/* libFLAC - Free Lossless Audio Codec library * Copyright (C) 2000-2009 Josh Coalson * Copyright (C) 2011-2022 Xiph.Org Foundation * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * - Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * - Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * - Neither the name of the Xiph.org Foundation nor the names of its * contributors may be used to endorse or promote products derived from * this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #ifdef HAVE_CONFIG_H # include <config.h> #endif #include <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/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 = …; /*********************************************************************** * * Private static data * ***********************************************************************/ static const FLAC__byte ID3V2_TAG_[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); /*********************************************************************** * * Private class data * ***********************************************************************/ FLAC__StreamDecoderPrivate; /*********************************************************************** * * Public static class data * ***********************************************************************/ FLAC_API const char * const FLAC__StreamDecoderStateString[] = …; FLAC_API const char * const FLAC__StreamDecoderInitStatusString[] = …; FLAC_API const char * const FLAC__StreamDecoderReadStatusString[] = …; FLAC_API const char * const FLAC__StreamDecoderSeekStatusString[] = …; FLAC_API const char * const FLAC__StreamDecoderTellStatusString[] = …; FLAC_API const char * const FLAC__StreamDecoderLengthStatusString[] = …; FLAC_API const char * const FLAC__StreamDecoderWriteStatusString[] = …; FLAC_API const char * const FLAC__StreamDecoderErrorStatusString[] = …; /*********************************************************************** * * Class constructor/destructor * ***********************************************************************/ FLAC_API FLAC__StreamDecoder *FLAC__stream_decoder_new(void) { … } FLAC_API void FLAC__stream_decoder_delete(FLAC__StreamDecoder *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_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 ) { … } 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 ) { … } 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_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 ) { … } 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 ) { … } 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 ) { … } 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 ) { … } 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 ) { … } FLAC_API FLAC__bool FLAC__stream_decoder_finish(FLAC__StreamDecoder *decoder) { … } FLAC_API FLAC__bool FLAC__stream_decoder_set_ogg_serial_number(FLAC__StreamDecoder *decoder, long value) { … } FLAC_API FLAC__bool FLAC__stream_decoder_set_md5_checking(FLAC__StreamDecoder *decoder, FLAC__bool value) { … } FLAC_API FLAC__bool FLAC__stream_decoder_set_metadata_respond(FLAC__StreamDecoder *decoder, FLAC__MetadataType type) { … } FLAC_API FLAC__bool FLAC__stream_decoder_set_metadata_respond_application(FLAC__StreamDecoder *decoder, const FLAC__byte id[4]) { … } FLAC_API FLAC__bool FLAC__stream_decoder_set_metadata_respond_all(FLAC__StreamDecoder *decoder) { … } FLAC_API FLAC__bool FLAC__stream_decoder_set_metadata_ignore(FLAC__StreamDecoder *decoder, FLAC__MetadataType type) { … } FLAC_API FLAC__bool FLAC__stream_decoder_set_metadata_ignore_application(FLAC__StreamDecoder *decoder, const FLAC__byte id[4]) { … } FLAC_API FLAC__bool FLAC__stream_decoder_set_metadata_ignore_all(FLAC__StreamDecoder *decoder) { … } FLAC_API FLAC__StreamDecoderState FLAC__stream_decoder_get_state(const FLAC__StreamDecoder *decoder) { … } FLAC_API const char *FLAC__stream_decoder_get_resolved_state_string(const FLAC__StreamDecoder *decoder) { … } FLAC_API FLAC__bool FLAC__stream_decoder_get_md5_checking(const FLAC__StreamDecoder *decoder) { … } FLAC_API FLAC__uint64 FLAC__stream_decoder_get_total_samples(const FLAC__StreamDecoder *decoder) { … } FLAC_API uint32_t FLAC__stream_decoder_get_channels(const FLAC__StreamDecoder *decoder) { … } FLAC_API FLAC__ChannelAssignment FLAC__stream_decoder_get_channel_assignment(const FLAC__StreamDecoder *decoder) { … } FLAC_API uint32_t FLAC__stream_decoder_get_bits_per_sample(const FLAC__StreamDecoder *decoder) { … } FLAC_API uint32_t FLAC__stream_decoder_get_sample_rate(const FLAC__StreamDecoder *decoder) { … } FLAC_API uint32_t FLAC__stream_decoder_get_blocksize(const FLAC__StreamDecoder *decoder) { … } FLAC_API FLAC__bool FLAC__stream_decoder_get_decode_position(const FLAC__StreamDecoder *decoder, FLAC__uint64 *position) { … } FLAC_API const void *FLAC__stream_decoder_get_client_data(FLAC__StreamDecoder *decoder) { … } FLAC_API FLAC__bool FLAC__stream_decoder_flush(FLAC__StreamDecoder *decoder) { … } FLAC_API FLAC__bool FLAC__stream_decoder_reset(FLAC__StreamDecoder *decoder) { … } FLAC_API FLAC__bool FLAC__stream_decoder_process_single(FLAC__StreamDecoder *decoder) { … } FLAC_API