/src/flac/src/libFLAC/stream_decoder.c

Source
/* libFLAC - Free Lossless Audio Codec library
 * Copyright (C) 2000-2009  Josh Coalson
 * Copyright (C) 2011-2025  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 <stdio.h>
#include <stdlib.h> /* for malloc() */
#include <string.h> /* for memset/memcpy() */
#include <sys/types.h> /* for off_t */
#include <sys/stat.h>  /* for stat() */
#include "share/compat.h"
#include "FLAC/assert.h"
#include "share/alloc.h"
#include "protected/stream_decoder.h"
#include "private/bitreader.h"
#include "private/bitmath.h"
#include "private/cpu.h"
#include "private/crc.h"
#include "private/fixed.h"
#include "private/format.h"
#include "private/lpc.h"
#include "private/md5.h"
#include "private/memory.h"
#include "private/macros.h"


/* technically this should be in an "export.c" but this is convenient enough */
FLAC_API int FLAC_API_SUPPORTS_OGG_FLAC = FLAC__HAS_OGG;


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

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

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

static void set_defaults_(FLAC__StreamDecoder *decoder);
static FILE *get_binary_stdin_(void);
static FLAC__bool allocate_output_(FLAC__StreamDecoder *decoder, uint32_t size, uint32_t channels, uint32_t bps);
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 read_metadata_streaminfo_(FLAC__StreamDecoder *decoder, FLAC__bool is_last, uint32_t length);
static FLAC__bool read_metadata_seektable_(FLAC__StreamDecoder *decoder, FLAC__bool is_last, uint32_t length);
static FLAC__bool read_metadata_vorbiscomment_(FLAC__StreamDecoder *decoder, FLAC__StreamMetadata_VorbisComment *obj, uint32_t length);
static FLAC__bool read_metadata_cuesheet_(FLAC__StreamDecoder *decoder, FLAC__StreamMetadata_CueSheet *obj);
static FLAC__bool read_metadata_picture_(FLAC__StreamDecoder *decoder, FLAC__StreamMetadata_Picture *obj);
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, FLAC__bool do_full_decode);
static FLAC__bool read_frame_header_(FLAC__StreamDecoder *decoder);
static FLAC__bool read_subframe_(FLAC__StreamDecoder *decoder, uint32_t channel, uint32_t bps, FLAC__bool do_full_decode);
static FLAC__bool read_subframe_constant_(FLAC__StreamDecoder *decoder, uint32_t channel, uint32_t bps, FLAC__bool do_full_decode);
static FLAC__bool read_subframe_fixed_(FLAC__StreamDecoder *decoder, uint32_t channel, uint32_t bps, const uint32_t order, FLAC__bool do_full_decode);
static FLAC__bool read_subframe_lpc_(FLAC__StreamDecoder *decoder, uint32_t channel, uint32_t bps, const uint32_t order, FLAC__bool do_full_decode);
static FLAC__bool read_subframe_verbatim_(FLAC__StreamDecoder *decoder, uint32_t channel, uint32_t bps, FLAC__bool do_full_decode);
static FLAC__bool read_residual_partitioned_rice_(FLAC__StreamDecoder *decoder, uint32_t predictor_order, uint32_t partition_order, FLAC__EntropyCodingMethod_PartitionedRiceContents *partitioned_rice_contents, FLAC__int32 *residual, FLAC__bool is_extended);
static FLAC__bool read_zero_padding_(FLAC__StreamDecoder *decoder);
static void       undo_channel_coding(FLAC__StreamDecoder *decoder);
static FLAC__bool read_callback_(FLAC__byte buffer[], size_t *bytes, void *client_data);
#if FLAC__HAS_OGG
static FLAC__StreamDecoderReadStatus read_callback_ogg_aspect_(const FLAC__StreamDecoder *decoder, FLAC__byte buffer[], size_t *bytes);
static FLAC__OggDecoderAspectReadStatus read_callback_proxy_(const void *void_decoder, FLAC__byte buffer[], size_t *bytes, void *client_data);
#endif
static FLAC__StreamDecoderWriteStatus write_audio_frame_to_client_(FLAC__StreamDecoder *decoder, const FLAC__Frame *frame, const FLAC__int32 * const buffer[]);
static void send_error_to_client_(const FLAC__StreamDecoder *decoder, FLAC__StreamDecoderErrorStatus status);
static FLAC__bool seek_to_absolute_sample_(FLAC__StreamDecoder *decoder, FLAC__uint64 stream_length, FLAC__uint64 target_sample);
#if FLAC__HAS_OGG
static FLAC__bool seek_to_absolute_sample_ogg_(FLAC__StreamDecoder *decoder, FLAC__uint64 stream_length, FLAC__uint64 target_sample);
#endif
static FLAC__StreamDecoderReadStatus file_read_callback_(const FLAC__StreamDecoder *decoder, FLAC__byte buffer[], size_t *bytes, void *client_data);
static FLAC__StreamDecoderSeekStatus file_seek_callback_(const FLAC__StreamDecoder *decoder, FLAC__uint64 absolute_byte_offset, void *client_data);
static FLAC__StreamDecoderTellStatus file_tell_callback_(const FLAC__StreamDecoder *decoder, FLAC__uint64 *absolute_byte_offset, void *client_data);
static FLAC__StreamDecoderLengthStatus file_length_callback_(const FLAC__StreamDecoder *decoder, FLAC__uint64 *stream_length, void *client_data);
static FLAC__bool file_eof_callback_(const FLAC__StreamDecoder *decoder, void *client_data);
static void reset_decoder_internal_(FLAC__StreamDecoder* decoder);

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

typedef struct FLAC__StreamDecoderPrivate {
  FLAC__bool is_ogg;
  FLAC__StreamDecoderReadCallback read_callback;
  FLAC__StreamDecoderSeekCallback seek_callback;
  FLAC__StreamDecoderTellCallback tell_callback;
  FLAC__StreamDecoderLengthCallback length_callback;
  FLAC__StreamDecoderEofCallback eof_callback;
  FLAC__StreamDecoderWriteCallback write_callback;
  FLAC__StreamDecoderMetadataCallback metadata_callback;
  FLAC__StreamDecoderErrorCallback error_callback;
  void *client_data;
  FILE *file; /* only used if FLAC__stream_decoder_init_file()/FLAC__stream_decoder_init_file() called, else NULL */
  FLAC__BitReader *input;
  FLAC__int32 *output[FLAC__MAX_CHANNELS];
  FLAC__int32 *residual[FLAC__MAX_CHANNELS]; /* WATCHOUT: these are the aligned pointers; the real pointers that should be free()'d are residual_unaligned[] below */
  FLAC__int64 *side_subframe;
  FLAC__bool side_subframe_in_use;
  FLAC__EntropyCodingMethod_PartitionedRiceContents partitioned_rice_contents[FLAC__MAX_CHANNELS];
  uint32_t output_capacity, output_channels;
  FLAC__uint32 fixed_block_size, next_fixed_block_size;
  FLAC__uint64 samples_decoded;
  FLAC__bool has_stream_info, has_seek_table;
  FLAC__StreamMetadata stream_info;
  FLAC__StreamMetadata seek_table;
  FLAC__bool metadata_filter[128]; /* MAGIC number 128 == total number of metadata block types == 1 << 7 */
  FLAC__byte *metadata_filter_ids;
  size_t 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 */
  /* unaligned (original) pointers to allocated data */
  FLAC__int32 *residual_unaligned[FLAC__MAX_CHANNELS];
  FLAC__bool do_md5_checking; /* initially gets protected_->md5_checking but is turned off after a seek or if the metadata has a zero MD5 */
  FLAC__bool internal_reset_hack; /* used only during init() so we can call reset to set up the decoder without rewinding the input */
  FLAC__bool is_seeking;
  FLAC__bool is_indexing; /* to be able to seek in chained streams */
  FLAC__MD5Context md5context;
  FLAC__byte computed_md5sum[16]; /* this is the sum we computed from the decoded data */
  /* (the rest of these are only used for seeking) */
  FLAC__Frame last_frame; /* holds the info of the last frame we decoded or seeked to */
  FLAC__bool last_frame_is_set;
  FLAC__uint64 first_frame_offset; /* hint to the seek routine of where in the stream the first audio frame starts */
  FLAC__uint64 last_seen_framesync; /* if tell callback works, the location of the last seen frame sync code, to rewind to if needed */
  FLAC__uint64 target_sample;
  uint32_t unparseable_frame_count; /* used to tell whether we're decoding a future version of FLAC or just got a bad sync */
  FLAC__bool got_a_frame; /* hack needed in Ogg FLAC seek routine and find_total_samples to check when process_single() actually writes a frame */
  FLAC__bool (*local_bitreader_read_rice_signed_block)(FLAC__BitReader *br, int vals[], uint32_t nvals, uint32_t parameter);
  FLAC__bool error_has_been_sent; /* To check whether a missing frame has been signalled yet */
#if FLAC__HAS_OGG
  FLAC__bool ogg_decoder_aspect_allocation_failure;
#endif
#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
  uint32_t fuzzing_rewind_count; /* To stop excessive rewinding, as it causes timeouts */
#endif
} 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_OGG_ERROR",
  "FLAC__STREAM_DECODER_SEEK_ERROR",
  "FLAC__STREAM_DECODER_ABORTED",
  "FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR",
  "FLAC__STREAM_DECODER_UNINITIALIZED",
  "FLAC__STREAM_DECODER_END_OF_LINK"
};

FLAC_API const char * const FLAC__StreamDecoderInitStatusString[] = {
  "FLAC__STREAM_DECODER_INIT_STATUS_OK",
  "FLAC__STREAM_DECODER_INIT_STATUS_UNSUPPORTED_CONTAINER",
  "FLAC__STREAM_DECODER_INIT_STATUS_INVALID_CALLBACKS",
  "FLAC__STREAM_DECODER_INIT_STATUS_MEMORY_ALLOCATION_ERROR",
  "FLAC__STREAM_DECODER_INIT_STATUS_ERROR_OPENING_FILE",
  "FLAC__STREAM_DECODER_INIT_STATUS_ALREADY_INITIALIZED"
};

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__STREAM_DECODER_READ_STATUS_END_OF_LINK"
};

FLAC_API const char * const FLAC__StreamDecoderSeekStatusString[] = {
  "FLAC__STREAM_DECODER_SEEK_STATUS_OK",
  "FLAC__STREAM_DECODER_SEEK_STATUS_ERROR",
  "FLAC__STREAM_DECODER_SEEK_STATUS_UNSUPPORTED"
};

FLAC_API const char * const FLAC__StreamDecoderTellStatusString[] = {
  "FLAC__STREAM_DECODER_TELL_STATUS_OK",
  "FLAC__STREAM_DECODER_TELL_STATUS_ERROR",
  "FLAC__STREAM_DECODER_TELL_STATUS_UNSUPPORTED"
};

FLAC_API const char * const FLAC__StreamDecoderLengthStatusString[] = {
  "FLAC__STREAM_DECODER_LENGTH_STATUS_OK",
  "FLAC__STREAM_DECODER_LENGTH_STATUS_ERROR",
  "FLAC__STREAM_DECODER_LENGTH_STATUS_UNSUPPORTED"
};

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",
  "FLAC__STREAM_DECODER_ERROR_STATUS_UNPARSEABLE_STREAM",
  "FLAC__STREAM_DECODER_ERROR_STATUS_BAD_METADATA",
  "FLAC__STREAM_DECODER_ERROR_STATUS_OUT_OF_BOUNDS",
  "FLAC__STREAM_DECODER_ERROR_STATUS_MISSING_FRAME"
};

/***********************************************************************
 *
 * Class constructor/destructor
 *
 ***********************************************************************/
FLAC_API FLAC__StreamDecoder *FLAC__stream_decoder_new(void)
{
  FLAC__StreamDecoder *decoder;
  uint32_t i;

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

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

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

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

  decoder->private_->input = FLAC__bitreader_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__bitreader_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_unaligned[i] = decoder->private_->residual[i] = 0;
  }

  decoder->private_->side_subframe = 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]);

  decoder->private_->file = 0;

  set_defaults_(decoder);

  decoder->protected_->state = FLAC__STREAM_DECODER_UNINITIALIZED;

  return decoder;
}

FLAC_API void FLAC__stream_decoder_delete(FLAC__StreamDecoder *decoder)
{
  uint32_t i;

  if (decoder == NULL)
    return ;

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

  (void)FLAC__stream_decoder_finish(decoder);

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

  FLAC__bitreader_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
 *
 ***********************************************************************/

static FLAC__StreamDecoderInitStatus init_stream_internal_(
  FLAC__StreamDecoder *decoder,
  FLAC__StreamDecoderReadCallback read_callback,
  FLAC__StreamDecoderSeekCallback seek_callback,
  FLAC__StreamDecoderTellCallback tell_callback,
  FLAC__StreamDecoderLengthCallback length_callback,
  FLAC__StreamDecoderEofCallback eof_callback,
  FLAC__StreamDecoderWriteCallback write_callback,
  FLAC__StreamDecoderMetadataCallback metadata_callback,
  FLAC__StreamDecoderErrorCallback error_callback,
  void *client_data,
  FLAC__bool is_ogg
)
{
  FLAC__ASSERT(0 != decoder);

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

  if(FLAC__HAS_OGG == 0 && is_ogg)
    return FLAC__STREAM_DECODER_INIT_STATUS_UNSUPPORTED_CONTAINER;

  if(
    0 == read_callback ||
    0 == write_callback ||
    0 == error_callback ||
    (seek_callback && (0 == tell_callback || 0 == length_callback || 0 == eof_callback))
  )
    return FLAC__STREAM_DECODER_INIT_STATUS_INVALID_CALLBACKS;

#if FLAC__HAS_OGG
  decoder->private_->is_ogg = is_ogg;
  if(is_ogg && !FLAC__ogg_decoder_aspect_init(&decoder->protected_->ogg_decoder_aspect)) {
    FLAC__ogg_decoder_aspect_finish(&decoder->protected_->ogg_decoder_aspect);
    return decoder->protected_->initstate = FLAC__STREAM_DECODER_INIT_STATUS_ERROR_OPENING_FILE;
  }
#endif

  FLAC__cpu_info(&decoder->private_->cpuinfo);
  decoder->private_->local_bitreader_read_rice_signed_block = FLAC__bitreader_read_rice_signed_block;

#ifdef FLAC__BMI2_SUPPORTED
  if (decoder->private_->cpuinfo.x86.bmi2) {
    decoder->private_->local_bitreader_read_rice_signed_block = FLAC__bitreader_read_rice_signed_block_bmi2;
  }
#endif

  /* from here on, errors are fatal */

  if(!FLAC__bitreader_init(decoder->private_->input, read_callback_, decoder)) {
    decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
    return FLAC__STREAM_DECODER_INIT_STATUS_MEMORY_ALLOCATION_ERROR;
  }

  decoder->private_->read_callback = read_callback;
  decoder->private_->seek_callback = seek_callback;
  decoder->private_->tell_callback = tell_callback;
  decoder->private_->length_callback = length_callback;
  decoder->private_->eof_callback = eof_callback;
  decoder->private_->write_callback = write_callback;
  decoder->private_->metadata_callback = metadata_callback;
  decoder->private_->error_callback = error_callback;
  decoder->private_->client_data = client_data;
  decoder->private_->fixed_block_size = decoder->private_->next_fixed_block_size = 0;
  decoder->private_->samples_decoded = 0;
  decoder->private_->has_stream_info = false;
  decoder->private_->cached = false;

  decoder->private_->do_md5_checking = decoder->protected_->md5_checking;
  decoder->private_->is_seeking = false;
  decoder->private_->is_indexing = false;

  decoder->private_->internal_reset_hack = true; /* so the following reset does not try to rewind the input */
  if(!FLAC__stream_decoder_reset(decoder)) {
    /* above call sets the state for us */
    return FLAC__STREAM_DECODER_INIT_STATUS_MEMORY_ALLOCATION_ERROR;
  }

  return FLAC__STREAM_DECODER_INIT_STATUS_OK;
}

FLAC_API FLAC__StreamDecoderInitStatus FLAC__stream_decoder_init_stream(
  FLAC__StreamDecoder *decoder,
  FLAC__StreamDecoderReadCallback read_callback,
  FLAC__StreamDecoderSeekCallback seek_callback,
  FLAC__StreamDecoderTellCallback tell_callback,
  FLAC__StreamDecoderLengthCallback length_callback,
  FLAC__StreamDecoderEofCallback eof_callback,
  FLAC__StreamDecoderWriteCallback write_callback,
  FLAC__StreamDecoderMetadataCallback metadata_callback,
  FLAC__StreamDecoderErrorCallback error_callback,
  void *client_data
)
{
  return init_stream_internal_(
    decoder,
    read_callback,
    seek_callback,
    tell_callback,
    length_callback,
    eof_callback,
    write_callback,
    metadata_callback,
    error_callback,
    client_data,
    /*is_ogg=*/false
  );
}

FLAC_API FLAC__StreamDecoderInitStatus FLAC__stream_decoder_init_ogg_stream(
  FLAC__StreamDecoder *decoder,
  FLAC__StreamDecoderReadCallback read_callback,
  FLAC__StreamDecoderSeekCallback seek_callback,
  FLAC__StreamDecoderTellCallback tell_callback,
  FLAC__StreamDecoderLengthCallback length_callback,
  FLAC__StreamDecoderEofCallback eof_callback,
  FLAC__StreamDecoderWriteCallback write_callback,
  FLAC__StreamDecoderMetadataCallback metadata_callback,
  FLAC__StreamDecoderErrorCallback error_callback,
  void *client_data
)
{
  return init_stream_internal_(
    decoder,
    read_callback,
    seek_callback,
    tell_callback,
    length_callback,
    eof_callback,
    write_callback,
    metadata_callback,
    error_callback,
    client_data,
    /*is_ogg=*/true
  );
}

static FLAC__StreamDecoderInitStatus init_FILE_internal_(
  FLAC__StreamDecoder *decoder,
  FILE *file,
  FLAC__StreamDecoderWriteCallback write_callback,
  FLAC__StreamDecoderMetadataCallback metadata_callback,
  FLAC__StreamDecoderErrorCallback error_callback,
  void *client_data,
  FLAC__bool is_ogg
)
{
  FLAC__ASSERT(0 != decoder);
  FLAC__ASSERT(0 != file);

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

  if(0 == write_callback || 0 == error_callback)
    return decoder->protected_->initstate = FLAC__STREAM_DECODER_INIT_STATUS_INVALID_CALLBACKS;

  /*
   * To make sure that our file does not go unclosed after an error, we
   * must assign the FILE pointer before any further error can occur in
   * this routine.
   */
  if(file == stdin)
    file = get_binary_stdin_(); /* just to be safe */

  decoder->private_->file = file;

  return init_stream_internal_(
    decoder,
    file_read_callback_,
    decoder->private_->file == stdin? 0: file_seek_callback_,
    decoder->private_->file == stdin? 0: file_tell_callback_,
    decoder->private_->file == stdin? 0: file_length_callback_,
    file_eof_callback_,
    write_callback,
    metadata_callback,
    error_callback,
    client_data,
    is_ogg
  );
}

FLAC_API FLAC__StreamDecoderInitStatus FLAC__stream_decoder_init_FILE(
  FLAC__StreamDecoder *decoder,
  FILE *file,
  FLAC__StreamDecoderWriteCallback write_callback,
  FLAC__StreamDecoderMetadataCallback metadata_callback,
  FLAC__StreamDecoderErrorCallback error_callback,
  void *client_data
)
{
  return init_FILE_internal_(decoder, file, write_callback, metadata_callback, error_callback, client_data, /*is_ogg=*/false);
}

