media/module/codecs/flac/dec/FLACDecoder.cpp - LeafOS-Project/android_frameworks_av - Gitiles

 /*
  * Copyright (C) 2017 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 //#define LOG_NDEBUG 0
 #define LOG_TAG "FLACDecoder"
 #include <utils/Log.h>

 #include "FLACDecoder.h"

 #include <audio_utils/primitives.h> // float_from_i32
 #include <media/stagefright/foundation/ADebug.h>
 #include <media/stagefright/foundation/hexdump.h>
 #include <media/stagefright/MediaDefs.h>
 #include <media/stagefright/MediaErrors.h>
 #include <media/stagefright/MetaData.h>

 namespace android {

 // These are the corresponding callbacks with C++ calling conventions
 FLAC__StreamDecoderReadStatus FLACDecoder::readCallback(
         FLAC__byte buffer[], size_t *bytes) {
     if (mBuffer == nullptr || mBufferLen == 0) {
         *bytes = 0;
         return FLAC__STREAM_DECODER_READ_STATUS_ABORT;
     }

     size_t actual = *bytes;
     if (actual > mBufferDataSize - mBufferPos) {
         actual = mBufferDataSize - mBufferPos;
     }
     memcpy(buffer, mBuffer + mBufferPos, actual);
     mBufferPos += actual;
     *bytes = actual;
     return (actual == 0 ? FLAC__STREAM_DECODER_READ_STATUS_END_OF_STREAM
                         : FLAC__STREAM_DECODER_READ_STATUS_CONTINUE);
 }

 FLAC__StreamDecoderWriteStatus FLACDecoder::writeCallback(
         const FLAC__Frame *frame, const FLAC__int32 * const buffer[])
 {
     if (!mWriteRequested) {
         ALOGE("writeCallback: unexpected");
         return FLAC__STREAM_DECODER_WRITE_STATUS_ABORT;
     }

     mWriteRequested = false;
     // FLAC decoder doesn't free or realloc buffer until next frame or finish
     mWriteHeader = frame->header;
     memmove(mWriteBuffer, buffer, sizeof(const FLAC__int32 * const) * getChannels());
     mWriteCompleted = true;
     return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;
 }

 void FLACDecoder::metadataCallback(const FLAC__StreamMetadata *metadata)
 {
     switch (metadata->type) {
         case FLAC__METADATA_TYPE_STREAMINFO:
         {
             if (mStreamInfoValid) {
                 ALOGE("metadataCallback: unexpected STREAMINFO");
             } else {
                 mStreamInfo = metadata->data.stream_info;
                 mStreamInfoValid = true;
             }
             break;
         }

         /* TODO: enable metadata parsing below.
         case FLAC__METADATA_TYPE_VORBIS_COMMENT:
         {
             const FLAC__StreamMetadata_VorbisComment *vc;
             vc = &metadata->data.vorbis_comment;
             for (FLAC__uint32 i = 0; i < vc->num_comments; ++i) {
                 FLAC__StreamMetadata_VorbisComment_Entry *vce;
                 vce = &vc->comments[i];
                 if (mFileMetadata != 0 && vce->entry != NULL) {
                     parseVorbisComment(mFileMetadata, (const char *) vce->entry,
                             vce->length);
                 }
             }
             break;
         }

         case FLAC__METADATA_TYPE_PICTURE:
         {
             if (mFileMetadata != 0) {
                 const FLAC__StreamMetadata_Picture *p = &metadata->data.picture;
                 mFileMetadata->setData(kKeyAlbumArt,
                         MetaData::TYPE_NONE, p->data, p->data_length);
                 mFileMetadata->setCString(kKeyAlbumArtMIME, p->mime_type);
             }
             break;
         }
         */

         default:
             ALOGW("metadataCallback: unexpected type %u", metadata->type);
             break;
     }
 }

 void FLACDecoder::errorCallback(FLAC__StreamDecoderErrorStatus status)
 {
     ALOGE("errorCallback: status=%d", status);
     mErrorStatus = status;
 }

