Updates to skimage tool to use it for testing.

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"
@@ skipping 73 matching lines @@
 private:
     const int fHeight;
     int fCurrY;
     int fDeltaY;
     const uint8_t* fStartYPtr;
     const uint8_t* fDeltaYPtr;
 };
 
 ///////////////////////////////////////////////////////////////////////////////
 
-//#define GIF_STAMP       "GIF"    /* First chars in file - GIF stamp. */
-//#define GIF_STAMP_LEN   (sizeof(GIF_STAMP) - 1)
-
 static int DecodeCallBackProc(GifFileType* fileType, GifByteType* out,
                               int size) {
     SkStream* stream = (SkStream*) fileType->UserData;
     return (int) stream->read(out, size);
 }
 
 void CheckFreeExtension(SavedImage* Image) {
     if (Image->ExtensionBlocks) {
 #if GIFLIB_MAJOR < 5
         FreeExtension(Image);
@@ skipping 251 matching lines @@
     } while (recType != TERMINATE_RECORD_TYPE);
 
 DONE:
     return true;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 DEFINE_DECODER_CREATOR(GIFImageDecoder);
 ///////////////////////////////////////////////////////////////////////////////
 
-#include "SkTRegistry.h"
-
-static SkImageDecoder* sk_libgif_dfactory(SkStream* stream) {
+static bool is_gif(SkStream* stream) {
     char buf[GIF_STAMP_LEN];
     if (stream->read(buf, GIF_STAMP_LEN) == GIF_STAMP_LEN) {
         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 true;
         }
     }
+    return false;
+}
+
+#include "SkTRegistry.h"
+
+static SkImageDecoder* sk_libgif_dfactory(SkStream* stream) {
+    if (is_gif(stream)) {
+        return SkNEW(SkGIFImageDecoder);
+    }
     return NULL;
 }
 
 static SkTRegistry<SkImageDecoder*, SkStream*> gReg(sk_libgif_dfactory);
+
+static SkImageDecoder::Format get_format_gif(SkStream* stream) {
+    if (is_gif(stream)) {
+        return SkImageDecoder::kGIF_Format;
+    }
+    return SkImageDecoder::kUnknown_Format;
+}
+
+static SkTRegistry<SkImageDecoder::Format, SkStream*> gFormatReg(get_format_gif);