FLAC_API FLAC__StreamDecoderInitStatus FLAC__stream_decoder_init_ogg_FILE(
  FLAC__StreamDecoder *decoder,
  FILE *file,
  FLAC__StreamDecoderWriteCallback write_callback,
  FLAC__StreamDecoderMetadataCallback metadata_callback,
  FLAC__StreamDecoderErrorCallback error_callback,
  void *client_data
)
{
  return init_FILE_internal_(decoder, file, write_callback, metadata_callback, error_callback, client_data, /*is_ogg=*/true);
}

static FLAC__StreamDecoderInitStatus init_file_internal_(
  FLAC__StreamDecoder *decoder,
  const char *filename,
  FLAC__StreamDecoderWriteCallback write_callback,
  FLAC__StreamDecoderMetadataCallback metadata_callback,
  FLAC__StreamDecoderErrorCallback error_callback,
  void *client_data,
  FLAC__bool is_ogg
)
{
  FILE *file;

  FLAC__ASSERT(0 != decoder);

  /*
   * To make sure that our file does not go unclosed after an error, we
   * have to do the same entrance checks here that are later performed
   * in FLAC__stream_decoder_init_FILE() before the FILE* is assigned.
   */
  if(decoder->protected_->state != FLAC__STREAM_DECODER_UNINITIALIZED)
    return decoder->protected_->initstate = FLAC__STREAM_DECODER_INIT_STATUS_ALREADY_INITIALIZED;

  if(0 == write_callback || 0 == error_callback)
    return decoder->protected_->initstate = FLAC__STREAM_DECODER_INIT_STATUS_INVALID_CALLBACKS;

  file = filename? flac_fopen(filename, "rb") : stdin;

  if(0 == file)
    return FLAC__STREAM_DECODER_INIT_STATUS_ERROR_OPENING_FILE;

  return init_FILE_internal_(decoder, file, write_callback, metadata_callback, error_callback, client_data, is_ogg);
}

FLAC_API FLAC__StreamDecoderInitStatus FLAC__stream_decoder_init_file(
  FLAC__StreamDecoder *decoder,
  const char *filename,
  FLAC__StreamDecoderWriteCallback write_callback,
  FLAC__StreamDecoderMetadataCallback metadata_callback,
  FLAC__StreamDecoderErrorCallback error_callback,
  void *client_data
)
{
  return init_file_internal_(decoder, filename, write_callback, metadata_callback, error_callback, client_data, /*is_ogg=*/false);
}

FLAC_API FLAC__StreamDecoderInitStatus FLAC__stream_decoder_init_ogg_file(
  FLAC__StreamDecoder *decoder,
  const char *filename,
  FLAC__StreamDecoderWriteCallback write_callback,
  FLAC__StreamDecoderMetadataCallback metadata_callback,
  FLAC__StreamDecoderErrorCallback error_callback,
  void *client_data
)
{
  return init_file_internal_(decoder, filename, write_callback, metadata_callback, error_callback, client_data, /*is_ogg=*/true);
}

FLAC_API FLAC__bool FLAC__stream_decoder_finish(FLAC__StreamDecoder *decoder)
{
  FLAC__bool md5_failed = false;
  uint32_t i;

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

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

  /* see the comment in FLAC__stream_decoder_reset() as to why we
   * always call FLAC__MD5Final()
   */
  FLAC__MD5Final(decoder->private_->computed_md5sum, &decoder->private_->md5context);

  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__bitreader_free(decoder->private_->input);
  for(i = 0; i < FLAC__MAX_CHANNELS; i++) {
    /* WATCHOUT:
     * FLAC__lpc_restore_signal_asm_ia32_mmx() and ..._intrin_sseN()
     * require 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_unaligned[i]) {
      free(decoder->private_->residual_unaligned[i]);
      decoder->private_->residual_unaligned[i] = decoder->private_->residual[i] = 0;
    }
  }
  if(0 != decoder->private_->side_subframe) {
    free(decoder->private_->side_subframe);
    decoder->private_->side_subframe = 0;
  }
  decoder->private_->output_capacity = 0;
  decoder->private_->output_channels = 0;

#if FLAC__HAS_OGG
  if(decoder->private_->is_ogg)
    FLAC__ogg_decoder_aspect_finish(&decoder->protected_->ogg_decoder_aspect);
#endif

  if(0 != decoder->private_->file) {
    if(decoder->private_->file != stdin)
      fclose(decoder->private_->file);
    decoder->private_->file = 0;
  }

  if(decoder->private_->do_md5_checking) {
    if(memcmp(decoder->private_->stream_info.data.stream_info.md5sum, decoder->private_->computed_md5sum, 16))
      md5_failed = true;
  }
  decoder->private_->is_seeking = false;
  decoder->private_->is_indexing = false;

  set_defaults_(decoder);

  decoder->protected_->state = FLAC__STREAM_DECODER_UNINITIALIZED;

  return !md5_failed;
}

FLAC_API FLAC__bool FLAC__stream_decoder_set_ogg_serial_number(FLAC__StreamDecoder *decoder, long 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;
#if FLAC__HAS_OGG
  /* can't check decoder->private_->is_ogg since that's not set until init time */
  FLAC__ogg_decoder_aspect_set_serial_number(&decoder->protected_->ogg_decoder_aspect, value);
  return true;
#else
  (void)value;
  return false;
#endif
}

FLAC_API FLAC__bool FLAC__stream_decoder_set_decode_chained_stream(FLAC__StreamDecoder* decoder, FLAC__bool value)
{
  FLAC__ASSERT(0 != decoder);
  FLAC__ASSERT(0 != decoder->protected_);
  if (decoder->protected_->state != FLAC__STREAM_DECODER_UNINITIALIZED)
    return false;
#if FLAC__HAS_OGG
  FLAC__ogg_decoder_aspect_set_decode_chained_stream(&decoder->protected_->ogg_decoder_aspect, value);
  return true;
#else
  (void)value;
  return false;
#endif
}

FLAC_API FLAC__bool FLAC__stream_decoder_set_md5_checking(FLAC__StreamDecoder *decoder, FLAC__bool value)
{
  FLAC__ASSERT(0 != decoder);
  FLAC__ASSERT(0 != decoder->protected_);
  if(decoder->protected_->state != FLAC__STREAM_DECODER_UNINITIALIZED)
    return false;
  decoder->protected_->md5_checking = 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((uint32_t)type <= FLAC__MAX_METADATA_TYPE_CODE);
  /* double protection */
  if((uint32_t)type > FLAC__MAX_METADATA_TYPE_CODE)
    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->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 = safe_realloc_mul_2op_(decoder->private_->metadata_filter_ids, decoder->private_->metadata_filter_ids_capacity, /*times*/2))) {
      decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
      return false;
    }
    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)
{
  uint32_t i;
  FLAC__ASSERT(0 != decoder);
  FLAC__ASSERT(0 != decoder->private_);
  FLAC__ASSERT(0 != decoder->protected_);
  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((uint32_t)type <= FLAC__MAX_METADATA_TYPE_CODE);
  /* double protection */
  if((uint32_t)type > FLAC__MAX_METADATA_TYPE_CODE)
    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->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 = safe_realloc_mul_2op_(decoder->private_->metadata_filter_ids, decoder->private_->metadata_filter_ids_capacity, /*times*/2))) {
      decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
      return false;
    }
    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_);
  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 const char *FLAC__stream_decoder_get_resolved_state_string(const FLAC__StreamDecoder *decoder)
{
  return FLAC__StreamDecoderStateString[decoder->protected_->state];
}

FLAC_API FLAC__bool FLAC__stream_decoder_get_decode_chained_stream(const FLAC__StreamDecoder* decoder)
{
  FLAC__ASSERT(0 != decoder);
  FLAC__ASSERT(0 != decoder->protected_);
#if FLAC__HAS_OGG
  return FLAC__ogg_decoder_aspect_get_decode_chained_stream(&decoder->protected_->ogg_decoder_aspect);
#else
  (void)decoder;
  return false;
#endif
}

FLAC_API FLAC__bool FLAC__stream_decoder_get_md5_checking(const FLAC__StreamDecoder *decoder)
{
  FLAC__ASSERT(0 != decoder);
  FLAC__ASSERT(0 != decoder->protected_);
  return decoder->protected_->md5_checking;
}

FLAC_API FLAC__uint64 FLAC__stream_decoder_get_total_samples(const FLAC__StreamDecoder *decoder)
{
  FLAC__ASSERT(0 != decoder);
  FLAC__ASSERT(0 != decoder->protected_);
  return decoder->private_->has_stream_info? decoder->private_->stream_info.data.stream_info.total_samples : 0;
}

FLAC_API uint32_t 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 uint32_t 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 uint32_t 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 uint32_t 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_get_decode_position(const FLAC__StreamDecoder *decoder, FLAC__uint64 *position)
{
  FLAC__ASSERT(0 != decoder);
  FLAC__ASSERT(0 != decoder->private_);
  FLAC__ASSERT(0 != position);

  if(FLAC__HAS_OGG && decoder->private_->is_ogg)
    return false;

  if(0 == decoder->private_->tell_callback)
    return false;
  if(decoder->private_->tell_callback(decoder, position, decoder->private_->client_data) != FLAC__STREAM_DECODER_TELL_STATUS_OK)
    return false;
  /* should never happen since all FLAC frames and metadata blocks are byte aligned, but check just in case */
  if(!FLAC__bitreader_is_consumed_byte_aligned(decoder->private_->input))
    return false;
  FLAC__ASSERT(*position >= FLAC__stream_decoder_get_input_bytes_unconsumed(decoder));
  *position -= FLAC__stream_decoder_get_input_bytes_unconsumed(decoder);
  return true;
}

FLAC_API const void *FLAC__stream_decoder_get_client_data(FLAC__StreamDecoder *decoder)
{
  return decoder->private_->client_data;
}

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(!decoder->private_->internal_reset_hack && decoder->protected_->state == FLAC__STREAM_DECODER_UNINITIALIZED)
    return false;
  if(decoder->protected_->state == FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR)
    return false;

  decoder->private_->samples_decoded = 0;
  decoder->private_->do_md5_checking = false;
  decoder->private_->last_seen_framesync = 0;
  decoder->private_->last_frame_is_set = false;

#if FLAC__HAS_OGG
  if(decoder->private_->is_ogg)
    FLAC__ogg_decoder_aspect_flush(&decoder->protected_->ogg_decoder_aspect);
#endif

  if(!FLAC__bitreader_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;
}

void reset_decoder_internal_(FLAC__StreamDecoder* decoder) {
  /* This code resets only the FLAC parser and decoder, not the Ogg part,
   * nor the input buffering etc. This is used to prepare the FLAC
   * decoder to receive another Ogg chain link */
  decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_METADATA;

  decoder->private_->has_stream_info = false;

  free(decoder->private_->seek_table.data.seek_table.points);
  decoder->private_->seek_table.data.seek_table.points = 0;
  decoder->private_->has_seek_table = false;

  decoder->private_->do_md5_checking = decoder->protected_->md5_checking;
  /*
   * This goes in reset() and not flush() because according to the spec, a
   * fixed-blocksize stream must stay that way through the whole stream.
   */
  decoder->private_->fixed_block_size = decoder->private_->next_fixed_block_size = 0;

  /* We initialize the FLAC__MD5Context even though we may never use it.  This
   * is because md5 checking may be turned on to start and then turned off if
   * a seek occurs.  So we init the context here and finalize it in
   * FLAC__stream_decoder_finish() to make sure things are always cleaned up
   * properly.
   */
  if(!decoder->private_->internal_reset_hack) {
    /* Only finish MD5 context when it has been initialized
     * (i.e. when internal_reset_hack is not set) */
    FLAC__MD5Final(decoder->private_->computed_md5sum, &decoder->private_->md5context);
  }
  else
    decoder->private_->internal_reset_hack = false;
  FLAC__MD5Init(&decoder->private_->md5context);

  decoder->private_->first_frame_offset = 0;
  decoder->private_->unparseable_frame_count = 0;
  decoder->private_->last_seen_framesync = 0;
  decoder->private_->last_frame_is_set = false;
  decoder->private_->error_has_been_sent = false;
}

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)) {
    /* above call sets the state for us */
    return false;
  }

#if FLAC__HAS_OGG
  /*@@@ could go in !internal_reset_hack block below */
  if(decoder->private_->is_ogg)
    FLAC__ogg_decoder_aspect_reset(&decoder->protected_->ogg_decoder_aspect);
#endif

  /* Rewind if necessary.  If FLAC__stream_decoder_init() is calling us,
   * (internal_reset_hack) don't try to rewind since we are already at
   * the beginning of the stream and don't want to fail if the input is
   * not seekable.
   */
  if(!decoder->private_->internal_reset_hack) {
    if(decoder->private_->file == stdin)
      return false; /* can't rewind stdin, reset fails */
    if(decoder->private_->seek_callback && decoder->private_->seek_callback(decoder, 0, decoder->private_->client_data) == FLAC__STREAM_DECODER_SEEK_STATUS_ERROR)
      return false; /* seekable and seek fails, reset fails */
  }

  reset_decoder_internal_(decoder);

  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, /*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_END_OF_LINK:
      case FLAC__STREAM_DECODER_ABORTED:
        return true;
      default:
        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_END_OF_LINK:
      case FLAC__STREAM_DECODER_ABORTED:
        return true;
      default:
        return false;
    }
  }
}

FLAC_API FLAC__bool FLAC__stream_decoder_process_until_end_of_link(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_END_OF_LINK:
      case FLAC__STREAM_DECODER_ABORTED:
        return true;
      default:
        return false;
    }
  }
}

FLAC_API FLAC__bool FLAC__stream_decoder_finish_link(FLAC__StreamDecoder *decoder)
{
  FLAC__bool md5_failed = false;

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

  if(decoder->protected_->state != FLAC__STREAM_DECODER_END_OF_LINK) {
    FLAC__ASSERT(0); /* This function should not be called in any other state */
    return true;
  }

  FLAC__MD5Final(decoder->private_->computed_md5sum, &decoder->private_->md5context);

  if(decoder->private_->do_md5_checking) {
    if(memcmp(decoder->private_->stream_info.data.stream_info.md5sum, decoder->private_->computed_md5sum, 16))
      md5_failed = true;
  }

  reset_decoder_internal_(decoder);

#if FLAC__HAS_OGG
  if(decoder->private_->is_ogg)
    FLAC__ogg_decoder_aspect_next_link(&decoder->protected_->ogg_decoder_aspect);
#endif

  return !md5_failed;
}

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) && decoder->protected_->state != FLAC__STREAM_DECODER_END_OF_LINK && decoder->protected_->state != FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR) {
          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_LINK:
        FLAC__stream_decoder_finish_link(decoder);
        break;
      case FLAC__STREAM_DECODER_END_OF_STREAM:
      case FLAC__STREAM_DECODER_ABORTED:
        return true;
      default:
        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;
      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_END_OF_LINK:
      case FLAC__STREAM_DECODER_ABORTED:
        return true;
      default:
        return false;
    }
  }
}

FLAC_API FLAC__bool FLAC__stream_decoder_skip_single_link(FLAC__StreamDecoder *decoder)
{
#if FLAC__HAS_OGG
  FLAC__OggDecoderAspectReadStatus status;
  FLAC__ASSERT_DECLARATION(FLAC__uint32 linknumber_start);
  FLAC__ASSERT(0 != decoder);
  FLAC__ASSERT(0 != decoder->protected_);

  if(!decoder->private_->is_ogg ||
     decoder->protected_->state == FLAC__STREAM_DECODER_ABORTED ||
     decoder->protected_->state == FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR ||
     decoder->protected_->state == FLAC__STREAM_DECODER_UNINITIALIZED)
    return false;

  FLAC__ASSERT_DECLARATION(linknumber_start = decoder->protected_->ogg_decoder_aspect.current_linknumber);

  if(!FLAC__bitreader_clear(decoder->private_->input)) {
    decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
    return false;
  }
  status = FLAC__ogg_decoder_aspect_skip_link(&decoder->protected_->ogg_decoder_aspect, read_callback_proxy_, decoder->private_->seek_callback, decoder->private_->tell_callback, decoder->private_->length_callback, decoder, decoder->private_->client_data);
  if(status == FLAC__OGG_DECODER_ASPECT_READ_STATUS_END_OF_STREAM) {
    decoder->protected_->state = FLAC__STREAM_DECODER_END_OF_STREAM;
    return true;
  }
  else if(status == FLAC__OGG_DECODER_ASPECT_READ_STATUS_CALLBACKS_NONFUNCTIONAL) {
    decoder->private_->is_seeking = true;
    FLAC__stream_decoder_process_until_end_of_link(decoder);
    if(decoder->protected_->state == FLAC__STREAM_DECODER_END_OF_LINK)
      FLAC__stream_decoder_finish_link(decoder);
    decoder->private_->is_seeking = false;
  }
  else if(status != FLAC__OGG_DECODER_ASPECT_READ_STATUS_OK) {
    decoder->protected_->state = FLAC__STREAM_DECODER_OGG_ERROR;
    return false;
  }
  else {
    FLAC__MD5Final(decoder->private_->computed_md5sum, &decoder->private_->md5context);
    reset_decoder_internal_(decoder);
  }

  FLAC__ASSERT(decoder->protected_->state == FLAC__STREAM_DECODER_END_OF_STREAM || decoder->protected_->ogg_decoder_aspect.current_linknumber > linknumber_start);
  return true;
#else
  (void)decoder;
  return false;
#endif
}

FLAC_API FLAC__bool FLAC__stream_decoder_seek_absolute(FLAC__StreamDecoder *decoder, FLAC__uint64 sample)
{
  FLAC__uint64 length;

  FLAC__ASSERT(0 != decoder);

  if(
    decoder->protected_->state != FLAC__STREAM_DECODER_SEARCH_FOR_METADATA &&
    decoder->protected_->state != FLAC__STREAM_DECODER_READ_METADATA &&
    decoder->protected_->state != FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC &&
    decoder->protected_->state != FLAC__STREAM_DECODER_READ_FRAME &&
    decoder->protected_->state != FLAC__STREAM_DECODER_END_OF_STREAM
  )
    return false;

  if(0 == decoder->private_->seek_callback)
    return false;

  FLAC__ASSERT(decoder->private_->seek_callback);
  FLAC__ASSERT(decoder->private_->tell_callback);
  FLAC__ASSERT(decoder->private_->length_callback);
  FLAC__ASSERT(decoder->private_->eof_callback);

  if(!FLAC__stream_decoder_get_decode_chained_stream(decoder) && FLAC__stream_decoder_get_total_samples(decoder) > 0 && sample >= FLAC__stream_decoder_get_total_samples(decoder))
    return false;

  decoder->private_->is_seeking = true;

  /* turn off md5 checking if a seek is attempted */
  decoder->private_->do_md5_checking = false;

  /* get the file length (currently our algorithm needs to know the length so it's also an error to get FLAC__STREAM_DECODER_LENGTH_STATUS_UNSUPPORTED) */
  if(decoder->private_->length_callback(decoder, &length, decoder->private_->client_data) != FLAC__STREAM_DECODER_LENGTH_STATUS_OK) {
    decoder->private_->is_seeking = false;
    return false;
  }

  /* if we haven't finished processing the metadata yet, do that so we have the STREAMINFO, SEEK_TABLE, and first_frame_offset */
  if(
    decoder->protected_->state == FLAC__STREAM_DECODER_SEARCH_FOR_METADATA ||
    decoder->protected_->state == FLAC__STREAM_DECODER_READ_METADATA
  ) {
    if(!FLAC__stream_decoder_process_until_end_of_metadata(decoder)) {
      /* above call sets the state for us */
      decoder->private_->is_seeking = false;
      return false;
    }
    /* check this again in case we didn't know total_samples the first time */
    if(FLAC__stream_decoder_get_total_samples(decoder) > 0 && sample >= FLAC__stream_decoder_get_total_samples(decoder)) {
      decoder->private_->is_seeking = false;
      return false;
    }
  }

  {
    const FLAC__bool ok =
#if FLAC__HAS_OGG
      decoder->private_->is_ogg?
      seek_to_absolute_sample_ogg_(decoder, length, sample) :
#endif
      seek_to_absolute_sample_(decoder, length, sample)
    ;
    decoder->private_->is_seeking = false;
    return ok;
  }
}

