stream_decoder.c

/* libFLAC - Free Lossless Audio Codec library
 * Copyright (C) 2000,2001,2002  Josh Coalson
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA  02111-1307, USA.
 */

#include <stdio.h>
#include <stdlib.h> /* for malloc() */
#include <string.h> /* for memset/memcpy() */
#include "FLAC/assert.h"
#include "protected/stream_decoder.h"
#include "private/bitbuffer.h"
#include "private/cpu.h"
#include "private/crc.h"
#include "private/fixed.h"
#include "private/format.h"
#include "private/lpc.h"

#ifdef max
#undef max
#endif
#define max(a,b) ((a)>(b)?(a):(b))

/***********************************************************************
 *
 * Private static data
 *
 ***********************************************************************/

static FLAC__byte ID3V2_TAG_[3] = { 'I', 'D', '3' };

/***********************************************************************
 *
 * Private class method prototypes
 *
 ***********************************************************************/

static void set_defaults_(FLAC__StreamDecoder *decoder);
static FLAC__bool allocate_output_(FLAC__StreamDecoder *decoder, unsigned size, unsigned channels);
static FLAC__bool has_id_filtered_(FLAC__StreamDecoder *decoder, FLAC__byte *id);
static FLAC__bool find_metadata_(FLAC__StreamDecoder *decoder);
static FLAC__bool read_metadata_(FLAC__StreamDecoder *decoder);
static FLAC__bool skip_id3v2_tag_(FLAC__StreamDecoder *decoder);
static FLAC__bool frame_sync_(FLAC__StreamDecoder *decoder);
static FLAC__bool read_frame_(FLAC__StreamDecoder *decoder, FLAC__bool *got_a_frame);
static FLAC__bool read_frame_header_(FLAC__StreamDecoder *decoder);
static FLAC__bool read_subframe_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps);
static FLAC__bool read_subframe_constant_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps);
static FLAC__bool read_subframe_fixed_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps, const unsigned order);
static FLAC__bool read_subframe_lpc_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps, const unsigned order);
static FLAC__bool read_subframe_verbatim_(FLAC__StreamDecoder *decoder, unsigned channel, unsigned bps);
static FLAC__bool read_residual_partitioned_rice_(FLAC__StreamDecoder *decoder, unsigned predictor_order, unsigned partition_order, FLAC__EntropyCodingMethod_PartitionedRiceContents *partitioned_rice_contents, FLAC__int32 *residual);
static FLAC__bool read_zero_padding_(FLAC__StreamDecoder *decoder);
static FLAC__bool read_callback_(FLAC__byte buffer[], unsigned *bytes, void *client_data);

/***********************************************************************
 *
 * Private class data
 *
 ***********************************************************************/

typedef struct FLAC__StreamDecoderPrivate {
	FLAC__StreamDecoderReadCallback read_callback;
	FLAC__StreamDecoderWriteCallback write_callback;
	FLAC__StreamDecoderMetadataCallback metadata_callback;
	FLAC__StreamDecoderErrorCallback error_callback;
	void (*local_lpc_restore_signal)(const FLAC__int32 residual[], unsigned data_len, const FLAC__int32 qlp_coeff[], unsigned order, int lp_quantization, FLAC__int32 data[]);
	void (*local_lpc_restore_signal_64bit)(const FLAC__int32 residual[], unsigned data_len, const FLAC__int32 qlp_coeff[], unsigned order, int lp_quantization, FLAC__int32 data[]);
	void (*local_lpc_restore_signal_16bit)(const FLAC__int32 residual[], unsigned data_len, const FLAC__int32 qlp_coeff[], unsigned order, int lp_quantization, FLAC__int32 data[]);
	void *client_data;
	FLAC__BitBuffer *input;
	FLAC__int32 *output[FLAC__MAX_CHANNELS];
	FLAC__int32 *residual[FLAC__MAX_CHANNELS];
	FLAC__EntropyCodingMethod_PartitionedRiceContents partitioned_rice_contents[FLAC__MAX_CHANNELS];
	unsigned output_capacity, output_channels;
	FLAC__uint32 last_frame_number;
	FLAC__uint64 samples_decoded;
	FLAC__bool has_stream_info, has_seek_table;
	FLAC__StreamMetadata stream_info;
	FLAC__StreamMetadata seek_table;
	FLAC__bool metadata_filter[FLAC__METADATA_TYPE_VORBIS_COMMENT+1];
	FLAC__byte *metadata_filter_ids;
	unsigned metadata_filter_ids_count, metadata_filter_ids_capacity; /* units for both are IDs, not bytes */
	FLAC__Frame frame;
	FLAC__bool cached; /* true if there is a byte in lookahead */
	FLAC__CPUInfo cpuinfo;
	FLAC__byte header_warmup[2]; /* contains the sync code and reserved bits */
	FLAC__byte lookahead; /* temp storage when we need to look ahead one byte in the stream */
} FLAC__StreamDecoderPrivate;

