stream_decoder.c

这是著名的TCPMP播放器在WINDWOWS,和WINCE下编译通过的源程序.笔者对其中的LIBMAD库做了针对ARM MPU的优化. 并增加了词幕功能.

					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, /*do_full_decode=*/true))
					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, /*do_full_decode=*/true))
					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;
		}
	}
}

FLAC_API FLAC__bool FLAC__stream_decoder_skip_single_frame(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:
			case FLAC__STREAM_DECODER_READ_METADATA:
				return false; /* above function sets the status for us */
			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, /*do_full_decode=*/false))
					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;
		}
	}
}

/***********************************************************************
 *
 * 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_unaligned[i]) {
			free(decoder->private_->residual_unaligned[i]);
			decoder->private_->residual_unaligned[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;

		/* WATCHOUT:
		 * minimum of quadword alignment for PPC vector optimizations is REQUIRED:
		 */
		if(!FLAC__memory_alloc_aligned_int32_array(size, &decoder->private_->residual_unaligned[i], &decoder->private_->residual[i])) {
			decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
			return false;
		}
	}

	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__bool is_last;
	FLAC__uint32 i, x, type, length;

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

	if(!FLAC__bitbuffer_read_raw_uint32(decoder->private_->input, &x, FLAC__STREAM_METADATA_IS_LAST_LEN, read_callback_, decoder))
		return false; /* the read_callback_ sets the state for us */
	is_last = x? true : false;

	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) {
		if(!read_metadata_streaminfo_(decoder, is_last, length))
			return false;

		decoder->private_->has_stream_info = true;
		if(decoder->private_->metadata_filter[FLAC__METADATA_TYPE_STREAMINFO])
			decoder->private_->metadata_callback(decoder, &decoder->private_->stream_info, decoder->private_->client_data);
	}
	else if(type == FLAC__METADATA_TYPE_SEEKTABLE) {
		if(!read_metadata_seektable_(decoder, is_last, length))
			return false;

		decoder->private_->has_seek_table = true;
		if(decoder->private_->metadata_filter[FLAC__METADATA_TYPE_SEEKTABLE])
			decoder->private_->metadata_callback(decoder, &decoder->private_->seek_table, decoder->private_->client_data);
	}
	else {
		FLAC__bool skip_it = !decoder->private_->metadata_filter[type];
		unsigned real_length = length;
		FLAC__StreamMetadata block;

		block.is_last = is_last;
		block.type = (FLAC__MetadataType)type;
		block.length = length;

		if(type == FLAC__METADATA_TYPE_APPLICATION) {
			if(!FLAC__bitbuffer_read_byte_block_aligned_no_crc(decoder->private_->input, block.data.application.id, FLAC__STREAM_METADATA_APPLICATION_ID_LEN/8, read_callback_, decoder))
				return false; /* the read_callback_ sets the state for us */

			real_length -= FLAC__STREAM_METADATA_APPLICATION_ID_LEN/8;