FLAC_API FLAC__uint64 FLAC__stream_decoder_find_total_samples(FLAC__StreamDecoder *decoder)
{
  if(
    decoder->protected_->state != FLAC__STREAM_DECODER_SEARCH_FOR_METADATA &&
    decoder->protected_->state != FLAC__STREAM_DECODER_READ_METADATA &&
    decoder->protected_->state != FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC &&
    decoder->protected_->state != FLAC__STREAM_DECODER_READ_FRAME &&
    decoder->protected_->state != FLAC__STREAM_DECODER_END_OF_STREAM
  )
    return 0;

  if(
    decoder->private_->length_callback == NULL ||
    decoder->private_->seek_callback == NULL ||
    decoder->private_->tell_callback == NULL
  )
    return 0;

#if FLAC__HAS_OGG
  if(decoder->private_->is_ogg && FLAC__ogg_decoder_aspect_get_decode_chained_stream(&decoder->protected_->ogg_decoder_aspect)) {
    /* Keep moving forward until reaching end-of-stream */
    uint32_t i;
    FLAC__uint64 total_samples = 0;
    decoder->private_->is_indexing = true;
    while(1) {
      FLAC__OggDecoderAspectReadStatus status;
      if(decoder->protected_->state == FLAC__STREAM_DECODER_END_OF_STREAM ||
         decoder->protected_->state == FLAC__STREAM_DECODER_OGG_ERROR ||
         decoder->protected_->state == FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR ||
         decoder->protected_->state == FLAC__STREAM_DECODER_ABORTED) {
        decoder->private_->is_indexing = false;
        decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
        return 0;
      }
      status = FLAC__ogg_decoder_aspect_skip_link(&decoder->protected_->ogg_decoder_aspect, read_callback_proxy_, decoder->private_->seek_callback, decoder->private_->tell_callback, decoder->private_->length_callback, decoder, decoder->private_->client_data);
      if(status == FLAC__OGG_DECODER_ASPECT_READ_STATUS_END_OF_STREAM)
        break;
      else if(status != FLAC__OGG_DECODER_ASPECT_READ_STATUS_OK) {
        decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
        return 0;
      }
    }
    decoder->private_->is_indexing = false;
    for(i = 0; i < decoder->protected_->ogg_decoder_aspect.number_of_links_indexed; i++) {
      total_samples += decoder->protected_->ogg_decoder_aspect.linkdetails[i].samples;
    }
    return total_samples;
  }
  else
#endif /* FLAC__HAS_OGG */
  { /* not decoding chained ogg */
    FLAC__uint64 length;
    FLAC__uint64 pos;
    uint32_t eof_distance = 1024; /* Some number, needs tuning */
    decoder->private_->is_seeking = true;
    decoder->private_->target_sample = UINT64_MAX;
    /* get the file length */
    if(decoder->private_->length_callback(decoder, &length, decoder->private_->client_data) != FLAC__STREAM_DECODER_LENGTH_STATUS_OK) {
      decoder->private_->is_indexing = false;
      return 0;
    }
    pos = length;
    for( ; ; eof_distance *= 2) {
      if(eof_distance > (1u << FLAC__STREAM_METADATA_LENGTH_LEN)) {
        /* Could not find a frame within a reasonable distance of EOF */
        return 0;
      }
      else if(pos == 0) {
        /* Did not find a frame while reading from the start of the file */
        return 0;
      }
      else if(eof_distance > length) {
        pos = 0;
      }
      else {
        pos = length - eof_distance;
      }

      if(decoder->private_->seek_callback(decoder, pos, decoder->private_->client_data) != FLAC__STREAM_DECODER_SEEK_STATUS_OK) {
        decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
        return 0;
      }
      if(!FLAC__stream_decoder_flush(decoder)) {
        /* above call sets the state for us */
        return 0;
      }

      decoder->private_->got_a_frame = false;
      if(!FLAC__stream_decoder_process_single(decoder) ||
         decoder->protected_->state == FLAC__STREAM_DECODER_ABORTED) {
        if(decoder->protected_->state != FLAC__STREAM_DECODER_ABORTED && decoder->protected_->state != FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR)
          decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
        return 0;
      }
      if(decoder->private_->got_a_frame) {
        /* Found a frame, but we need the last frame and the frame before that, unless the last frame is
         * also the first frame */
        if(decoder->private_->frame.header.number.sample_number > 0) {
          /* For now, assume this is not the last frame, set blocksize, and continue.
           * If it turns out this is not the last frame, we'll start over anyway */
          decoder->private_->fixed_block_size = decoder->private_->last_frame.header.blocksize;
          if(!FLAC__stream_decoder_process_single(decoder) ||
             decoder->protected_->state == FLAC__STREAM_DECODER_ABORTED) {
            if(decoder->protected_->state != FLAC__STREAM_DECODER_ABORTED && decoder->protected_->state != FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR)
              decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
            return 0;
          }
          if(decoder->protected_->state == FLAC__STREAM_DECODER_END_OF_STREAM) {
            /* Found last frame, but need to find frame before that too */
            continue;
          }
        }
        if(!FLAC__stream_decoder_process_until_end_of_stream(decoder))
          return 0;
        FLAC__ASSERT(decoder->private_->is_seeking);
        FLAC__ASSERT(decoder->private_->last_frame_is_set);
        decoder->private_->is_seeking = false;
        return (FLAC__uint64)decoder->private_->last_frame.header.number.sample_number + (FLAC__uint64)decoder->private_->last_frame.header.blocksize;

      }
    }
  }
  return 0;
}

FLAC_API int32_t FLAC__stream_decoder_get_link_lengths(FLAC__StreamDecoder *decoder, FLAC__uint64 **link_lengths)
{
  /* If we don't have Ogg, this is (for now) useless, fail */
#if FLAC__HAS_OGG
  uint32_t i;

  /* Check whether we're decoding chaines ogg, and decoder is somewhat valid */
  if(!decoder->private_->is_ogg ||
     !FLAC__stream_decoder_get_decode_chained_stream(decoder) ||
     decoder->protected_->state == FLAC__STREAM_DECODER_ABORTED ||
     decoder->protected_->state == FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR ||
     decoder->protected_->state == FLAC__STREAM_DECODER_UNINITIALIZED)
    return FLAC__STREAM_DECODER_GET_LINK_LENGTHS_INVALID;

  /* Check whether link details are known. If not, fail */
  if(decoder->protected_->ogg_decoder_aspect.number_of_links_indexed == 0 ||
     !decoder->protected_->ogg_decoder_aspect.linkdetails[decoder->protected_->ogg_decoder_aspect.number_of_links_indexed - 1].is_last)
    return FLAC__STREAM_DECODER_GET_LINK_LENGTHS_NOT_INDEXED;

  if(link_lengths != NULL) {
    *link_lengths = safe_malloc_mul_2op_p(sizeof(FLAC__uint64), decoder->protected_->ogg_decoder_aspect.number_of_links_indexed);
    if(*link_lengths == NULL)
      return FLAC__STREAM_DECODER_GET_LINK_LENGTHS_MEMORY_ALLOCATION_ERROR;

    for(i = 0; i < decoder->protected_->ogg_decoder_aspect.number_of_links_indexed; i++)
      (*link_lengths)[i] = decoder->protected_->ogg_decoder_aspect.linkdetails[i].samples;
  }

  return decoder->protected_->ogg_decoder_aspect.number_of_links_indexed;
#else
  (void)decoder;
  (void)link_lengths;
  return FLAC__STREAM_DECODER_GET_LINK_LENGTHS_INVALID;
#endif
}


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

uint32_t FLAC__stream_decoder_get_input_bytes_unconsumed(const FLAC__StreamDecoder *decoder)
{
  FLAC__ASSERT(0 != decoder);
  FLAC__ASSERT(FLAC__bitreader_is_consumed_byte_aligned(decoder->private_->input));
  FLAC__ASSERT(!(FLAC__bitreader_get_input_bits_unconsumed(decoder->private_->input) & 7));
  return FLAC__bitreader_get_input_bits_unconsumed(decoder->private_->input) / 8;
}

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

void set_defaults_(FLAC__StreamDecoder *decoder)
{
  decoder->private_->is_ogg = false;
  decoder->private_->read_callback = 0;
  decoder->private_->seek_callback = 0;
  decoder->private_->tell_callback = 0;
  decoder->private_->length_callback = 0;
  decoder->private_->eof_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;

  decoder->protected_->md5_checking = false;

#if FLAC__HAS_OGG
  FLAC__ogg_decoder_aspect_set_defaults(&decoder->protected_->ogg_decoder_aspect);
#endif
}

/*
 * This will forcibly set stdin to binary mode (for OSes that require it)
 */
FILE *get_binary_stdin_(void)
{
  /* if something breaks here it is probably due to the presence or
   * absence of an underscore before the identifiers 'setmode',
   * 'fileno', and/or 'O_BINARY'; check your system header files.
   */
#if defined _MSC_VER || defined __MINGW32__
  _setmode(_fileno(stdin), _O_BINARY);
#elif defined __EMX__
  setmode(fileno(stdin), O_BINARY);
#endif

  return stdin;
}

FLAC__bool allocate_output_(FLAC__StreamDecoder *decoder, uint32_t size, uint32_t channels, uint32_t bps)
{
  uint32_t i;
  FLAC__int32 *tmp;

  if(size <= decoder->private_->output_capacity && channels <= decoder->private_->output_channels &&
     (bps < 32 || decoder->private_->side_subframe != 0))
    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;
    }
  }

  if(0 != decoder->private_->side_subframe) {
    free(decoder->private_->side_subframe);
    decoder->private_->side_subframe = 0;
  }

  /* Only grow per-channel buffers, even if number of channels increases */
  if(decoder->private_->output_capacity > size) {
    size = decoder->private_->output_capacity;
  }

  for(i = 0; i < channels; i++) {
    /* WATCHOUT:
     * FLAC__lpc_restore_signal_asm_ia32_mmx() and ..._intrin_sseN()
     * require 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 = safe_malloc_muladd2_(sizeof(FLAC__int32), /*times (*/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;

    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;
    }
  }

  if(bps == 32) {
    decoder->private_->side_subframe = safe_malloc_mul_2op_p(sizeof(FLAC__int64), /*times (*/size);
    if(decoder->private_->side_subframe == NULL) {
      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)
{
  size_t 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;
  uint32_t i, id;
  FLAC__bool first = true;

  FLAC__ASSERT(FLAC__bitreader_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__bitreader_read_raw_uint32(decoder->private_->input, &x, 8))
        return false; /* read_callback_ sets the state for us */
    }
    if(x == FLAC__STREAM_SYNC_STRING[i]) {
      first = true;
      i++;
      id = 0;
      continue;
    }

    if(id >= 3)
      return false;

    if(x == ID3V2_TAG_[id]) {
      id++;
      i = 0;
      if(id == 3) {
        if(!skip_id3v2_tag_(decoder))
          return false; /* skip_id3v2_tag_ sets the state for us */
      }
      continue;
    }
    id = 0;
    if(x == 0xff) { /* MAGIC NUMBER for the first 8 frame sync bits */
      decoder->private_->header_warmup[0] = (FLAC__byte)x;
      if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, 8))
        return false; /* 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 >> 1 == 0x7c) { /* MAGIC NUMBER for the last 6 sync bits and reserved 7th bit */
        decoder->private_->header_warmup[1] = (FLAC__byte)x;
        decoder->protected_->state = FLAC__STREAM_DECODER_READ_FRAME;
        return true;
      }
    }
    i = 0;
    if(first) {
      send_error_to_client_(decoder, FLAC__STREAM_DECODER_ERROR_STATUS_LOST_SYNC);
      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__bitreader_is_consumed_byte_aligned(decoder->private_->input));

  if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, FLAC__STREAM_METADATA_IS_LAST_LEN))
    return false; /* read_callback_ sets the state for us */
  is_last = x? true : false;

  if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &type, FLAC__STREAM_METADATA_TYPE_LEN))
    return false; /* read_callback_ sets the state for us */

  if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &length, FLAC__STREAM_METADATA_LENGTH_LEN))
    return false; /* 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(0 == memcmp(decoder->private_->stream_info.data.stream_info.md5sum, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0", 16))
      decoder->private_->do_md5_checking = false;
    if(!decoder->private_->is_seeking && decoder->private_->metadata_filter[FLAC__METADATA_TYPE_STREAMINFO] && decoder->private_->metadata_callback)
      decoder->private_->metadata_callback(decoder, &decoder->private_->stream_info, decoder->private_->client_data);
  }
  else if(type == FLAC__METADATA_TYPE_SEEKTABLE) {
    /* just in case we already have a seek table, and reading the next one fails: */
    decoder->private_->has_seek_table = false;

    if(length > 0) {
      if(!read_metadata_seektable_(decoder, is_last, length))
        return false;

      decoder->private_->has_seek_table = true;
      if(!decoder->private_->is_seeking && decoder->private_->metadata_filter[FLAC__METADATA_TYPE_SEEKTABLE] && decoder->private_->metadata_callback)
        decoder->private_->metadata_callback(decoder, &decoder->private_->seek_table, decoder->private_->client_data);
    }
  }
  else {
    FLAC__bool skip_it = !decoder->private_->metadata_filter[type];
    uint32_t real_length = length;
    FLAC__StreamMetadata block;

    memset(&block, 0, sizeof(block));
    block.is_last = is_last;
    block.type = (FLAC__MetadataType)type;
    block.length = length;

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

      if(real_length < FLAC__STREAM_METADATA_APPLICATION_ID_LEN/8) { /* underflow check */
        decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;/*@@@@@@ maybe wrong error? need to resync?*/
        return false;
      }

      real_length -= FLAC__STREAM_METADATA_APPLICATION_ID_LEN/8;

      if(decoder->private_->metadata_filter_ids_count > 0 && has_id_filtered_(decoder, block.data.application.id))
        skip_it = !skip_it;
    }

    if(skip_it) {
      if(!FLAC__bitreader_skip_byte_block_aligned_no_crc(decoder->private_->input, real_length))
        return false; /* read_callback_ sets the state for us */
    }
    else {
      FLAC__bool ok = true;
      FLAC__bitreader_set_limit(decoder->private_->input, real_length*8);
      switch(type) {
        case FLAC__METADATA_TYPE_PADDING:
          /* skip the padding bytes */
          if(!FLAC__bitreader_skip_byte_block_aligned_no_crc(decoder->private_->input, real_length))
            ok = false; /* read_callback_ sets the state for us */
          break;
        case FLAC__METADATA_TYPE_APPLICATION:
          /* remember, we read the ID already */
          if(real_length > 0) {
            if(0 == (block.data.application.data = malloc(real_length))) {
              decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
              ok = false;
            }
            else if(!FLAC__bitreader_read_byte_block_aligned_no_crc(decoder->private_->input, block.data.application.data, real_length))
              ok = false; /* read_callback_ sets the state for us */
          }
          else
            block.data.application.data = 0;
          break;
        case FLAC__METADATA_TYPE_VORBIS_COMMENT:
          if(!read_metadata_vorbiscomment_(decoder, &block.data.vorbis_comment, real_length))
            ok = false;
          break;
        case FLAC__METADATA_TYPE_CUESHEET:
          if(!read_metadata_cuesheet_(decoder, &block.data.cue_sheet))
            ok = false;
          break;
        case FLAC__METADATA_TYPE_PICTURE:
          if(!read_metadata_picture_(decoder, &block.data.picture))
            ok = false;
          break;
        case FLAC__METADATA_TYPE_STREAMINFO:
        case FLAC__METADATA_TYPE_SEEKTABLE:
          FLAC__ASSERT(0);
          break;
        default:
          if(real_length > 0) {
            if(0 == (block.data.unknown.data = malloc(real_length))) {
              decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
              ok = false;
            }
            else if(!FLAC__bitreader_read_byte_block_aligned_no_crc(decoder->private_->input, block.data.unknown.data, real_length))
              ok = false; /* read_callback_ sets the state for us */
          }
          else
            block.data.unknown.data = 0;
          break;
      }
      if(FLAC__bitreader_limit_remaining(decoder->private_->input) > 0) {
        /* Content in metadata block didn't fit in block length
         * We cannot know whether the length or the content was
         * corrupt, so stop parsing metadata */
        send_error_to_client_(decoder, FLAC__STREAM_DECODER_ERROR_STATUS_BAD_METADATA);
        if(decoder->protected_->state == FLAC__STREAM_DECODER_READ_METADATA)
          decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
        ok = false;
      }
      FLAC__bitreader_remove_limit(decoder->private_->input);
      if(ok && !decoder->private_->is_seeking && decoder->private_->metadata_callback)
        decoder->private_->metadata_callback(decoder, &block, decoder->private_->client_data);

      /* now we have to free any malloc()ed data in the block */
      switch(type) {
        case FLAC__METADATA_TYPE_PADDING:
          break;
        case FLAC__METADATA_TYPE_APPLICATION:
          if(0 != block.data.application.data)
            free(block.data.application.data);
          break;
        case FLAC__METADATA_TYPE_VORBIS_COMMENT:
          if(0 != block.data.vorbis_comment.vendor_string.entry)
            free(block.data.vorbis_comment.vendor_string.entry);
          if(block.data.vorbis_comment.num_comments > 0)
            for(i = 0; i < block.data.vorbis_comment.num_comments; i++)
              if(0 != block.data.vorbis_comment.comments[i].entry)
                free(block.data.vorbis_comment.comments[i].entry);
          if(0 != block.data.vorbis_comment.comments)
            free(block.data.vorbis_comment.comments);
          break;
        case FLAC__METADATA_TYPE_CUESHEET:
          if(block.data.cue_sheet.num_tracks > 0 && 0 != block.data.cue_sheet.tracks)
            for(i = 0; i < block.data.cue_sheet.num_tracks; i++)
              if(0 != block.data.cue_sheet.tracks[i].indices)
                free(block.data.cue_sheet.tracks[i].indices);
          if(0 != block.data.cue_sheet.tracks)
            free(block.data.cue_sheet.tracks);
          break;
        case FLAC__METADATA_TYPE_PICTURE:
          if(0 != block.data.picture.mime_type)
            free(block.data.picture.mime_type);
          if(0 != block.data.picture.description)
            free(block.data.picture.description);
          if(0 != block.data.picture.data)
            free(block.data.picture.data);
          break;
        case FLAC__METADATA_TYPE_STREAMINFO:
        case FLAC__METADATA_TYPE_SEEKTABLE:
          FLAC__ASSERT(0);
        default:
          if(0 != block.data.unknown.data)
            free(block.data.unknown.data);
          break;
      }

      if(!ok) /* anything that unsets "ok" should also make sure decoder->protected_->state is updated */
        return false;
    }
  }

  if(is_last) {
    /* if this fails, it's OK, it's just a hint for the seek routine */
    if(!FLAC__stream_decoder_get_decode_position(decoder, &decoder->private_->first_frame_offset))
      decoder->private_->first_frame_offset = 0;
    decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
  }

  return true;
}

FLAC__bool read_metadata_streaminfo_(FLAC__StreamDecoder *decoder, FLAC__bool is_last, uint32_t length)
{
  FLAC__uint32 x;
  uint32_t bits, used_bits = 0;

