1 files changed, 739 insertions, 0 deletions
diff --git a/dom/media/wave/WaveDemuxer.cpp b/dom/media/wave/WaveDemuxer.cpp
new file mode 100644
index 0000000000..814883dc54
--- /dev/null
+++ b/dom/media/wave/WaveDemuxer.cpp
@@ -0,0 +1,739 @@
+/* -*- 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 "WaveDemuxer.h"
+
+#include <inttypes.h>
+#include <algorithm>
+
+#include "mozilla/Assertions.h"
+#include "mozilla/EndianUtils.h"
+#include "mozilla/Utf8.h"
+#include "BufferReader.h"
+#include "VideoUtils.h"
+#include "TimeUnits.h"
+
+using mozilla::media::TimeIntervals;
+using mozilla::media::TimeUnit;
+
+namespace mozilla {
+
+// WAVDemuxer
+
+WAVDemuxer::WAVDemuxer(MediaResource* aSource) : mSource(aSource) {
+  DDLINKCHILD("source", aSource);
+}
+
+bool WAVDemuxer::InitInternal() {
+  if (!mTrackDemuxer) {
+    mTrackDemuxer = new WAVTrackDemuxer(mSource.GetResource());
+    DDLINKCHILD("track demuxer", mTrackDemuxer.get());
+  }
+  return mTrackDemuxer->Init();
+}
+
+RefPtr<WAVDemuxer::InitPromise> WAVDemuxer::Init() {
+  if (!InitInternal()) {
+    return InitPromise::CreateAndReject(NS_ERROR_DOM_MEDIA_METADATA_ERR,
+                                        __func__);
+  }
+  return InitPromise::CreateAndResolve(NS_OK, __func__);
+}
+
+uint32_t WAVDemuxer::GetNumberTracks(TrackInfo::TrackType aType) const {
+  return aType == TrackInfo::kAudioTrack ? 1u : 0u;
+}
+
+already_AddRefed<MediaTrackDemuxer> WAVDemuxer::GetTrackDemuxer(
+    TrackInfo::TrackType aType, uint32_t aTrackNumber) {
+  if (!mTrackDemuxer) {
+    return nullptr;
+  }
+  return RefPtr<WAVTrackDemuxer>(mTrackDemuxer).forget();
+}
+
+bool WAVDemuxer::IsSeekable() const { return true; }
+
+// WAVTrackDemuxer
+
+WAVTrackDemuxer::WAVTrackDemuxer(MediaResource* aSource)
+    : mSource(aSource),
+      mOffset(0),
+      mFirstChunkOffset(0),
+      mNumParsedChunks(0),
+      mChunkIndex(0),
+      mDataLength(0),
+      mTotalChunkLen(0),
+      mSamplesPerChunk(0),
+      mSamplesPerSecond(0),
+      mChannels(0),
+      mSampleFormat(0) {
+  DDLINKCHILD("source", aSource);
+  Reset();
+}
+
+bool WAVTrackDemuxer::Init() {
+  Reset();
+  FastSeek(TimeUnit());
+
+  if (!mInfo) {
+    mInfo = MakeUnique<AudioInfo>();
+    mInfo->mCodecSpecificConfig =
+        AudioCodecSpecificVariant{WaveCodecSpecificData{}};
+  }
+
+  if (!RIFFParserInit()) {
+    return false;
+  }
+
+  while (true) {
+    if (!HeaderParserInit()) {
+      return false;
+    }
+
+    uint32_t aChunkName = mHeaderParser.GiveHeader().ChunkName();
+    uint32_t aChunkSize = mHeaderParser.GiveHeader().ChunkSize();
+
+    if (aChunkName == FRMT_CODE) {
+      if (!FmtChunkParserInit()) {
+        return false;
+      }
+    } else if (aChunkName == LIST_CODE) {
+      mHeaderParser.Reset();
+      uint64_t endOfListChunk = static_cast<uint64_t>(mOffset) + aChunkSize;
+      if (endOfListChunk > UINT32_MAX) {
+        return false;
+      }
+      if (!ListChunkParserInit(aChunkSize)) {
+        mOffset = endOfListChunk;
+      }
+    } else if (aChunkName == DATA_CODE) {
+      mDataLength = aChunkSize;
+      if (mFirstChunkOffset != mOffset) {
+        mFirstChunkOffset = mOffset;
+      }
+      break;
+    } else {
+      mOffset += aChunkSize;  // Skip other irrelevant chunks.