/***********************************************************************
 *
 * Public static class data
 *
 ***********************************************************************/

FLAC_API const char * const FLAC__StreamDecoderStateString[] = {
	"FLAC__STREAM_DECODER_SEARCH_FOR_METADATA",
	"FLAC__STREAM_DECODER_READ_METADATA",
	"FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC",
	"FLAC__STREAM_DECODER_READ_FRAME",
	"FLAC__STREAM_DECODER_END_OF_STREAM",
	"FLAC__STREAM_DECODER_ABORTED",
	"FLAC__STREAM_DECODER_UNPARSEABLE_STREAM",
	"FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR",
	"FLAC__STREAM_DECODER_ALREADY_INITIALIZED",
	"FLAC__STREAM_DECODER_INVALID_CALLBACK",
	"FLAC__STREAM_DECODER_UNINITIALIZED"
};

FLAC_API const char * const FLAC__StreamDecoderReadStatusString[] = {
	"FLAC__STREAM_DECODER_READ_STATUS_CONTINUE",
	"FLAC__STREAM_DECODER_READ_STATUS_END_OF_STREAM",
	"FLAC__STREAM_DECODER_READ_STATUS_ABORT"
};

FLAC_API const char * const FLAC__StreamDecoderWriteStatusString[] = {
	"FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE",
	"FLAC__STREAM_DECODER_WRITE_STATUS_ABORT"
};

FLAC_API const char * const FLAC__StreamDecoderErrorStatusString[] = {
	"FLAC__STREAM_DECODER_ERROR_STATUS_LOST_SYNC",
	"FLAC__STREAM_DECODER_ERROR_STATUS_BAD_HEADER",
	"FLAC__STREAM_DECODER_ERROR_STATUS_FRAME_CRC_MISMATCH"
};

/***********************************************************************
 *
 * Class constructor/destructor
 *
 ***********************************************************************/
FLAC_API FLAC__StreamDecoder *FLAC__stream_decoder_new()
{
	FLAC__StreamDecoder *decoder;
	unsigned i;

	FLAC__ASSERT(sizeof(int) >= 4); /* we want to die right away if this is not true */

	decoder = (FLAC__StreamDecoder*)calloc(1, sizeof(FLAC__StreamDecoder));
	if(decoder == 0) {
		return 0;
	}

	decoder->protected_ = (FLAC__StreamDecoderProtected*)calloc(1, sizeof(FLAC__StreamDecoderProtected));
	if(decoder->protected_ == 0) {
		free(decoder);
		return 0;
	}

	decoder->private_ = (FLAC__StreamDecoderPrivate*)calloc(1, sizeof(FLAC__StreamDecoderPrivate));
	if(decoder->private_ == 0) {
		free(decoder->protected_);
		free(decoder);
		return 0;
	}

	decoder->private_->input = FLAC__bitbuffer_new();
	if(decoder->private_->input == 0) {
		free(decoder->private_);
		free(decoder->protected_);
		free(decoder);
		return 0;
	}

	decoder->private_->metadata_filter_ids_capacity = 16;
	if(0 == (decoder->private_->metadata_filter_ids = malloc((FLAC__STREAM_METADATA_APPLICATION_ID_LEN/8) * decoder->private_->metadata_filter_ids_capacity))) {
		FLAC__bitbuffer_delete(decoder->private_->input);
		free(decoder->private_);
		free(decoder->protected_);
		free(decoder);
		return 0;
	}

	for(i = 0; i < FLAC__MAX_CHANNELS; i++) {
		decoder->private_->output[i] = 0;
		decoder->private_->residual[i] = 0;
	}

	decoder->private_->output_capacity = 0;
	decoder->private_->output_channels = 0;
	decoder->private_->has_seek_table = false;

	for(i = 0; i < FLAC__MAX_CHANNELS; i++)
		FLAC__format_entropy_coding_method_partitioned_rice_contents_init(&decoder->private_->partitioned_rice_contents[i]);

	set_defaults_(decoder);

	decoder->protected_->state = FLAC__STREAM_DECODER_UNINITIALIZED;

	return decoder;
}

FLAC_API void FLAC__stream_decoder_delete(FLAC__StreamDecoder *decoder)
{
	unsigned i;

	FLAC__ASSERT(0 != decoder);
	FLAC__ASSERT(0 != decoder->protected_);
	FLAC__ASSERT(0 != decoder->private_);
	FLAC__ASSERT(0 != decoder->private_->input);

	FLAC__stream_decoder_finish(decoder);

	if(0 != decoder->private_->metadata_filter_ids)
		free(decoder->private_->metadata_filter_ids);

