Add a specific header for providers of file and format handling routines,

moving here structs and function declarations formerly in file.h



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@89514 65c4cc65-6c06-0410-ace0-fbb531ad65f3

include/asterisk/mod_format.h

@@ -0,0 +1,143 @@
+/*
+ * 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
+
+/*!
+ * Each supported file format is described by the following fields.
+ * 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) */
+	int 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;
+};
+
+/*!
+ * 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 *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;
+};
+
+/*! 
+ * \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 */