 // Copy samples from FLAC native 32-bit non-interleaved to 16-bit signed
 // or 32-bit float interleaved.
 // TODO: Consider moving to audio_utils.  See similar code at FLACExtractor.cpp
 // These are candidates for optimization if needed.
 static void copyTo16Signed(
         short *dst,
         const int *const *src,
         unsigned nSamples,
         unsigned nChannels,
         unsigned bitsPerSample) {
     const int leftShift = 16 - (int)bitsPerSample; // cast to int to prevent unsigned overflow.
     if (leftShift >= 0) {
         for (unsigned i = 0; i < nSamples; ++i) {
             for (unsigned c = 0; c < nChannels; ++c) {
                 *dst++ = src[c][i] << leftShift;
             }
         }
     } else {
         const int rightShift = -leftShift;
         for (unsigned i = 0; i < nSamples; ++i) {
             for (unsigned c = 0; c < nChannels; ++c) {
                 *dst++ = src[c][i] >> rightShift;
             }
         }
     }
 }

 static void copyToFloat(
         float *dst,
         const int *const *src,
         unsigned nSamples,
         unsigned nChannels,
         unsigned bitsPerSample) {
     const unsigned leftShift = 32 - bitsPerSample;
     for (unsigned i = 0; i < nSamples; ++i) {
         for (unsigned c = 0; c < nChannels; ++c) {
             *dst++ = float_from_i32(src[c][i] << leftShift);
         }
     }
 }

 // static
 FLACDecoder *FLACDecoder::Create() {
     FLACDecoder *decoder = new (std::nothrow) FLACDecoder();
     if (decoder == NULL || decoder->init() != OK) {
         delete decoder;
         return NULL;
     }
     return decoder;
 }

 FLACDecoder::FLACDecoder()
     : mDecoder(NULL),
       mBuffer(NULL),
       mBufferLen(0),
       mBufferPos(0),
       mBufferDataSize(0),
       mStreamInfoValid(false),
       mWriteRequested(false),
       mWriteCompleted(false),
       mErrorStatus((FLAC__StreamDecoderErrorStatus) -1) {
     ALOGV("ctor:");
     memset(&mStreamInfo, 0, sizeof(mStreamInfo));
     memset(&mWriteHeader, 0, sizeof(mWriteHeader));
     memset(&mWriteBuffer, 0, sizeof(mWriteBuffer));
 }

 FLACDecoder::~FLACDecoder() {
     ALOGV("dtor:");
     if (mDecoder != NULL) {
         FLAC__stream_decoder_delete(mDecoder);
         mDecoder = NULL;
     }
     if (mBuffer != NULL) {
         free(mBuffer);
     }
 }

 status_t FLACDecoder::init() {
     ALOGV("init:");
     // setup libFLAC stream decoder
     mDecoder = FLAC__stream_decoder_new();
     if (mDecoder == NULL) {
         ALOGE("init: failed to create libFLAC stream decoder");
         return NO_INIT;
     }
     FLAC__stream_decoder_set_md5_checking(mDecoder, false);
     FLAC__stream_decoder_set_metadata_ignore_all(mDecoder);
     FLAC__stream_decoder_set_metadata_respond(
             mDecoder, FLAC__METADATA_TYPE_STREAMINFO);
     /*
     FLAC__stream_decoder_set_metadata_respond(
             mDecoder, FLAC__METADATA_TYPE_PICTURE);
     FLAC__stream_decoder_set_metadata_respond(
             mDecoder, FLAC__METADATA_TYPE_VORBIS_COMMENT);
     */
     static auto read_callback =
         [] (const FLAC__StreamDecoder * /* decoder */,
             FLAC__byte buffer[],
             size_t *bytes,
             void *client_data) -> FLAC__StreamDecoderReadStatus {
             return ((FLACDecoder *) client_data)->readCallback(buffer, bytes); };

     static auto write_callback =
         [] (const FLAC__StreamDecoder * /* decoder */,
             const FLAC__Frame *frame,
             const FLAC__int32 * const buffer[],
             void *client_data) -> FLAC__StreamDecoderWriteStatus {
             return ((FLACDecoder *) client_data)->writeCallback(frame, buffer); };

     static auto metadata_callback =
         [] (const FLAC__StreamDecoder * /* decoder */,
             const FLAC__StreamMetadata *metadata,
             void *client_data) {
             ((FLACDecoder *) client_data)->metadataCallback(metadata); };

     static auto error_callback =
         [] (const FLAC__StreamDecoder * /* decoder */,
             FLAC__StreamDecoderErrorStatus status,
             void *client_data) {
             ((FLACDecoder *) client_data)->errorCallback(status); };