	FLAC__bitbuffer_delete(decoder->private_->input);

	for(i = 0; i < FLAC__MAX_CHANNELS; i++)
		FLAC__format_entropy_coding_method_partitioned_rice_contents_clear(&decoder->private_->partitioned_rice_contents[i]);

	free(decoder->private_);
	free(decoder->protected_);
	free(decoder);
}

/***********************************************************************
 *
 * Public class methods
 *
 ***********************************************************************/

FLAC_API FLAC__StreamDecoderState FLAC__stream_decoder_init(FLAC__StreamDecoder *decoder)
{
	FLAC__ASSERT(0 != decoder);

	if(decoder->protected_->state != FLAC__STREAM_DECODER_UNINITIALIZED)
		return decoder->protected_->state = FLAC__STREAM_DECODER_ALREADY_INITIALIZED;

	if(0 == decoder->private_->read_callback || 0 == decoder->private_->write_callback || 0 == decoder->private_->metadata_callback || 0 == decoder->private_->error_callback)
		return decoder->protected_->state = FLAC__STREAM_DECODER_INVALID_CALLBACK;

	if(!FLAC__bitbuffer_init(decoder->private_->input))
		return decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;

	decoder->private_->last_frame_number = 0;
	decoder->private_->samples_decoded = 0;
	decoder->private_->has_stream_info = false;
	decoder->private_->cached = false;

	/*
	 * get the CPU info and set the function pointers
	 */
	FLAC__cpu_info(&decoder->private_->cpuinfo);
	/* first default to the non-asm routines */
	decoder->private_->local_lpc_restore_signal = FLAC__lpc_restore_signal;
	decoder->private_->local_lpc_restore_signal_64bit = FLAC__lpc_restore_signal_wide;
	decoder->private_->local_lpc_restore_signal_16bit = FLAC__lpc_restore_signal;
	/* now override with asm where appropriate */
#ifndef FLAC__NO_ASM
	if(decoder->private_->cpuinfo.use_asm) {
#ifdef FLAC__CPU_IA32
		FLAC__ASSERT(decoder->private_->cpuinfo.type == FLAC__CPUINFO_TYPE_IA32);
#ifdef FLAC__HAS_NASM
		if(decoder->private_->cpuinfo.data.ia32.mmx) {
			decoder->private_->local_lpc_restore_signal = FLAC__lpc_restore_signal_asm_ia32;
			decoder->private_->local_lpc_restore_signal_16bit = FLAC__lpc_restore_signal_asm_ia32_mmx;
		}
		else {
			decoder->private_->local_lpc_restore_signal = FLAC__lpc_restore_signal_asm_ia32;
			decoder->private_->local_lpc_restore_signal_16bit = FLAC__lpc_restore_signal_asm_ia32;
		}
#endif
#endif
	}
#endif

	if(!FLAC__stream_decoder_reset(decoder))
		return decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;

	return decoder->protected_->state;
}

FLAC_API void FLAC__stream_decoder_finish(FLAC__StreamDecoder *decoder)
{
	unsigned i;
	FLAC__ASSERT(0 != decoder);
	if(decoder->protected_->state == FLAC__STREAM_DECODER_UNINITIALIZED)
		return;
	if(decoder->private_->has_seek_table) {
		FLAC__ASSERT(0 != decoder->private_->seek_table.data.seek_table.points);
		free(decoder->private_->seek_table.data.seek_table.points);
		decoder->private_->seek_table.data.seek_table.points = 0;
		decoder->private_->has_seek_table = false;
	}
	FLAC__bitbuffer_free(decoder->private_->input);
	for(i = 0; i < FLAC__MAX_CHANNELS; i++) {
		/* WATCHOUT:
		 * FLAC__lpc_restore_signal_asm_ia32_mmx() requires that the
		 * output arrays have a buffer of up to 3 zeroes in front
		 * (at negative indices) for alignment purposes; we use 4
		 * to keep the data well-aligned.
		 */
		if(0 != decoder->private_->output[i]) {
			free(decoder->private_->output[i]-4);
			decoder->private_->output[i] = 0;
		}
		if(0 != decoder->private_->residual[i]) {
			free(decoder->private_->residual[i]);
			decoder->private_->residual[i] = 0;
		}
	}
	decoder->private_->output_capacity = 0;
	decoder->private_->output_channels = 0;

	set_defaults_(decoder);

	decoder->protected_->state = FLAC__STREAM_DECODER_UNINITIALIZED;
}

FLAC_API FLAC__bool FLAC__stream_decoder_set_read_callback(FLAC__StreamDecoder *decoder, FLAC__StreamDecoderReadCallback value)
{
	FLAC__ASSERT(0 != decoder);
	FLAC__ASSERT(0 != decoder->private_);
	FLAC__ASSERT(0 != decoder->protected_);
	if(decoder->protected_->state != FLAC__STREAM_DECODER_UNINITIALIZED)
		return false;
	decoder->private_->read_callback = value;
	return true;
}

