ref: 53d55013598d7cd214d01cbf0b026844fe7ca8d2
dir: /sys/src/cmd/audio/libFLAC/ogg_decoder_aspect.c/
/* libFLAC - Free Lossless Audio Codec
* Copyright (C) 2002-2009 Josh Coalson
* Copyright (C) 2011-2022 Xiph.Org Foundation
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* - Neither the name of the Xiph.org Foundation nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <string.h> /* for memcpy() */
#include "FLAC/assert.h"
#include "private/ogg_decoder_aspect.h"
#include "private/ogg_mapping.h"
#include "private/macros.h"
/***********************************************************************
*
* Public class methods
*
***********************************************************************/
FLAC__bool FLAC__ogg_decoder_aspect_init(FLAC__OggDecoderAspect *aspect)
{
/* we will determine the serial number later if necessary */
if(ogg_stream_init(&aspect->stream_state, aspect->serial_number) != 0)
return false;
if(ogg_sync_init(&aspect->sync_state) != 0)
return false;
aspect->version_major = ~(0u);
aspect->version_minor = ~(0u);
aspect->need_serial_number = aspect->use_first_serial_number;
aspect->end_of_stream = false;
aspect->have_working_page = false;
return true;
}
void FLAC__ogg_decoder_aspect_finish(FLAC__OggDecoderAspect *aspect)
{
(void)ogg_sync_clear(&aspect->sync_state);
(void)ogg_stream_clear(&aspect->stream_state);
}
void FLAC__ogg_decoder_aspect_set_serial_number(FLAC__OggDecoderAspect *aspect, long value)
{
aspect->use_first_serial_number = false;
aspect->serial_number = value;
}
void FLAC__ogg_decoder_aspect_set_defaults(FLAC__OggDecoderAspect *aspect)
{
aspect->use_first_serial_number = true;
}
void FLAC__ogg_decoder_aspect_flush(FLAC__OggDecoderAspect *aspect)
{
(void)ogg_stream_reset(&aspect->stream_state);
(void)ogg_sync_reset(&aspect->sync_state);
aspect->end_of_stream = false;
aspect->have_working_page = false;
}
void FLAC__ogg_decoder_aspect_reset(FLAC__OggDecoderAspect *aspect)
{
FLAC__ogg_decoder_aspect_flush(aspect);
if(aspect->use_first_serial_number)
aspect->need_serial_number = true;
}
FLAC__OggDecoderAspectReadStatus FLAC__ogg_decoder_aspect_read_callback_wrapper(FLAC__OggDecoderAspect *aspect, FLAC__byte buffer[], size_t *bytes, FLAC__OggDecoderAspectReadCallbackProxy read_callback, const FLAC__StreamDecoder *decoder, void *client_data)
{
static const size_t OGG_BYTES_CHUNK = 8192;
const size_t bytes_requested = *bytes;
/*
* The FLAC decoding API uses pull-based reads, whereas Ogg decoding
* is push-based. In libFLAC, when you ask to decode a frame, the
* decoder will eventually call the read callback to supply some data,
* but how much it asks for depends on how much free space it has in
* its internal buffer. It does not try to grow its internal buffer
* to accommodate a whole frame because then the internal buffer size
* could not be limited, which is necessary in embedded applications.
*
* Ogg however grows its internal buffer until a whole page is present;
* only then can you get decoded data out. So we can't just ask for
* the same number of bytes from Ogg, then pass what's decoded down to
* libFLAC. If what libFLAC is asking for will not contain a whole
* page, then we will get no data from ogg_sync_pageout(), and at the
* same time cannot just read more data from the client for the purpose
* of getting a whole decoded page because the decoded size might be
* larger than libFLAC's internal buffer.
*
* Instead, whenever this read callback wrapper is called, we will
* continually request data from the client until we have at least one
* page, and manage pages internally so that we can send pieces of
* pages down to libFLAC in such a way that we obey its size
* requirement. To limit the amount of callbacks, we will always try
* to read in enough pages to return the full number of bytes
* requested.
