SkCodec* SkCodec::NewFromStream(SkStream* stream,
SkPngChunkReader* chunkReader) {
if (!stream) {
return nullptr;
}
SkAutoTDelete<SkStream> streamDeleter(stream);
// 14 is enough to read all of the supported types.
const size_t bytesToRead = 14;
SkASSERT(bytesToRead <= MinBufferedBytesNeeded());
char buffer[bytesToRead];
size_t bytesRead = stream->peek(buffer, bytesToRead);
// It is also possible to have a complete image less than bytesToRead bytes
// (e.g. a 1 x 1 wbmp), meaning peek() would return less than bytesToRead.
// Assume that if bytesRead < bytesToRead, but > 0, the stream is shorter
// than bytesToRead, so pass that directly to the decoder.
// It also is possible the stream uses too small a buffer for peeking, but
// we trust the caller to use a large enough buffer.
if (0 == bytesRead) {
SkCodecPrintf("Could not peek!\n");
// It is possible the stream does not support peeking, but does support
// rewinding.
// Attempt to read() and pass the actual amount read to the decoder.
bytesRead = stream->read(buffer, bytesToRead);
if (!stream->rewind()) {
SkCodecPrintf("Could not rewind!\n");
return nullptr;
}
}
SkAutoTDelete<SkCodec> codec(nullptr);
// PNG is special, since we want to be able to supply an SkPngChunkReader.
// But this code follows the same pattern as the loop.
if (SkPngCodec::IsPng(buffer, bytesRead)) {
codec.reset(SkPngCodec::NewFromStream(streamDeleter.detach(), chunkReader));
} else {
for (DecoderProc proc : gDecoderProcs) {
if (proc.IsFormat(buffer, bytesRead)) {
codec.reset(proc.NewFromStream(streamDeleter.detach()));
break;
}
}
}
// Set the max size at 128 megapixels (512 MB for kN32).
// This is about 4x smaller than a test image that takes a few minutes for
// dm to decode and draw.
const int32_t maxSize = 1 << 27;
if (codec && codec->getInfo().width() * codec->getInfo().height() > maxSize) {
SkCodecPrintf("Error: Image size too large, cannot decode.\n");
return nullptr;
} else {
return codec.detach();
}
}
SkCodec* SkCodec::NewFromStream(SkStream* stream,
SkPngChunkReader* chunkReader) {
if (!stream) {
return nullptr;
}
SkAutoTDelete<SkStream> streamDeleter(stream);
// 14 is enough to read all of the supported types.
const size_t bytesToRead = 14;
SkASSERT(bytesToRead <= MinBufferedBytesNeeded());
char buffer[bytesToRead];
size_t bytesRead = stream->peek(buffer, bytesToRead);
// It is also possible to have a complete image less than bytesToRead bytes
// (e.g. a 1 x 1 wbmp), meaning peek() would return less than bytesToRead.
// Assume that if bytesRead < bytesToRead, but > 0, the stream is shorter
// than bytesToRead, so pass that directly to the decoder.
// It also is possible the stream uses too small a buffer for peeking, but
// we trust the caller to use a large enough buffer.
if (0 == bytesRead) {
// TODO: After implementing peek in CreateJavaOutputStreamAdaptor.cpp, this
// printf could be useful to notice failures.
// SkCodecPrintf("Encoded image data failed to peek!\n");
// It is possible the stream does not support peeking, but does support
// rewinding.
// Attempt to read() and pass the actual amount read to the decoder.
bytesRead = stream->read(buffer, bytesToRead);
if (!stream->rewind()) {
SkCodecPrintf("Encoded image data could not peek or rewind to determine format!\n");
return nullptr;
}
}
// PNG is special, since we want to be able to supply an SkPngChunkReader.
// But this code follows the same pattern as the loop.
#ifdef SK_CODEC_DECODES_PNG
if (SkPngCodec::IsPng(buffer, bytesRead)) {
return SkPngCodec::NewFromStream(streamDeleter.detach(), chunkReader);
} else
#endif
{
for (DecoderProc proc : gDecoderProcs) {
if (proc.IsFormat(buffer, bytesRead)) {
return proc.NewFromStream(streamDeleter.detach());
}
}
#ifdef SK_CODEC_DECODES_RAW
// Try to treat the input as RAW if all the other checks failed.
return SkRawCodec::NewFromStream(streamDeleter.detach());
#endif
}
return nullptr;
}