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

  decoder->private_->stream_info.type = FLAC__METADATA_TYPE_STREAMINFO;
  decoder->private_->stream_info.is_last = is_last;
  decoder->private_->stream_info.length = length;

  bits = FLAC__STREAM_METADATA_STREAMINFO_MIN_BLOCK_SIZE_LEN;
  if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, bits))
    return false; /* read_callback_ sets the state for us */
  decoder->private_->stream_info.data.stream_info.min_blocksize = x;
  used_bits += bits;

  bits = FLAC__STREAM_METADATA_STREAMINFO_MAX_BLOCK_SIZE_LEN;
  if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, FLAC__STREAM_METADATA_STREAMINFO_MAX_BLOCK_SIZE_LEN))
    return false; /* read_callback_ sets the state for us */
  decoder->private_->stream_info.data.stream_info.max_blocksize = x;
  used_bits += bits;

  bits = FLAC__STREAM_METADATA_STREAMINFO_MIN_FRAME_SIZE_LEN;
  if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, FLAC__STREAM_METADATA_STREAMINFO_MIN_FRAME_SIZE_LEN))
    return false; /* read_callback_ sets the state for us */
  decoder->private_->stream_info.data.stream_info.min_framesize = x;
  used_bits += bits;

  bits = FLAC__STREAM_METADATA_STREAMINFO_MAX_FRAME_SIZE_LEN;
  if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, FLAC__STREAM_METADATA_STREAMINFO_MAX_FRAME_SIZE_LEN))
    return false; /* read_callback_ sets the state for us */
  decoder->private_->stream_info.data.stream_info.max_framesize = x;
  used_bits += bits;

  bits = FLAC__STREAM_METADATA_STREAMINFO_SAMPLE_RATE_LEN;
  if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, FLAC__STREAM_METADATA_STREAMINFO_SAMPLE_RATE_LEN))
    return false; /* read_callback_ sets the state for us */
  decoder->private_->stream_info.data.stream_info.sample_rate = x;
  used_bits += bits;

  bits = FLAC__STREAM_METADATA_STREAMINFO_CHANNELS_LEN;
  if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, FLAC__STREAM_METADATA_STREAMINFO_CHANNELS_LEN))
    return false; /* read_callback_ sets the state for us */
  decoder->private_->stream_info.data.stream_info.channels = x+1;
  used_bits += bits;

  bits = FLAC__STREAM_METADATA_STREAMINFO_BITS_PER_SAMPLE_LEN;
  if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, FLAC__STREAM_METADATA_STREAMINFO_BITS_PER_SAMPLE_LEN))
    return false; /* read_callback_ sets the state for us */
  decoder->private_->stream_info.data.stream_info.bits_per_sample = x+1;
  used_bits += bits;

  bits = FLAC__STREAM_METADATA_STREAMINFO_TOTAL_SAMPLES_LEN;
  if(!FLAC__bitreader_read_raw_uint64(decoder->private_->input, &decoder->private_->stream_info.data.stream_info.total_samples, FLAC__STREAM_METADATA_STREAMINFO_TOTAL_SAMPLES_LEN))
    return false; /* read_callback_ sets the state for us */
  used_bits += bits;

  if(!FLAC__bitreader_read_byte_block_aligned_no_crc(decoder->private_->input, decoder->private_->stream_info.data.stream_info.md5sum, 16))
    return false; /* read_callback_ sets the state for us */
  used_bits += 16*8;

  /* skip the rest of the block */
  FLAC__ASSERT(used_bits % 8 == 0);
  if (length < (used_bits / 8))
    return false; /* read_callback_ sets the state for us */
  length -= (used_bits / 8);
  if(!FLAC__bitreader_skip_byte_block_aligned_no_crc(decoder->private_->input, length))
    return false; /* read_callback_ sets the state for us */

  return true;
}

FLAC__bool read_metadata_seektable_(FLAC__StreamDecoder *decoder, FLAC__bool is_last, uint32_t length)
{
  FLAC__uint32 i, x;
  FLAC__uint64 xx;

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

  decoder->private_->seek_table.type = FLAC__METADATA_TYPE_SEEKTABLE;
  decoder->private_->seek_table.is_last = is_last;
  decoder->private_->seek_table.length = length;

  if(length % FLAC__STREAM_METADATA_SEEKPOINT_LENGTH) {
    FLAC__bitreader_limit_invalidate(decoder->private_->input);
    return false;
  }

  decoder->private_->seek_table.data.seek_table.num_points = length / FLAC__STREAM_METADATA_SEEKPOINT_LENGTH;

  /* use realloc since we may pass through here several times (e.g. after seeking) */
  if(0 == (decoder->private_->seek_table.data.seek_table.points = safe_realloc_mul_2op_(decoder->private_->seek_table.data.seek_table.points, decoder->private_->seek_table.data.seek_table.num_points, /*times*/sizeof(FLAC__StreamMetadata_SeekPoint)))) {
    decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
    return false;
  }
  for(i = 0; i < decoder->private_->seek_table.data.seek_table.num_points; i++) {
    if(!FLAC__bitreader_read_raw_uint64(decoder->private_->input, &xx, FLAC__STREAM_METADATA_SEEKPOINT_SAMPLE_NUMBER_LEN))
      return false; /* read_callback_ sets the state for us */
    decoder->private_->seek_table.data.seek_table.points[i].sample_number = xx;

    if(!FLAC__bitreader_read_raw_uint64(decoder->private_->input, &xx, FLAC__STREAM_METADATA_SEEKPOINT_STREAM_OFFSET_LEN))
      return false; /* read_callback_ sets the state for us */
    decoder->private_->seek_table.data.seek_table.points[i].stream_offset = xx;

    if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, FLAC__STREAM_METADATA_SEEKPOINT_FRAME_SAMPLES_LEN))
      return false; /* read_callback_ sets the state for us */
    decoder->private_->seek_table.data.seek_table.points[i].frame_samples = x;
  }
  length -= (decoder->private_->seek_table.data.seek_table.num_points * FLAC__STREAM_METADATA_SEEKPOINT_LENGTH);

  FLAC__ASSERT(length == 0);

  return true;
}

FLAC__bool read_metadata_vorbiscomment_(FLAC__StreamDecoder *decoder, FLAC__StreamMetadata_VorbisComment *obj, uint32_t length)
{
  FLAC__uint32 i;

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

  /* read vendor string */
  if (length >= 8) {
    length -= 8; /* vendor string length + num comments entries alone take 8 bytes */
    FLAC__ASSERT(FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN == 32);
    if (!FLAC__bitreader_read_uint32_little_endian(decoder->private_->input, &obj->vendor_string.length))
      return false; /* read_callback_ sets the state for us */
    if (length < obj->vendor_string.length) {
      obj->vendor_string.length = 0;
      obj->vendor_string.entry = 0;
      goto skip;
    }
    else
      length -= obj->vendor_string.length;
    if (0 == (obj->vendor_string.entry = safe_malloc_add_2op_(obj->vendor_string.length, /*+*/1))) {
      decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
      return false;
    }
    if (!FLAC__bitreader_read_byte_block_aligned_no_crc(decoder->private_->input, obj->vendor_string.entry, obj->vendor_string.length))
      return false; /* read_callback_ sets the state for us */
    obj->vendor_string.entry[obj->vendor_string.length] = '\0';

    /* read num comments */
    FLAC__ASSERT(FLAC__STREAM_METADATA_VORBIS_COMMENT_NUM_COMMENTS_LEN == 32);
    if (!FLAC__bitreader_read_uint32_little_endian(decoder->private_->input, &obj->num_comments))
      return false; /* read_callback_ sets the state for us */

    /* read comments */
    if (obj->num_comments > 100000) {
      /* Possibly malicious file. */
      obj->num_comments = 0;
      return false;
    }
    if (obj->num_comments > 0) {
      if (0 == (obj->comments = safe_malloc_mul_2op_p(obj->num_comments, /*times*/sizeof(FLAC__StreamMetadata_VorbisComment_Entry)))) {
        obj->num_comments = 0;
        decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
        return false;
      }
      for (i = 0; i < obj->num_comments; i++) {
        /* Initialize here just to make sure. */
        obj->comments[i].length = 0;
        obj->comments[i].entry = 0;

        FLAC__ASSERT(FLAC__STREAM_METADATA_VORBIS_COMMENT_ENTRY_LENGTH_LEN == 32);
        if (length < 4) {
          obj->num_comments = i;
          goto skip;
        }
        else
          length -= 4;
        if (!FLAC__bitreader_read_uint32_little_endian(decoder->private_->input, &obj->comments[i].length)) {
          obj->num_comments = i;
          return false; /* read_callback_ sets the state for us */
        }
        if (length < obj->comments[i].length) {
          obj->num_comments = i;
          FLAC__bitreader_limit_invalidate(decoder->private_->input);
          return false;
        }
        else
          length -= obj->comments[i].length;
        if (0 == (obj->comments[i].entry = safe_malloc_add_2op_(obj->comments[i].length, /*+*/1))) {
          decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
          obj->num_comments = i;
          return false;
        }
        memset (obj->comments[i].entry, 0, obj->comments[i].length) ;
        if (!FLAC__bitreader_read_byte_block_aligned_no_crc(decoder->private_->input, obj->comments[i].entry, obj->comments[i].length)) {
          /* Current i-th entry is bad, so we delete it. */
          free (obj->comments[i].entry) ;
          obj->comments[i].entry = NULL ;
          obj->num_comments = i;
          goto skip;
        }
        obj->comments[i].entry[obj->comments[i].length] = '\0';
      }
    }
  }
  else {
    FLAC__bitreader_limit_invalidate(decoder->private_->input);
    return false;
  }

  skip:
  if (length > 0) {
    /* length > 0 can only happen on files with invalid data in comments */
    if(obj->num_comments < 1) {
      free(obj->comments);
      obj->comments = NULL;
    }
    FLAC__bitreader_limit_invalidate(decoder->private_->input);
    return false;
  }

  return true;
}

FLAC__bool read_metadata_cuesheet_(FLAC__StreamDecoder *decoder, FLAC__StreamMetadata_CueSheet *obj)
{
  FLAC__uint32 i, j, x;

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

  memset(obj, 0, sizeof(FLAC__StreamMetadata_CueSheet));

  FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN % 8 == 0);
  if(!FLAC__bitreader_read_byte_block_aligned_no_crc(decoder->private_->input, (FLAC__byte*)obj->media_catalog_number, FLAC__STREAM_METADATA_CUESHEET_MEDIA_CATALOG_NUMBER_LEN/8))
    return false; /* read_callback_ sets the state for us */

  if(!FLAC__bitreader_read_raw_uint64(decoder->private_->input, &obj->lead_in, FLAC__STREAM_METADATA_CUESHEET_LEAD_IN_LEN))
    return false; /* read_callback_ sets the state for us */

  if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, FLAC__STREAM_METADATA_CUESHEET_IS_CD_LEN))
    return false; /* read_callback_ sets the state for us */
  obj->is_cd = x? true : false;

  if(!FLAC__bitreader_skip_bits_no_crc(decoder->private_->input, FLAC__STREAM_METADATA_CUESHEET_RESERVED_LEN))
    return false; /* read_callback_ sets the state for us */

  if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, FLAC__STREAM_METADATA_CUESHEET_NUM_TRACKS_LEN))
    return false; /* read_callback_ sets the state for us */
  obj->num_tracks = x;

  if(obj->num_tracks > 0) {
    if(0 == (obj->tracks = safe_calloc_(obj->num_tracks, sizeof(FLAC__StreamMetadata_CueSheet_Track)))) {
      decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
      return false;
    }
    for(i = 0; i < obj->num_tracks; i++) {
      FLAC__StreamMetadata_CueSheet_Track *track = &obj->tracks[i];
      if(!FLAC__bitreader_read_raw_uint64(decoder->private_->input, &track->offset, FLAC__STREAM_METADATA_CUESHEET_TRACK_OFFSET_LEN))
        return false; /* read_callback_ sets the state for us */

      if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, FLAC__STREAM_METADATA_CUESHEET_TRACK_NUMBER_LEN))
        return false; /* read_callback_ sets the state for us */
      track->number = (FLAC__byte)x;

      FLAC__ASSERT(FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN % 8 == 0);
      if(!FLAC__bitreader_read_byte_block_aligned_no_crc(decoder->private_->input, (FLAC__byte*)track->isrc, FLAC__STREAM_METADATA_CUESHEET_TRACK_ISRC_LEN/8))
        return false; /* read_callback_ sets the state for us */

      if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, FLAC__STREAM_METADATA_CUESHEET_TRACK_TYPE_LEN))
        return false; /* read_callback_ sets the state for us */
      track->type = x;

      if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, FLAC__STREAM_METADATA_CUESHEET_TRACK_PRE_EMPHASIS_LEN))
        return false; /* read_callback_ sets the state for us */
      track->pre_emphasis = x;

      if(!FLAC__bitreader_skip_bits_no_crc(decoder->private_->input, FLAC__STREAM_METADATA_CUESHEET_TRACK_RESERVED_LEN))
        return false; /* read_callback_ sets the state for us */

      if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, FLAC__STREAM_METADATA_CUESHEET_TRACK_NUM_INDICES_LEN))
        return false; /* read_callback_ sets the state for us */
      track->num_indices = (FLAC__byte)x;

      if(track->num_indices > 0) {
        if(0 == (track->indices = safe_calloc_(track->num_indices, sizeof(FLAC__StreamMetadata_CueSheet_Index)))) {
          decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
          return false;
        }
        for(j = 0; j < track->num_indices; j++) {
          FLAC__StreamMetadata_CueSheet_Index *indx = &track->indices[j];
          if(!FLAC__bitreader_read_raw_uint64(decoder->private_->input, &indx->offset, FLAC__STREAM_METADATA_CUESHEET_INDEX_OFFSET_LEN))
            return false; /* read_callback_ sets the state for us */

          if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, FLAC__STREAM_METADATA_CUESHEET_INDEX_NUMBER_LEN))
            return false; /* read_callback_ sets the state for us */
          indx->number = (FLAC__byte)x;

          if(!FLAC__bitreader_skip_bits_no_crc(decoder->private_->input, FLAC__STREAM_METADATA_CUESHEET_INDEX_RESERVED_LEN))
            return false; /* read_callback_ sets the state for us */
        }
      }
    }
  }
  else { /* obj->num_tracks == 0 */
    FLAC__bitreader_limit_invalidate(decoder->private_->input);
    return false;
  }

  return true;
}

FLAC__bool read_metadata_picture_(FLAC__StreamDecoder *decoder, FLAC__StreamMetadata_Picture *obj)
{
  FLAC__uint32 x;

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

  /* read type */
  if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, FLAC__STREAM_METADATA_PICTURE_TYPE_LEN))
    return false; /* read_callback_ sets the state for us */
  if(x < FLAC__STREAM_METADATA_PICTURE_TYPE_UNDEFINED)
    obj->type = x;
  else
    obj->type = FLAC__STREAM_METADATA_PICTURE_TYPE_OTHER;

  /* read MIME type */
  if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, FLAC__STREAM_METADATA_PICTURE_MIME_TYPE_LENGTH_LEN))
    return false; /* read_callback_ sets the state for us */
  if(FLAC__bitreader_limit_remaining(decoder->private_->input) < x){
    FLAC__bitreader_limit_invalidate(decoder->private_->input);
    return false;
  }
  if(0 == (obj->mime_type = safe_malloc_add_2op_(x, /*+*/1))) {
    decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
    return false;
  }
  if(x > 0) {
    if(!FLAC__bitreader_read_byte_block_aligned_no_crc(decoder->private_->input, (FLAC__byte*)obj->mime_type, x))
      return false; /* read_callback_ sets the state for us */
  }
  obj->mime_type[x] = '\0';

  /* read description */
  if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, FLAC__STREAM_METADATA_PICTURE_DESCRIPTION_LENGTH_LEN))
    return false; /* read_callback_ sets the state for us */
  if(FLAC__bitreader_limit_remaining(decoder->private_->input) < x){
    FLAC__bitreader_limit_invalidate(decoder->private_->input);
    return false;
  }
  if(0 == (obj->description = safe_malloc_add_2op_(x, /*+*/1))) {
    decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
    return false;
  }
  if(x > 0) {
    if(!FLAC__bitreader_read_byte_block_aligned_no_crc(decoder->private_->input, obj->description, x))
      return false; /* read_callback_ sets the state for us */
  }
  obj->description[x] = '\0';

  /* read width */
  if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &obj->width, FLAC__STREAM_METADATA_PICTURE_WIDTH_LEN))
    return false; /* read_callback_ sets the state for us */

  /* read height */
  if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &obj->height, FLAC__STREAM_METADATA_PICTURE_HEIGHT_LEN))
    return false; /* read_callback_ sets the state for us */

  /* read depth */
  if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &obj->depth, FLAC__STREAM_METADATA_PICTURE_DEPTH_LEN))
    return false; /* read_callback_ sets the state for us */

  /* read colors */
  if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &obj->colors, FLAC__STREAM_METADATA_PICTURE_COLORS_LEN))
    return false; /* read_callback_ sets the state for us */

  /* read data */
  if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &(obj->data_length), FLAC__STREAM_METADATA_PICTURE_DATA_LENGTH_LEN))
    return false; /* read_callback_ sets the state for us */
  if(FLAC__bitreader_limit_remaining(decoder->private_->input) < obj->data_length){
    FLAC__bitreader_limit_invalidate(decoder->private_->input);
    return false;
  }
  if(0 == (obj->data = safe_malloc_(obj->data_length))) {
    decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
    return false;
  }
  if(obj->data_length > 0) {
    if(!FLAC__bitreader_read_byte_block_aligned_no_crc(decoder->private_->input, obj->data, obj->data_length))
      return false; /* read_callback_ sets the state for us */
  }

  return true;
}

FLAC__bool skip_id3v2_tag_(FLAC__StreamDecoder *decoder)
{
  FLAC__uint32 x;
  uint32_t i, skip;

  /* skip the version and flags bytes */
  if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, 24))
    return false; /* read_callback_ sets the state for us */
  /* get the size (in bytes) to skip */
  skip = 0;
  for(i = 0; i < 4; i++) {
    if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, 8))
      return false; /* read_callback_ sets the state for us */
    skip <<= 7;
    skip |= (x & 0x7f);
  }
  /* skip the rest of the tag */
  if(!FLAC__bitreader_skip_byte_block_aligned_no_crc(decoder->private_->input, skip))
    return false; /* read_callback_ sets the state for us */
  return true;
}

FLAC__bool frame_sync_(FLAC__StreamDecoder *decoder)
{
  FLAC__uint32 x;
  FLAC__bool first = true;

  /* make sure we're byte aligned */
  if(!FLAC__bitreader_is_consumed_byte_aligned(decoder->private_->input)) {
    if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, FLAC__bitreader_bits_left_for_byte_alignment(decoder->private_->input)))
      return false; /* read_callback_ sets the state for us */
  }

  while(1) {
    if(decoder->private_->cached) {
      x = (FLAC__uint32)decoder->private_->lookahead;
      decoder->private_->cached = false;
    }
    else {
      if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, 8))
        return false; /* read_callback_ sets the state for us */
    }
    if(x == 0xff) { /* MAGIC NUMBER for the first 8 frame sync bits */
      decoder->private_->header_warmup[0] = (FLAC__byte)x;
      if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, 8))
        return false; /* 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 >> 1 == 0x7c) { /* MAGIC NUMBER for the last 6 sync bits and reserved 7th bit */
        decoder->private_->header_warmup[1] = (FLAC__byte)x;
        decoder->protected_->state = FLAC__STREAM_DECODER_READ_FRAME;

        /* Save location so we can rewind in case the frame turns
         * out to be invalid after the header */
        FLAC__bitreader_set_framesync_location(decoder->private_->input);
        if(!FLAC__stream_decoder_get_decode_position(decoder, &decoder->private_->last_seen_framesync))
          decoder->private_->last_seen_framesync = 0;
        return true;
      }
    }
    if(first) {
      send_error_to_client_(decoder, FLAC__STREAM_DECODER_ERROR_STATUS_LOST_SYNC);
      first = false;
    }
  }

  return true;
}

FLAC__bool read_frame_(FLAC__StreamDecoder *decoder, FLAC__bool *got_a_frame, FLAC__bool do_full_decode)
{
  uint32_t channel;
  uint32_t i;
  uint32_t frame_crc; /* the one we calculate from the input stream */
  FLAC__uint32 x;

  *got_a_frame = false;
  decoder->private_->side_subframe_in_use = false;