*/
*bytes = 0;
while (*bytes < bytes_requested && !aspect->end_of_stream) {
if (aspect->have_working_page) {
if (aspect->have_working_packet) {
size_t n = bytes_requested - *bytes;
if ((size_t)aspect->working_packet.bytes <= n) {
/* the rest of the packet will fit in the buffer */
n = aspect->working_packet.bytes;
memcpy(buffer, aspect->working_packet.packet, n);
*bytes += n;
buffer += n;
aspect->have_working_packet = false;
}
else {
/* only n bytes of the packet will fit in the buffer */
memcpy(buffer, aspect->working_packet.packet, n);
*bytes += n;
buffer += n;
aspect->working_packet.packet += n;
aspect->working_packet.bytes -= n;
}
}
else {
/* try and get another packet */
const int ret = ogg_stream_packetout(&aspect->stream_state, &aspect->working_packet);
if (ret > 0) {
aspect->have_working_packet = true;
/* if it is the first header packet, check for magic and a supported Ogg FLAC mapping version */
if (aspect->working_packet.bytes > 0 && aspect->working_packet.packet[0] == FLAC__OGG_MAPPING_FIRST_HEADER_PACKET_TYPE) {
const FLAC__byte *b = aspect->working_packet.packet;
const uint32_t header_length =
FLAC__OGG_MAPPING_PACKET_TYPE_LENGTH +
FLAC__OGG_MAPPING_MAGIC_LENGTH +
FLAC__OGG_MAPPING_VERSION_MAJOR_LENGTH +
FLAC__OGG_MAPPING_VERSION_MINOR_LENGTH +
FLAC__OGG_MAPPING_NUM_HEADERS_LENGTH;
if (aspect->working_packet.bytes < (long)header_length)
return FLAC__OGG_DECODER_ASPECT_READ_STATUS_NOT_FLAC;
b += FLAC__OGG_MAPPING_PACKET_TYPE_LENGTH;
if (memcmp(b, FLAC__OGG_MAPPING_MAGIC, FLAC__OGG_MAPPING_MAGIC_LENGTH))
return FLAC__OGG_DECODER_ASPECT_READ_STATUS_NOT_FLAC;
b += FLAC__OGG_MAPPING_MAGIC_LENGTH;
aspect->version_major = (uint32_t)(*b);
b += FLAC__OGG_MAPPING_VERSION_MAJOR_LENGTH;
aspect->version_minor = (uint32_t)(*b);
if (aspect->version_major != 1)
return FLAC__OGG_DECODER_ASPECT_READ_STATUS_UNSUPPORTED_MAPPING_VERSION;
aspect->working_packet.packet += header_length;
aspect->working_packet.bytes -= header_length;
}
}
else if (ret == 0) {
aspect->have_working_page = false;
}
else { /* ret < 0 */
/* lost sync, we'll leave the working page for the next call */
return FLAC__OGG_DECODER_ASPECT_READ_STATUS_LOST_SYNC;
}
}
}
else {
/* try and get another page */
const int ret = ogg_sync_pageout(&aspect->sync_state, &aspect->working_page);
if (ret > 0) {
/* got a page, grab the serial number if necessary */
if(aspect->need_serial_number) {
aspect->stream_state.serialno = aspect->serial_number = ogg_page_serialno(&aspect->working_page);
aspect->need_serial_number = false;
}
if(ogg_stream_pagein(&aspect->stream_state, &aspect->working_page) == 0) {
aspect->have_working_page = true;
aspect->have_working_packet = false;
}
/* else do nothing, could be a page from another stream */
}
else if (ret == 0) {
/* need more data */
const size_t ogg_bytes_to_read = flac_max(bytes_requested - *bytes, OGG_BYTES_CHUNK);
char *oggbuf = ogg_sync_buffer(&aspect->sync_state, ogg_bytes_to_read);
if(0 == oggbuf) {
return FLAC__OGG_DECODER_ASPECT_READ_STATUS_MEMORY_ALLOCATION_ERROR;
}
else {
size_t ogg_bytes_read = ogg_bytes_to_read;
switch(read_callback(decoder, (FLAC__byte*)oggbuf, &ogg_bytes_read, client_data)) {
case FLAC__OGG_DECODER_ASPECT_READ_STATUS_OK:
break;
case FLAC__OGG_DECODER_ASPECT_READ_STATUS_END_OF_STREAM:
aspect->end_of_stream = true;
break;
case FLAC__OGG_DECODER_ASPECT_READ_STATUS_ABORT:
return FLAC__OGG_DECODER_ASPECT_READ_STATUS_ABORT;
default:
FLAC__ASSERT(0);
}
if(ogg_sync_wrote(&aspect->sync_state, ogg_bytes_read) < 0) {
/* double protection; this will happen if the read callback returns more bytes than the max requested, which would overflow Ogg's internal buffer */
FLAC__ASSERT(0);
return FLAC__OGG_DECODER_ASPECT_READ_STATUS_ERROR;
}
}
}
else { /* ret < 0 */
/* lost sync, bail out */
return FLAC__OGG_DECODER_ASPECT_READ_STATUS_LOST_SYNC;
}
}
}
if (aspect->end_of_stream && *bytes == 0) {
return FLAC__OGG_DECODER_ASPECT_READ_STATUS_END_OF_STREAM;
}
return FLAC__OGG_DECODER_ASPECT_READ_STATUS_OK;
}