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 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

 /* vim:set ts=2 sw=2 sts=2 et cindent: */

 /* This Source Code Form is subject to the terms of the Mozilla Public

  * License, v. 2.0. If a copy of the MPL was not distributed with this

  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

 #include "nsError.h"

 #include "AbstractMediaDecoder.h"

 #include "MediaResource.h"

 #include "WaveReader.h"

 #include "mozilla/dom/TimeRanges.h"

 #include "MediaDecoderStateMachine.h"

 #include "VideoUtils.h"

 #include "nsISeekableStream.h"

 #include <stdint.h>

 #include "mozilla/ArrayUtils.h"

 #include "mozilla/CheckedInt.h"

 #include "mozilla/Endian.h"

 #include <algorithm>

 namespace mozilla {

 // Un-comment to enable logging of seek bisections.

 //#define SEEK_LOGGING

 #ifdef PR_LOGGING

 extern PRLogModuleInfo* gMediaDecoderLog;

 #define LOG(type, msg) PR_LOG(gMediaDecoderLog, type, msg)

 #ifdef SEEK_LOGGING

 #define SEEK_LOG(type, msg) PR_LOG(gMediaDecoderLog, type, msg)

 #else

 #define SEEK_LOG(type, msg)

 #endif

 #else

 #define LOG(type, msg)

 #define SEEK_LOG(type, msg)

 #endif

 struct waveIdToName {

   uint32_t id;

   nsCString name;

 };

 // Magic values that identify RIFF chunks we're interested in.

 static const uint32_t RIFF_CHUNK_MAGIC = 0x52494646;

 static const uint32_t WAVE_CHUNK_MAGIC = 0x57415645;

 static const uint32_t FRMT_CHUNK_MAGIC = 0x666d7420;

 static const uint32_t DATA_CHUNK_MAGIC = 0x64617461;

 static const uint32_t LIST_CHUNK_MAGIC = 0x4c495354;

 // Size of chunk header.  4 byte chunk header type and 4 byte size field.

 static const uint16_t CHUNK_HEADER_SIZE = 8;

 // Size of RIFF header.  RIFF chunk and 4 byte RIFF type.

 static const uint16_t RIFF_INITIAL_SIZE = CHUNK_HEADER_SIZE + 4;

 // Size of required part of format chunk.  Actual format chunks may be

 // extended (for non-PCM encodings), but we skip any extended data.

 static const uint16_t WAVE_FORMAT_CHUNK_SIZE = 16;

 // PCM encoding type from format chunk.  Linear PCM is the only encoding

 // supported by AudioStream.

 static const uint16_t WAVE_FORMAT_ENCODING_PCM = 1;

 // We reject files with more than this number of channels if we're decoding for

 // playback.

 static const uint8_t MAX_CHANNELS = 2;

 namespace {

   uint32_t

   ReadUint32BE(const char** aBuffer)

   {

     uint32_t result = BigEndian::readUint32(*aBuffer);

     *aBuffer += sizeof(uint32_t);

     return result;

   }

   uint32_t

   ReadUint32LE(const char** aBuffer)

   {

     uint32_t result = LittleEndian::readUint32(*aBuffer);

     *aBuffer += sizeof(uint32_t);

     return result;

   }

   uint16_t

   ReadUint16LE(const char** aBuffer)

   {

     uint16_t result = LittleEndian::readUint16(*aBuffer);

     *aBuffer += sizeof(uint16_t);

     return result;

   }

   int16_t

   ReadInt16LE(const char** aBuffer)

   {

     uint16_t result = LittleEndian::readInt16(*aBuffer);

     *aBuffer += sizeof(int16_t);

     return result;

   }

   uint8_t

   ReadUint8(const char** aBuffer)

   {

     uint8_t result = uint8_t((*aBuffer)[0]);

     *aBuffer += sizeof(uint8_t);

     return result;

   }

 }

 WaveReader::WaveReader(AbstractMediaDecoder* aDecoder)

   : MediaDecoderReader(aDecoder)

 {

   MOZ_COUNT_CTOR(WaveReader);

 }

 WaveReader::~WaveReader()

 {

   MOZ_COUNT_DTOR(WaveReader);