+    }
+    if (mOffset & 1) {
+      // Wave files are 2-byte aligned so we need to round up
+      mOffset += 1;
+    }
+    mHeaderParser.Reset();
+  }
+
+  int64_t streamLength = StreamLength();
+  // If the chunk length and the resource length are not equal, use the
+  // resource length as the "real" data chunk length, if it's longer than the
+  // chunk size.
+  if (streamLength != -1) {
+    uint64_t streamLengthPositive = static_cast<uint64_t>(streamLength);
+    if (streamLengthPositive > mFirstChunkOffset &&
+        mDataLength > streamLengthPositive - mFirstChunkOffset) {
+      mDataLength = streamLengthPositive - mFirstChunkOffset;
+    }
+  }
+
+  mSamplesPerSecond = mFmtParser.FmtChunk().SampleRate();
+  mChannels = mFmtParser.FmtChunk().Channels();
+  mSampleFormat = mFmtParser.FmtChunk().SampleFormat();
+  if (!mSamplesPerSecond || !mChannels || !mSampleFormat) {
+    return false;
+  }
+  mSamplesPerChunk = DATA_CHUNK_SIZE * 8 / mChannels / mSampleFormat;
+
+  mInfo->mRate = mSamplesPerSecond;
+  mInfo->mChannels = mChannels;
+  mInfo->mBitDepth = mSampleFormat;
+  mInfo->mProfile = mFmtParser.FmtChunk().WaveFormat() & 0x00FF;
+  mInfo->mExtendedProfile = (mFmtParser.FmtChunk().WaveFormat() & 0xFF00) >> 8;
+  mInfo->mMimeType = "audio/wave; codecs=";
+  mInfo->mMimeType.AppendInt(mFmtParser.FmtChunk().WaveFormat());
+  mInfo->mDuration = Duration();
+
+  return mInfo->mDuration.IsPositive();
+}
+
+bool WAVTrackDemuxer::RIFFParserInit() {
+  RefPtr<MediaRawData> riffHeader = GetFileHeader(FindRIFFHeader());
+  if (!riffHeader) {
+    return false;
+  }
+  BufferReader RIFFReader(riffHeader->Data(), 12);
+  Unused << mRIFFParser.Parse(RIFFReader);
+  return mRIFFParser.RiffHeader().IsValid(11);
+}
+
+bool WAVTrackDemuxer::HeaderParserInit() {
+  RefPtr<MediaRawData> header = GetFileHeader(FindChunkHeader());
+  if (!header) {
+    return false;
+  }
+  BufferReader HeaderReader(header->Data(), 8);
+  Unused << mHeaderParser.Parse(HeaderReader);
+  return true;
+}
+
+bool WAVTrackDemuxer::FmtChunkParserInit() {
+  RefPtr<MediaRawData> fmtChunk = GetFileHeader(FindFmtChunk());
+  if (!fmtChunk) {
+    return false;
+  }
+  BufferReader fmtReader(fmtChunk->Data(),
+                         mHeaderParser.GiveHeader().ChunkSize());
+  Unused << mFmtParser.Parse(fmtReader);
+  return true;
+}
+
+bool WAVTrackDemuxer::ListChunkParserInit(uint32_t aChunkSize) {
+  uint32_t bytesRead = 0;
+
+  RefPtr<MediaRawData> infoTag = GetFileHeader(FindInfoTag());
+  if (!infoTag) {
+    return false;
+  }
+
+  BufferReader infoTagReader(infoTag->Data(), 4);
+  auto res = infoTagReader.ReadU32();
+  if (res.isErr() || (res.isOk() && res.unwrap() != INFO_CODE)) {
+    return false;
+  }
+
+  bytesRead += 4;
+
+  while (bytesRead < aChunkSize) {
+    if (!HeaderParserInit()) {
+      return false;
+    }
+
+    bytesRead += 8;
+
+    uint32_t id = mHeaderParser.GiveHeader().ChunkName();
+    uint32_t length = mHeaderParser.GiveHeader().ChunkSize();
+
+    // SubChunk Length Cannot Exceed List Chunk length.
