/*
* Copyright (C) 2003-2014 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_HXX
#define MPD_DECODER_BUFFER_HXX
#include "Compiler.h"
#include "util/DynamicFifoBuffer.hxx"
#include <stddef.h>
struct Decoder;
class InputStream;
template<typename T> struct ConstBuffer;
/**
* 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 DecoderBuffer {
Decoder *const decoder;
InputStream &is;
DynamicFifoBuffer<uint8_t> buffer;
/**
* Creates a new buffer.
*
* @param _decoder the decoder object, used for decoder_read(),
* may be nullptr
* @param _is the input stream object where we should read from
* @param _size the maximum size of the buffer
*/
DecoderBuffer(Decoder *_decoder, InputStream &_is,
size_t _size)
:decoder(_decoder), is(_is), buffer(_size) {}
};
gcc_pure
const InputStream &
decoder_buffer_get_stream(const DecoderBuffer *buffer);
void
decoder_buffer_clear(DecoderBuffer *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(DecoderBuffer *buffer);
/**
* How many bytes are stored in the buffer?
*/
gcc_pure
size_t
decoder_buffer_available(const DecoderBuffer *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
*/
gcc_pure
ConstBuffer<void>
decoder_buffer_read(const DecoderBuffer *buffer);
/**
* Wait until this number of bytes are available. Returns nullptr on
* error.
*/
ConstBuffer<void>
decoder_buffer_need(DecoderBuffer *buffer, size_t min_size);
/**
* 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(DecoderBuffer *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(DecoderBuffer *buffer, size_t nbytes);
#endif