  /* init the CRC */
  frame_crc = 0;
  frame_crc = FLAC__CRC16_UPDATE(decoder->private_->header_warmup[0], frame_crc);
  frame_crc = FLAC__CRC16_UPDATE(decoder->private_->header_warmup[1], frame_crc);
  FLAC__bitreader_reset_read_crc16(decoder->private_->input, (FLAC__uint16)frame_crc);

  if(!read_frame_header_(decoder))
    return false;
  if(decoder->protected_->state == FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC) /* means we didn't sync on a valid header */
    return true;
  if(!allocate_output_(decoder, decoder->private_->frame.header.blocksize, decoder->private_->frame.header.channels, decoder->private_->frame.header.bits_per_sample))
    return false;
  for(channel = 0; channel < decoder->private_->frame.header.channels; channel++) {
    /*
     * first figure the correct bits-per-sample of the subframe
     */
    uint32_t bps = decoder->private_->frame.header.bits_per_sample;
    switch(decoder->private_->frame.header.channel_assignment) {
      case FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT:
        /* no adjustment needed */
        break;
      case FLAC__CHANNEL_ASSIGNMENT_LEFT_SIDE:
        FLAC__ASSERT(decoder->private_->frame.header.channels == 2);
        if(channel == 1)
          bps++;
        break;
      case FLAC__CHANNEL_ASSIGNMENT_RIGHT_SIDE:
        FLAC__ASSERT(decoder->private_->frame.header.channels == 2);
        if(channel == 0)
          bps++;
        break;
      case FLAC__CHANNEL_ASSIGNMENT_MID_SIDE:
        FLAC__ASSERT(decoder->private_->frame.header.channels == 2);
        if(channel == 1)
          bps++;
        break;
      default:
        FLAC__ASSERT(0);
    }
    /*
     * now read it
     */
    if(!read_subframe_(decoder, channel, bps, do_full_decode)){
      /* read_callback_ sets the state for us */
      if(decoder->protected_->state == FLAC__STREAM_DECODER_END_OF_STREAM)
        break;
      else
        return false;
    }
    if(decoder->protected_->state != FLAC__STREAM_DECODER_READ_FRAME)
      break;
  }

  if(decoder->protected_->state != FLAC__STREAM_DECODER_END_OF_STREAM)
    if(!read_zero_padding_(decoder))
      return false;

  /*
   * Read the frame CRC-16 from the footer and check
   */
  if(decoder->protected_->state == FLAC__STREAM_DECODER_READ_FRAME) {
    frame_crc = FLAC__bitreader_get_read_crc16(decoder->private_->input);
    if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, FLAC__FRAME_FOOTER_CRC_LEN)) {
      /* read_callback_ sets the state for us */
      if(decoder->protected_->state != FLAC__STREAM_DECODER_END_OF_STREAM)
        return false;
    }
#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
  }
  if(decoder->protected_->state == FLAC__STREAM_DECODER_READ_FRAME && frame_crc == x) {
#endif
    if(do_full_decode) {
      /* Undo any special channel coding */
      undo_channel_coding(decoder);
      /* Check whether decoded data actually fits bps */
      for(channel = 0; channel < decoder->private_->frame.header.channels; channel++) {
        int shift_bits = 32 - decoder->private_->frame.header.bits_per_sample;
        int lower_limit = INT32_MIN >> shift_bits;
        int upper_limit = INT32_MAX >> shift_bits;
        for(i = 0; i < decoder->private_->frame.header.blocksize; i++) {
          /* Check whether shift_bits MSBs are 'empty' by shifting up and down */
          if((decoder->private_->output[channel][i] < lower_limit) ||
             (decoder->private_->output[channel][i] > upper_limit)) {
            /* Bad frame, emit error */
            send_error_to_client_(decoder, FLAC__STREAM_DECODER_ERROR_STATUS_OUT_OF_BOUNDS);
            decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
            break;
          }
        }
      }
    }
  }
#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
  else if (decoder->protected_->state == FLAC__STREAM_DECODER_READ_FRAME) {
    /* Bad frame, emit error */
    send_error_to_client_(decoder, FLAC__STREAM_DECODER_ERROR_STATUS_FRAME_CRC_MISMATCH);
    decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
  }
#endif

  /* Check whether frames are missing, if so, add silence to compensate */
  if(decoder->private_->last_frame_is_set && decoder->protected_->state == FLAC__STREAM_DECODER_READ_FRAME && !decoder->private_->is_seeking && do_full_decode) {
    FLAC__ASSERT(decoder->private_->frame.header.number_type == FLAC__FRAME_NUMBER_TYPE_SAMPLE_NUMBER);
    FLAC__ASSERT(decoder->private_->last_frame.header.number_type == FLAC__FRAME_NUMBER_TYPE_SAMPLE_NUMBER);
    if(decoder->private_->last_frame.header.number.sample_number + decoder->private_->last_frame.header.blocksize < decoder->private_->frame.header.number.sample_number) {
      uint32_t padding_samples_needed = decoder->private_->frame.header.number.sample_number - (decoder->private_->last_frame.header.number.sample_number + decoder->private_->last_frame.header.blocksize);
      /* Send an error that we lost sync, but only in case no error
       * has been sent yet. This is the case if exactly one or more
       * frames are missing, and the frames before and after it
       * are complete */
      if(!decoder->private_->error_has_been_sent)
        send_error_to_client_(decoder, FLAC__STREAM_DECODER_ERROR_STATUS_MISSING_FRAME);
      /* Do some extra validation to assure last frame an current frame
       * header are both valid before adding silence inbetween
       * Technically both frames could be valid with differing sample_rates,
       * channels and bits_per_sample, but it is quite rare */
      if(decoder->private_->last_frame.header.sample_rate == decoder->private_->frame.header.sample_rate &&
         decoder->private_->last_frame.header.channels == decoder->private_->frame.header.channels &&
         decoder->private_->last_frame.header.bits_per_sample == decoder->private_->frame.header.bits_per_sample &&
         decoder->private_->last_frame.header.blocksize >= 16) {
        FLAC__Frame empty_frame;
        FLAC__int32 * empty_buffer[FLAC__MAX_CHANNELS] = {NULL};
        empty_frame.header = decoder->private_->last_frame.header;
        empty_frame.footer.crc = 0;
        for(i = 0; i < empty_frame.header.channels; i++) {
          empty_buffer[i] = safe_calloc_(empty_frame.header.blocksize, sizeof(FLAC__int32));
          if(empty_buffer[i] == NULL) {
            for(i = 0; i < empty_frame.header.channels; i++)
              if(empty_buffer[i] != NULL)
                free(empty_buffer[i]);
            decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
            return false;
          }
        }
        /* No repairs larger than 5 seconds or 50 frames are made, to not
         * unexpectedly create enormous files when one of the headers was
         * corrupt after all */
        if(padding_samples_needed > (5*empty_frame.header.sample_rate))
          padding_samples_needed = 5*empty_frame.header.sample_rate;
        if(padding_samples_needed > (50*empty_frame.header.blocksize))
          padding_samples_needed = 50*empty_frame.header.blocksize;
        while(padding_samples_needed){
          empty_frame.header.number.sample_number += empty_frame.header.blocksize;
          if(padding_samples_needed < empty_frame.header.blocksize)
            empty_frame.header.blocksize = padding_samples_needed;
          padding_samples_needed -= empty_frame.header.blocksize;
          decoder->protected_->blocksize = empty_frame.header.blocksize;

          FLAC__ASSERT(empty_frame.header.number_type == FLAC__FRAME_NUMBER_TYPE_SAMPLE_NUMBER);
          decoder->private_->samples_decoded = empty_frame.header.number.sample_number + empty_frame.header.blocksize;

          for(channel = 0; channel < empty_frame.header.channels; channel++) {
            empty_frame.subframes[channel].type = FLAC__SUBFRAME_TYPE_CONSTANT;
            empty_frame.subframes[channel].data.constant.value = 0;
            empty_frame.subframes[channel].wasted_bits = 0;
          }

          if(write_audio_frame_to_client_(decoder, &empty_frame, (const FLAC__int32 * const *)empty_buffer) != FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE) {
            decoder->protected_->state = FLAC__STREAM_DECODER_ABORTED;
            for(i = 0; i < empty_frame.header.channels; i++)
              if(empty_buffer[i] != NULL)
                free(empty_buffer[i]);
            return false;
          }
        }
        for(i = 0; i < empty_frame.header.channels; i++)
          if(empty_buffer[i] != NULL)
            free(empty_buffer[i]);

      }
    }
  }

  decoder->private_->error_has_been_sent = false;

  if(decoder->protected_->state == FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC || decoder->protected_->state == FLAC__STREAM_DECODER_END_OF_STREAM) {
#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
    decoder->private_->fuzzing_rewind_count++; /* To stop excessive rewinding, as it causes timeouts */
#endif
    /* Got corruption, rewind if possible. Return value of seek
    * isn't checked, if the seek fails the decoder will continue anyway */
    if(!FLAC__bitreader_rewind_to_after_last_seen_framesync(decoder->private_->input)){
#ifndef NDEBUG
      flac_fprintf(stderr, "Rewinding, seeking necessary\n");
#endif
      if(decoder->private_->seek_callback && decoder->private_->last_seen_framesync){
        /* Last framesync isn't in bitreader anymore, rewind with seek if possible */
#ifndef NDEBUG
        FLAC__uint64 current_decode_position;
        if(FLAC__stream_decoder_get_decode_position(decoder, &current_decode_position))
          flac_fprintf(stderr, "Bitreader was %" PRIu64 " bytes short\n", current_decode_position-decoder->private_->last_seen_framesync);
#endif
        if(decoder->private_->seek_callback(decoder, decoder->private_->last_seen_framesync, decoder->private_->client_data) == FLAC__STREAM_DECODER_SEEK_STATUS_ERROR) {
          decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
          return false;
        }
        if(!FLAC__bitreader_clear(decoder->private_->input)) {
          decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
          return false;
        }
      }
    }
#ifndef NDEBUG
    else{
      flac_fprintf(stderr, "Rewinding, seeking not necessary\n");
    }
#endif
  }
  else {
    *got_a_frame = true;
#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
    decoder->private_->fuzzing_rewind_count = 0;
#endif

    /* we wait to update fixed_block_size until here, when we're sure we've got a proper frame and hence a correct blocksize */
    if(decoder->private_->next_fixed_block_size)
      decoder->private_->fixed_block_size = decoder->private_->next_fixed_block_size;

    /* put the latest values into the public section of the decoder instance */
    decoder->protected_->channels = decoder->private_->frame.header.channels;
    decoder->protected_->channel_assignment = decoder->private_->frame.header.channel_assignment;
    decoder->protected_->bits_per_sample = decoder->private_->frame.header.bits_per_sample;
    decoder->protected_->sample_rate = decoder->private_->frame.header.sample_rate;
    decoder->protected_->blocksize = decoder->private_->frame.header.blocksize;

    FLAC__ASSERT(decoder->private_->frame.header.number_type == FLAC__FRAME_NUMBER_TYPE_SAMPLE_NUMBER);
    decoder->private_->samples_decoded = decoder->private_->frame.header.number.sample_number + decoder->private_->frame.header.blocksize;

    /* write it */
    if(do_full_decode) {
      if(write_audio_frame_to_client_(decoder, &decoder->private_->frame, (const FLAC__int32 * const *)decoder->private_->output) != FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE) {
        decoder->protected_->state = FLAC__STREAM_DECODER_ABORTED;
        return false;
      }
    }
  }

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

FLAC__bool read_frame_header_(FLAC__StreamDecoder *decoder)
{
  FLAC__uint32 x;
  FLAC__uint64 xx;
  uint32_t i, blocksize_hint = 0, sample_rate_hint = 0;
  FLAC__byte crc8, raw_header[16]; /* MAGIC NUMBER based on the maximum frame header size, including CRC */
  uint32_t raw_header_len;
  FLAC__bool is_unparseable = false;

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

  /* init the raw header with the saved bits from synchronization */
  raw_header[0] = decoder->private_->header_warmup[0];
  raw_header[1] = decoder->private_->header_warmup[1];
  raw_header_len = 2;

  /* check to make sure that reserved bit is 0 */
  if(raw_header[1] & 0x02) /* MAGIC NUMBER */
    is_unparseable = true;

  /*
   * Note that along the way as we read the header, we look for a sync
   * code inside.  If we find one it would indicate that our original
   * sync was bad since there cannot be a sync code in a valid header.
   *
   * Three kinds of things can go wrong when reading the frame header:
   *  1) We may have sync'ed incorrectly and not landed on a frame header.
   *     If we don't find a sync code, it can end up looking like we read
   *     a valid but unparseable header, until getting to the frame header
   *     CRC.  Even then we could get a false positive on the CRC.
   *  2) We may have sync'ed correctly but on an unparseable frame (from a
   *     future encoder).
   *  3) We may be on a damaged frame which appears valid but unparseable.
   *
   * For all these reasons, we try and read a complete frame header as
   * long as it seems valid, even if unparseable, up until the frame
   * header CRC.
   */

  /*
   * read in the raw header as bytes so we can CRC it, and parse it on the way
   */
  for(i = 0; i < 2; i++) {
    if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, 8))
      return false; /* read_callback_ sets the state for us */
    if(x == 0xff) { /* MAGIC NUMBER for the first 8 frame sync bits */
      /* if we get here it means our original sync was erroneous since the sync code cannot appear in the header */
      decoder->private_->lookahead = (FLAC__byte)x;
      decoder->private_->cached = true;
      send_error_to_client_(decoder, FLAC__STREAM_DECODER_ERROR_STATUS_BAD_HEADER);
      decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
      return true;
    }
    raw_header[raw_header_len++] = (FLAC__byte)x;
  }

  switch(x = raw_header[2] >> 4) {
    case 0:
      is_unparseable = true;
      break;
    case 1:
      decoder->private_->frame.header.blocksize = 192;
      break;
    case 2:
    case 3:
    case 4:
    case 5:
      decoder->private_->frame.header.blocksize = 576 << (x-2);
      break;
    case 6:
    case 7:
      blocksize_hint = x;
      break;
    case 8:
    case 9:
    case 10:
    case 11:
    case 12:
    case 13:
    case 14:
    case 15:
      decoder->private_->frame.header.blocksize = 256 << (x-8);
      break;
    default:
      FLAC__ASSERT(0);
      break;
  }

  switch(x = raw_header[2] & 0x0f) {
    case 0:
      if(decoder->private_->has_stream_info)
        decoder->private_->frame.header.sample_rate = decoder->private_->stream_info.data.stream_info.sample_rate;
      else
        is_unparseable = true;
      break;
    case 1:
      decoder->private_->frame.header.sample_rate = 88200;
      break;
    case 2:
      decoder->private_->frame.header.sample_rate = 176400;
      break;
    case 3:
      decoder->private_->frame.header.sample_rate = 192000;
      break;
    case 4:
      decoder->private_->frame.header.sample_rate = 8000;
      break;
    case 5:
      decoder->private_->frame.header.sample_rate = 16000;
      break;
    case 6:
      decoder->private_->frame.header.sample_rate = 22050;
      break;
    case 7:
      decoder->private_->frame.header.sample_rate = 24000;
      break;
    case 8:
      decoder->private_->frame.header.sample_rate = 32000;
      break;
    case 9:
      decoder->private_->frame.header.sample_rate = 44100;
      break;
    case 10:
      decoder->private_->frame.header.sample_rate = 48000;
      break;
    case 11:
      decoder->private_->frame.header.sample_rate = 96000;
      break;
    case 12:
    case 13:
    case 14:
      sample_rate_hint = x;
      break;
    case 15:
      send_error_to_client_(decoder, FLAC__STREAM_DECODER_ERROR_STATUS_BAD_HEADER);
      decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
      return true;
    default:
      FLAC__ASSERT(0);
  }

  x = (uint32_t)(raw_header[3] >> 4);
  if(x & 8) {
    decoder->private_->frame.header.channels = 2;
    switch(x & 7) {
      case 0:
        decoder->private_->frame.header.channel_assignment = FLAC__CHANNEL_ASSIGNMENT_LEFT_SIDE;
        break;
      case 1:
        decoder->private_->frame.header.channel_assignment = FLAC__CHANNEL_ASSIGNMENT_RIGHT_SIDE;
        break;
      case 2:
        decoder->private_->frame.header.channel_assignment = FLAC__CHANNEL_ASSIGNMENT_MID_SIDE;
        break;
      default:
        is_unparseable = true;
        break;
    }
  }
  else {
    decoder->private_->frame.header.channels = (uint32_t)x + 1;
    decoder->private_->frame.header.channel_assignment = FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT;
  }

  switch(x = (uint32_t)(raw_header[3] & 0x0e) >> 1) {
    case 0:
      if(decoder->private_->has_stream_info)
        decoder->private_->frame.header.bits_per_sample = decoder->private_->stream_info.data.stream_info.bits_per_sample;
      else
        is_unparseable = true;
      break;
    case 1:
      decoder->private_->frame.header.bits_per_sample = 8;
      break;
    case 2:
      decoder->private_->frame.header.bits_per_sample = 12;
      break;
    case 3:
      is_unparseable = true;
      break;
    case 4:
      decoder->private_->frame.header.bits_per_sample = 16;
      break;
    case 5:
      decoder->private_->frame.header.bits_per_sample = 20;
      break;
    case 6:
      decoder->private_->frame.header.bits_per_sample = 24;
      break;
    case 7:
      decoder->private_->frame.header.bits_per_sample = 32;
      break;
    default:
      FLAC__ASSERT(0);
      break;
  }

#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
  /* check to make sure that reserved bit is 0 */
  if(raw_header[3] & 0x01) /* MAGIC NUMBER */
    is_unparseable = true;
#endif

  /* read the frame's starting sample number (or frame number as the case may be) */
  if(
    raw_header[1] & 0x01 ||
    /*@@@ this clause is a concession to the old way of doing variable blocksize; the only known implementation is flake and can probably be removed without inconveniencing anyone */
    (decoder->private_->has_stream_info && decoder->private_->stream_info.data.stream_info.min_blocksize != decoder->private_->stream_info.data.stream_info.max_blocksize)
  ) { /* variable blocksize */
    if(!FLAC__bitreader_read_utf8_uint64(decoder->private_->input, &xx, raw_header, &raw_header_len))
      return false; /* read_callback_ sets the state for us */
    if(xx == FLAC__U64L(0xffffffffffffffff)) { /* i.e. non-UTF8 code... */
      decoder->private_->lookahead = raw_header[raw_header_len-1]; /* back up as much as we can */
      decoder->private_->cached = true;
      send_error_to_client_(decoder, FLAC__STREAM_DECODER_ERROR_STATUS_BAD_HEADER);
      decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
      return true;
    }
    decoder->private_->frame.header.number_type = FLAC__FRAME_NUMBER_TYPE_SAMPLE_NUMBER;
    decoder->private_->frame.header.number.sample_number = xx;
  }
  else { /* fixed blocksize */
    if(!FLAC__bitreader_read_utf8_uint32(decoder->private_->input, &x, raw_header, &raw_header_len))
      return false; /* read_callback_ sets the state for us */
    if(x == 0xffffffff) { /* i.e. non-UTF8 code... */
      decoder->private_->lookahead = raw_header[raw_header_len-1]; /* back up as much as we can */
      decoder->private_->cached = true;
      send_error_to_client_(decoder, FLAC__STREAM_DECODER_ERROR_STATUS_BAD_HEADER);
      decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
      return true;
    }
    decoder->private_->frame.header.number_type = FLAC__FRAME_NUMBER_TYPE_FRAME_NUMBER;
    decoder->private_->frame.header.number.frame_number = x;
  }

  if(blocksize_hint) {
    if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, 8))
      return false; /* read_callback_ sets the state for us */
    raw_header[raw_header_len++] = (FLAC__byte)x;
    if(blocksize_hint == 7) {
      FLAC__uint32 _x;
      if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &_x, 8))
        return false; /* read_callback_ sets the state for us */
      raw_header[raw_header_len++] = (FLAC__byte)_x;
      x = (x << 8) | _x;
    }
    decoder->private_->frame.header.blocksize = x+1;
    if(decoder->private_->frame.header.blocksize > 65535) { /* invalid blocksize (65536) specified */
      decoder->private_->lookahead = raw_header[raw_header_len-1]; /* back up as much as we can */
      decoder->private_->cached = true;
      send_error_to_client_(decoder, FLAC__STREAM_DECODER_ERROR_STATUS_BAD_HEADER);
      decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
      return true;
    }