+    if (length > aChunkSize - bytesRead) {
+      length = aChunkSize - bytesRead;
+    }
+
+    MediaByteRange mRange = {mOffset, mOffset + length};
+    RefPtr<MediaRawData> mChunkData = GetFileHeader(mRange);
+    if (!mChunkData) {
+      return false;
+    }
+
+    const char* rawData = reinterpret_cast<const char*>(mChunkData->Data());
+
+    nsCString val(rawData, length);
+    if (length > 0 && val[length - 1] == '\0') {
+      val.SetLength(length - 1);
+    }
+
+    if (length % 2) {
+      mOffset += 1;
+      length += length % 2;
+    }
+
+    bytesRead += length;
+
+    if (!IsUtf8(val)) {
+      mHeaderParser.Reset();
+      continue;
+    }
+
+    switch (id) {
+      case 0x49415254:  // IART
+        mInfo->mTags.AppendElement(MetadataTag("artist"_ns, val));
+        break;
+      case 0x49434d54:  // ICMT
+        mInfo->mTags.AppendElement(MetadataTag("comments"_ns, val));
+        break;
+      case 0x49474e52:  // IGNR
+        mInfo->mTags.AppendElement(MetadataTag("genre"_ns, val));
+        break;
+      case 0x494e414d:  // INAM
+        mInfo->mTags.AppendElement(MetadataTag("name"_ns, val));
+        break;
+    }
+
+    mHeaderParser.Reset();
+  }
+  return true;
+}
+
+media::TimeUnit WAVTrackDemuxer::SeekPosition() const {
+  TimeUnit pos = Duration(mChunkIndex);
+  if (Duration() > TimeUnit()) {
+    pos = std::min(Duration(), pos);
+  }
+  return pos;
+}
+
+RefPtr<MediaRawData> WAVTrackDemuxer::DemuxSample() {
+  return GetNextChunk(FindNextChunk());
+}
+
+UniquePtr<TrackInfo> WAVTrackDemuxer::GetInfo() const { return mInfo->Clone(); }
+
+RefPtr<WAVTrackDemuxer::SeekPromise> WAVTrackDemuxer::Seek(
+    const TimeUnit& aTime) {
+  FastSeek(aTime);
+  const TimeUnit seekTime = ScanUntil(aTime);
+  return SeekPromise::CreateAndResolve(seekTime, __func__);
+}
+
+TimeUnit WAVTrackDemuxer::FastSeek(const TimeUnit& aTime) {
+  if (aTime.ToMicroseconds()) {
+    mChunkIndex = ChunkIndexFromTime(aTime);
+  } else {
+    mChunkIndex = 0;
+  }
+
+  mOffset = OffsetFromChunkIndex(mChunkIndex);
+
+  if (mOffset > mFirstChunkOffset && StreamLength() > 0) {
+    mOffset = std::min(static_cast<uint64_t>(StreamLength() - 1), mOffset);
+  }
+
+  return Duration(mChunkIndex);
+}
+
+TimeUnit WAVTrackDemuxer::ScanUntil(const TimeUnit& aTime) {
+  if (!aTime.ToMicroseconds()) {
+    return FastSeek(aTime);
+  }
+
+  if (Duration(mChunkIndex) > aTime) {
+    FastSeek(aTime);
+  }
+
+  return SeekPosition();
+}
+
+RefPtr<WAVTrackDemuxer::SamplesPromise> WAVTrackDemuxer::GetSamples(
+    int32_t aNumSamples) {
+  MOZ_ASSERT(aNumSamples);
+
+  RefPtr<SamplesHolder> datachunks = new SamplesHolder();
+
+  while (aNumSamples--) {
+    RefPtr<MediaRawData> datachunk = GetNextChunk(FindNextChunk());
+    if (!datachunk) {
+      break;
+    }
+    if (!datachunk->HasValidTime()) {
+      return SamplesPromise::CreateAndReject(NS_ERROR_DOM_MEDIA_DEMUXER_ERR,