 }

 nsresult WaveReader::Init(MediaDecoderReader* aCloneDonor)

 {

   return NS_OK;

 }

 nsresult WaveReader::ReadMetadata(MediaInfo* aInfo,

                                   MetadataTags** aTags)

 {

   NS_ASSERTION(mDecoder->OnDecodeThread(), "Should be on decode thread.");

   bool loaded = LoadRIFFChunk();

   if (!loaded) {

     return NS_ERROR_FAILURE;

   }

   nsAutoPtr<dom::HTMLMediaElement::MetadataTags> tags;

   bool loadAllChunks = LoadAllChunks(tags);

   if (!loadAllChunks) {

     return NS_ERROR_FAILURE;

   }

   mInfo.mAudio.mHasAudio = true;

   mInfo.mAudio.mRate = mSampleRate;

   mInfo.mAudio.mChannels = mChannels;

   *aInfo = mInfo;

   *aTags = tags.forget();

   ReentrantMonitorAutoEnter mon(mDecoder->GetReentrantMonitor());

   mDecoder->SetMediaDuration(

     static_cast<int64_t>(BytesToTime(GetDataLength()) * USECS_PER_S));

   return NS_OK;

 }

 template <typename T> T UnsignedByteToAudioSample(uint8_t aValue);

 template <typename T> T SignedShortToAudioSample(int16_t aValue);

 template <> inline float

 UnsignedByteToAudioSample<float>(uint8_t aValue)

 {

   return aValue * (2.0f / UINT8_MAX) - 1.0f;

 }

 template <> inline int16_t

 UnsignedByteToAudioSample<int16_t>(uint8_t aValue)

 {

   return int16_t(aValue * UINT16_MAX / UINT8_MAX + INT16_MIN);

 }

 template <> inline float

 SignedShortToAudioSample<float>(int16_t aValue)

 {

   return AudioSampleToFloat(aValue);

 }

 template <> inline int16_t

 SignedShortToAudioSample<int16_t>(int16_t aValue)

 {

   return aValue;

 }

 bool WaveReader::DecodeAudioData()

 {

   NS_ASSERTION(mDecoder->OnDecodeThread(), "Should be on decode thread.");

   int64_t pos = GetPosition() - mWavePCMOffset;

   int64_t len = GetDataLength();

   int64_t remaining = len - pos;

   NS_ASSERTION(remaining >= 0, "Current wave position is greater than wave file length");

   static const int64_t BLOCK_SIZE = 4096;

   int64_t readSize = std::min(BLOCK_SIZE, remaining);

   int64_t frames = readSize / mFrameSize;

   static_assert(uint64_t(BLOCK_SIZE) < UINT_MAX /

                 sizeof(AudioDataValue) / MAX_CHANNELS,

                 "bufferSize calculation could overflow.");

   const size_t bufferSize = static_cast<size_t>(frames * mChannels);

   nsAutoArrayPtr<AudioDataValue> sampleBuffer(new AudioDataValue[bufferSize]);

   static_assert(uint64_t(BLOCK_SIZE) < UINT_MAX / sizeof(char),

                 "BLOCK_SIZE too large for enumerator.");

   nsAutoArrayPtr<char> dataBuffer(new char[static_cast<size_t>(readSize)]);

   if (!ReadAll(dataBuffer, readSize)) {

     return false;

   }

   // convert data to samples

   const char* d = dataBuffer.get();

   AudioDataValue* s = sampleBuffer.get();

   for (int i = 0; i < frames; ++i) {

     for (unsigned int j = 0; j < mChannels; ++j) {

       if (mSampleFormat == FORMAT_U8) {

         uint8_t v =  ReadUint8(&d);

         *s++ = UnsignedByteToAudioSample<AudioDataValue>(v);

       } else if (mSampleFormat == FORMAT_S16) {

         int16_t v =  ReadInt16LE(&d);

         *s++ = SignedShortToAudioSample<AudioDataValue>(v);

       }

     }

   }

   double posTime = BytesToTime(pos);

   double readSizeTime = BytesToTime(readSize);

   NS_ASSERTION(posTime <= INT64_MAX / USECS_PER_S, "posTime overflow");

   NS_ASSERTION(readSizeTime <= INT64_MAX / USECS_PER_S, "readSizeTime overflow");