  }

  if(sample_rate_hint) {
    if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, 8))
      return false; /* read_callback_ sets the state for us */
    raw_header[raw_header_len++] = (FLAC__byte)x;
    if(sample_rate_hint != 12) {
      FLAC__uint32 _x;
      if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &_x, 8))
        return false; /* read_callback_ sets the state for us */
      raw_header[raw_header_len++] = (FLAC__byte)_x;
      x = (x << 8) | _x;
    }
    if(sample_rate_hint == 12)
      decoder->private_->frame.header.sample_rate = x*1000;
    else if(sample_rate_hint == 13)
      decoder->private_->frame.header.sample_rate = x;
    else
      decoder->private_->frame.header.sample_rate = x*10;
  }

  /* read the CRC-8 byte */
  if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, 8))
    return false; /* read_callback_ sets the state for us */
  crc8 = (FLAC__byte)x;

#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
  if(FLAC__crc8(raw_header, raw_header_len) != crc8) {
#else
  if(decoder->private_->fuzzing_rewind_count > 8 && (FLAC__crc8(raw_header, raw_header_len) << 4) != (crc8 << 4)) {
#endif
    send_error_to_client_(decoder, FLAC__STREAM_DECODER_ERROR_STATUS_BAD_HEADER);
    decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
    return true;
  }

  /* calculate the sample number from the frame number if needed */
  decoder->private_->next_fixed_block_size = 0;
  if(decoder->private_->frame.header.number_type == FLAC__FRAME_NUMBER_TYPE_FRAME_NUMBER) {
    x = decoder->private_->frame.header.number.frame_number;
    decoder->private_->frame.header.number_type = FLAC__FRAME_NUMBER_TYPE_SAMPLE_NUMBER;
    if(decoder->private_->fixed_block_size)
      decoder->private_->frame.header.number.sample_number = (FLAC__uint64)decoder->private_->fixed_block_size * (FLAC__uint64)x;
    else if(decoder->private_->has_stream_info) {
      if(decoder->private_->stream_info.data.stream_info.min_blocksize == decoder->private_->stream_info.data.stream_info.max_blocksize) {
        decoder->private_->frame.header.number.sample_number = (FLAC__uint64)decoder->private_->stream_info.data.stream_info.min_blocksize * (FLAC__uint64)x;
        decoder->private_->next_fixed_block_size = decoder->private_->stream_info.data.stream_info.max_blocksize;
      }
      else
        is_unparseable = true;
    }
    else if(x == 0) {
      decoder->private_->frame.header.number.sample_number = 0;
      decoder->private_->next_fixed_block_size = decoder->private_->frame.header.blocksize;
    }
    else {
      /* can only get here if the stream has invalid frame numbering and no STREAMINFO, so assume it's not the last (possibly short) frame */
      decoder->private_->frame.header.number.sample_number = (FLAC__uint64)decoder->private_->frame.header.blocksize * (FLAC__uint64)x;
    }
  }

  if(is_unparseable) {
    send_error_to_client_(decoder, FLAC__STREAM_DECODER_ERROR_STATUS_UNPARSEABLE_STREAM);
    decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
    return true;
  }

  return true;
}

FLAC__bool read_subframe_(FLAC__StreamDecoder *decoder, uint32_t channel, uint32_t bps, FLAC__bool do_full_decode)
{
  FLAC__uint32 x;
  FLAC__bool wasted_bits;
  uint32_t i;

  if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &x, 8)) /* MAGIC NUMBER */
    return false; /* read_callback_ sets the state for us */

  wasted_bits = (x & 1);
  x &= 0xfe;

  if(wasted_bits) {
    uint32_t u;
    if(!FLAC__bitreader_read_unary_unsigned(decoder->private_->input, &u))
      return false; /* read_callback_ sets the state for us */
    decoder->private_->frame.subframes[channel].wasted_bits = u+1;
    if (decoder->private_->frame.subframes[channel].wasted_bits >= bps) {
      send_error_to_client_(decoder, FLAC__STREAM_DECODER_ERROR_STATUS_LOST_SYNC);
      decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
      return true;
    }
    bps -= decoder->private_->frame.subframes[channel].wasted_bits;
  }
  else
    decoder->private_->frame.subframes[channel].wasted_bits = 0;

  /*
   * Lots of magic numbers here
   */
  if(x & 0x80) {
    send_error_to_client_(decoder, FLAC__STREAM_DECODER_ERROR_STATUS_LOST_SYNC);
    decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
    return true;
  }
  else if(x == 0) {
    if(!read_subframe_constant_(decoder, channel, bps, do_full_decode))
      return false;
  }
  else if(x == 2) {
    if(!read_subframe_verbatim_(decoder, channel, bps, do_full_decode))
      return false;
  }
  else if(x < 16) {
    send_error_to_client_(decoder, FLAC__STREAM_DECODER_ERROR_STATUS_UNPARSEABLE_STREAM);
    decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
    return true;
  }
  else if(x <= 24) {
    uint32_t predictor_order = (x>>1)&7;
    if(decoder->private_->frame.header.blocksize <= predictor_order){
      send_error_to_client_(decoder, FLAC__STREAM_DECODER_ERROR_STATUS_LOST_SYNC);
      decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
      return true;
    }
    if(!read_subframe_fixed_(decoder, channel, bps, predictor_order, do_full_decode))
      return false;
    if(decoder->protected_->state == FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC) /* means bad sync or got corruption */
      return true;
  }
  else if(x < 64) {
    send_error_to_client_(decoder, FLAC__STREAM_DECODER_ERROR_STATUS_UNPARSEABLE_STREAM);
    decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
    return true;
  }
  else {
    uint32_t predictor_order = ((x>>1)&31)+1;
    if(decoder->private_->frame.header.blocksize <= predictor_order){
      send_error_to_client_(decoder, FLAC__STREAM_DECODER_ERROR_STATUS_LOST_SYNC);
      decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
      return true;
    }
    if(!read_subframe_lpc_(decoder, channel, bps, predictor_order, do_full_decode))
      return false;
    if(decoder->protected_->state == FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC) /* means bad sync or got corruption */
      return true;
  }

  if(wasted_bits && do_full_decode) {
    x = decoder->private_->frame.subframes[channel].wasted_bits;
    if((bps + x) < 33) {
      for(i = 0; i < decoder->private_->frame.header.blocksize; i++) {
        uint32_t val = decoder->private_->output[channel][i];
        decoder->private_->output[channel][i] = (val << x);
      }
    }
    else {
      /* When there are wasted bits, bps is never 33 and so
       * side_subframe is never already in use */
      FLAC__ASSERT(!decoder->private_->side_subframe_in_use);
      decoder->private_->side_subframe_in_use = true;
      for(i = 0; i < decoder->private_->frame.header.blocksize; i++) {
        uint64_t val = decoder->private_->output[channel][i];
        decoder->private_->side_subframe[i] = (val << x);
      }
    }
  }

  return true;
}

FLAC__bool read_subframe_constant_(FLAC__StreamDecoder *decoder, uint32_t channel, uint32_t bps, FLAC__bool do_full_decode)
{
  FLAC__Subframe_Constant *subframe = &decoder->private_->frame.subframes[channel].data.constant;
  FLAC__int64 x;
  uint32_t i;

  decoder->private_->frame.subframes[channel].type = FLAC__SUBFRAME_TYPE_CONSTANT;

  if(!FLAC__bitreader_read_raw_int64(decoder->private_->input, &x, bps))
    return false; /* read_callback_ sets the state for us */

  subframe->value = x;

  /* decode the subframe */
  if(do_full_decode) {
    if(bps <= 32) {
      FLAC__int32 *output = decoder->private_->output[channel];
      for(i = 0; i < decoder->private_->frame.header.blocksize; i++)
        output[i] = x;
    } else {
      FLAC__int64 *output = decoder->private_->side_subframe;
      decoder->private_->side_subframe_in_use = true;
      for(i = 0; i < decoder->private_->frame.header.blocksize; i++)
        output[i] = x;
    }
  }

  return true;
}

FLAC__bool read_subframe_fixed_(FLAC__StreamDecoder *decoder, uint32_t channel, uint32_t bps, const uint32_t order, FLAC__bool do_full_decode)
{
  FLAC__Subframe_Fixed *subframe = &decoder->private_->frame.subframes[channel].data.fixed;
  FLAC__int64 i64;
  FLAC__uint32 u32;
  uint32_t u;

  decoder->private_->frame.subframes[channel].type = FLAC__SUBFRAME_TYPE_FIXED;

  subframe->residual = decoder->private_->residual[channel];
  subframe->order = order;

  /* read warm-up samples */
  for(u = 0; u < order; u++) {
    if(!FLAC__bitreader_read_raw_int64(decoder->private_->input, &i64, bps))
      return false; /* read_callback_ sets the state for us */
    subframe->warmup[u] = i64;
  }

  /* read entropy coding method info */
  if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &u32, FLAC__ENTROPY_CODING_METHOD_TYPE_LEN))
    return false; /* read_callback_ sets the state for us */
  subframe->entropy_coding_method.type = (FLAC__EntropyCodingMethodType)u32;
  switch(subframe->entropy_coding_method.type) {
    case FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE:
    case FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE2:
      if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &u32, FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ORDER_LEN))
        return false; /* read_callback_ sets the state for us */
      if((decoder->private_->frame.header.blocksize >> u32 < order) ||
         (decoder->private_->frame.header.blocksize % (1 << u32) > 0)) {
        send_error_to_client_(decoder, FLAC__STREAM_DECODER_ERROR_STATUS_LOST_SYNC);
        decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
        return true;
      }
      subframe->entropy_coding_method.data.partitioned_rice.order = u32;
      subframe->entropy_coding_method.data.partitioned_rice.contents = &decoder->private_->partitioned_rice_contents[channel];
      break;
    default:
      send_error_to_client_(decoder, FLAC__STREAM_DECODER_ERROR_STATUS_UNPARSEABLE_STREAM);
      decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
      return true;
  }

  /* read residual */
  switch(subframe->entropy_coding_method.type) {
    case FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE:
    case FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE2:
      if(!read_residual_partitioned_rice_(decoder, order, subframe->entropy_coding_method.data.partitioned_rice.order, &decoder->private_->partitioned_rice_contents[channel], decoder->private_->residual[channel], /*is_extended=*/subframe->entropy_coding_method.type == FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE2))
        return false;
      break;
    default:
      FLAC__ASSERT(0);
  }

  /* decode the subframe */
  if(do_full_decode) {
    if(bps < 33){
      uint32_t i;
      for(i = 0; i < order; i++)
        decoder->private_->output[channel][i] = subframe->warmup[i];
      if(bps+order <= 32)
        FLAC__fixed_restore_signal(decoder->private_->residual[channel], decoder->private_->frame.header.blocksize-order, order, decoder->private_->output[channel]+order);
      else
        FLAC__fixed_restore_signal_wide(decoder->private_->residual[channel], decoder->private_->frame.header.blocksize-order, order, decoder->private_->output[channel]+order);
    }
    else {
      decoder->private_->side_subframe_in_use = true;
      memcpy(decoder->private_->side_subframe, subframe->warmup, sizeof(FLAC__int64) * order);
      FLAC__fixed_restore_signal_wide_33bit(decoder->private_->residual[channel], decoder->private_->frame.header.blocksize-order, order, decoder->private_->side_subframe+order);
    }
  }

  return true;
}

FLAC__bool read_subframe_lpc_(FLAC__StreamDecoder *decoder, uint32_t channel, uint32_t bps, const uint32_t order, FLAC__bool do_full_decode)
{
  FLAC__Subframe_LPC *subframe = &decoder->private_->frame.subframes[channel].data.lpc;
  FLAC__int32 i32;
  FLAC__int64 i64;
  FLAC__uint32 u32;
  uint32_t u;

  decoder->private_->frame.subframes[channel].type = FLAC__SUBFRAME_TYPE_LPC;

  subframe->residual = decoder->private_->residual[channel];
  subframe->order = order;

  /* read warm-up samples */
  for(u = 0; u < order; u++) {
    if(!FLAC__bitreader_read_raw_int64(decoder->private_->input, &i64, bps))
      return false; /* read_callback_ sets the state for us */
    subframe->warmup[u] = i64;
  }

  /* read qlp coeff precision */
  if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &u32, FLAC__SUBFRAME_LPC_QLP_COEFF_PRECISION_LEN))
    return false; /* read_callback_ sets the state for us */
  if(u32 == (1u << FLAC__SUBFRAME_LPC_QLP_COEFF_PRECISION_LEN) - 1) {
    send_error_to_client_(decoder, FLAC__STREAM_DECODER_ERROR_STATUS_LOST_SYNC);
    decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
    return true;
  }
  subframe->qlp_coeff_precision = u32+1;

  /* read qlp shift */
  if(!FLAC__bitreader_read_raw_int32(decoder->private_->input, &i32, FLAC__SUBFRAME_LPC_QLP_SHIFT_LEN))
    return false; /* read_callback_ sets the state for us */
  if(i32 < 0) {
    send_error_to_client_(decoder, FLAC__STREAM_DECODER_ERROR_STATUS_LOST_SYNC);
    decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
    return true;
  }
  subframe->quantization_level = i32;

  /* read quantized lp coefficiencts */
  for(u = 0; u < order; u++) {
    if(!FLAC__bitreader_read_raw_int32(decoder->private_->input, &i32, subframe->qlp_coeff_precision))
      return false; /* read_callback_ sets the state for us */
    subframe->qlp_coeff[u] = i32;
  }

  /* read entropy coding method info */
  if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &u32, FLAC__ENTROPY_CODING_METHOD_TYPE_LEN))
    return false; /* read_callback_ sets the state for us */
  subframe->entropy_coding_method.type = (FLAC__EntropyCodingMethodType)u32;
  switch(subframe->entropy_coding_method.type) {
    case FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE:
    case FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE2:
      if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &u32, FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ORDER_LEN))
        return false; /* read_callback_ sets the state for us */
      if((decoder->private_->frame.header.blocksize >> u32 < order) ||
         (decoder->private_->frame.header.blocksize % (1 << u32) > 0)) {
        send_error_to_client_(decoder, FLAC__STREAM_DECODER_ERROR_STATUS_LOST_SYNC);
        decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
        return true;
      }
      subframe->entropy_coding_method.data.partitioned_rice.order = u32;
      subframe->entropy_coding_method.data.partitioned_rice.contents = &decoder->private_->partitioned_rice_contents[channel];
      break;
    default:
      send_error_to_client_(decoder, FLAC__STREAM_DECODER_ERROR_STATUS_UNPARSEABLE_STREAM);
      decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
      return true;
  }

  /* read residual */
  switch(subframe->entropy_coding_method.type) {
    case FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE:
    case FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE2:
      if(!read_residual_partitioned_rice_(decoder, order, subframe->entropy_coding_method.data.partitioned_rice.order, &decoder->private_->partitioned_rice_contents[channel], decoder->private_->residual[channel], /*is_extended=*/subframe->entropy_coding_method.type == FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE2))
        return false;
      break;
    default:
      FLAC__ASSERT(0);
  }

  /* decode the subframe */
  if(do_full_decode) {
    if(bps <= 32) {
      uint32_t i;
      for(i = 0; i < order; i++)
        decoder->private_->output[channel][i] = subframe->warmup[i];
      if(FLAC__lpc_max_residual_bps(bps, subframe->qlp_coeff, order, subframe->quantization_level) <= 32 &&
         FLAC__lpc_max_prediction_before_shift_bps(bps, subframe->qlp_coeff, order) <= 32)
        FLAC__lpc_restore_signal(decoder->private_->residual[channel], decoder->private_->frame.header.blocksize-order, subframe->qlp_coeff, order, subframe->quantization_level, decoder->private_->output[channel]+order);
      else
        FLAC__lpc_restore_signal_wide(decoder->private_->residual[channel], decoder->private_->frame.header.blocksize-order, subframe->qlp_coeff, order, subframe->quantization_level, decoder->private_->output[channel]+order);
    }
    else {
      decoder->private_->side_subframe_in_use = true;
      memcpy(decoder->private_->side_subframe, subframe->warmup, sizeof(FLAC__int64) * order);
      FLAC__lpc_restore_signal_wide_33bit(decoder->private_->residual[channel], decoder->private_->frame.header.blocksize-order, subframe->qlp_coeff, order, subframe->quantization_level, decoder->private_->side_subframe+order);
    }
  }

  return true;
}

FLAC__bool read_subframe_verbatim_(FLAC__StreamDecoder *decoder, uint32_t channel, uint32_t bps, FLAC__bool do_full_decode)
{
  FLAC__Subframe_Verbatim *subframe = &decoder->private_->frame.subframes[channel].data.verbatim;
  uint32_t i;

  decoder->private_->frame.subframes[channel].type = FLAC__SUBFRAME_TYPE_VERBATIM;

  if(bps < 33) {
    FLAC__int32 x, *residual = decoder->private_->residual[channel];

    subframe->data_type = FLAC__VERBATIM_SUBFRAME_DATA_TYPE_INT32;
    subframe->data.int32 = residual;

    for(i = 0; i < decoder->private_->frame.header.blocksize; i++) {
      if(!FLAC__bitreader_read_raw_int32(decoder->private_->input, &x, bps))
        return false; /* read_callback_ sets the state for us */
      residual[i] = x;
    }

    /* decode the subframe */
    if(do_full_decode)
      memcpy(decoder->private_->output[channel], subframe->data.int32, sizeof(FLAC__int32) * decoder->private_->frame.header.blocksize);
  }
  else {
    FLAC__int64 x, *side = decoder->private_->side_subframe;

    subframe->data_type = FLAC__VERBATIM_SUBFRAME_DATA_TYPE_INT64;
    subframe->data.int64 = side;
    decoder->private_->side_subframe_in_use = true;

    for(i = 0; i < decoder->private_->frame.header.blocksize; i++) {
      if(!FLAC__bitreader_read_raw_int64(decoder->private_->input, &x, bps))
        return false; /* read_callback_ sets the state for us */
      side[i] = x;
    }
  }

  return true;
}

FLAC__bool read_residual_partitioned_rice_(FLAC__StreamDecoder *decoder, uint32_t predictor_order, uint32_t partition_order, FLAC__EntropyCodingMethod_PartitionedRiceContents *partitioned_rice_contents, FLAC__int32 *residual, FLAC__bool is_extended)
{
  FLAC__uint32 rice_parameter;
  int i;
  uint32_t partition, sample, u;
  const uint32_t partitions = 1u << partition_order;
  const uint32_t partition_samples = decoder->private_->frame.header.blocksize >> partition_order;
  const uint32_t plen = is_extended? FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE2_PARAMETER_LEN : FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_PARAMETER_LEN;
  const uint32_t pesc = is_extended? FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE2_ESCAPE_PARAMETER : FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_ESCAPE_PARAMETER;

