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/*
* Copyright (C) 2003-2011 The Music Player Daemon Project
* 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifndef MPD_DECODER_BUFFER_H
#define MPD_DECODER_BUFFER_H
#include <stdbool.h>
#include <stddef.h>
/**
* This objects handles buffered reads in decoder plugins easily. You
* create a buffer object, and use its high-level methods to fill and
* read it. It will automatically handle shifting the buffer.
*/
struct decoder_buffer;
struct decoder;
struct input_stream;
/**
* Creates a new buffer.
*
* @param decoder the decoder object, used for decoder_read(), may be NULL
* @param is the input stream object where we should read from
* @param size the maximum size of the buffer
* @return the new decoder_buffer object
*/
struct decoder_buffer *
decoder_buffer_new(struct decoder *decoder, struct input_stream *is,
size_t size);
/**
* Frees resources used by the decoder_buffer object.
*/
void
decoder_buffer_free(struct decoder_buffer *buffer);
bool
decoder_buffer_is_empty(const struct decoder_buffer *buffer);
bool
decoder_buffer_is_full(const struct decoder_buffer *buffer);
/**
* Read data from the input_stream and append it to the buffer.
*
* @return true if data was appended; false if there is no data
* available (yet), end of file, I/O error or a decoder command was
* received
*/
bool
decoder_buffer_fill(struct decoder_buffer *buffer);
/**
* Reads data from the buffer. This data is not yet consumed, you
* have to call decoder_buffer_consume() to do that. The returned
* buffer becomes invalid after a decoder_buffer_fill() or a
* decoder_buffer_consume() call.
*
* @param buffer the decoder_buffer object
* @param length_r pointer to a size_t where you will receive the
* number of bytes available
* @return a pointer to the read buffer, or NULL if there is no data
* available
*/
const void *
decoder_buffer_read(const struct decoder_buffer *buffer, size_t *length_r);
/**
* Consume (delete, invalidate) a part of the buffer. The "nbytes"
* parameter must not be larger than the length returned by
* decoder_buffer_read().
*
* @param buffer the decoder_buffer object
* @param nbytes the number of bytes to consume
*/
void
decoder_buffer_consume(struct decoder_buffer *buffer, size_t nbytes);
/**
* Skips the specified number of bytes, discarding its data.
*
* @param buffer the decoder_buffer object
* @param nbytes the number of bytes to skip
* @return true on success, false on error
*/
bool
decoder_buffer_skip(struct decoder_buffer *buffer, size_t nbytes);
#endif
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