path: root/src/decoder/dsdlib.c

/*
 * Copyright (C) 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.
 */

/* \file
 *
 * This file contains functions used by the DSF and DSDIFF decoders.
 *
 */

#include "config.h"
#include "dsf_decoder_plugin.h"
#include "decoder_api.h"
#include "util/bit_reverse.h"
#include "dsdlib.h"
#include "dsdiff_decoder_plugin.h"

#include <unistd.h>
#include <stdio.h> /* for SEEK_SET, SEEK_CUR */

bool
dsdlib_id_equals(const struct dsdlib_id *id, const char *s)
{
	assert(id != NULL);
	assert(s != NULL);
	assert(strlen(s) == sizeof(id->value));

	return memcmp(id->value, s, sizeof(id->value)) == 0;
}

bool
dsdlib_read(struct decoder *decoder, struct input_stream *is,
	    void *data, size_t length)
{
	size_t nbytes = decoder_read(decoder, is, data, length);
	return nbytes == length;
}

/**
 * Skip the #input_stream to the specified offset.
 */
bool
dsdlib_skip_to(struct decoder *decoder, struct input_stream *is,
	       goffset offset)
{
	if (is->seekable)
		return input_stream_seek(is, offset, SEEK_SET, NULL);

	if (is->offset > offset)
		return false;

	char buffer[8192];
	while (is->offset < offset) {
		size_t length = sizeof(buffer);
		if (offset - is->offset < (goffset)length)
			length = offset - is->offset;

		size_t nbytes = decoder_read(decoder, is, buffer, length);
		if (nbytes == 0)
			return false;
	}

	assert(is->offset == offset);
	return true;
}

/**
 * Skip some bytes from the #input_stream.
 */
bool
dsdlib_skip(struct decoder *decoder, struct input_stream *is,
	    goffset delta)
{
	assert(delta >= 0);

	if (delta == 0)
		return true;

	if (is->seekable)
		return input_stream_seek(is, delta, SEEK_CUR, NULL);

	char buffer[8192];
	while (delta > 0) {
		size_t length = sizeof(buffer);
		if ((goffset)length > delta)
			length = delta;

		size_t nbytes = decoder_read(decoder, is, buffer, length);
		if (nbytes == 0)
			return false;

		delta -= nbytes;
	}

	return true;
}