   NS_ASSERTION(frames < INT32_MAX, "frames overflow");

   mAudioQueue.Push(new AudioData(pos,

                                  static_cast<int64_t>(posTime * USECS_PER_S),

                                  static_cast<int64_t>(readSizeTime * USECS_PER_S),

                                  static_cast<int32_t>(frames),

                                  sampleBuffer.forget(),

                                  mChannels));

   return true;

 }

 bool WaveReader::DecodeVideoFrame(bool &aKeyframeSkip,

                                       int64_t aTimeThreshold)

 {

   NS_ASSERTION(mDecoder->OnDecodeThread(), "Should be on decode thread.");

   return false;

 }

 nsresult WaveReader::Seek(int64_t aTarget, int64_t aStartTime, int64_t aEndTime, int64_t aCurrentTime)

 {

   NS_ASSERTION(mDecoder->OnDecodeThread(), "Should be on decode thread.");

   LOG(PR_LOG_DEBUG, ("%p About to seek to %lld", mDecoder, aTarget));

   if (NS_FAILED(ResetDecode())) {

     return NS_ERROR_FAILURE;

   }

   double d = BytesToTime(GetDataLength());

   NS_ASSERTION(d < INT64_MAX / USECS_PER_S, "Duration overflow"); 

   int64_t duration = static_cast<int64_t>(d * USECS_PER_S);

   double seekTime = std::min(aTarget, duration) / static_cast<double>(USECS_PER_S);

   int64_t position = RoundDownToFrame(static_cast<int64_t>(TimeToBytes(seekTime)));

   NS_ASSERTION(INT64_MAX - mWavePCMOffset > position, "Integer overflow during wave seek");

   position += mWavePCMOffset;

   return mDecoder->GetResource()->Seek(nsISeekableStream::NS_SEEK_SET, position);

 }

 static double RoundToUsecs(double aSeconds) {

   return floor(aSeconds * USECS_PER_S) / USECS_PER_S;

 }

 nsresult WaveReader::GetBuffered(dom::TimeRanges* aBuffered, int64_t aStartTime)

 {

   if (!mInfo.HasAudio()) {

     return NS_OK;

   }

   int64_t startOffset = mDecoder->GetResource()->GetNextCachedData(mWavePCMOffset);

   while (startOffset >= 0) {

     int64_t endOffset = mDecoder->GetResource()->GetCachedDataEnd(startOffset);

     // Bytes [startOffset..endOffset] are cached.

     NS_ASSERTION(startOffset >= mWavePCMOffset, "Integer underflow in GetBuffered");

     NS_ASSERTION(endOffset >= mWavePCMOffset, "Integer underflow in GetBuffered");

     // We need to round the buffered ranges' times to microseconds so that they

     // have the same precision as the currentTime and duration attribute on 

     // the media element.

     aBuffered->Add(RoundToUsecs(BytesToTime(startOffset - mWavePCMOffset)),

                    RoundToUsecs(BytesToTime(endOffset - mWavePCMOffset)));

     startOffset = mDecoder->GetResource()->GetNextCachedData(endOffset);

   }

   return NS_OK;

 }

 bool

 WaveReader::ReadAll(char* aBuf, int64_t aSize, int64_t* aBytesRead)

 {

   uint32_t got = 0;

   if (aBytesRead) {

     *aBytesRead = 0;

   }

   do {

     uint32_t read = 0;

     if (NS_FAILED(mDecoder->GetResource()->Read(aBuf + got, uint32_t(aSize - got), &read))) {

       NS_WARNING("Resource read failed");

       return false;

     }

     if (read == 0) {

       return false;

     }

     got += read;

     if (aBytesRead) {

       *aBytesRead = got;

     }

   } while (got != aSize);

   return true;

 }

 bool

 WaveReader::LoadRIFFChunk()

 {

   char riffHeader[RIFF_INITIAL_SIZE];

   const char* p = riffHeader;

   NS_ABORT_IF_FALSE(mDecoder->GetResource()->Tell() == 0,

                     "LoadRIFFChunk called when resource in invalid state");

   if (!ReadAll(riffHeader, sizeof(riffHeader))) {

     return false;