+                                             __func__);
+    }
+    datachunks->AppendSample(datachunk);
+  }
+
+  if (datachunks->GetSamples().IsEmpty()) {
+    return SamplesPromise::CreateAndReject(NS_ERROR_DOM_MEDIA_END_OF_STREAM,
+                                           __func__);
+  }
+
+  return SamplesPromise::CreateAndResolve(datachunks, __func__);
+}
+
+void WAVTrackDemuxer::Reset() {
+  FastSeek(TimeUnit());
+  mParser.Reset();
+  mHeaderParser.Reset();
+  mRIFFParser.Reset();
+  mFmtParser.Reset();
+}
+
+RefPtr<WAVTrackDemuxer::SkipAccessPointPromise>
+WAVTrackDemuxer::SkipToNextRandomAccessPoint(const TimeUnit& aTimeThreshold) {
+  return SkipAccessPointPromise::CreateAndReject(
+      SkipFailureHolder(NS_ERROR_DOM_MEDIA_DEMUXER_ERR, 0), __func__);
+}
+
+int64_t WAVTrackDemuxer::GetResourceOffset() const { return mOffset; }
+
+TimeIntervals WAVTrackDemuxer::GetBuffered() {
+  TimeUnit duration = Duration();
+
+  if (duration <= TimeUnit()) {
+    return TimeIntervals();
+  }
+
+  AutoPinned<MediaResource> stream(mSource.GetResource());
+  return GetEstimatedBufferedTimeRanges(stream, duration.ToMicroseconds());
+}
+
+int64_t WAVTrackDemuxer::StreamLength() const { return mSource.GetLength(); }
+
+TimeUnit WAVTrackDemuxer::Duration() const {
+  if (!mDataLength || !mChannels || !mSampleFormat) {
+    return TimeUnit();
+  }
+
+  int64_t numSamples =
+      static_cast<int64_t>(mDataLength) * 8 / mChannels / mSampleFormat;
+
+  int64_t numUSeconds = USECS_PER_S * numSamples / mSamplesPerSecond;
+
+  if (USECS_PER_S * numSamples % mSamplesPerSecond > mSamplesPerSecond / 2) {
+    numUSeconds++;
+  }
+
+  return TimeUnit::FromMicroseconds(numUSeconds);
+}
+
+TimeUnit WAVTrackDemuxer::Duration(int64_t aNumDataChunks) const {
+  if (!mSamplesPerSecond || !mSamplesPerChunk) {
+    return TimeUnit();
+  }
+  const double usPerDataChunk =
+      USECS_PER_S * static_cast<double>(mSamplesPerChunk) / mSamplesPerSecond;
+  return TimeUnit::FromMicroseconds(aNumDataChunks * usPerDataChunk);
+}
+
+TimeUnit WAVTrackDemuxer::DurationFromBytes(uint32_t aNumBytes) const {
+  if (!mSamplesPerSecond || !mChannels || !mSampleFormat) {
+    return TimeUnit();
+  }
+
+  uint64_t numSamples = aNumBytes * 8 / mChannels / mSampleFormat;
+
+  uint64_t numUSeconds = USECS_PER_S * numSamples / mSamplesPerSecond;
+
+  if (USECS_PER_S * numSamples % mSamplesPerSecond > mSamplesPerSecond / 2) {
+    numUSeconds++;
+  }
+
+  return TimeUnit::FromMicroseconds(numUSeconds);
+}
+
+MediaByteRange WAVTrackDemuxer::FindNextChunk() {
+  if (mOffset + DATA_CHUNK_SIZE < mFirstChunkOffset + mDataLength) {
+    return {mOffset, mOffset + DATA_CHUNK_SIZE};
+  } else {
+    return {mOffset, mFirstChunkOffset + mDataLength};
+  }
+}
+
+MediaByteRange WAVTrackDemuxer::FindChunkHeader() {
+  return {mOffset, mOffset + CHUNK_HEAD_SIZE};
+}
+
+MediaByteRange WAVTrackDemuxer::FindRIFFHeader() {
