void GIFImageDecoder::decode(size_t index)
{
parse(GIFFrameCountQuery);
if (failed())
return;
updateAggressivePurging(index);
Vector<size_t> framesToDecode;
size_t frameToDecode = index;
do {
framesToDecode.append(frameToDecode);
frameToDecode = m_frameBufferCache[frameToDecode].requiredPreviousFrameIndex();
} while (frameToDecode != kNotFound && m_frameBufferCache[frameToDecode].getStatus() != ImageFrame::FrameComplete);
for (auto i = framesToDecode.rbegin(); i != framesToDecode.rend(); ++i) {
if (!m_reader->decode(*i)) {
setFailed();
return;
}
if (m_purgeAggressively)
clearCacheExceptFrame(*i);
// We need more data to continue decoding.
if (m_frameBufferCache[*i].getStatus() != ImageFrame::FrameComplete)
break;
}
// It is also a fatal error if all data is received and we have decoded all
// frames available but the file is truncated.
if (index >= m_frameBufferCache.size() - 1 && isAllDataReceived() && m_reader && !m_reader->parseCompleted())
setFailed();
}
bool WEBPImageDecoder::updateDemuxer() {
if (failed())
return false;
if (m_haveAlreadyParsedThisData)
return true;
m_haveAlreadyParsedThisData = true;
const unsigned webpHeaderSize = 30;
if (m_data->size() < webpHeaderSize)
return false; // Await VP8X header so WebPDemuxPartial succeeds.
WebPDemuxDelete(m_demux);
m_consolidatedData = m_data->getAsSkData();
WebPData inputData = {
reinterpret_cast<const uint8_t*>(m_consolidatedData->data()),
m_consolidatedData->size()};
m_demux = WebPDemuxPartial(&inputData, &m_demuxState);
if (!m_demux || (isAllDataReceived() && m_demuxState != WEBP_DEMUX_DONE)) {
if (!m_demux)
m_consolidatedData.reset();
return setFailed();
}
ASSERT(m_demuxState > WEBP_DEMUX_PARSING_HEADER);
if (!WebPDemuxGetI(m_demux, WEBP_FF_FRAME_COUNT))
return false; // Wait until the encoded image frame data arrives.
if (!isDecodedSizeAvailable()) {
int width = WebPDemuxGetI(m_demux, WEBP_FF_CANVAS_WIDTH);
int height = WebPDemuxGetI(m_demux, WEBP_FF_CANVAS_HEIGHT);
if (!setSize(width, height))
return setFailed();
m_formatFlags = WebPDemuxGetI(m_demux, WEBP_FF_FORMAT_FLAGS);
if (!(m_formatFlags & ANIMATION_FLAG)) {
m_repetitionCount = cAnimationNone;
} else {
// Since we have parsed at least one frame, even if partially,
// the global animation (ANIM) properties have been read since
// an ANIM chunk must precede the ANMF frame chunks.
m_repetitionCount = WebPDemuxGetI(m_demux, WEBP_FF_LOOP_COUNT);
// Repetition count is always <= 16 bits.
ASSERT(m_repetitionCount == (m_repetitionCount & 0xffff));
if (!m_repetitionCount)
m_repetitionCount = cAnimationLoopInfinite;
// FIXME: Implement ICC profile support for animated images.
m_formatFlags &= ~ICCP_FLAG;
}
if ((m_formatFlags & ICCP_FLAG) && !ignoresColorSpace())
readColorProfile();
}
ASSERT(isDecodedSizeAvailable());
size_t frameCount = WebPDemuxGetI(m_demux, WEBP_FF_FRAME_COUNT);
updateAggressivePurging(frameCount);
return true;
}