FLAC_API FLAC__bool FLAC__stream_decoder_set_write_callback(FLAC__StreamDecoder *decoder, FLAC__StreamDecoderWriteCallback value)
{
	FLAC__ASSERT(0 != decoder);
	FLAC__ASSERT(0 != decoder->private_);
	FLAC__ASSERT(0 != decoder->protected_);
	if(decoder->protected_->state != FLAC__STREAM_DECODER_UNINITIALIZED)
		return false;
	decoder->private_->write_callback = value;
	return true;
}

FLAC_API FLAC__bool FLAC__stream_decoder_set_metadata_callback(FLAC__StreamDecoder *decoder, FLAC__StreamDecoderMetadataCallback value)
{
	FLAC__ASSERT(0 != decoder);
	FLAC__ASSERT(0 != decoder->private_);
	FLAC__ASSERT(0 != decoder->protected_);
	if(decoder->protected_->state != FLAC__STREAM_DECODER_UNINITIALIZED)
		return false;
	decoder->private_->metadata_callback = value;
	return true;
}

FLAC_API FLAC__bool FLAC__stream_decoder_set_error_callback(FLAC__StreamDecoder *decoder, FLAC__StreamDecoderErrorCallback value)
{
	FLAC__ASSERT(0 != decoder);
	FLAC__ASSERT(0 != decoder->private_);
	FLAC__ASSERT(0 != decoder->protected_);
	if(decoder->protected_->state != FLAC__STREAM_DECODER_UNINITIALIZED)
		return false;
	decoder->private_->error_callback = value;
	return true;
}

FLAC_API FLAC__bool FLAC__stream_decoder_set_client_data(FLAC__StreamDecoder *decoder, void *value)
{
	FLAC__ASSERT(0 != decoder);
	FLAC__ASSERT(0 != decoder->private_);
	FLAC__ASSERT(0 != decoder->protected_);
	if(decoder->protected_->state != FLAC__STREAM_DECODER_UNINITIALIZED)
		return false;
	decoder->private_->client_data = value;
	return true;
}

FLAC_API FLAC__bool FLAC__stream_decoder_set_metadata_respond(FLAC__StreamDecoder *decoder, FLAC__MetadataType type)
{
	FLAC__ASSERT(0 != decoder);
	FLAC__ASSERT(0 != decoder->private_);
	FLAC__ASSERT(0 != decoder->protected_);
	FLAC__ASSERT(type <= FLAC__METADATA_TYPE_VORBIS_COMMENT);
	if(decoder->protected_->state != FLAC__STREAM_DECODER_UNINITIALIZED)
		return false;
	decoder->private_->metadata_filter[type] = true;
	if(type == FLAC__METADATA_TYPE_APPLICATION)
		decoder->private_->metadata_filter_ids_count = 0;
	return true;
}

FLAC_API FLAC__bool FLAC__stream_decoder_set_metadata_respond_application(FLAC__StreamDecoder *decoder, const FLAC__byte id[4])
{
	FLAC__ASSERT(0 != decoder);
	FLAC__ASSERT(0 != decoder->private_);
	FLAC__ASSERT(0 != decoder->protected_);
	FLAC__ASSERT(0 != id);
	if(decoder->protected_->state != FLAC__STREAM_DECODER_UNINITIALIZED)
		return false;

	if(decoder->private_->metadata_filter[FLAC__METADATA_TYPE_APPLICATION])
		return true;

	FLAC__ASSERT(0 != decoder->private_->metadata_filter_ids);

	if(decoder->private_->metadata_filter_ids_count == decoder->private_->metadata_filter_ids_capacity) {
		if(0 == (decoder->private_->metadata_filter_ids = realloc(decoder->private_->metadata_filter_ids, decoder->private_->metadata_filter_ids_capacity * 2)))
			return decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
		decoder->private_->metadata_filter_ids_capacity *= 2;
	}

	memcpy(decoder->private_->metadata_filter_ids + decoder->private_->metadata_filter_ids_count * (FLAC__STREAM_METADATA_APPLICATION_ID_LEN/8), id, (FLAC__STREAM_METADATA_APPLICATION_ID_LEN/8));
	decoder->private_->metadata_filter_ids_count++;

	return true;
}

FLAC_API FLAC__bool FLAC__stream_decoder_set_metadata_respond_all(FLAC__StreamDecoder *decoder)
{
	unsigned i;
	FLAC__ASSERT(0 != decoder);
	FLAC__ASSERT(0 != decoder->private_);
	FLAC__ASSERT(0 != decoder->protected_);
	if(decoder->protected_->state != FLAC__STREAM_DECODER_UNINITIALIZED)
		return false;
	for(i = 0; i < sizeof(decoder->private_->metadata_filter) / sizeof(decoder->private_->metadata_filter[0]); i++)
		decoder->private_->metadata_filter[i] = true;
	decoder->private_->metadata_filter_ids_count = 0;
	return true;
}