+  return {mOffset, mOffset + RIFF_CHUNK_SIZE};
+}
+
+MediaByteRange WAVTrackDemuxer::FindFmtChunk() {
+  return {mOffset, mOffset + mHeaderParser.GiveHeader().ChunkSize()};
+}
+
+MediaByteRange WAVTrackDemuxer::FindListChunk() {
+  return {mOffset, mOffset + mHeaderParser.GiveHeader().ChunkSize()};
+}
+
+MediaByteRange WAVTrackDemuxer::FindInfoTag() { return {mOffset, mOffset + 4}; }
+
+bool WAVTrackDemuxer::SkipNextChunk(const MediaByteRange& aRange) {
+  UpdateState(aRange);
+  return true;
+}
+
+already_AddRefed<MediaRawData> WAVTrackDemuxer::GetNextChunk(
+    const MediaByteRange& aRange) {
+  if (!aRange.Length()) {
+    return nullptr;
+  }
+
+  RefPtr<MediaRawData> datachunk = new MediaRawData();
+  datachunk->mOffset = aRange.mStart;
+
+  UniquePtr<MediaRawDataWriter> chunkWriter(datachunk->CreateWriter());
+  if (!chunkWriter->SetSize(static_cast<uint32_t>(aRange.Length()))) {
+    return nullptr;
+  }
+
+  const uint32_t read =
+      Read(chunkWriter->Data(), datachunk->mOffset, datachunk->Size());
+
+  if (read != aRange.Length()) {
+    return nullptr;
+  }
+
+  UpdateState(aRange);
+  ++mNumParsedChunks;
+  ++mChunkIndex;
+
+  datachunk->mTime = Duration(mChunkIndex - 1);
+
+  if (static_cast<uint32_t>(mChunkIndex) * DATA_CHUNK_SIZE < mDataLength) {
+    datachunk->mDuration = Duration(1);
+  } else {
+    uint32_t mBytesRemaining = mDataLength - mChunkIndex * DATA_CHUNK_SIZE;
+    datachunk->mDuration = DurationFromBytes(mBytesRemaining);
+  }
+  datachunk->mTimecode = datachunk->mTime;
+  datachunk->mKeyframe = true;
+
+  MOZ_ASSERT(!datachunk->mTime.IsNegative());
+  MOZ_ASSERT(!datachunk->mDuration.IsNegative());
+
+  return datachunk.forget();
+}
+
+already_AddRefed<MediaRawData> WAVTrackDemuxer::GetFileHeader(
+    const MediaByteRange& aRange) {
+  if (!aRange.Length()) {
+    return nullptr;
+  }
+
+  RefPtr<MediaRawData> fileHeader = new MediaRawData();
+  fileHeader->mOffset = aRange.mStart;
+
+  UniquePtr<MediaRawDataWriter> headerWriter(fileHeader->CreateWriter());
+  if (!headerWriter->SetSize(static_cast<uint32_t>(aRange.Length()))) {
+    return nullptr;
+  }
+
+  const uint32_t read =
+      Read(headerWriter->Data(), fileHeader->mOffset, fileHeader->Size());
+
+  if (read != aRange.Length()) {
+    return nullptr;
+  }
+
+  UpdateState(aRange);
+
+  return fileHeader.forget();
+}
+
+uint64_t WAVTrackDemuxer::OffsetFromChunkIndex(uint32_t aChunkIndex) const {
+  return mFirstChunkOffset + aChunkIndex * DATA_CHUNK_SIZE;
+}
+
+uint64_t WAVTrackDemuxer::ChunkIndexFromTime(
+    const media::TimeUnit& aTime) const {
+  if (!mSamplesPerChunk || !mSamplesPerSecond) {
+    return 0;
+  }
+  uint64_t chunkIndex =
+      (aTime.ToSeconds() * mSamplesPerSecond / mSamplesPerChunk) - 1;
+  return chunkIndex;
+}
+
+void WAVTrackDemuxer::UpdateState(const MediaByteRange& aRange) {
+  // Full chunk parsed, move offset to its end.
