path: root/src/pcm_export.h

/*
 * Copyright (C) 2003-2012 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 PCM_EXPORT_H
#define PCM_EXPORT_H

#include "check.h"
#include "pcm_buffer.h"
#include "audio_format.h"

#include <stdbool.h>

struct audio_format;

/**
 * An object that handles export of PCM samples to some instance
 * outside of MPD.  It has a few more options to tweak the binary
 * representation which are not supported by the pcm_convert library.
 */
struct pcm_export_state {
	/**
	 * The buffer is used to pack samples, removing padding.
	 *
	 * @see #pack24
	 */
	struct pcm_buffer pack_buffer;

	/**
	 * The buffer is used to reverse the byte order.
	 *
	 * @see #reverse_endian
	 */
	struct pcm_buffer reverse_buffer;

	/**
	 * Pack 24 bit samples?
	 */
	bool pack24;

	/**
	 * Export the samples in reverse byte order?  A non-zero value
	 * means the option is enabled and represents the size of each
	 * sample (2 or bigger).
	 */
	uint8_t reverse_endian;
};

/**
 * Initialize a #pcm_export_state object.
 */
void
pcm_export_init(struct pcm_export_state *state);

/**
 * Deinitialize a #pcm_export_state object and free allocated memory.
 */
void
pcm_export_deinit(struct pcm_export_state *state);

/**
 * Open the #pcm_export_state object.
 *
 * There is no "close" method.  This function may be called multiple
 * times to reuse the object, until pcm_export_deinit() is called.
 *
 * This function cannot fail.
 */
void
pcm_export_open(struct pcm_export_state *state,
		enum sample_format sample_format,
		bool pack, bool reverse_endian);

/**
 * Export a PCM buffer.
 *
 * @param state an initialized and open pcm_export_state object
 * @param src the source PCM buffer
 * @param src_size the size of #src in bytes
 * @param dest_size_r returns the number of bytes of the destination buffer
 * @return the destination buffer (may be a pointer to the source buffer)
 */
const void *
pcm_export(struct pcm_export_state *state, const void *src, size_t src_size,
	   size_t *dest_size_r);

#endif