FLAC_API FLAC__bool FLAC__stream_decoder_set_metadata_ignore(FLAC__StreamDecoder *decoder, FLAC__MetadataType type)
{
	FLAC__ASSERT(0 != decoder);
	FLAC__ASSERT(0 != decoder->private_);
	FLAC__ASSERT(0 != decoder->protected_);
	FLAC__ASSERT(type <= FLAC__METADATA_TYPE_VORBIS_COMMENT);
	if(decoder->protected_->state != FLAC__STREAM_DECODER_UNINITIALIZED)
		return false;
	decoder->private_->metadata_filter[type] = false;
	if(type == FLAC__METADATA_TYPE_APPLICATION)
		decoder->private_->metadata_filter_ids_count = 0;
	return true;
}

FLAC_API FLAC__bool FLAC__stream_decoder_set_metadata_ignore_application(FLAC__StreamDecoder *decoder, const FLAC__byte id[4])
{
	FLAC__ASSERT(0 != decoder);
	FLAC__ASSERT(0 != decoder->private_);
	FLAC__ASSERT(0 != decoder->protected_);
	FLAC__ASSERT(0 != id);
	if(decoder->protected_->state != FLAC__STREAM_DECODER_UNINITIALIZED)
		return false;

	if(!decoder->private_->metadata_filter[FLAC__METADATA_TYPE_APPLICATION])
		return true;

	FLAC__ASSERT(0 != decoder->private_->metadata_filter_ids);

	if(decoder->private_->metadata_filter_ids_count == decoder->private_->metadata_filter_ids_capacity) {
		if(0 == (decoder->private_->metadata_filter_ids = realloc(decoder->private_->metadata_filter_ids, decoder->private_->metadata_filter_ids_capacity * 2)))
			return decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
		decoder->private_->metadata_filter_ids_capacity *= 2;
	}

	memcpy(decoder->private_->metadata_filter_ids + decoder->private_->metadata_filter_ids_count * (FLAC__STREAM_METADATA_APPLICATION_ID_LEN/8), id, (FLAC__STREAM_METADATA_APPLICATION_ID_LEN/8));
	decoder->private_->metadata_filter_ids_count++;

	return true;
}

FLAC_API FLAC__bool FLAC__stream_decoder_set_metadata_ignore_all(FLAC__StreamDecoder *decoder)
{
	FLAC__ASSERT(0 != decoder);
	FLAC__ASSERT(0 != decoder->private_);
	FLAC__ASSERT(0 != decoder->protected_);
	if(decoder->protected_->state != FLAC__STREAM_DECODER_UNINITIALIZED)
		return false;
	memset(decoder->private_->metadata_filter, 0, sizeof(decoder->private_->metadata_filter));
	decoder->private_->metadata_filter_ids_count = 0;
	return true;
}

FLAC_API FLAC__StreamDecoderState FLAC__stream_decoder_get_state(const FLAC__StreamDecoder *decoder)
{
	FLAC__ASSERT(0 != decoder);
	FLAC__ASSERT(0 != decoder->protected_);
	return decoder->protected_->state;
}

FLAC_API unsigned FLAC__stream_decoder_get_channels(const FLAC__StreamDecoder *decoder)
{
	FLAC__ASSERT(0 != decoder);
	FLAC__ASSERT(0 != decoder->protected_);
	return decoder->protected_->channels;
}

FLAC_API FLAC__ChannelAssignment FLAC__stream_decoder_get_channel_assignment(const FLAC__StreamDecoder *decoder)
{
	FLAC__ASSERT(0 != decoder);
	FLAC__ASSERT(0 != decoder->protected_);
	return decoder->protected_->channel_assignment;
}

FLAC_API unsigned FLAC__stream_decoder_get_bits_per_sample(const FLAC__StreamDecoder *decoder)
{
	FLAC__ASSERT(0 != decoder);
	FLAC__ASSERT(0 != decoder->protected_);
	return decoder->protected_->bits_per_sample;
}

FLAC_API unsigned FLAC__stream_decoder_get_sample_rate(const FLAC__StreamDecoder *decoder)
{
	FLAC__ASSERT(0 != decoder);
	FLAC__ASSERT(0 != decoder->protected_);
	return decoder->protected_->sample_rate;
}

FLAC_API unsigned FLAC__stream_decoder_get_blocksize(const FLAC__StreamDecoder *decoder)
{
	FLAC__ASSERT(0 != decoder);
	FLAC__ASSERT(0 != decoder->protected_);
	return decoder->protected_->blocksize;
}