     FLAC__StreamDecoderInitStatus initStatus =
         FLAC__stream_decoder_init_stream(
                 mDecoder,
                 read_callback,
                 NULL /* seek_callback */,
                 NULL /* tell_callback */,
                 NULL /* length_callback */,
                 NULL /* eof_callback */,
                 write_callback,
                 metadata_callback,
                 error_callback,
                 (void *)this);
     if (initStatus != FLAC__STREAM_DECODER_INIT_STATUS_OK) {
         ALOGE("init: init_stream failed, returned %d", initStatus);
         return NO_INIT;
     }
     return OK;
 }

 void FLACDecoder::flush() {
     ALOGV("flush:");
     mBufferPos = 0;
     mBufferDataSize = 0;
     mStreamInfoValid = false;
     if (!FLAC__stream_decoder_reset(mDecoder)) {
         ALOGE("flush: failed to reset FLAC stream decoder");
     }
 }

 status_t FLACDecoder::parseMetadata(const uint8_t *inBuffer, size_t inBufferLen) {
     ALOGV("parseMetadata: input size(%zu)", inBufferLen);
     //hexdump(inBuffer, inBufferLen);

     if (mStreamInfoValid) {
         ALOGE("parseMetadata: already have full metadata blocks");
         return ERROR_MALFORMED;
     }

     status_t err = addDataToBuffer(inBuffer, inBufferLen);
     if (err != OK) {
         ALOGE("parseMetadata: addDataToBuffer returns error %d", err);
         return err;
     }

     if (!FLAC__stream_decoder_process_until_end_of_metadata(mDecoder)) {
         if (!FLAC__stream_decoder_reset(mDecoder)) {
             ALOGE("parseMetadata: failed to reset FLAC stream decoder");
             return FAILED_TRANSACTION;
         }
         mBufferPos = 0;
         ALOGV("parseMetadata: do not have full metadata blocks yet");
         return WOULD_BLOCK;
     }

     if (!mStreamInfoValid) {
         ALOGE("parseMetadata: missing STREAMINFO");
         return ERROR_MALFORMED;
     }

     // check block size
     if (getMaxBlockSize() == 0) {
         ALOGE("wrong max blocksize %u", getMaxBlockSize());
         mStreamInfoValid = false;
         return ERROR_MALFORMED;
     }

     // check channel count
     if (getChannels() == 0 || getChannels() > kMaxChannels) {
         ALOGE("unsupported channel count %u", getChannels());
         mStreamInfoValid = false;
         return ERROR_MALFORMED;
     }

     // check bit depth
     switch (getBitsPerSample()) {
         case 8:
         case 16:
         case 24:
         case 32: // generally rare, but is supported in the framework
             break;

         default:
             ALOGE("parseMetadata: unsupported bits per sample %u", getBitsPerSample());
             mStreamInfoValid = false;
             return ERROR_MALFORMED;
     }

     // Now we have all metadata blocks.
     mBufferPos = 0;
     mBufferDataSize = 0;

     return OK;
 }

 status_t FLACDecoder::decodeOneFrame(const uint8_t *inBuffer, size_t inBufferLen,
         void *outBuffer, size_t *outBufferLen, bool outputFloat) {
     ALOGV("decodeOneFrame: input size(%zu)", inBufferLen);

     if (!mStreamInfoValid) {
         ALOGW("decodeOneFrame: no streaminfo metadata block");
     }

     if (inBufferLen != 0) {
         status_t err = addDataToBuffer(inBuffer, inBufferLen);
         if (err != OK) {
             ALOGW("decodeOneFrame: addDataToBuffer returns error %d", err);
             return err;
         }
     }

     mWriteRequested = true;
     mWriteCompleted = false;
     if (!FLAC__stream_decoder_process_single(mDecoder)) {
         ALOGE("decodeOneFrame: process_single failed");
         return ERROR_MALFORMED;
     }
     if (!mWriteCompleted) {
         ALOGV("decodeOneFrame: write did not complete");
         if (outBufferLen) {
             *outBufferLen = 0;
         }
         return OK;
     }

