod_format.h:47
char name[80]
Definition: mod_format.h:44
struct ast_trans_pvt * trans
Definition: mod_format.h:112
#define AST_LIST_ENTRY(type)
Declare a forward link structure inside a list entry.
Definition: linkedlists.h:409
struct ast_format * lastwriteformat
Definition: mod_format.h:114
struct ast_format_def::@270 list
int(* trunc)(struct ast_filestream *fs)
Definition: mod_format.h:69
char * filename
Definition: mod_format.h:107
This structure is allocated by file.c in one chunk, together with buf_size and desc_size bytes of mem...
Definition: mod_format.h:101
Data structure associated with a single frame of data.
struct ast_filestream * vfs
Definition: mod_format.h:110
off_t(* tell)(struct ast_filestream *fs)
Definition: mod_format.h:70
int(* write)(struct ast_filestream *, struct ast_frame *)
Definition: mod_format.h:66