   }

   static_assert(sizeof(uint32_t) * 3 <= RIFF_INITIAL_SIZE,

                 "Reads would overflow riffHeader buffer.");

   if (ReadUint32BE(&p) != RIFF_CHUNK_MAGIC) {

     NS_WARNING("resource data not in RIFF format");

     return false;

   }

   // Skip over RIFF size field.

   p += sizeof(uint32_t);

   if (ReadUint32BE(&p) != WAVE_CHUNK_MAGIC) {

     NS_WARNING("Expected WAVE chunk");

     return false;

   }

   return true;

 }

 bool

 WaveReader::LoadFormatChunk(uint32_t aChunkSize)

 {

   uint32_t rate, channels, frameSize, sampleFormat;

   char waveFormat[WAVE_FORMAT_CHUNK_SIZE];

   const char* p = waveFormat;

   // RIFF chunks are always word (two byte) aligned.

   NS_ABORT_IF_FALSE(mDecoder->GetResource()->Tell() % 2 == 0,

                     "LoadFormatChunk called with unaligned resource");

   if (!ReadAll(waveFormat, sizeof(waveFormat))) {

     return false;

   }

   static_assert(sizeof(uint16_t) +

                 sizeof(uint16_t) +

                 sizeof(uint32_t) +

                 4 +

                 sizeof(uint16_t) +

                 sizeof(uint16_t) <= sizeof(waveFormat),

                 "Reads would overflow waveFormat buffer.");

   if (ReadUint16LE(&p) != WAVE_FORMAT_ENCODING_PCM) {

     NS_WARNING("WAVE is not uncompressed PCM, compressed encodings are not supported");

     return false;

   }

   channels = ReadUint16LE(&p);

   rate = ReadUint32LE(&p);

   // Skip over average bytes per second field.

   p += 4;

   frameSize = ReadUint16LE(&p);

   sampleFormat = ReadUint16LE(&p);

   // PCM encoded WAVEs are not expected to have an extended "format" chunk,

   // but I have found WAVEs that have a extended "format" chunk with an

   // extension size of 0 bytes.  Be polite and handle this rather than

   // considering the file invalid.  This code skips any extension of the

   // "format" chunk.

   if (aChunkSize > WAVE_FORMAT_CHUNK_SIZE) {

     char extLength[2];

     const char* p = extLength;

     if (!ReadAll(extLength, sizeof(extLength))) {

       return false;

     }

     static_assert(sizeof(uint16_t) <= sizeof(extLength),

                   "Reads would overflow extLength buffer.");

     uint16_t extra = ReadUint16LE(&p);

     if (aChunkSize - (WAVE_FORMAT_CHUNK_SIZE + 2) != extra) {

       NS_WARNING("Invalid extended format chunk size");

       return false;

     }

     extra += extra % 2;

     if (extra > 0) {

       static_assert(UINT16_MAX + (UINT16_MAX % 2) < UINT_MAX / sizeof(char),

                     "chunkExtension array too large for iterator.");

       nsAutoArrayPtr<char> chunkExtension(new char[extra]);

       if (!ReadAll(chunkExtension.get(), extra)) {

         return false;

       }

     }

   }

   // RIFF chunks are always word (two byte) aligned.

   NS_ABORT_IF_FALSE(mDecoder->GetResource()->Tell() % 2 == 0,

                     "LoadFormatChunk left resource unaligned");

   // Make sure metadata is fairly sane.  The rate check is fairly arbitrary,

   // but the channels check is intentionally limited to mono or stereo

   // when the media is intended for direct playback because that's what the

   // audio backend currently supports.

   unsigned int actualFrameSize = (sampleFormat == 8 ? 1 : 2) * channels;

   if (rate < 100 || rate > 96000 ||

       (((channels < 1 || channels > MAX_CHANNELS) ||

        (frameSize != 1 && frameSize != 2 && frameSize != 4)) &&

        !mIgnoreAudioOutputFormat) ||

        (sampleFormat != 8 && sampleFormat != 16) ||

       frameSize != actualFrameSize) {

     NS_WARNING("Invalid WAVE metadata");

     return false;

   }

   ReentrantMonitorAutoEnter monitor(mDecoder->GetReentrantMonitor());

   mSampleRate = rate;

   mChannels = channels;

   mFrameSize = frameSize;

   if (sampleFormat == 8) {

     mSampleFormat = FORMAT_U8;

   } else {

     mSampleFormat = FORMAT_S16;

   }

   return true;

 }

 bool

 WaveReader::FindDataOffset(uint32_t aChunkSize)

 {

   // RIFF chunks are always word (two byte) aligned.