     // frame header should be consistent with STREAMINFO
     unsigned blocksize = mWriteHeader.blocksize;
     if (blocksize == 0 || blocksize > getMaxBlockSize()) {
         ALOGE("decodeOneFrame: write invalid blocksize %u", blocksize);
         return ERROR_MALFORMED;
     }
     if (mWriteHeader.sample_rate != getSampleRate() ||
         mWriteHeader.channels != getChannels() ||
         mWriteHeader.bits_per_sample != getBitsPerSample()) {
         ALOGE("decodeOneFrame: parameters are changed mid-stream: %d/%d/%d -> %d/%d/%d",
                 getSampleRate(), getChannels(), getBitsPerSample(),
                 mWriteHeader.sample_rate, mWriteHeader.channels, mWriteHeader.bits_per_sample);
         return ERROR_MALFORMED;
     }
     if (mWriteHeader.number_type != FLAC__FRAME_NUMBER_TYPE_SAMPLE_NUMBER) {
         ALOGE("decodeOneFrame: number type is %d, expected %d",
                 mWriteHeader.number_type, FLAC__FRAME_NUMBER_TYPE_SAMPLE_NUMBER);
         return ERROR_MALFORMED;
     }

     const unsigned channels = getChannels();
     const size_t sampleSize = outputFloat ? sizeof(float) : sizeof(int16_t);
     const size_t frameSize = channels * sampleSize;
     size_t bufferSize = blocksize * frameSize;
     if (bufferSize > *outBufferLen) {
         ALOGW("decodeOneFrame: output buffer holds only partial frame %zu:%zu",
                 *outBufferLen, bufferSize);
         blocksize = *outBufferLen / frameSize;
         bufferSize = blocksize * frameSize;
     }

     // copy PCM from FLAC write buffer to output buffer, with interleaving

     const unsigned bitsPerSample = getBitsPerSample();
     if (outputFloat) {
         copyToFloat(reinterpret_cast<float*>(outBuffer),
                     mWriteBuffer,
                     blocksize,
                     channels,
                     bitsPerSample);
     } else {
         copyTo16Signed(reinterpret_cast<short*>(outBuffer),
                        mWriteBuffer,
                        blocksize,
                        channels,
                        bitsPerSample);
     }
     *outBufferLen = bufferSize;
     return OK;
 }

 status_t FLACDecoder::addDataToBuffer(const uint8_t *inBuffer, size_t inBufferLen) {
     // mBufferPos should be no larger than mBufferDataSize
     if (inBufferLen > SIZE_MAX - (mBufferDataSize - mBufferPos)) {
         ALOGE("addDataToBuffer: input buffer is too large");
         return ERROR_MALFORMED;
     }

     if (inBufferLen > mBufferLen - mBufferDataSize) {
         if (mBufferPos > 0) {
             memmove(mBuffer, mBuffer + mBufferPos, mBufferDataSize - mBufferPos);
             mBufferDataSize -= mBufferPos;
             mBufferPos = 0;
         }
         if (inBufferLen > mBufferLen - mBufferDataSize) {
             mBuffer = (uint8_t*)realloc(mBuffer, mBufferDataSize + inBufferLen);
             if (mBuffer == nullptr) {
                 mBufferDataSize = 0;
                 mBufferLen = 0;
                 ALOGE("addDataToBuffer: failed to allocate memory for input buffer");
                 return NO_MEMORY;
             }
             mBufferLen = mBufferDataSize + inBufferLen;
         }
     }

     memcpy(mBuffer + mBufferDataSize, inBuffer, inBufferLen);
     mBufferDataSize += inBufferLen;
     return OK;
 }

