static void InsertNoDuplicates(nsTArray<nsString>& aArray,
const nsAString& aString)
{
size_t i = aArray.IndexOfFirstElementGt(aString);
if (i > 0 && aArray[i-1].Equals(aString)) {
return;
}
aArray.InsertElementAt(i, aString);
}
void WebMBufferedParser::Append(const unsigned char* aBuffer, uint32_t aLength,
nsTArray<WebMTimeDataOffset>& aMapping,
ReentrantMonitor& aReentrantMonitor)
{
static const uint32_t EBML_ID = 0x1a45dfa3;
static const uint32_t SEGMENT_ID = 0x18538067;
static const uint32_t SEGINFO_ID = 0x1549a966;
static const uint32_t TRACKS_ID = 0x1654AE6B;
static const uint32_t CLUSTER_ID = 0x1f43b675;
static const uint32_t TIMECODESCALE_ID = 0x2ad7b1;
static const unsigned char TIMECODE_ID = 0xe7;
static const unsigned char BLOCK_ID = 0xa1;
static const unsigned char SIMPLEBLOCK_ID = 0xa3;
static const uint32_t BLOCK_TIMECODE_LENGTH = 2;
static const unsigned char CLUSTER_SYNC_ID[] = { 0x1f, 0x43, 0xb6, 0x75 };
const unsigned char* p = aBuffer;
// Parse each byte in aBuffer one-by-one, producing timecodes and updating
// aMapping as we go. Parser pauses at end of stream (which may be at any
// point within the parse) and resumes parsing the next time Append is
// called with new data.
while (p < aBuffer + aLength) {
switch (mState) {
case READ_ELEMENT_ID:
mVIntRaw = true;
mState = READ_VINT;
mNextState = READ_ELEMENT_SIZE;
break;
case READ_ELEMENT_SIZE:
mVIntRaw = false;
mElement.mID = mVInt;
mState = READ_VINT;
mNextState = PARSE_ELEMENT;
break;
case FIND_CLUSTER_SYNC:
if (*p++ == CLUSTER_SYNC_ID[mClusterSyncPos]) {
mClusterSyncPos += 1;
} else {
mClusterSyncPos = 0;
}
if (mClusterSyncPos == sizeof(CLUSTER_SYNC_ID)) {
mVInt.mValue = CLUSTER_ID;
mVInt.mLength = sizeof(CLUSTER_SYNC_ID);
mState = READ_ELEMENT_SIZE;
}
break;
case PARSE_ELEMENT:
mElement.mSize = mVInt;
switch (mElement.mID.mValue) {
case SEGMENT_ID:
mState = READ_ELEMENT_ID;
break;
case SEGINFO_ID:
mGotTimecodeScale = true;
mState = READ_ELEMENT_ID;
break;
case TIMECODE_ID:
mVInt = VInt();
mVIntLeft = mElement.mSize.mValue;
mState = READ_VINT_REST;
mNextState = READ_CLUSTER_TIMECODE;
break;
case TIMECODESCALE_ID:
mVInt = VInt();
mVIntLeft = mElement.mSize.mValue;
mState = READ_VINT_REST;
mNextState = READ_TIMECODESCALE;
break;
case CLUSTER_ID:
mClusterOffset = mCurrentOffset + (p - aBuffer) -
(mElement.mID.mLength + mElement.mSize.mLength);
// Handle "unknown" length;
if (mElement.mSize.mValue + 1 != uint64_t(1) << (mElement.mSize.mLength * 7)) {
mClusterEndOffset = mClusterOffset + mElement.mID.mLength + mElement.mSize.mLength + mElement.mSize.mValue;
} else {
mClusterEndOffset = -1;
}
mState = READ_ELEMENT_ID;
break;
case SIMPLEBLOCK_ID:
/* FALLTHROUGH */
case BLOCK_ID:
mBlockSize = mElement.mSize.mValue;
mBlockTimecode = 0;
mBlockTimecodeLength = BLOCK_TIMECODE_LENGTH;
