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/*
* Asterisk -- An open source telephony toolkit.
*
* Copyright (C) 1999 - 2006, Digium, Inc.
*
* Mark Spencer <markster@digium.com>
*
* See http://www.asterisk.org for more information about
* the Asterisk project. Please do not directly contact
* any of the maintainers of this project for assistance;
* the project provides a web site, mailing lists and IRC
* channels for your use.
*
* This program is free software, distributed under the terms of
* the GNU General Public License Version 2. See the LICENSE file
* at the top of the source tree.
*/
/*! \file
* \brief Header for providers of file and format handling routines.
* Clients of these routines should include "asterisk/file.h" instead.
*/
#ifndef _ASTERISK_MOD_FORMAT_H
#define _ASTERISK_MOD_FORMAT_H
#include "asterisk/file.h"
#include "asterisk/frame.h"
#if defined(__cplusplus) || defined(c_plusplus)
extern "C" {
#endif
/*! \brief
* Each supported file format is described by the following structure.
*
* Not all are necessary, the support routine implement default
* values for some of them.
* A handler typically fills a structure initializing the desired
* fields, and then calls ast_format_register() with the (readonly)
* structure as an argument.
*/
struct ast_format {
char name[80]; /*!< Name of format */
char exts[80]; /*!< Extensions (separated by | if more than one)
this format can read. First is assumed for writing (e.g. .mp3) */
format_t format; /*!< Format of frames it uses/provides (one only) */
/*!
* \brief Prepare an input stream for playback.
* \return 0 on success, -1 on error.
* The FILE is already open (in s->f) so this function only needs to perform
* any applicable validity checks on the file. If none is required, the
* function can be omitted.
*/
int (*open)(struct ast_filestream *s);
/*!
* \brief Prepare a stream for output, and comment it appropriately if applicable.
* \return 0 on success, -1 on error.
* Same as the open, the FILE is already open so the function just needs to
* prepare any header and other fields, if any.
* The function can be omitted if nothing is needed.
*/
int (*rewrite)(struct ast_filestream *s, const char *comment);
/*! Write a frame to a channel */
int (*write)(struct ast_filestream *, struct ast_frame *);
/*! seek num samples into file, whence - like a normal seek but with offset in samples */
int (*seek)(struct ast_filestream *, off_t, int);
int (*trunc)(struct ast_filestream *fs); /*!< trunc file to current position */
off_t (*tell)(struct ast_filestream *fs); /*!< tell current position */
/*! Read the next frame from the filestream (if available) and report
* when to get next frame (in samples)
*/
struct ast_frame * (*read)(struct ast_filestream *, int *whennext);
/*! Do any closing actions, if any. The descriptor and structure are closed
* and destroyed by the generic routines, so they must not be done here. */
void (*close)(struct ast_filestream *);
char * (*getcomment)(struct ast_filestream *); /*!< Retrieve file comment */
AST_LIST_ENTRY(ast_format) list; /*!< Link */
/*!
* If the handler needs a buffer (for read, typically)
* and/or a private descriptor, put here the
* required size (in bytes) and the support routine will allocate them
* for you, pointed by s->buf and s->private, respectively.
* When allocating a buffer, remember to leave AST_FRIENDLY_OFFSET
* spare bytes at the bginning.
*/
int buf_size; /*!< size of frame buffer, if any, aligned to 8 bytes. */
int desc_size; /*!< size of private descriptor, if any */
struct ast_module *module;
};
/*! \brief
* This structure is allocated by file.c in one chunk,
* together with buf_size and desc_size bytes of memory
* to be used for private purposes (e.g. buffers etc.)
*/
struct ast_filestream {
/*! Everybody reserves a block of AST_RESERVED_POINTERS pointers for us */
struct ast_format *fmt; /* need to write to the lock and usecnt */
int flags;
mode_t mode;
char *open_filename;
char *filename;
char *realfilename;
/*! Video file stream */
struct ast_filestream *vfs;
/*! Transparently translate from another format -- just once */
struct ast_trans_pvt *trans;
struct ast_tranlator_pvt *tr;
int lastwriteformat;
int lasttimeout;
struct ast_channel *owner;
FILE *f;
struct ast_frame fr; /*!< frame produced by read, typically */
char *buf; /*!< buffer pointed to by ast_frame; */
void *_private; /*!< pointer to private buffer */
const char *orig_chan_name;
char *write_buffer;
};
/*!
* \brief Register a new file format capability.
* Adds a format to Asterisk's format abilities.
* \retval 0 on success
* \retval -1 on failure
*/
int __ast_format_register(const struct ast_format *f, struct ast_module *mod);
#define ast_format_register(f) __ast_format_register(f, ast_module_info->self)
/*!
* \brief Unregisters a file format
* \param name the name of the format you wish to unregister
* Unregisters a format based on the name of the format.
* \retval 0 on success
* \retval -1 on failure to unregister
*/
int ast_format_unregister(const char *name);
#if defined(__cplusplus) || defined(c_plusplus)
}
#endif
#endif /* _ASTERISK_MOD_FORMAT_H */
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