 }  // namespace android
	/*
	* Copyright (C) 2017 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	//#define LOG_NDEBUG 0
	#define LOG_TAG "FLACDecoder"
	#include <utils/Log.h>

	#include "FLACDecoder.h"

	#include <audio_utils/primitives.h> // float_from_i32
	#include <media/stagefright/foundation/ADebug.h>
	#include <media/stagefright/foundation/hexdump.h>
	#include <media/stagefright/MediaDefs.h>
	#include <media/stagefright/MediaErrors.h>
	#include <media/stagefright/MetaData.h>

	namespace android {

	// These are the corresponding callbacks with C++ calling conventions
	FLAC__StreamDecoderReadStatus FLACDecoder::readCallback(
	FLAC__byte buffer[], size_t *bytes) {
	if (mBuffer == nullptr \|\| mBufferLen == 0) {
	*bytes = 0;
	return FLAC__STREAM_DECODER_READ_STATUS_ABORT;
	}

	size_t actual = *bytes;
	if (actual > mBufferDataSize - mBufferPos) {
	actual = mBufferDataSize - mBufferPos;
	}
	memcpy(buffer, mBuffer + mBufferPos, actual);
	mBufferPos += actual;
	*bytes = actual;
	return (actual == 0 ? FLAC__STREAM_DECODER_READ_STATUS_END_OF_STREAM
	: FLAC__STREAM_DECODER_READ_STATUS_CONTINUE);
	}

	FLAC__StreamDecoderWriteStatus FLACDecoder::writeCallback(
	const FLAC__Frame frame, const FLAC__int32 const buffer[])
	{
	if (!mWriteRequested) {
	ALOGE("writeCallback: unexpected");
	return FLAC__STREAM_DECODER_WRITE_STATUS_ABORT;
	}

	mWriteRequested = false;
	// FLAC decoder doesn't free or realloc buffer until next frame or finish
	mWriteHeader = frame->header;
	memmove(mWriteBuffer, buffer, sizeof(const FLAC__int32 * const) * getChannels());
	mWriteCompleted = true;
	return FLAC__STREAM_DECODER_WRITE_STATUS_CONTINUE;
	}

	void FLACDecoder::metadataCallback(const FLAC__StreamMetadata *metadata)
	{
	switch (metadata->type) {
	case FLAC__METADATA_TYPE_STREAMINFO:
	{
	if (mStreamInfoValid) {
	ALOGE("metadataCallback: unexpected STREAMINFO");
	} else {
	mStreamInfo = metadata->data.stream_info;
	mStreamInfoValid = true;
	}
	break;
	}

	/* TODO: enable metadata parsing below.
	case FLAC__METADATA_TYPE_VORBIS_COMMENT:
	{
	const FLAC__StreamMetadata_VorbisComment *vc;
	vc = &metadata->data.vorbis_comment;
	for (FLAC__uint32 i = 0; i < vc->num_comments; ++i) {
	FLAC__StreamMetadata_VorbisComment_Entry *vce;
	vce = &vc->comments[i];
	if (mFileMetadata != 0 && vce->entry != NULL) {
	parseVorbisComment(mFileMetadata, (const char *) vce->entry,
	vce->length);
	}
	}
	break;
	}

	case FLAC__METADATA_TYPE_PICTURE:
	{
	if (mFileMetadata != 0) {
	const FLAC__StreamMetadata_Picture *p = &metadata->data.picture;
	mFileMetadata->setData(kKeyAlbumArt,
	MetaData::TYPE_NONE, p->data, p->data_length);
	mFileMetadata->setCString(kKeyAlbumArtMIME, p->mime_type);
	}
	break;
	}
	*/

	default:
	ALOGW("metadataCallback: unexpected type %u", metadata->type);
	break;
	}
	}

	void FLACDecoder::errorCallback(FLAC__StreamDecoderErrorStatus status)
	{
	ALOGE("errorCallback: status=%d", status);
	mErrorStatus = status;
	}