  /* invalid predictor and partition orders mush be handled in the callers */
  FLAC__ASSERT(partition_order > 0? partition_samples >= predictor_order : decoder->private_->frame.header.blocksize >= predictor_order);

  if(!FLAC__format_entropy_coding_method_partitioned_rice_contents_ensure_size(partitioned_rice_contents, flac_max(6u, partition_order))) {
    decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
    return false;
  }

  sample = 0;
  for(partition = 0; partition < partitions; partition++) {
    if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &rice_parameter, plen))
      return false; /* read_callback_ sets the state for us */
    partitioned_rice_contents->parameters[partition] = rice_parameter;
    if(rice_parameter < pesc) {
      partitioned_rice_contents->raw_bits[partition] = 0;
      u = (partition == 0) ? partition_samples - predictor_order : partition_samples;
      if(!decoder->private_->local_bitreader_read_rice_signed_block(decoder->private_->input, residual + sample, u, rice_parameter)){
        if(decoder->protected_->state == FLAC__STREAM_DECODER_READ_FRAME) {
          /* no error was set, read_callback_ didn't set it, so
           * invalid rice symbol was found */
          send_error_to_client_(decoder, FLAC__STREAM_DECODER_ERROR_STATUS_LOST_SYNC);
          decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
          return true;
        }
        else
          return false; /* read_callback_ sets the state for us */
      }
      sample += u;
    }
    else {
      if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &rice_parameter, FLAC__ENTROPY_CODING_METHOD_PARTITIONED_RICE_RAW_LEN))
        return false; /* read_callback_ sets the state for us */
      partitioned_rice_contents->raw_bits[partition] = rice_parameter;
      if(rice_parameter == 0) {
        for(u = (partition == 0)? predictor_order : 0; u < partition_samples; u++, sample++)
          residual[sample] = 0;
      }
      else{
        for(u = (partition == 0)? predictor_order : 0; u < partition_samples; u++, sample++) {
          if(!FLAC__bitreader_read_raw_int32(decoder->private_->input, &i, rice_parameter))
            return false; /* read_callback_ sets the state for us */
          residual[sample] = i;
        }
      }
    }
  }

  return true;
}

FLAC__bool read_zero_padding_(FLAC__StreamDecoder *decoder)
{
  if(!FLAC__bitreader_is_consumed_byte_aligned(decoder->private_->input)) {
    FLAC__uint32 zero = 0;
    if(!FLAC__bitreader_read_raw_uint32(decoder->private_->input, &zero, FLAC__bitreader_bits_left_for_byte_alignment(decoder->private_->input)))
      return false; /* read_callback_ sets the state for us */
#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
    if(zero != 0) {
      send_error_to_client_(decoder, FLAC__STREAM_DECODER_ERROR_STATUS_LOST_SYNC);
      decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC;
    }
#endif
  }
  return true;
}

FLAC__bool read_callback_(FLAC__byte buffer[], size_t *bytes, void *client_data)
{
  FLAC__StreamDecoder *decoder = (FLAC__StreamDecoder *)client_data;

  if(
#if FLAC__HAS_OGG
    /* see [1] HACK NOTE below for why we don't call the eof_callback when decoding Ogg FLAC */
    !decoder->private_->is_ogg &&
#endif
    decoder->private_->eof_callback && decoder->private_->eof_callback(decoder, decoder->private_->client_data)
  ) {
    *bytes = 0;
    decoder->protected_->state = FLAC__STREAM_DECODER_END_OF_STREAM;
    return false;
  }
  else if(*bytes > 0) {
    /* While seeking, it is possible for our seek to land in the
     * middle of audio data that looks exactly like a frame header
     * from a future version of an encoder.  When that happens, our
     * error callback will get an
     * FLAC__STREAM_DECODER_UNPARSEABLE_STREAM and increment its
     * unparseable_frame_count.  But there is a remote possibility
     * that it is properly synced at such a "future-codec frame",
     * so to make sure, we wait to see many "unparseable" errors in
     * a row before bailing out.
     */
    if(decoder->private_->is_seeking && decoder->private_->unparseable_frame_count > 20) {
      decoder->protected_->state = FLAC__STREAM_DECODER_ABORTED;
      return false;
    }
    else {
      const FLAC__StreamDecoderReadStatus status =
#if FLAC__HAS_OGG
        decoder->private_->is_ogg?
        read_callback_ogg_aspect_(decoder, buffer, bytes) :
#endif
        decoder->private_->read_callback(decoder, buffer, bytes, decoder->private_->client_data)
      ;
      if(status == FLAC__STREAM_DECODER_READ_STATUS_ABORT) {
#if FLAC__HAS_OGG
        if(decoder->private_->ogg_decoder_aspect_allocation_failure) {
          decoder->protected_->state = FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR;
          return false;
        }
#endif
        decoder->protected_->state = FLAC__STREAM_DECODER_ABORTED;
        return false;
      }
      else if(*bytes == 0) {
        if(status == FLAC__STREAM_DECODER_READ_STATUS_END_OF_LINK) {
          if(FLAC__bitreader_is_consumed_byte_aligned(decoder->private_->input))
            decoder->protected_->state = FLAC__STREAM_DECODER_END_OF_LINK;
          else
            decoder->protected_->state = FLAC__STREAM_DECODER_OGG_ERROR;
          return false;
        }
        else if(
          status == FLAC__STREAM_DECODER_READ_STATUS_END_OF_STREAM ||
          (
#if FLAC__HAS_OGG
            /* see [1] HACK NOTE below for why we don't call the eof_callback when decoding Ogg FLAC */
            !decoder->private_->is_ogg &&
#endif
            decoder->private_->eof_callback && decoder->private_->eof_callback(decoder, decoder->private_->client_data)
          )
        ) {
          decoder->protected_->state = FLAC__STREAM_DECODER_END_OF_STREAM;
          return false;
        }
        else
          return true;
      }
      else
        return true;
    }
  }
  else {
    /* abort to avoid a deadlock */
    decoder->protected_->state = FLAC__STREAM_DECODER_ABORTED;
    return false;
  }
  /* [1] @@@ HACK NOTE: The end-of-stream checking has to be hacked around
   * for Ogg FLAC.  This is because the ogg decoder aspect can lose sync
   * and at the same time hit the end of the stream (for example, seeking
   * to a point that is after the beginning of the last Ogg page).  There
   * is no way to report an Ogg sync loss through the callbacks (see note
   * in read_callback_ogg_aspect_()) so it returns CONTINUE with *bytes==0.
   * So to keep the decoder from stopping at this point we gate the call
   * to the eof_callback and let the Ogg decoder aspect set the
   * end-of-stream state when it is needed.
   */
}

#if defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION) && !defined(FUZZING_BUILD_MODE_FLAC_SANITIZE_SIGNED_INTEGER_OVERFLOW)
/* The attribute below is to silence the undefined sanitizer of oss-fuzz.
 * Because fuzzing feeds bogus predictors and residual samples to the
 * decoder, having overflows in this section is unavoidable. Also,
 * because the calculated values are audio path only, there is no
 * potential for security problems */
__attribute__((no_sanitize("signed-integer-overflow")))
#endif
void undo_channel_coding(FLAC__StreamDecoder *decoder) {
  uint32_t i;
  switch(decoder->private_->frame.header.channel_assignment) {
  case FLAC__CHANNEL_ASSIGNMENT_INDEPENDENT:
    /* do nothing */
    break;
  case FLAC__CHANNEL_ASSIGNMENT_LEFT_SIDE:
    FLAC__ASSERT(decoder->private_->frame.header.channels == 2);
    FLAC__ASSERT(decoder->private_->side_subframe_in_use != /* logical XOR */ (decoder->private_->frame.header.bits_per_sample < 32));
    for(i = 0; i < decoder->private_->frame.header.blocksize; i++)
      if(decoder->private_->side_subframe_in_use)
        decoder->private_->output[1][i] = decoder->private_->output[0][i] - decoder->private_->side_subframe[i];
      else
        decoder->private_->output[1][i] = decoder->private_->output[0][i] - decoder->private_->output[1][i];
    break;
  case FLAC__CHANNEL_ASSIGNMENT_RIGHT_SIDE:
    FLAC__ASSERT(decoder->private_->frame.header.channels == 2);
    FLAC__ASSERT(decoder->private_->side_subframe_in_use != /* logical XOR */ (decoder->private_->frame.header.bits_per_sample < 32));
    for(i = 0; i < decoder->private_->frame.header.blocksize; i++)
      if(decoder->private_->side_subframe_in_use)
        decoder->private_->output[0][i] = decoder->private_->output[1][i] + decoder->private_->side_subframe[i];
      else
        decoder->private_->output[0][i] += decoder->private_->output[1][i];
    break;
  case FLAC__CHANNEL_ASSIGNMENT_MID_SIDE:
    FLAC__ASSERT(decoder->private_->frame.header.channels == 2);
    FLAC__ASSERT(decoder->private_->side_subframe_in_use != /* logical XOR */ (decoder->private_->frame.header.bits_per_sample < 32));
    for(i = 0; i < decoder->private_->frame.header.blocksize; i++) {
      if(!decoder->private_->side_subframe_in_use){
        FLAC__int32 mid, side;
        mid = decoder->private_->output[0][i];
        side = decoder->private_->output[1][i];
        mid = ((uint32_t) mid) << 1;
        mid |= (side & 1); /* i.e. if 'side' is odd... */
        decoder->private_->output[0][i] = (mid + side) >> 1;
        decoder->private_->output[1][i] = (mid - side) >> 1;
      }
      else { /* bps == 32 */
        FLAC__int64 mid;
        mid = ((uint64_t)decoder->private_->output[0][i]) << 1;
        mid |= (decoder->private_->side_subframe[i] & 1); /* i.e. if 'side' is odd... */
        decoder->private_->output[0][i] = (mid + decoder->private_->side_subframe[i]) >> 1;
        decoder->private_->output[1][i] = (mid - decoder->private_->side_subframe[i]) >> 1;
      }
    }
    break;
  default:
    FLAC__ASSERT(0);
    break;
  }
}

#if FLAC__HAS_OGG
FLAC__StreamDecoderReadStatus read_callback_ogg_aspect_(const FLAC__StreamDecoder *decoder, FLAC__byte buffer[], size_t *bytes)
{
  switch(FLAC__ogg_decoder_aspect_read_callback_wrapper(&decoder->protected_->ogg_decoder_aspect, buffer, bytes, read_callback_proxy_, decoder->private_->tell_callback, decoder, decoder->private_->client_data)) {
    case FLAC__OGG_DECODER_ASPECT_READ_STATUS_OK:
      return FLAC__STREAM_DECODER_READ_STATUS_CONTINUE;
    /* we don't really have a way to handle lost sync via read
     * callback so we'll let it pass and let the underlying
     * FLAC decoder catch the error
     */
    case FLAC__OGG_DECODER_ASPECT_READ_STATUS_LOST_SYNC:
      return FLAC__STREAM_DECODER_READ_STATUS_CONTINUE;
    case FLAC__OGG_DECODER_ASPECT_READ_STATUS_END_OF_STREAM:
      return FLAC__STREAM_DECODER_READ_STATUS_END_OF_STREAM;
    case FLAC__OGG_DECODER_ASPECT_READ_STATUS_END_OF_LINK:
      return FLAC__STREAM_DECODER_READ_STATUS_END_OF_LINK;
    case FLAC__OGG_DECODER_ASPECT_READ_STATUS_NOT_FLAC:
    case FLAC__OGG_DECODER_ASPECT_READ_STATUS_UNSUPPORTED_MAPPING_VERSION:
    case FLAC__OGG_DECODER_ASPECT_READ_STATUS_ABORT:
    case FLAC__OGG_DECODER_ASPECT_READ_STATUS_ERROR:
      return FLAC__STREAM_DECODER_READ_STATUS_ABORT;
    case FLAC__OGG_DECODER_ASPECT_READ_STATUS_MEMORY_ALLOCATION_ERROR:
      decoder->private_->ogg_decoder_aspect_allocation_failure = true;
      return FLAC__STREAM_DECODER_READ_STATUS_ABORT;
    default:
      FLAC__ASSERT(0);
      /* double protection */
      return FLAC__STREAM_DECODER_READ_STATUS_ABORT;
  }
}

FLAC__OggDecoderAspectReadStatus read_callback_proxy_(const void *void_decoder, FLAC__byte buffer[], size_t *bytes, void *client_data)
{
  FLAC__StreamDecoder *decoder = (FLAC__StreamDecoder*)void_decoder;

  switch(decoder->private_->read_callback(decoder, buffer, bytes, client_data)) {
    case FLAC__STREAM_DECODER_READ_STATUS_CONTINUE:
      return FLAC__OGG_DECODER_ASPECT_READ_STATUS_OK;
    case FLAC__STREAM_DECODER_READ_STATUS_END_OF_STREAM:
      return FLAC__OGG_DECODER_ASPECT_READ_STATUS_END_OF_STREAM;
    case FLAC__STREAM_DECODER_READ_STATUS_ABORT:
      return FLAC__OGG_DECODER_ASPECT_READ_STATUS_ABORT;
    default:
      /* double protection: */
      FLAC__ASSERT(0);
      return FLAC__OGG_DECODER_ASPECT_READ_STATUS_ABORT;
  }
}
#endif

FLAC__StreamDecoderWriteStatus write_audio_frame_to_client_(FLAC__StreamDecoder *decoder, const FLAC__Frame *frame, const FLAC__int32 * const buffer[])
{
  decoder->private_->last_frame = *frame; /* save the frame */
  decoder->private_->last_frame_is_set = true;
  if(decoder->private_->is_seeking && !decoder->private_->is_indexing) {
    FLAC__uint64 this_frame_sample = frame->header.number.sample_number;
    FLAC__uint64 next_frame_sample = this_frame_sample + (FLAC__uint64)frame->header.blocksize;
    FLAC__uint64 target_sample = decoder->private_->target_sample;

    FLAC__ASSERT(frame->header.number_type == FLAC__FRAME_NUMBER_TYPE_SAMPLE_NUMBER);

    decoder->private_->got_a_frame = true;

    if(this_frame_sample <= target_sample && target_sample < next_frame_sample) { /* we hit our target frame */
      uint32_t delta = (uint32_t)(target_sample - this_frame_sample);
      /* kick out of seek mode */
      decoder->private_->is_seeking = false;
      /* shift out the samples before target_sample */
      if(delta > 0) {
        uint32_t channel;
        const FLAC__int32 *newbuffer[FLAC__MAX_CHANNELS];
        for(channel = 0; channel < frame->header.channels; channel++) {
          newbuffer[channel] = buffer[channel] + delta;
          decoder->private_->last_frame.subframes[channel].type = FLAC__SUBFRAME_TYPE_VERBATIM;
          decoder->private_->last_frame.subframes[channel].data.verbatim.data_type = FLAC__VERBATIM_SUBFRAME_DATA_TYPE_INT32;
          decoder->private_->last_frame.subframes[channel].data.verbatim.data.int32 = newbuffer[channel];
        }
        decoder->private_->last_frame.header.blocksize -= delta;
        decoder->private_->last_frame.header.number.sample_number += (FLAC__uint64)delta;
        /* write the relevant samples */
        return decoder->private_->write_callback(decoder, &decoder->private_->last_frame, newbuffer, decoder->private_->client_data);
      }
      else {
        /* write the relevant samples */
        return decoder->private_->write_callback(decoder, frame, buffer, decoder->private_->client_data);
      }
    }
    else {
      return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;
    }
  }
  else if(!decoder->private_->is_indexing) {
    /*
     * If we never got STREAMINFO, turn off MD5 checking to save
     * cycles since we don't have a sum to compare to anyway
     */
    if(!decoder->private_->has_stream_info)
      decoder->private_->do_md5_checking = false;
    if(decoder->private_->do_md5_checking) {
      if(!FLAC__MD5Accumulate(&decoder->private_->md5context, buffer, frame->header.channels, frame->header.blocksize, (frame->header.bits_per_sample+7) / 8))
        return FLAC__STREAM_DECODER_WRITE_STATUS_ABORT;
    }
    return decoder->private_->write_callback(decoder, frame, buffer, decoder->private_->client_data);
  }
  else { /* decoder->private_->is_indexing == true */
    return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;
  }
}

void send_error_to_client_(const FLAC__StreamDecoder *decoder, FLAC__StreamDecoderErrorStatus status)
{
  if(!decoder->private_->is_seeking) {
    decoder->private_->error_has_been_sent = true;
    decoder->private_->error_callback(decoder, status, decoder->private_->client_data);
  }
  else if(status == FLAC__STREAM_DECODER_ERROR_STATUS_UNPARSEABLE_STREAM)
    decoder->private_->unparseable_frame_count++;
}

FLAC__bool seek_to_absolute_sample_(FLAC__StreamDecoder *decoder, FLAC__uint64 stream_length, FLAC__uint64 target_sample)
{
  FLAC__uint64 first_frame_offset = decoder->private_->first_frame_offset, lower_bound, upper_bound, lower_bound_sample, upper_bound_sample, this_frame_sample;
  FLAC__int64 pos = -1;
  int i;
  uint32_t approx_bytes_per_frame;
  FLAC__bool first_seek = true, seek_from_lower_bound = false;
  const FLAC__uint64 total_samples = FLAC__stream_decoder_get_total_samples(decoder);
  const uint32_t min_blocksize = decoder->private_->stream_info.data.stream_info.min_blocksize;
  const uint32_t max_blocksize = decoder->private_->stream_info.data.stream_info.max_blocksize;
  const uint32_t max_framesize = decoder->private_->stream_info.data.stream_info.max_framesize;
  const uint32_t min_framesize = decoder->private_->stream_info.data.stream_info.min_framesize;
  /* take these from the current frame in case they've changed mid-stream */
  uint32_t channels = FLAC__stream_decoder_get_channels(decoder);
  uint32_t bps = FLAC__stream_decoder_get_bits_per_sample(decoder);
  const FLAC__StreamMetadata_SeekTable *seek_table = decoder->private_->has_seek_table? &decoder->private_->seek_table.data.seek_table : 0;

  /* use values from stream info if we didn't decode a frame */
  if(channels == 0)
    channels = decoder->private_->stream_info.data.stream_info.channels;
  if(bps == 0)
    bps = decoder->private_->stream_info.data.stream_info.bits_per_sample;

  /* we are just guessing here */
  if(max_framesize > 0)
    approx_bytes_per_frame = (max_framesize + min_framesize) / 2 + 1;
  /*
   * Check if it's a known fixed-blocksize stream.  Note that though
   * the spec doesn't allow zeroes in the STREAMINFO block, we may
   * never get a STREAMINFO block when decoding so the value of
   * min_blocksize might be zero.
   */
  else if(min_blocksize == max_blocksize && min_blocksize > 0) {
    /* note there are no () around 'bps/8' to keep precision up since it's an integer calculation */
    approx_bytes_per_frame = min_blocksize * channels * bps/8 + 64;
  }
  else
    approx_bytes_per_frame = 4096 * channels * bps/8 + 64;

  /*
   * First, we set an upper and lower bound on where in the
   * stream we will search.  For now we take the current position
   * as one bound and, depending on where the target position lies,
   * the beginning of the first frame or the end of the stream as
   * the other bound.
   */
  lower_bound = first_frame_offset;
  lower_bound_sample = 0;
  upper_bound = stream_length;
  upper_bound_sample = total_samples > 0 ? total_samples : target_sample /*estimate it*/;

  if(decoder->protected_->state == FLAC__STREAM_DECODER_SEARCH_FOR_FRAME_SYNC &&
     decoder->private_->samples_decoded != 0) {
    if(target_sample < decoder->private_->samples_decoded) {
      if(FLAC__stream_decoder_get_decode_position(decoder, &upper_bound))
        upper_bound_sample = decoder->private_->samples_decoded;
    } else {
      if(FLAC__stream_decoder_get_decode_position(decoder, &lower_bound))
        lower_bound_sample = decoder->private_->samples_decoded;
    }
  }

  /*
   * Now we refine the bounds if we have a seektable with
   * suitable points.  Note that according to the spec they
   * must be ordered by ascending sample number.
   *
   * Note: to protect against invalid seek tables we will ignore points
   * that have frame_samples==0 or sample_number>=total_samples. Also,
   * because math is limited to 64-bit ints, seekpoints with an offset
   * larger than 2^63 (8 exbibyte) are rejected.
   */
  if(seek_table) {
    FLAC__uint64 new_lower_bound = lower_bound;
    FLAC__uint64 new_upper_bound = upper_bound;
    FLAC__uint64 new_lower_bound_sample = lower_bound_sample;
    FLAC__uint64 new_upper_bound_sample = upper_bound_sample;