+  mOffset = static_cast<uint32_t>(aRange.mEnd);
+  mTotalChunkLen += static_cast<uint64_t>(aRange.Length());
+}
+
+uint32_t WAVTrackDemuxer::Read(uint8_t* aBuffer, int64_t aOffset,
+                               int32_t aSize) {
+  const int64_t streamLen = StreamLength();
+  if (mInfo && streamLen > 0) {
+    int64_t max = streamLen > aOffset ? streamLen - aOffset : 0;
+    aSize = std::min<int64_t>(aSize, max);
+  }
+  uint32_t read = 0;
+  const nsresult rv = mSource.ReadAt(aOffset, reinterpret_cast<char*>(aBuffer),
+                                     static_cast<uint32_t>(aSize), &read);
+  NS_ENSURE_SUCCESS(rv, 0);
+  return read;
+}
+
+// RIFFParser
+
+Result<uint32_t, nsresult> RIFFParser::Parse(BufferReader& aReader) {
+  for (auto res = aReader.ReadU8();
+       res.isOk() && !mRiffHeader.ParseNext(res.unwrap());
+       res = aReader.ReadU8()) {
+  }
+
+  if (mRiffHeader.IsValid()) {
+    return RIFF_CHUNK_SIZE;
+  }
+
+  return 0;
+}
+
+void RIFFParser::Reset() { mRiffHeader.Reset(); }
+
+const RIFFParser::RIFFHeader& RIFFParser::RiffHeader() const {
+  return mRiffHeader;
+}
+
+// RIFFParser::RIFFHeader
+
+RIFFParser::RIFFHeader::RIFFHeader() { Reset(); }
+
+void RIFFParser::RIFFHeader::Reset() {
+  memset(mRaw, 0, sizeof(mRaw));
+  mPos = 0;
+}
+
+bool RIFFParser::RIFFHeader::ParseNext(uint8_t c) {
+  if (!Update(c)) {
+    Reset();
+    if (!Update(c)) {
+      Reset();
+    }
+  }
+  return IsValid();
+}
+
+bool RIFFParser::RIFFHeader::IsValid(int aPos) const {
+  if (aPos > -1 && aPos < 4) {
+    return RIFF[aPos] == mRaw[aPos];
+  } else if (aPos > 7 && aPos < 12) {
+    return WAVE[aPos - 8] == mRaw[aPos];
+  } else {
+    return true;
+  }
+}
+
+bool RIFFParser::RIFFHeader::IsValid() const { return mPos >= RIFF_CHUNK_SIZE; }
+
+bool RIFFParser::RIFFHeader::Update(uint8_t c) {
+  if (mPos < RIFF_CHUNK_SIZE) {
+    mRaw[mPos] = c;
+  }
+  return IsValid(mPos++);
+}
+
+// HeaderParser
+
+Result<uint32_t, nsresult> HeaderParser::Parse(BufferReader& aReader) {
+  for (auto res = aReader.ReadU8();
+       res.isOk() && !mHeader.ParseNext(res.unwrap()); res = aReader.ReadU8()) {
+  }
+
+  if (mHeader.IsValid()) {
+    return CHUNK_HEAD_SIZE;
+  }
+
+  return 0;
+}
+
+void HeaderParser::Reset() { mHeader.Reset(); }
+
+const HeaderParser::ChunkHeader& HeaderParser::GiveHeader() const {
+  return mHeader;
+}
+
+// HeaderParser::ChunkHeader
+
+HeaderParser::ChunkHeader::ChunkHeader() { Reset(); }
+
+void HeaderParser::ChunkHeader::Reset() {
+  memset(mRaw, 0, sizeof(mRaw));
+  mPos = 0;
+}
+