	// Copy samples from FLAC native 32-bit non-interleaved to 16-bit signed
	// or 32-bit float interleaved.
	// TODO: Consider moving to audio_utils. See similar code at FLACExtractor.cpp
	// These are candidates for optimization if needed.
	static void copyTo16Signed(
	short *dst,
	const int const src,
	unsigned nSamples,
	unsigned nChannels,
	unsigned bitsPerSample) {
	const int leftShift = 16 - (int)bitsPerSample; // cast to int to prevent unsigned overflow.
	if (leftShift >= 0) {
	for (unsigned i = 0; i < nSamples; ++i) {
	for (unsigned c = 0; c < nChannels; ++c) {
	*dst++ = src[c][i] << leftShift;
	}
	}
	} else {
	const int rightShift = -leftShift;
	for (unsigned i = 0; i < nSamples; ++i) {
	for (unsigned c = 0; c < nChannels; ++c) {
	*dst++ = src[c][i] >> rightShift;
	}
	}
	}
	}

	static void copyToFloat(
	float *dst,
	const int const src,
	unsigned nSamples,
	unsigned nChannels,
	unsigned bitsPerSample) {
	const unsigned leftShift = 32 - bitsPerSample;
	for (unsigned i = 0; i < nSamples; ++i) {
	for (unsigned c = 0; c < nChannels; ++c) {
	*dst++ = float_from_i32(src[c][i] << leftShift);
	}
	}
	}

	// static
	FLACDecoder *FLACDecoder::Create() {
	FLACDecoder *decoder = new (std::nothrow) FLACDecoder();
	if (decoder == NULL \|\| decoder->init() != OK) {
	delete decoder;
	return NULL;
	}
	return decoder;
	}

	FLACDecoder::FLACDecoder()
	: mDecoder(NULL),
	mBuffer(NULL),
	mBufferLen(0),
	mBufferPos(0),
	mBufferDataSize(0),
	mStreamInfoValid(false),
	mWriteRequested(false),
	mWriteCompleted(false),
	mErrorStatus((FLAC__StreamDecoderErrorStatus) -1) {
	ALOGV("ctor:");
	memset(&mStreamInfo, 0, sizeof(mStreamInfo));
	memset(&mWriteHeader, 0, sizeof(mWriteHeader));
	memset(&mWriteBuffer, 0, sizeof(mWriteBuffer));
	}

	FLACDecoder::~FLACDecoder() {
	ALOGV("dtor:");
	if (mDecoder != NULL) {
	FLAC__stream_decoder_delete(mDecoder);
	mDecoder = NULL;
	}
	if (mBuffer != NULL) {
	free(mBuffer);
	}
	}

	status_t FLACDecoder::init() {
	ALOGV("init:");
	// setup libFLAC stream decoder
	mDecoder = FLAC__stream_decoder_new();
	if (mDecoder == NULL) {
	ALOGE("init: failed to create libFLAC stream decoder");
	return NO_INIT;
	}
	FLAC__stream_decoder_set_md5_checking(mDecoder, false);
	FLAC__stream_decoder_set_metadata_ignore_all(mDecoder);
	FLAC__stream_decoder_set_metadata_respond(
	mDecoder, FLAC__METADATA_TYPE_STREAMINFO);
	/*
	FLAC__stream_decoder_set_metadata_respond(
	mDecoder, FLAC__METADATA_TYPE_PICTURE);
	FLAC__stream_decoder_set_metadata_respond(
	mDecoder, FLAC__METADATA_TYPE_VORBIS_COMMENT);
	*/
	static auto read_callback =
	[] (const FLAC__StreamDecoder * /* decoder */,
	FLAC__byte buffer[],
	size_t *bytes,
	void *client_data) -> FLAC__StreamDecoderReadStatus {
	return ((FLACDecoder *) client_data)->readCallback(buffer, bytes); };

	static auto write_callback =
	[] (const FLAC__StreamDecoder * /* decoder */,
	const FLAC__Frame *frame,
	const FLAC__int32 * const buffer[],
	void *client_data) -> FLAC__StreamDecoderWriteStatus {
	return ((FLACDecoder *) client_data)->writeCallback(frame, buffer); };

	static auto metadata_callback =
	[] (const FLAC__StreamDecoder * /* decoder */,
	const FLAC__StreamMetadata *metadata,
	void *client_data) {
	((FLACDecoder *) client_data)->metadataCallback(metadata); };

	static auto error_callback =
	[] (const FLAC__StreamDecoder * /* decoder */,
	FLAC__StreamDecoderErrorStatus status,
	void *client_data) {
	((FLACDecoder *) client_data)->errorCallback(status); };