FLAC_API FLAC__bool FLAC__stream_decoder_flush(FLAC__StreamDecoder *decoder)
{
	FLAC__ASSERT(0 != decoder);
	FLAC__ASSERT(0 != decoder->private_);
	FLAC__ASSERT(0 != decoder->protected_);

	if(!FLAC__bitbuffer_clear(decoder->private_->input)) {
		decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
		return false;
	}
	decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;

	return true;
}

FLAC_API FLAC__bool FLAC__stream_decoder_reset(FLAC__StreamDecoder *decoder)
{
	FLAC__ASSERT(0 != decoder);
	FLAC__ASSERT(0 != decoder->private_);
	FLAC__ASSERT(0 != decoder->protected_);

	if(!FLAC__stream_decoder_flush(decoder)) {
		decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
		return false;
	}
	decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_METADATA;

	decoder->private_->samples_decoded = 0;

	return true;
}

FLAC_API FLAC__bool FLAC__stream_decoder_process_single(FLAC__StreamDecoder *decoder)
{
	FLAC__bool got_a_frame;
	FLAC__ASSERT(0 != decoder);
	FLAC__ASSERT(0 != decoder->protected_);

	while(1) {
		switch(decoder->protected_->state) {
			case FLAC__STREAM_DECODER_SEARCH_FOR_METADATA:
				if(!find_metadata_(decoder))
					return false; /* above function sets the status for us */
				break;
			case FLAC__STREAM_DECODER_READ_METADATA:
				if(!read_metadata_(decoder))
					return false; /* above function sets the status for us */
				else
					return true;
			case FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC:
				if(!frame_sync_(decoder))
					return true; /* above function sets the status for us */
				break;
			case FLAC__STREAM_DECODER_READ_FRAME:
				if(!read_frame_(decoder, &got_a_frame))
					return false; /* above function sets the status for us */
				if(got_a_frame)
					return true; /* above function sets the status for us */
				break;
			case FLAC__STREAM_DECODER_END_OF_STREAM:
			case FLAC__STREAM_DECODER_ABORTED:
				return true;
			default:
				FLAC__ASSERT(0);
				return false;
		}
	}
}

FLAC_API FLAC__bool FLAC__stream_decoder_process_until_end_of_metadata(FLAC__StreamDecoder *decoder)
{
	FLAC__ASSERT(0 != decoder);
	FLAC__ASSERT(0 != decoder->protected_);

	while(1) {
		switch(decoder->protected_->state) {
			case FLAC__STREAM_DECODER_SEARCH_FOR_METADATA:
				if(!find_metadata_(decoder))
					return false; /* above function sets the status for us */
				break;
			case FLAC__STREAM_DECODER_READ_METADATA:
				if(!read_metadata_(decoder))
					return false; /* above function sets the status for us */
				break;
			case FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC:
			case FLAC__STREAM_DECODER_READ_FRAME:
			case FLAC__STREAM_DECODER_END_OF_STREAM:
			case FLAC__STREAM_DECODER_ABORTED:
				return true;
			default:
				FLAC__ASSERT(0);
				return false;
		}
	}
}

FLAC_API FLAC__bool FLAC__stream_decoder_process_until_end_of_stream(FLAC__StreamDecoder *decoder)
{
	FLAC__bool dummy;
	FLAC__ASSERT(0 != decoder);
	FLAC__ASSERT(0 != decoder->protected_);

	while(1) {
		switch(decoder->protected_->state) {
			case FLAC__STREAM_DECODER_SEARCH_FOR_METADATA:
				if(!find_metadata_(decoder))
					return false; /* above function sets the status for us */
				break;
			case FLAC__STREAM_DECODER_READ_METADATA:
				if(!read_metadata_(decoder))
					return false; /* above function sets the status for us */
				break;
			case FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC:
				if(!frame_sync_(decoder))
					return true; /* above function sets the status for us */
				break;
			case FLAC__STREAM_DECODER_READ_FRAME:
				if(!read_frame_(decoder, &dummy))
					return false; /* above function sets the status for us */
				break;
			case FLAC__STREAM_DECODER_END_OF_STREAM:
			case FLAC__STREAM_DECODER_ABORTED:
				return true;
			default:
				FLAC__ASSERT(0);
				return false;
		}
	}
}

/***********************************************************************
 *
 * Protected class methods
 *
 ***********************************************************************/

unsigned FLAC__stream_decoder_get_input_bytes_unconsumed(const FLAC__StreamDecoder *decoder)
{
	FLAC__ASSERT(0 != decoder);
	return FLAC__bitbuffer_get_input_bytes_unconsumed(decoder->private_->input);
}

