/* the Music Player Daemon (MPD)
* Copyright (C) 2003-2007 by Warren Dukes (warren.dukes@gmail.com)
* This project's homepage is: http://www.musicpd.org
*
* This program 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 2 of the License, or
* (at your option) any later version.
*
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef MPD_INPUT_STREAM_H
#define MPD_INPUT_STREAM_H
#include <stddef.h>
#include <stdbool.h>
#include <sys/types.h>
struct input_stream;
struct input_plugin {
bool (*open)(struct input_stream *is, const char *url);
void (*close)(struct input_stream *is);
struct tag *(*tag)(struct input_stream *is);
int (*buffer)(struct input_stream *is);
size_t (*read)(struct input_stream *is, void *ptr, size_t size);
bool (*eof)(struct input_stream *is);
bool (*seek)(struct input_stream *is, off_t offset, int whence);
};
struct input_stream {
/**
* the plugin which implements this input stream
*/
const struct input_plugin *plugin;
/**
* an opaque pointer managed by the plugin
*/
void *data;
/**
* indicates whether the stream is ready for reading and
* whether the other attributes in this struct are valid
*/
bool ready;
/**
* if true, then the stream is fully seekable
*/
bool seekable;
/**
* an optional errno error code, set to non-zero after an error occured
*/
int error;
/**
* the size of the resource, or -1 if unknown
*/
off_t size;
/**
* the current offset within the stream
*/
off_t offset;
/**
* the MIME content type of the resource, or NULL if unknown
*/
char *mime;
};
/**
* Initializes this library and all input_stream implementations.
*/
void input_stream_global_init(void);
/**
* Deinitializes this library and all input_stream implementations.
*/
void input_stream_global_finish(void);
/**
* Opens a new input stream. You may not access it until the "ready"
* flag is set.
*
* @param is the input_stream object allocated by the caller
* @return true on success
*/
bool
input_stream_open(struct input_stream *is, const char *url);
/**
* Closes the input stream and free resources. This does not free the
* input_stream pointer itself, because it is assumed to be allocated
* by the caller.
*/
void
input_stream_close(struct input_stream *is);
/**
* Seeks to the specified position in the stream. This will most
* likely fail if the "seekable" flag is false.
*
* @param is the input_stream object
* @param offset the relative offset
* @param whence the base of the seek, one of SEEK_SET, SEEK_CUR, SEEK_END
*/
bool
input_stream_seek(struct input_stream *is, off_t offset, int whence);
/**
* Returns true if the stream has reached end-of-file.
*/
bool input_stream_eof(struct input_stream *is);
/**
* Reads the tag from the stream.
*
* @return a tag object which must be freed with tag_free(), or NULL
* if the tag has not changed since the last call
*/
struct tag *
input_stream_tag(struct input_stream *is);
/**
* Reads some of the stream into its buffer. The following return
* codes are defined: -1 = error, 1 = something was buffered, 0 =
* nothing was buffered.
*
* The semantics of this function are not well-defined, and it will
* eventually be removed.
*/
int input_stream_buffer(struct input_stream *is);
/**
* Reads data from the stream into the caller-supplied buffer.
* Returns 0 on error or eof (check with input_stream_eof()).
*
* @param is the input_stream object
* @param ptr the buffer to read into
* @param size the maximum number of bytes to read
* @return the number of bytes read
*/
size_t
input_stream_read(struct input_stream *is, void *ptr, size_t size);
#endif
