Prototype of RAW decoding in Skia.

src/codec/SkCodec.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBmpCodec.h"
 #include "SkCodec.h"
 #include "SkData.h"
 #include "SkCodec_libgif.h"
 #include "SkCodec_libico.h"
 #include "SkCodec_libpng.h"
 #include "SkCodec_wbmp.h"
 #include "SkCodecPriv.h"
 #if !defined(GOOGLE3)
 #include "SkJpegCodec.h"
 #endif
 #include "SkStream.h"
 #include "SkWebpCodec.h"
+#include "SkRawCodec.h"
 
 struct DecoderProc {
     bool (*IsFormat)(const void*, size_t);
     SkCodec* (*NewFromStream)(SkStream*);
 };
 
 static const DecoderProc gDecoderProcs[] = {
 #if !defined(GOOGLE3)
     { SkJpegCodec::IsJpeg, SkJpegCodec::NewFromStream },
 #endif
     { SkWebpCodec::IsWebp, SkWebpCodec::NewFromStream },
     { SkGifCodec::IsGif, SkGifCodec::NewFromStream },
     { SkIcoCodec::IsIco, SkIcoCodec::NewFromStream },
     { SkBmpCodec::IsBmp, SkBmpCodec::NewFromStream },
     { SkWbmpCodec::IsWbmp, SkWbmpCodec::NewFromStream }
 };
 
 size_t SkCodec::MinBufferedBytesNeeded() {
     return WEBP_VP8_HEADER_SIZE;
 }
 
 SkCodec* SkCodec::NewFromStream(SkStream* stream,
                                 SkPngChunkReader* chunkReader) {
     if (!stream) {
         return nullptr;
     }
 
     SkAutoTDelete<SkStream> streamDeleter(stream);
 
+

[scroggo, 2015/12/18 15:56:26]

nit: extra blank line.

[yujieqin, 2016/01/06 18:47:19]

Done.

     // 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
@@ skipping 18 matching lines @@
     // 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;
             }
         }
+
+        // Try read more for RAW cases.

[msarett, 2015/12/18 16:26:12]

Is there a reason that we can't add RAW to gDecoderProcs above?

[scroggo, 2015/12/18 16:47:05]

SkRawCodec::IsRaw reads the whole stream, rather than the first 14 bytes. As I
stated in the other CL, it would be nice if we could just read some sort of
signature at the beginning.

[yujieqin, 2016/01/06 18:47:19]

As discussed in the buganizer, we don't need IsRaw() anymore. The RawCodec will
be always created if all the other checks failed.

+        if (SkRawCodec::IsRaw(stream)) {
+            codec.reset(SkRawCodec::NewFromStream(streamDeleter.detach()));
+        }
     }
 
     // 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 {
@@ skipping 276 matching lines @@
             SkASSERT(1 == linesRequested || this->getInfo().height() == linesRequested);
             const SkImageInfo fillInfo = info.makeWH(info.width(), 1);
             for (int srcY = linesDecoded; srcY < linesRequested; srcY++) {
                 fillDst = SkTAddOffset<void>(dst, this->outputScanline(srcY) * rowBytes);
                 fill_proc(fillInfo, fillDst, rowBytes, fillValue, zeroInit, sampler);
             }
             break;
         }
     }
 }