/***********************************************************************
 *
 * Private class methods
 *
 ***********************************************************************/

void set_defaults_(FLAC__StreamDecoder *decoder)
{
	decoder->private_->read_callback = 0;
	decoder->private_->write_callback = 0;
	decoder->private_->metadata_callback = 0;
	decoder->private_->error_callback = 0;
	decoder->private_->client_data = 0;

	memset(decoder->private_->metadata_filter, 0, sizeof(decoder->private_->metadata_filter));
	decoder->private_->metadata_filter[FLAC__METADATA_TYPE_STREAMINFO] = true;
	decoder->private_->metadata_filter_ids_count = 0;
}

FLAC__bool allocate_output_(FLAC__StreamDecoder *decoder, unsigned size, unsigned channels)
{
	unsigned i;
	FLAC__int32 *tmp;

	if(size <= decoder->private_->output_capacity && channels <= decoder->private_->output_channels)
		return true;

	/* simply using realloc() is not practical because the number of channels may change mid-stream */

	for(i = 0; i < FLAC__MAX_CHANNELS; i++) {
		if(0 != decoder->private_->output[i]) {
			free(decoder->private_->output[i]-4);
			decoder->private_->output[i] = 0;
		}
		if(0 != decoder->private_->residual[i]) {
			free(decoder->private_->residual[i]);
			decoder->private_->residual[i] = 0;
		}
	}

	for(i = 0; i < channels; i++) {
		/* WATCHOUT:
		 * FLAC__lpc_restore_signal_asm_ia32_mmx() requires that the
		 * output arrays have a buffer of up to 3 zeroes in front
		 * (at negative indices) for alignment purposes; we use 4
		 * to keep the data well-aligned.
		 */
		tmp = (FLAC__int32*)malloc(sizeof(FLAC__int32)*(size+4));
		if(tmp == 0) {
			decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
			return false;
		}
		memset(tmp, 0, sizeof(FLAC__int32)*4);
		decoder->private_->output[i] = tmp + 4;

		tmp = (FLAC__int32*)malloc(sizeof(FLAC__int32)*size);
		if(tmp == 0) {
			decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
			return false;
		}
		decoder->private_->residual[i] = tmp;
	}

	decoder->private_->output_capacity = size;
	decoder->private_->output_channels = channels;

	return true;
}

FLAC__bool has_id_filtered_(FLAC__StreamDecoder *decoder, FLAC__byte *id)
{
	unsigned i;

	FLAC__ASSERT(0 != decoder);
	FLAC__ASSERT(0 != decoder->private_);

	for(i = 0; i < decoder->private_->metadata_filter_ids_count; i++)
		if(0 == memcmp(decoder->private_->metadata_filter_ids + i * (FLAC__STREAM_METADATA_APPLICATION_ID_LEN/8), id, (FLAC__STREAM_METADATA_APPLICATION_ID_LEN/8)))
			return true;

	return false;
}

FLAC__bool find_metadata_(FLAC__StreamDecoder *decoder)
{
	FLAC__uint32 x;
	unsigned i, id;
	FLAC__bool first = true;

	FLAC__ASSERT(FLAC__bitbuffer_is_consumed_byte_aligned(decoder->private_->input));

	for(i = id = 0; i < 4; ) {
		if(decoder->private_->cached) {
			x = (FLAC__uint32)decoder->private_->lookahead;
			decoder->private_->cached = false;
		}
		else {
			if(!FLAC__bitbuffer_read_raw_uint32(decoder->private_->input, &x, 8, read_callback_, decoder))
				return false; /* the read_callback_ sets the state for us */
		}
		if(x == FLAC__STREAM_SYNC_STRING[i]) {
			first = true;
			i++;
			id = 0;
			continue;
		}
		if(x == ID3V2_TAG_[id]) {
			id++;
			i = 0;
			if(id == 3) {
				if(!skip_id3v2_tag_(decoder))
					return false; /* the read_callback_ sets the state for us */
			}
			continue;
		}
		if(x == 0xff) { /* MAGIC NUMBER for the first 8 frame sync bits */
			decoder->private_->header_warmup[0] = (FLAC__byte)x;
			if(!FLAC__bitbuffer_read_raw_uint32(decoder->private_->input, &x, 8, read_callback_, decoder))
				return false; /* the read_callback_ sets the state for us */

			/* we have to check if we just read two 0xff's in a row; the second may actually be the beginning of the sync code */
			/* else we have to check if the second byte is the end of a sync code */
			if(x == 0xff) { /* MAGIC NUMBER for the first 8 frame sync bits */
				decoder->private_->lookahead = (FLAC__byte)x;
				decoder->private_->cached = true;
			}
			else if(x >> 2 == 0x3e) { /* MAGIC NUMBER for the last 6 sync bits */
				decoder->private_->header_warmup[1] = (FLAC__byte)x;
				decoder->protected_->state = FLAC__STREAM_DECODER_READ_FRAME;
				return true;
			}
		}
		i = 0;
		if(first) {
			decoder->private_->error_callback(decoder, FLAC__STREAM_DECODER_ERROR_STATUS_LOST_SYNC, decoder->private_->client_data);
			first = false;
		}
	}

	decoder->protected_->state = FLAC__STREAM_DECODER_READ_METADATA;
	return true;
}

FLAC__bool read_metadata_(FLAC__StreamDecoder *decoder)
{
	FLAC__uint32 i, x, last_block, type, length;
	FLAC__uint64 xx;