   NS_ABORT_IF_FALSE(mDecoder->GetResource()->Tell() % 2 == 0,

                     "FindDataOffset called with unaligned resource");

   int64_t offset = mDecoder->GetResource()->Tell();

   if (offset <= 0 || offset > UINT32_MAX) {

     NS_WARNING("PCM data offset out of range");

     return false;

   }

   ReentrantMonitorAutoEnter monitor(mDecoder->GetReentrantMonitor());

   mWaveLength = aChunkSize;

   mWavePCMOffset = uint32_t(offset);

   return true;

 }

 double

 WaveReader::BytesToTime(int64_t aBytes) const

 {

   NS_ABORT_IF_FALSE(aBytes >= 0, "Must be >= 0");

   return float(aBytes) / mSampleRate / mFrameSize;

 }

 int64_t

 WaveReader::TimeToBytes(double aTime) const

 {

   NS_ABORT_IF_FALSE(aTime >= 0.0f, "Must be >= 0");

   return RoundDownToFrame(int64_t(aTime * mSampleRate * mFrameSize));

 }

 int64_t

 WaveReader::RoundDownToFrame(int64_t aBytes) const

 {

   NS_ABORT_IF_FALSE(aBytes >= 0, "Must be >= 0");

   return aBytes - (aBytes % mFrameSize);

 }

 int64_t

 WaveReader::GetDataLength()

 {

   int64_t length = mWaveLength;

   // If the decoder has a valid content length, and it's shorter than the

   // expected length of the PCM data, calculate the playback duration from

   // the content length rather than the expected PCM data length.

   int64_t streamLength = mDecoder->GetResource()->GetLength();

   if (streamLength >= 0) {

     int64_t dataLength = std::max<int64_t>(0, streamLength - mWavePCMOffset);

     length = std::min(dataLength, length);

   }

   return length;

 }

 int64_t

 WaveReader::GetPosition()

 {

   return mDecoder->GetResource()->Tell();

 }

 bool

 WaveReader::GetNextChunk(uint32_t* aChunk, uint32_t* aChunkSize)

 {

   NS_ABORT_IF_FALSE(aChunk, "Must have aChunk");

   NS_ABORT_IF_FALSE(aChunkSize, "Must have aChunkSize");

   NS_ABORT_IF_FALSE(mDecoder->GetResource()->Tell() % 2 == 0,

                     "GetNextChunk called with unaligned resource");

   char chunkHeader[CHUNK_HEADER_SIZE];

   const char* p = chunkHeader;

   if (!ReadAll(chunkHeader, sizeof(chunkHeader))) {

     return false;

   }

   static_assert(sizeof(uint32_t) * 2 <= CHUNK_HEADER_SIZE,

                 "Reads would overflow chunkHeader buffer.");

   *aChunk = ReadUint32BE(&p);

   *aChunkSize = ReadUint32LE(&p);

   return true;

 }

 bool

 WaveReader::LoadListChunk(uint32_t aChunkSize,

                           nsAutoPtr<dom::HTMLMediaElement::MetadataTags> &aTags)

 {

   // List chunks are always word (two byte) aligned.

   NS_ABORT_IF_FALSE(mDecoder->GetResource()->Tell() % 2 == 0,

                     "LoadListChunk called with unaligned resource");

   static const unsigned int MAX_CHUNK_SIZE = 1 << 16;

   static_assert(uint64_t(MAX_CHUNK_SIZE) < UINT_MAX / sizeof(char),

                 "MAX_CHUNK_SIZE too large for enumerator.");

   if (aChunkSize > MAX_CHUNK_SIZE) {

     return false;

   }

   nsAutoArrayPtr<char> chunk(new char[aChunkSize]);

   if (!ReadAll(chunk.get(), aChunkSize)) {

     return false;