FLAC__bool FLAC__stream_decoder_process_until_end_of_metadata(FLAC__StreamDecoder *decoder) { … } FLAC_API FLAC__bool FLAC__stream_decoder_process_until_end_of_stream(FLAC__StreamDecoder *decoder) { … } FLAC_API FLAC__bool FLAC__stream_decoder_skip_single_frame(FLAC__StreamDecoder *decoder) { … } FLAC_API FLAC__bool FLAC__stream_decoder_seek_absolute(FLAC__StreamDecoder *decoder, FLAC__uint64 sample) { … } /*********************************************************************** * * Protected class methods * ***********************************************************************/ uint32_t FLAC__stream_decoder_get_input_bytes_unconsumed(const FLAC__StreamDecoder *decoder) { … } /*********************************************************************** * * Private class methods * ***********************************************************************/ void set_defaults_(FLAC__StreamDecoder *decoder) { … } /* * This will forcibly set stdin to binary mode (for OSes that require it) */ FILE *get_binary_stdin_(void) { … } FLAC__bool allocate_output_(FLAC__StreamDecoder *decoder, uint32_t size, uint32_t channels, uint32_t bps) { … } FLAC__bool has_id_filtered_(FLAC__StreamDecoder *decoder, FLAC__byte *id) { … } FLAC__bool find_metadata_(FLAC__StreamDecoder *decoder) { … } FLAC__bool read_metadata_(FLAC__StreamDecoder *decoder) { … } FLAC__bool read_metadata_streaminfo_(FLAC__StreamDecoder *decoder, FLAC__bool is_last, uint32_t length) { … } FLAC__bool read_metadata_seektable_(FLAC__StreamDecoder *decoder, FLAC__bool is_last, uint32_t length) { … } FLAC__bool read_metadata_vorbiscomment_(FLAC__StreamDecoder *decoder, FLAC__StreamMetadata_VorbisComment *obj, uint32_t length) { … } FLAC__bool read_metadata_cuesheet_(FLAC__StreamDecoder *decoder, FLAC__StreamMetadata_CueSheet *obj) { … } FLAC__bool read_metadata_picture_(FLAC__StreamDecoder *decoder, FLAC__StreamMetadata_Picture *obj) { … } FLAC__bool skip_id3v2_tag_(FLAC__StreamDecoder *decoder) { … } FLAC__bool frame_sync_(FLAC__StreamDecoder *decoder) { … } FLAC__bool read_frame_(FLAC__StreamDecoder *decoder, FLAC__bool *got_a_frame, FLAC__bool do_full_decode) { … } FLAC__bool read_frame_header_(FLAC__StreamDecoder *decoder) { … } FLAC__bool read_subframe_(FLAC__StreamDecoder *decoder, uint32_t channel, uint32_t bps, FLAC__bool do_full_decode) { … } FLAC__bool read_subframe_constant_(FLAC__StreamDecoder *decoder, uint32_t channel, uint32_t bps, FLAC__bool do_full_decode) { … } FLAC__bool read_subframe_fixed_(FLAC__StreamDecoder *decoder, uint32_t channel, uint32_t bps, const uint32_t order, FLAC__bool do_full_decode) { … } FLAC__bool read_subframe_lpc_(FLAC__StreamDecoder *decoder, uint32_t channel, uint32_t bps, const uint32_t order, FLAC__bool do_full_decode) { … } FLAC__bool read_subframe_verbatim_(FLAC__StreamDecoder *decoder, uint32_t channel, uint32_t bps, FLAC__bool do_full_decode) { … } 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__bool read_zero_padding_(FLAC__StreamDecoder *decoder) { … } FLAC__bool read_callback_(FLAC__byte buffer[], size_t *bytes, void *client_data) { … } #ifdef FUZZING_BUILD_MODE_NO_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) { … } #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, 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_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: case FLAC__OGG_DECODER_ASPECT_READ_STATUS_MEMORY_ALLOCATION_ERROR: 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[]) { … } void send_error_to_client_(const FLAC__StreamDecoder *decoder, FLAC__StreamDecoderErrorStatus status) { … } FLAC__bool seek_to_absolute_sample_(FLAC__StreamDecoder *decoder, FLAC__uint64 stream_length, FLAC__uint64 target_sample) { … } #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 = FLAC__stream_decoder_get_total_samples(decoder); FLAC__uint64 this_frame_sample = (FLAC__uint64)0 - 1; FLAC__uint64 pos = 0; /* only initialized to avoid compiler warning */ FLAC__bool did_a_seek; 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 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)); #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)); else /* @@@ WATCHOUT, ~2TB limit */ pos = (FLAC__int64)((((target_sample-left_sample)>>8) * ((right_pos-left_pos)>>8)) / ((right_sample-left_sample)>>16)); #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) { 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; } } } } return true; } #endif FLAC__StreamDecoderReadStatus file_read_callback_(const FLAC__StreamDecoder *decoder, FLAC__byte buffer[], size_t *bytes, void *client_data) { … } FLAC__StreamDecoderSeekStatus file_seek_callback_(const FLAC__StreamDecoder *decoder, FLAC__uint64 absolute_byte_offset, void *client_data) { … } FLAC__StreamDecoderTellStatus file_tell_callback_(const FLAC__StreamDecoder *decoder, FLAC__uint64 *absolute_byte_offset, void *client_data) { … } FLAC__StreamDecoderLengthStatus file_length_callback_(const FLAC__StreamDecoder *decoder, FLAC__uint64 *stream_length, void *client_data) { … } FLAC__bool file_eof_callback_(const FLAC__StreamDecoder *decoder, void *client_data) { … }
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