	FLAC__StreamDecoderInitStatus initStatus =
	FLAC__stream_decoder_init_stream(
	mDecoder,
	read_callback,
	NULL /* seek_callback */,
	NULL /* tell_callback */,
	NULL /* length_callback */,
	NULL /* eof_callback */,
	write_callback,
	metadata_callback,
	error_callback,
	(void *)this);
	if (initStatus != FLAC__STREAM_DECODER_INIT_STATUS_OK) {
	ALOGE("init: init_stream failed, returned %d", initStatus);
	return NO_INIT;
	}
	return OK;
	}

	void FLACDecoder::flush() {
	ALOGV("flush:");
	mBufferPos = 0;
	mBufferDataSize = 0;
	mStreamInfoValid = false;
	if (!FLAC__stream_decoder_reset(mDecoder)) {
	ALOGE("flush: failed to reset FLAC stream decoder");
	}
	}

	status_t FLACDecoder::parseMetadata(const uint8_t *inBuffer, size_t inBufferLen) {
	ALOGV("parseMetadata: input size(%zu)", inBufferLen);
	//hexdump(inBuffer, inBufferLen);

	if (mStreamInfoValid) {
	ALOGE("parseMetadata: already have full metadata blocks");
	return ERROR_MALFORMED;
	}

	status_t err = addDataToBuffer(inBuffer, inBufferLen);
	if (err != OK) {
	ALOGE("parseMetadata: addDataToBuffer returns error %d", err);
	return err;
	}

	if (!FLAC__stream_decoder_process_until_end_of_metadata(mDecoder)) {
	if (!FLAC__stream_decoder_reset(mDecoder)) {
	ALOGE("parseMetadata: failed to reset FLAC stream decoder");
	return FAILED_TRANSACTION;
	}
	mBufferPos = 0;
	ALOGV("parseMetadata: do not have full metadata blocks yet");
	return WOULD_BLOCK;
	}

	if (!mStreamInfoValid) {
	ALOGE("parseMetadata: missing STREAMINFO");
	return ERROR_MALFORMED;
	}

	// check block size
	if (getMaxBlockSize() == 0) {
	ALOGE("wrong max blocksize %u", getMaxBlockSize());
	mStreamInfoValid = false;
	return ERROR_MALFORMED;
	}

	// check channel count
	if (getChannels() == 0 \|\| getChannels() > kMaxChannels) {
	ALOGE("unsupported channel count %u", getChannels());
	mStreamInfoValid = false;
	return ERROR_MALFORMED;
	}

	// check bit depth
	switch (getBitsPerSample()) {
	case 8:
	case 16:
	case 24:
	case 32: // generally rare, but is supported in the framework
	break;

	default:
	ALOGE("parseMetadata: unsupported bits per sample %u", getBitsPerSample());
	mStreamInfoValid = false;
	return ERROR_MALFORMED;
	}

	// Now we have all metadata blocks.
	mBufferPos = 0;
	mBufferDataSize = 0;

	return OK;
	}

	status_t FLACDecoder::decodeOneFrame(const uint8_t *inBuffer, size_t inBufferLen,
	void outBuffer, size_t outBufferLen, bool outputFloat) {
	ALOGV("decodeOneFrame: input size(%zu)", inBufferLen);

	if (!mStreamInfoValid) {
	ALOGW("decodeOneFrame: no streaminfo metadata block");
	}

	if (inBufferLen != 0) {
	status_t err = addDataToBuffer(inBuffer, inBufferLen);
	if (err != OK) {
	ALOGW("decodeOneFrame: addDataToBuffer returns error %d", err);
	return err;
	}
	}

	mWriteRequested = true;
	mWriteCompleted = false;
	if (!FLAC__stream_decoder_process_single(mDecoder)) {
	ALOGE("decodeOneFrame: process_single failed");
	return ERROR_MALFORMED;
	}
	if (!mWriteCompleted) {
	ALOGV("decodeOneFrame: write did not complete");
	if (outBufferLen) {
	*outBufferLen = 0;
	}
	return OK;
	}

