FlacCommon.hxx

/*
 * Copyright 2003-2018 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.
 */

/*
 * Common data structures and functions used by FLAC and OggFLAC
 */

#ifndef MPD_FLAC_COMMON_HXX
#define MPD_FLAC_COMMON_HXX

#include "FlacInput.hxx"
#include "FlacPcm.hxx"
#include "../DecoderAPI.hxx"
#include "util/ConstBuffer.hxx"

#include <FLAC/stream_decoder.h>

struct FlacDecoder : public FlacInput {
	/**
	 * Has DecoderClient::Ready() been called yet?
	 */
	bool initialized = false;

	/**
	 * Does the FLAC file contain an unsupported audio format?
	 */
	bool unsupported = false;

	/**
	 * The kbit_rate parameter for the next
	 * DecoderBridge::SubmitData() call.
	 */
	uint16_t kbit_rate;

	FlacPcmImport pcm_import;

	/**
	 * End of last frame's position within the stream.  This is
	 * used for bit rate calculations.
	 */
	FLAC__uint64 position = 0;

	Tag tag;

	/**
	 * Decoded PCM data obtained by our libFLAC write callback.
	 * If this is non-empty, then DecoderBridge::SubmitData()
	 * should be called.
	 */
	ConstBuffer<void> chunk = nullptr;

	FlacDecoder(DecoderClient &_client, InputStream &_input_stream)
		:FlacInput(_input_stream, &_client) {}

	/**
	 * Wrapper for DecoderClient::Ready().
	 */
	bool Initialize(unsigned sample_rate, unsigned bits_per_sample,
			unsigned channels, FLAC__uint64 total_frames);

	void OnMetadata(const FLAC__StreamMetadata &metadata);

	FLAC__StreamDecoderWriteStatus OnWrite(const FLAC__Frame &frame,
					       const FLAC__int32 *const buf[],
					       FLAC__uint64 nbytes);

	/**
	 * Calculate the delta (in bytes) between the last frame and
	 * the current frame.
	 */
	FLAC__uint64 GetDeltaPosition(const FLAC__StreamDecoder &sd);

private:
	void OnStreamInfo(const FLAC__StreamMetadata_StreamInfo &stream_info);
	void OnVorbisComment(const FLAC__StreamMetadata_VorbisComment &vc);

	/**
	 * This function attempts to call DecoderClient::Ready() in case there
	 * was no STREAMINFO block.  This is allowed for nonseekable streams,
	 * where the server sends us only a part of the file, without
	 * providing the STREAMINFO block from the beginning of the file
	 * (e.g. when seeking with SqueezeBox Server).
	 */
	bool OnFirstFrame(const FLAC__FrameHeader &header);
};

#endif /* _FLAC_COMMON_H */