Upstream Android modifications to the image encoders/decoders.

src/images/SkImageDecoder_libgif.cpp

 
 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "SkImageDecoder.h"
 #include "SkColor.h"
 #include "SkColorPriv.h"
 #include "SkStream.h"
 #include "SkTemplates.h"
 #include "SkPackBits.h"
 
 #include "gif_lib.h"
 
 class SkGIFImageDecoder : public SkImageDecoder {
 public:
-    virtual Format getFormat() const {
+    virtual Format getFormat() const SK_OVERRIDE {
         return kGIF_Format;
     }
 
 protected:
-    virtual bool onDecode(SkStream* stream, SkBitmap* bm, Mode mode);
+    virtual bool onDecode(SkStream* stream, SkBitmap* bm, Mode mode) SK_OVERRIDE;
+
+private:
+    typedef SkImageDecoder INHERITED;
 };
 
 static const uint8_t gStartingIterlaceYValue[] = {
     0, 4, 2, 1
 };
 static const uint8_t gDeltaIterlaceYValue[] = {
     8, 8, 4, 2
 };
 
 /*  Implement the GIF interlace algorithm in an iterator.
@@ skipping 157 matching lines @@
                 return error_return(gif, *bm, "ImageCount < 1");
             }
 
             width = gif->SWidth;
             height = gif->SHeight;
             if (width <= 0 || height <= 0 ||
                 !this->chooseFromOneChoice(SkBitmap::kIndex8_Config,
                                            width, height)) {
                 return error_return(gif, *bm, "chooseFromOneChoice");
             }
+            
+            if (SkImageDecoder::kDecodeBounds_Mode == mode) {
+                bm->setConfig(SkBitmap::kIndex8_Config, width, height);
+                return true;
+            }
+
+            // No Bitmap reuse supported for this format
+            if (!bm->isNull()) {
+                return false;
+            }
 
             bm->setConfig(SkBitmap::kIndex8_Config, width, height);
-            if (SkImageDecoder::kDecodeBounds_Mode == mode)
-                return true;
-
             SavedImage* image = &gif->SavedImages[gif->ImageCount-1];
             const GifImageDesc& desc = image->ImageDesc;
 
             // check for valid descriptor
             if (   (desc.Top | desc.Left) < 0 ||
                     desc.Left + desc.Width > width ||
                     desc.Top + desc.Height > height) {
                 return error_return(gif, *bm, "TopLeft");
             }
 
@@ skipping 144 matching lines @@
         if (memcmp(GIF_STAMP,   buf, GIF_STAMP_LEN) == 0 ||
                 memcmp(GIF87_STAMP, buf, GIF_STAMP_LEN) == 0 ||
                 memcmp(GIF89_STAMP, buf, GIF_STAMP_LEN) == 0) {
             return SkNEW(SkGIFImageDecoder);
         }
     }
     return NULL;
 }
 
 static SkTRegistry<SkImageDecoder*, SkStream*> gReg(sk_libgif_dfactory);