	// frame header should be consistent with STREAMINFO
	unsigned blocksize = mWriteHeader.blocksize;
	if (blocksize == 0 \|\| blocksize > getMaxBlockSize()) {
	ALOGE("decodeOneFrame: write invalid blocksize %u", blocksize);
	return ERROR_MALFORMED;
	}
	if (mWriteHeader.sample_rate != getSampleRate() \|\|
	mWriteHeader.channels != getChannels() \|\|
	mWriteHeader.bits_per_sample != getBitsPerSample()) {
	ALOGE("decodeOneFrame: parameters are changed mid-stream: %d/%d/%d -> %d/%d/%d",
	getSampleRate(), getChannels(), getBitsPerSample(),
	mWriteHeader.sample_rate, mWriteHeader.channels, mWriteHeader.bits_per_sample);
	return ERROR_MALFORMED;
	}
	if (mWriteHeader.number_type != FLAC__FRAME_NUMBER_TYPE_SAMPLE_NUMBER) {
	ALOGE("decodeOneFrame: number type is %d, expected %d",
	mWriteHeader.number_type, FLAC__FRAME_NUMBER_TYPE_SAMPLE_NUMBER);
	return ERROR_MALFORMED;
	}

	const unsigned channels = getChannels();
	const size_t sampleSize = outputFloat ? sizeof(float) : sizeof(int16_t);
	const size_t frameSize = channels * sampleSize;
	size_t bufferSize = blocksize * frameSize;
	if (bufferSize > *outBufferLen) {
	ALOGW("decodeOneFrame: output buffer holds only partial frame %zu:%zu",
	*outBufferLen, bufferSize);
	blocksize = *outBufferLen / frameSize;
	bufferSize = blocksize * frameSize;
	}

	// copy PCM from FLAC write buffer to output buffer, with interleaving

	const unsigned bitsPerSample = getBitsPerSample();
	if (outputFloat) {
	copyToFloat(reinterpret_cast<float*>(outBuffer),
	mWriteBuffer,
	blocksize,
	channels,
	bitsPerSample);
	} else {
	copyTo16Signed(reinterpret_cast<short*>(outBuffer),
	mWriteBuffer,
	blocksize,
	channels,
	bitsPerSample);
	}
	*outBufferLen = bufferSize;
	return OK;
	}

	status_t FLACDecoder::addDataToBuffer(const uint8_t *inBuffer, size_t inBufferLen) {
	// mBufferPos should be no larger than mBufferDataSize
	if (inBufferLen > SIZE_MAX - (mBufferDataSize - mBufferPos)) {
	ALOGE("addDataToBuffer: input buffer is too large");
	return ERROR_MALFORMED;
	}

	if (inBufferLen > mBufferLen - mBufferDataSize) {
	if (mBufferPos > 0) {
	memmove(mBuffer, mBuffer + mBufferPos, mBufferDataSize - mBufferPos);
	mBufferDataSize -= mBufferPos;
	mBufferPos = 0;
	}
	if (inBufferLen > mBufferLen - mBufferDataSize) {
	mBuffer = (uint8_t*)realloc(mBuffer, mBufferDataSize + inBufferLen);
	if (mBuffer == nullptr) {
	mBufferDataSize = 0;
	mBufferLen = 0;
	ALOGE("addDataToBuffer: failed to allocate memory for input buffer");
	return NO_MEMORY;
	}
	mBufferLen = mBufferDataSize + inBufferLen;
	}
	}

	memcpy(mBuffer + mBufferDataSize, inBuffer, inBufferLen);
	mBufferDataSize += inBufferLen;
	return OK;
	}

	} // namespace android