mpd/src/MusicChunk.cxx

/*
 * Copyright (C) 2003-2013 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.
 */

#include "config.h"
#include "MusicChunk.hxx"
#include "audio_format.h"
#include "Tag.hxx"

#include <assert.h>

music_chunk::~music_chunk()
{
	delete tag;
}

#ifndef NDEBUG
bool
music_chunk::CheckFormat(const struct audio_format &other_format) const
{
	assert(audio_format_valid(&other_format));

	return length == 0 ||
		audio_format_equals(&audio_format, &other_format);
}
#endif

void *
music_chunk::Write(const struct audio_format &af,
		   float data_time, uint16_t _bit_rate,
		   size_t *max_length_r)
{
	assert(CheckFormat(af));
	assert(length == 0 || audio_format_valid(&audio_format));

	if (length == 0) {
		/* if the chunk is empty, nobody has set bitRate and
		   times yet */

		bit_rate = _bit_rate;
		times = data_time;
	}

	const size_t frame_size = audio_format_frame_size(&af);
	size_t num_frames = (sizeof(data) - length) / frame_size;
	if (num_frames == 0)
		return NULL;

#ifndef NDEBUG
	audio_format = af;
#endif

	*max_length_r = num_frames * frame_size;
	return data + length;
}

bool
music_chunk::Expand(const struct audio_format &af, size_t _length)
{
	const size_t frame_size = audio_format_frame_size(&af);

	assert(length + _length <= sizeof(data));
	assert(audio_format_equals(&audio_format, &af));

	length += _length;

	return length + frame_size > sizeof(data);
}