nsresult WaveReader::ReadMetadata(nsVideoInfo* aInfo,
MetadataTags** aTags)
{
NS_ASSERTION(mDecoder->OnDecodeThread(), "Should be on decode thread.");
bool loaded = LoadRIFFChunk() && LoadFormatChunk() && FindDataOffset();
if (!loaded) {
return NS_ERROR_FAILURE;
}
mInfo.mHasAudio = true;
mInfo.mHasVideo = false;
mInfo.mAudioRate = mSampleRate;
mInfo.mAudioChannels = mChannels;
*aInfo = mInfo;
*aTags = nullptr;
ReentrantMonitorAutoEnter mon(mDecoder->GetReentrantMonitor());
mDecoder->GetStateMachine()->SetDuration(
static_cast<int64_t>(BytesToTime(GetDataLength()) * USECS_PER_S));
return NS_OK;
}
bool
WaveReader::LoadAllChunks(nsAutoPtr<dom::HTMLMediaElement::MetadataTags> &aTags)
{
// Chunks are always word (two byte) aligned.
MOZ_ASSERT(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;
}