    /* find the closest seek point <= target_sample, if it exists */
    for(i = (int)seek_table->num_points - 1; i >= 0; i--) {
      if(
        seek_table->points[i].sample_number != FLAC__STREAM_METADATA_SEEKPOINT_PLACEHOLDER &&
        seek_table->points[i].frame_samples > 0 && /* defense against bad seekpoints */
        (total_samples <= 0 || seek_table->points[i].sample_number < total_samples) && /* defense against bad seekpoints */
        seek_table->points[i].sample_number <= target_sample
      )
        break;
    }
    if(i >= 0) { /* i.e. we found a suitable seek point... */
      new_lower_bound = first_frame_offset + seek_table->points[i].stream_offset;
      new_lower_bound_sample = seek_table->points[i].sample_number;
    }

    /* find the closest seek point > target_sample, if it exists */
    for(i = 0; i < (int)seek_table->num_points; i++) {
      if(
        seek_table->points[i].sample_number != FLAC__STREAM_METADATA_SEEKPOINT_PLACEHOLDER &&
        seek_table->points[i].frame_samples > 0 && /* defense against bad seekpoints */
        (total_samples <= 0 || seek_table->points[i].sample_number < total_samples) && /* defense against bad seekpoints */
        seek_table->points[i].sample_number > target_sample
      )
        break;
    }
    if(i < (int)seek_table->num_points) { /* i.e. we found a suitable seek point... */
      new_upper_bound = first_frame_offset + seek_table->points[i].stream_offset;
      new_upper_bound_sample = seek_table->points[i].sample_number;
    }
    /* final protection against unsorted seek tables; keep original values if bogus */
    if(new_upper_bound >= new_lower_bound) {
      lower_bound = new_lower_bound;
      upper_bound = new_upper_bound;
      lower_bound_sample = new_lower_bound_sample;
      upper_bound_sample = new_upper_bound_sample;
    }
  }

#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
  FLAC__ASSERT(upper_bound_sample >= lower_bound_sample);
#endif
  /* there are 3 insidious ways that the following equality occurs, which
   * we need to fix:
   *  1) total_samples is 0 (unknown) and target_sample is 0
   *  2) total_samples is 0 (unknown) and target_sample happens to be
   *     exactly equal to the last seek point in the seek table; this
   *     means there is no seek point above it, and upper_bound_samples
   *     remains equal to the estimate (of target_samples) we made above
   * in either case it does not hurt to move upper_bound_sample up by 1
   *  3) the file is corrupt
   */
  if(upper_bound_sample == lower_bound_sample) {
    if(total_samples == 0)
      upper_bound_sample++;
    else {
      decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
      return false;
    }
  }

  decoder->private_->target_sample = target_sample;
  while(1) {
    /* check whether decoder is still valid so bad state isn't overwritten
     * with seek error */
    if(decoder->protected_->state == FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR ||
       decoder->protected_->state == FLAC__STREAM_DECODER_ABORTED)
      return false;
    /* check if the bounds are still ok */
    if (lower_bound_sample >= upper_bound_sample ||
        lower_bound > upper_bound ||
        upper_bound >= INT64_MAX ||
        target_sample > upper_bound_sample) {
      decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
      return false;
    }
    if(seek_from_lower_bound) {
      pos = lower_bound;
    }
    else {
#ifndef FLAC__INTEGER_ONLY_LIBRARY
      pos = (FLAC__int64)lower_bound + (FLAC__int64)((double)(target_sample - lower_bound_sample) / (double)(upper_bound_sample - lower_bound_sample) * (double)(upper_bound - lower_bound)) - approx_bytes_per_frame;
#else
      /* a little less accurate: */
      if(upper_bound - lower_bound < 0xffffffff)
        pos = (FLAC__int64)lower_bound + (FLAC__int64)(((target_sample - lower_bound_sample) * (upper_bound - lower_bound)) / (upper_bound_sample - lower_bound_sample)) - approx_bytes_per_frame;
      else { /* @@@ WATCHOUT, ~2TB limit */
              FLAC__uint64 ratio = (1<<16) / (upper_bound_sample - lower_bound_sample);
        pos = (FLAC__int64)lower_bound + (FLAC__int64)((((target_sample - lower_bound_sample)>>8) * ((upper_bound - lower_bound)>>8) * ratio)) - approx_bytes_per_frame;
      }
#endif
    }
    if(pos >= (FLAC__int64)upper_bound)
      pos = (FLAC__int64)upper_bound - 1;
    if(pos < (FLAC__int64)lower_bound)
      pos = (FLAC__int64)lower_bound;
    if(decoder->private_->seek_callback(decoder, (FLAC__uint64)pos, decoder->private_->client_data) != FLAC__STREAM_DECODER_SEEK_STATUS_OK) {
      decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
      return false;
    }
    if(!FLAC__stream_decoder_flush(decoder)) {
      /* above call sets the state for us */
      return false;
    }
    /* Now we need to get a frame.  First we need to reset our
     * unparseable_frame_count; if we get too many unparseable
     * frames in a row, the read callback will return
     * FLAC__STREAM_DECODER_READ_STATUS_ABORT, causing
     * FLAC__stream_decoder_process_single() to return false.
     */
    decoder->private_->unparseable_frame_count = 0;
    if(!FLAC__stream_decoder_process_single(decoder) || decoder->protected_->state == FLAC__STREAM_DECODER_ABORTED || 0 == decoder->private_->samples_decoded) {
      /* No frame could be decoded */
      if(decoder->protected_->state != FLAC__STREAM_DECODER_ABORTED && decoder->private_->eof_callback(decoder, decoder->private_->client_data) && !seek_from_lower_bound){
        /* decoder has hit end of stream while processing corrupt
         * frame. To remedy this, try decoding a frame at the lower
         * bound so the seek after that hopefully ends up somewhere
         * else */
        seek_from_lower_bound = true;
        continue;
      }
      else {
        if(decoder->protected_->state != FLAC__STREAM_DECODER_ABORTED && decoder->protected_->state != FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR)
          decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
        return false;
      }
    }
    seek_from_lower_bound = false;

    /* our write callback will change the state when it gets to the target frame */
    /* actually, we could have got_a_frame if our decoder is at FLAC__STREAM_DECODER_END_OF_STREAM so we need to check for that also */
    if(!decoder->private_->is_seeking)
      break;

    FLAC__ASSERT(decoder->private_->last_frame.header.number_type == FLAC__FRAME_NUMBER_TYPE_SAMPLE_NUMBER);
    this_frame_sample = decoder->private_->last_frame.header.number.sample_number;

    if(this_frame_sample + decoder->private_->last_frame.header.blocksize >= upper_bound_sample && !first_seek) {
      if (pos == (FLAC__int64)lower_bound) {
        /* can't move back any more than the first frame, something is fatally wrong */
        decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
        return false;
      }
      /* our last move backwards wasn't big enough, try again */
      approx_bytes_per_frame = approx_bytes_per_frame? approx_bytes_per_frame * 2 : 16;
      continue;
    }
    /* allow one seek over upper bound, so we can get a correct upper_bound_sample for streams with unknown total_samples */
    first_seek = false;

    /* make sure we are not seeking in corrupted stream */
    if (this_frame_sample < lower_bound_sample) {
      decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
      return false;
    }

    /* we need to narrow the search */
    if(target_sample < this_frame_sample) {
      upper_bound_sample = this_frame_sample + decoder->private_->last_frame.header.blocksize;
/*@@@@@@ what will decode position be if at end of stream? */
      if(!FLAC__stream_decoder_get_decode_position(decoder, &upper_bound)) {
        decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
        return false;
      }
      approx_bytes_per_frame = (uint32_t)(2 * (upper_bound - pos) / 3 + 16);
    }
    else { /* target_sample >= this_frame_sample + this frame's blocksize */
      lower_bound_sample = this_frame_sample + decoder->private_->last_frame.header.blocksize;
      if(!FLAC__stream_decoder_get_decode_position(decoder, &lower_bound)) {
        decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
        return false;
      }
      approx_bytes_per_frame = (uint32_t)(2 * (lower_bound - pos) / 3 + 16);
    }
  }

  return true;
}

#if FLAC__HAS_OGG
FLAC__bool seek_to_absolute_sample_ogg_(FLAC__StreamDecoder *decoder, FLAC__uint64 stream_length, FLAC__uint64 target_sample)
{
  FLAC__uint64 left_pos = 0, right_pos = stream_length;
  FLAC__uint64 left_sample = 0, right_sample = 0;
  FLAC__uint64 this_frame_sample = (FLAC__uint64)0 - 1;
  FLAC__uint64 pos = 0; /* only initialized to avoid compiler warning */
  FLAC__bool did_a_seek;
  FLAC__OggDecoderAspect_TargetLink *target_link;
  uint32_t current_linknumber = decoder->protected_->ogg_decoder_aspect.current_linknumber;
  uint32_t iteration = 0;

  /* In the first iterations, we will calculate the target byte position
   * by the distance from the target sample to left_sample and
   * right_sample (let's call it "proportional search").  After that, we
   * will switch to binary search.
   */
  uint32_t BINARY_SEARCH_AFTER_ITERATION = 2;

  /* We will switch to a linear search once our current sample is less
   * than this number of samples ahead of the target sample
   */
  static const FLAC__uint64 LINEAR_SEARCH_WITHIN_SAMPLES = FLAC__MAX_BLOCK_SIZE * 2;

  if(FLAC__ogg_decoder_aspect_get_decode_chained_stream(&decoder->protected_->ogg_decoder_aspect)) {
    /* Check whether target sample is contained by indexed links.
     * If it is not keep moving forward until found */
    decoder->private_->is_indexing = true;
    while(NULL == (target_link = FLAC__ogg_decoder_aspect_get_target_link(&decoder->protected_->ogg_decoder_aspect, target_sample))) {
      FLAC__OggDecoderAspectReadStatus status;
      if(decoder->protected_->state == FLAC__STREAM_DECODER_END_OF_STREAM ||
         decoder->protected_->state == FLAC__STREAM_DECODER_OGG_ERROR ||
         decoder->protected_->state == FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR ||
         decoder->protected_->state == FLAC__STREAM_DECODER_ABORTED) {
        /* Target sample is not contained in stream or other error */
        decoder->private_->is_indexing = false;
        decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
        return false;
      }
      status = FLAC__ogg_decoder_aspect_skip_link(&decoder->protected_->ogg_decoder_aspect, read_callback_proxy_, decoder->private_->seek_callback, decoder->private_->tell_callback, decoder->private_->length_callback, decoder, decoder->private_->client_data);
      if(status == FLAC__OGG_DECODER_ASPECT_READ_STATUS_END_OF_STREAM)
        decoder->protected_->state = FLAC__STREAM_DECODER_END_OF_STREAM;
      else if(status != FLAC__OGG_DECODER_ASPECT_READ_STATUS_OK) {
        decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
        return false;
      }
    }
    decoder->private_->is_indexing = false;
    /* Target link found, send metadata if necessary */
    FLAC__ogg_decoder_aspect_set_seek_parameters(&decoder->protected_->ogg_decoder_aspect, target_link);
    if(target_link->linknumber != current_linknumber) {
      if(decoder->private_->seek_callback((FLAC__StreamDecoder*)decoder, (FLAC__uint64)target_link->start_byte, decoder->private_->client_data) != FLAC__STREAM_DECODER_SEEK_STATUS_OK) {
        decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
        return false;
      }
      if(!FLAC__stream_decoder_flush(decoder)) {
        /* above call sets the state for us */
        return false;
      }
      decoder->protected_->state = FLAC__STREAM_DECODER_SEARCH_FOR_METADATA;
      decoder->private_->is_seeking = false;
      if(!FLAC__stream_decoder_process_until_end_of_metadata(decoder)) {
        decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
        return false;
      }
      decoder->private_->is_seeking = true;
    }
    /* set boundaries */
    left_pos = target_link->start_byte;
    left_sample = 0;
    right_pos = target_link->end_byte;
    right_sample = target_link->samples_this_link;
    target_sample -= target_link->samples_in_preceding_links;
  }
  else {
    right_sample = FLAC__stream_decoder_get_total_samples(decoder);

    /* If the total number of samples is unknown, use a large value, and
     * force binary search immediately.
     */
    if(right_sample == 0) {
      right_sample = (FLAC__uint64)(-1);
      BINARY_SEARCH_AFTER_ITERATION = 0;
    }
  }

  decoder->private_->target_sample = target_sample;
  for( ; ; iteration++) {
    /* Do sanity checks on bounds */
    if(right_pos <= left_pos || right_pos - left_pos < 9) {
      /* FLAC frame is at least 9 byte in size */
      decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
      return false;
    }
    if (iteration == 0 || this_frame_sample > target_sample || target_sample - this_frame_sample > LINEAR_SEARCH_WITHIN_SAMPLES) {
      if (iteration >= BINARY_SEARCH_AFTER_ITERATION) {
        pos = (right_pos + left_pos) / 2;
      }
      else {
#ifndef FLAC__INTEGER_ONLY_LIBRARY
        pos = (FLAC__uint64)((double)(target_sample - left_sample) / (double)(right_sample - left_sample) * (double)(right_pos - left_pos)) + left_pos;
#else
        /* a little less accurate: */
        if ((target_sample-left_sample <= 0xffffffff) && (right_pos-left_pos <= 0xffffffff))
          pos = (FLAC__int64)(((target_sample-left_sample) * (right_pos-left_pos)) / (right_sample-left_sample)) + left_pos;
        else /* @@@ WATCHOUT, ~2TB limit */
          pos = (FLAC__int64)((((target_sample-left_sample)>>8) * ((right_pos-left_pos)>>8)) / ((right_sample-left_sample)>>16)) + left_pos;
#endif
        /* @@@ TODO: might want to limit pos to some distance
         * before EOF, to make sure we land before the last frame,
         * thereby getting a this_frame_sample and so having a better
         * estimate.
         */
      }

      /* physical seek */
      if(decoder->private_->seek_callback((FLAC__StreamDecoder*)decoder, (FLAC__uint64)pos, decoder->private_->client_data) != FLAC__STREAM_DECODER_SEEK_STATUS_OK) {
        decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
        return false;
      }
      if(!FLAC__stream_decoder_flush(decoder)) {
        /* above call sets the state for us */
        return false;
      }
      did_a_seek = true;
    }
    else
      did_a_seek = false;

    decoder->private_->got_a_frame = false;
    if(!FLAC__stream_decoder_process_single(decoder) ||
       decoder->protected_->state == FLAC__STREAM_DECODER_ABORTED) {
      if(decoder->protected_->state != FLAC__STREAM_DECODER_ABORTED && decoder->protected_->state != FLAC__STREAM_DECODER_MEMORY_ALLOCATION_ERROR)
        decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
      return false;
    }
    if(!decoder->private_->got_a_frame) {
      if(did_a_seek) {
        /* this can happen if we seek to a point after the last frame; we drop
         * to binary search right away in this case to avoid any wasted
         * iterations of proportional search.
         */
        right_pos = pos;
        BINARY_SEARCH_AFTER_ITERATION = 0;
      }
      else {
        /* this can probably only happen if total_samples is unknown and the
         * target_sample is past the end of the stream
         */
        decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
        return false;
      }
    }
    /* our write callback will change the state when it gets to the target frame */
    else if(!decoder->private_->is_seeking) {
      break;
    }
    else {
      this_frame_sample = decoder->private_->last_frame.header.number.sample_number;
      FLAC__ASSERT(decoder->private_->last_frame.header.number_type == FLAC__FRAME_NUMBER_TYPE_SAMPLE_NUMBER);

      if (did_a_seek) {
        if (this_frame_sample <= target_sample) {
          /* The 'equal' case should not happen, since
           * FLAC__stream_decoder_process_single()
           * should recognize that it has hit the
           * target sample and we would exit through
           * the 'break' above.
           */
          FLAC__ASSERT(this_frame_sample != target_sample);

          left_sample = this_frame_sample;
          /* sanity check to avoid infinite loop */
          if (left_pos == pos) {
            decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
            return false;
          }
          left_pos = pos;
        }
        else {
          right_sample = this_frame_sample;
          /* sanity check to avoid infinite loop */
          if (right_pos == pos) {
            decoder->protected_->state = FLAC__STREAM_DECODER_SEEK_ERROR;
            return false;
          }
          right_pos = pos;
        }
      }
    }
  }
  /* Tell ogg decoder aspect that seeking is done */
  FLAC__ogg_decoder_aspect_set_seek_parameters(&decoder->protected_->ogg_decoder_aspect, 0);
  return true;
}
#endif

FLAC__StreamDecoderReadStatus file_read_callback_(const FLAC__StreamDecoder *decoder, FLAC__byte buffer[], size_t *bytes, void *client_data)
{
  (void)client_data;

  if(*bytes > 0) {
    *bytes = fread(buffer, sizeof(FLAC__byte), *bytes, decoder->private_->file);
    if(ferror(decoder->private_->file))
      return FLAC__STREAM_DECODER_READ_STATUS_ABORT;
    else if(*bytes == 0)
      return FLAC__STREAM_DECODER_READ_STATUS_END_OF_STREAM;
    else
      return FLAC__STREAM_DECODER_READ_STATUS_CONTINUE;
  }
  else
    return FLAC__STREAM_DECODER_READ_STATUS_ABORT; /* abort to avoid a deadlock */
}

FLAC__StreamDecoderSeekStatus file_seek_callback_(const FLAC__StreamDecoder *decoder, FLAC__uint64 absolute_byte_offset, void *client_data)
{
  (void)client_data;

  if(decoder->private_->file == stdin)
    return FLAC__STREAM_DECODER_SEEK_STATUS_UNSUPPORTED;
  else if(fseeko(decoder->private_->file, (FLAC__off_t)absolute_byte_offset, SEEK_SET) < 0)
    return FLAC__STREAM_DECODER_SEEK_STATUS_ERROR;
  else
    return FLAC__STREAM_DECODER_SEEK_STATUS_OK;
}

FLAC__StreamDecoderTellStatus file_tell_callback_(const FLAC__StreamDecoder *decoder, FLAC__uint64 *absolute_byte_offset, void *client_data)
{
  FLAC__off_t pos;
  (void)client_data;

  if(decoder->private_->file == stdin)
    return FLAC__STREAM_DECODER_TELL_STATUS_UNSUPPORTED;
  else if((pos = ftello(decoder->private_->file)) < 0)
    return FLAC__STREAM_DECODER_TELL_STATUS_ERROR;
  else {
    *absolute_byte_offset = (FLAC__uint64)pos;
    return FLAC__STREAM_DECODER_TELL_STATUS_OK;
  }
}

FLAC__StreamDecoderLengthStatus file_length_callback_(const FLAC__StreamDecoder *decoder, FLAC__uint64 *stream_length, void *client_data)
{
  struct flac_stat_s filestats;
  (void)client_data;

  if(decoder->private_->file == stdin)
    return FLAC__STREAM_DECODER_LENGTH_STATUS_UNSUPPORTED;

#ifndef FLAC__USE_FILELENGTHI64
  if(flac_fstat(fileno(decoder->private_->file), &filestats) != 0)
#else
  filestats.st_size = _filelengthi64(fileno(decoder->private_->file));
  if(filestats.st_size < 0)
#endif
    return FLAC__STREAM_DECODER_LENGTH_STATUS_ERROR;
  else {
    *stream_length = (FLAC__uint64)filestats.st_size;
    return FLAC__STREAM_DECODER_LENGTH_STATUS_OK;
  }
}

FLAC__bool file_eof_callback_(const FLAC__StreamDecoder *decoder, void *client_data)
{
  (void)client_data;

  return feof(decoder->private_->file)? true : false;
}

Coverage Report

Created: 2026-08-31 06:48