   }

   static const uint32_t INFO_LIST_MAGIC = 0x494e464f;

   const char *p = chunk.get();

   if (ReadUint32BE(&p) != INFO_LIST_MAGIC) {

     return false;

   }

   const waveIdToName ID_TO_NAME[] = {

     { 0x49415254, NS_LITERAL_CSTRING("artist") },   // IART

     { 0x49434d54, NS_LITERAL_CSTRING("comments") }, // ICMT

     { 0x49474e52, NS_LITERAL_CSTRING("genre") },    // IGNR

     { 0x494e414d, NS_LITERAL_CSTRING("name") },     // INAM

   };

   const char* const end = chunk.get() + aChunkSize;

   aTags = new dom::HTMLMediaElement::MetadataTags;

   while (p + 8 < end) {

     uint32_t id = ReadUint32BE(&p);

     // Uppercase tag id, inspired by GStreamer's Wave parser.

     id &= 0xDFDFDFDF;

     uint32_t length = ReadUint32LE(&p);

     // Subchunk shall not exceed parent chunk.

     if (p + length > end) {

       break;

     }

     // Wrap the string, adjusting length to account for optional

     // null termination in the chunk.

     nsCString val(p, length);

     if (length > 0 && val[length - 1] == '\0') {

       val.SetLength(length - 1);

     }

     // Chunks in List::INFO are always word (two byte) aligned. So round up if

     // necessary.

     length += length % 2;

     p += length;

     if (!IsUTF8(val)) {

       continue;

     }

     for (size_t i = 0; i < mozilla::ArrayLength(ID_TO_NAME); ++i) {

       if (id == ID_TO_NAME[i].id) {

         aTags->Put(ID_TO_NAME[i].name, val);

         break;

       }

     }

   }

   return true;

 }

 bool

 WaveReader::LoadAllChunks(nsAutoPtr<dom::HTMLMediaElement::MetadataTags> &aTags)

 {

   // Chunks are always word (two byte) aligned.

   NS_ABORT_IF_FALSE(mDecoder->GetResource()->Tell() % 2 == 0,

                     "LoadAllChunks called with unaligned resource");

   bool loadFormatChunk = false;

   bool findDataOffset = false;

   for (;;) {

     static const unsigned int CHUNK_HEADER_SIZE = 8;

     char chunkHeader[CHUNK_HEADER_SIZE];

     const char* p = chunkHeader;

     if (!ReadAll(chunkHeader, sizeof(chunkHeader))) {

       return false;

     }

     static_assert(sizeof(uint32_t) * 2 <= CHUNK_HEADER_SIZE,

                   "Reads would overflow chunkHeader buffer.");

     uint32_t magic = ReadUint32BE(&p);

     uint32_t chunkSize = ReadUint32LE(&p);

     int64_t chunkStart = GetPosition();

     switch (magic) {

       case FRMT_CHUNK_MAGIC:

         loadFormatChunk = LoadFormatChunk(chunkSize);

         if (!loadFormatChunk) {

           return false;

         }

         break;

       case LIST_CHUNK_MAGIC:

         if (!aTags) {

           LoadListChunk(chunkSize, aTags);

         }

         break;

       case DATA_CHUNK_MAGIC:

         findDataOffset = FindDataOffset(chunkSize);

         return loadFormatChunk && findDataOffset;

       default:

         break;

     }

     // RIFF chunks are two-byte aligned, so round up if necessary.

     chunkSize += chunkSize % 2;

     // Move forward to next chunk

     CheckedInt64 forward = CheckedInt64(chunkStart) + chunkSize - GetPosition();

     if (!forward.isValid() || forward.value() < 0) {

       return false;

     }

     static const int64_t MAX_CHUNK_SIZE = 1 << 16;

     static_assert(uint64_t(MAX_CHUNK_SIZE) < UINT_MAX / sizeof(char),

                   "MAX_CHUNK_SIZE too large for enumerator.");

     nsAutoArrayPtr<char> chunk(new char[MAX_CHUNK_SIZE]);

     while (forward.value() > 0) {

       int64_t size = std::min(forward.value(), MAX_CHUNK_SIZE);

       if (!ReadAll(chunk.get(), size)) {

         return false;

       }

       forward -= size;

     }

   }

   return false;

 }

 } // namespace mozilla