+bool HeaderParser::ChunkHeader::ParseNext(uint8_t c) {
+  Update(c);
+  return IsValid();
+}
+
+bool HeaderParser::ChunkHeader::IsValid() const {
+  return mPos >= CHUNK_HEAD_SIZE;
+}
+
+uint32_t HeaderParser::ChunkHeader::ChunkName() const {
+  return static_cast<uint32_t>(
+      ((mRaw[0] << 24) | (mRaw[1] << 16) | (mRaw[2] << 8) | (mRaw[3])));
+}
+
+uint32_t HeaderParser::ChunkHeader::ChunkSize() const {
+  return static_cast<uint32_t>(
+      ((mRaw[7] << 24) | (mRaw[6] << 16) | (mRaw[5] << 8) | (mRaw[4])));
+}
+
+void HeaderParser::ChunkHeader::Update(uint8_t c) {
+  if (mPos < CHUNK_HEAD_SIZE) {
+    mRaw[mPos++] = c;
+  }
+}
+
+// FormatParser
+
+Result<uint32_t, nsresult> FormatParser::Parse(BufferReader& aReader) {
+  for (auto res = aReader.ReadU8();
+       res.isOk() && !mFmtChunk.ParseNext(res.unwrap());
+       res = aReader.ReadU8()) {
+  }
+
+  if (mFmtChunk.IsValid()) {
+    return FMT_CHUNK_MIN_SIZE;
+  }
+
+  return 0;
+}
+
+void FormatParser::Reset() { mFmtChunk.Reset(); }
+
+const FormatParser::FormatChunk& FormatParser::FmtChunk() const {
+  return mFmtChunk;
+}
+
+// FormatParser::FormatChunk
+
+FormatParser::FormatChunk::FormatChunk() { Reset(); }
+
+void FormatParser::FormatChunk::Reset() {
+  memset(mRaw, 0, sizeof(mRaw));
+  mPos = 0;
+}
+
+uint16_t FormatParser::FormatChunk::WaveFormat() const {
+  return (mRaw[1] << 8) | (mRaw[0]);
+}
+
+uint16_t FormatParser::FormatChunk::Channels() const {
+  return (mRaw[3] << 8) | (mRaw[2]);
+}
+
+uint32_t FormatParser::FormatChunk::SampleRate() const {
+  return static_cast<uint32_t>((mRaw[7] << 24) | (mRaw[6] << 16) |
+                               (mRaw[5] << 8) | (mRaw[4]));
+}
+
+uint16_t FormatParser::FormatChunk::FrameSize() const {
+  return (mRaw[13] << 8) | (mRaw[12]);
+}
+
+uint16_t FormatParser::FormatChunk::SampleFormat() const {
+  return (mRaw[15] << 8) | (mRaw[14]);
+}
+
+bool FormatParser::FormatChunk::ParseNext(uint8_t c) {
+  Update(c);
+  return IsValid();
+}
+
+bool FormatParser::FormatChunk::IsValid() const {
+  return (FrameSize() == SampleRate() * Channels() / 8) &&
+         (mPos >= FMT_CHUNK_MIN_SIZE);
+}
+
+void FormatParser::FormatChunk::Update(uint8_t c) {
+  if (mPos < FMT_CHUNK_MIN_SIZE) {
+    mRaw[mPos++] = c;
+  }
+}
+
+// DataParser
+
+DataParser::DataParser() = default;
+
+void DataParser::Reset() { mChunk.Reset(); }
+
+const DataParser::DataChunk& DataParser::CurrentChunk() const { return mChunk; }
+
+// DataParser::DataChunk
+
+void DataParser::DataChunk::Reset() { mPos = 0; }
+
+}  // namespace mozilla