mBlockOffset = mCurrentOffset + (p - aBuffer) -
(mElement.mID.mLength + mElement.mSize.mLength);
mState = READ_VINT;
mNextState = READ_BLOCK_TIMECODE;
break;
case TRACKS_ID:
mSkipBytes = mElement.mSize.mValue;
mState = CHECK_INIT_FOUND;
break;
case EBML_ID:
mLastInitStartOffset = mCurrentOffset + (p - aBuffer) -
(mElement.mID.mLength + mElement.mSize.mLength);
/* FALLTHROUGH */
default:
mSkipBytes = mElement.mSize.mValue;
mState = SKIP_DATA;
mNextState = READ_ELEMENT_ID;
break;
}
break;
case READ_VINT: {
unsigned char c = *p++;
uint32_t mask;
mVInt.mLength = VIntLength(c, &mask);
mVIntLeft = mVInt.mLength - 1;
mVInt.mValue = mVIntRaw ? c : c & ~mask;
mState = READ_VINT_REST;
break;
}
case READ_VINT_REST:
if (mVIntLeft) {
mVInt.mValue <<= 8;
mVInt.mValue |= *p++;
mVIntLeft -= 1;
} else {
mState = mNextState;
}
break;
case READ_TIMECODESCALE:
MOZ_ASSERT(mGotTimecodeScale);
mTimecodeScale = mVInt.mValue;
mState = READ_ELEMENT_ID;
break;
case READ_CLUSTER_TIMECODE:
mClusterTimecode = mVInt.mValue;
mState = READ_ELEMENT_ID;
break;
case READ_BLOCK_TIMECODE:
if (mBlockTimecodeLength) {
mBlockTimecode <<= 8;
mBlockTimecode |= *p++;
mBlockTimecodeLength -= 1;
} else {
// It's possible we've parsed this data before, so avoid inserting
// duplicate WebMTimeDataOffset entries.
{
ReentrantMonitorAutoEnter mon(aReentrantMonitor);
int64_t endOffset = mBlockOffset + mBlockSize +
mElement.mID.mLength + mElement.mSize.mLength;
uint32_t idx = aMapping.IndexOfFirstElementGt(endOffset);
if (idx == 0 || aMapping[idx - 1] != endOffset) {
// Don't insert invalid negative timecodes.
if (mBlockTimecode >= 0 || mClusterTimecode >= uint16_t(abs(mBlockTimecode))) {
MOZ_ASSERT(mGotTimecodeScale);
uint64_t absTimecode = mClusterTimecode + mBlockTimecode;
absTimecode *= mTimecodeScale;
WebMTimeDataOffset entry(endOffset, absTimecode, mLastInitStartOffset,
mClusterOffset, mClusterEndOffset);
aMapping.InsertElementAt(idx, entry);
}
}
}
// Skip rest of block header and the block's payload.
mBlockSize -= mVInt.mLength;
mBlockSize -= BLOCK_TIMECODE_LENGTH;
mSkipBytes = uint32_t(mBlockSize);
mState = SKIP_DATA;
mNextState = READ_ELEMENT_ID;
}
break;
case SKIP_DATA:
if (mSkipBytes) {
uint32_t left = aLength - (p - aBuffer);
left = std::min(left, mSkipBytes);
p += left;
mSkipBytes -= left;
}
if (!mSkipBytes) {
mBlockEndOffset = mCurrentOffset + (p - aBuffer);
mState = mNextState;
}
break;
case CHECK_INIT_FOUND:
if (mSkipBytes) {
uint32_t left = aLength - (p - aBuffer);
left = std::min(left, mSkipBytes);
p += left;
mSkipBytes -= left;
}
if (!mSkipBytes) {
if (mInitEndOffset < 0) {
mInitEndOffset = mCurrentOffset + (p - aBuffer);
mBlockEndOffset = mCurrentOffset + (p - aBuffer);
}
mState = READ_ELEMENT_ID;
}
break;
}
}
NS_ASSERTION(p == aBuffer + aLength, "Must have parsed to end of data.");
mCurrentOffset += aLength;
}