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"
 #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 SK_OVERRIDE {
         return kGIF_Format;
     }
 
+    virtual Format onGetFormat(SkStream*) const SK_OVERRIDE;
+
 protected:
     virtual bool onDecode(SkStream* stream, SkBitmap* bm, Mode mode) SK_OVERRIDE;
 
 private:
     typedef SkImageDecoder INHERITED;
 };
 
 static const uint8_t gStartingIterlaceYValue[] = {
     0, 4, 2, 1
 };
@@ skipping 49 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 247 matching lines @@
 
         default:    /* Should be trapped by DGifGetRecordType */
             break;
         }
     } while (recType != TERMINATE_RECORD_TYPE);
 
 DONE:
     return true;
 }
 
+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 true;
+        }
+    }
+    return false;
+}
+
+SkImageDecoder::Format SkGIFImageDecoder::onGetFormat(SkStream* stream) const {
+    if (is_gif(stream)) {
+        return kGIF_Format;
+    }
+    return kUnknown_Format;
+}
+
 ///////////////////////////////////////////////////////////////////////////////
 DEFINE_DECODER_CREATOR(GIFImageDecoder);
 ///////////////////////////////////////////////////////////////////////////////
 
 #include "SkTRegistry.h"
 
 static SkImageDecoder* sk_libgif_dfactory(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);
-        }
+    if (is_gif(stream)) {
+        return SkNEW(SkGIFImageDecoder);
     }
     return NULL;
 }
 
 static SkTRegistry<SkImageDecoder*, SkStream*> gReg(sk_libgif_dfactory);