	FLAC__ASSERT(FLAC__bitbuffer_is_consumed_byte_aligned(decoder->private_->input));

	if(!FLAC__bitbuffer_read_raw_uint32(decoder->private_->input, &last_block, FLAC__STREAM_METADATA_IS_LAST_LEN, read_callback_, decoder))
		return false; /* the read_callback_ sets the state for us */
	if(!FLAC__bitbuffer_read_raw_uint32(decoder->private_->input, &type, FLAC__STREAM_METADATA_TYPE_LEN, read_callback_, decoder))
		return false; /* the read_callback_ sets the state for us */
	if(!FLAC__bitbuffer_read_raw_uint32(decoder->private_->input, &length, FLAC__STREAM_METADATA_LENGTH_LEN, read_callback_, decoder))
		return false; /* the read_callback_ sets the state for us */
	if(type == FLAC__METADATA_TYPE_STREAMINFO) {
		unsigned used_bits = 0;
		decoder->private_->stream_info.type = type;
		decoder->private_->stream_info.is_last = last_block;
		decoder->private_->stream_info.length = length;

		if(!FLAC__bitbuffer_read_raw_uint32(decoder->private_->input, &x, FLAC__STREAM_METADATA_STREAMINFO_MIN_BLOCK_SIZE_LEN, read_callback_, decoder))
			return false; /* the read_callback_ sets the state for us */
		decoder->private_->stream_info.data.stream_info.min_blocksize = x;
		used_bits += FLAC__STREAM_METADATA_STREAMINFO_MIN_BLOCK_SIZE_LEN;

		if(!FLAC__bitbuffer_read_raw_uint32(decoder->private_->input, &x, FLAC__STREAM_METADATA_STREAMINFO_MAX_BLOCK_SIZE_LEN, read_callback_, decoder))
			return false; /* the read_callback_ sets the state for us */
		decoder->private_->stream_info.data.stream_info.max_blocksize = x;
		used_bits += FLAC__STREAM_METADATA_STREAMINFO_MAX_BLOCK_SIZE_LEN;

		if(!FLAC__bitbuffer_read_raw_uint32(decoder->private_->input, &x, FLAC__STREAM_METADATA_STREAMINFO_MIN_FRAME_SIZE_LEN, read_callback_, decoder))
			return false; /* the read_callback_ sets the state for us */
		decoder->private_->stream_info.data.stream_info.min_framesize = x;
		used_bits += FLAC__STREAM_METADATA_STREAMINFO_MIN_FRAME_SIZE_LEN;

		if(!FLAC__bitbuffer_read_raw_uint32(decoder->private_->input, &x, FLAC__STREAM_METADATA_STREAMINFO_MAX_FRAME_SIZE_LEN, read_callback_, decoder))
			return false; /* the read_callback_ sets the state for us */
		decoder->private_->stream_info.data.stream_info.max_framesize = x;
		used_bits += FLAC__STREAM_METADATA_STREAMINFO_MAX_FRAME_SIZE_LEN;

		if(!FLAC__bitbuffer_read_raw_uint32(decoder->private_->input, &x, FLAC__STREAM_METADATA_STREAMINFO_SAMPLE_RATE_LEN, read_callback_, decoder))
			return false; /* the read_callback_ sets the state for us */
		decoder->private_->stream_info.data.stream_info.sample_rate = x;
		used_bits += FLAC__STREAM_METADATA_STREAMINFO_SAMPLE_RATE_LEN;

		if(!FLAC__bitbuffer_read_raw_uint32(decoder->private_->input, &x, FLAC__STREAM_METADATA_STREAMINFO_CHANNELS_LEN, read_callback_, decoder))
			return false; /* the read_callback_ sets the state for us */
		decoder->private_->stream_info.data.stream_info.channels = x+1;
		used_bits += FLAC__STREAM_METADATA_STREAMINFO_CHANNELS_LEN;

		if(!FLAC__bitbuffer_read_raw_uint32(decoder->private_->input, &x, FLAC__STREAM_METADATA_STREAMINFO_BITS_PER_SAMPLE_LEN, read_callback_, decoder))
			return false; /* the read_callback_ sets the state for us */
		decoder->private_->stream_info.data.stream_info.bits_per_sample = x+1;