Add an option on SkImageDecoder to skip writing 0s.

bench/SkipZeroesBench.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBenchmark.h"
 #include "SkBitmap.h"
 #include "SkData.h"
 #include "SkForceLinking.h"
 #include "SkImageDecoder.h"
 #include "SkOSFile.h"
 #include "SkStream.h"
 #include "SkString.h"
 
 __SK_FORCE_IMAGE_DECODER_LINKING;
 
 class SkCanvas;
 
-class ImageDecodeBench : public SkBenchmark {
+class SkipZeroesBench : public SkBenchmark {
 public:
-    ImageDecodeBench(void* p, const char* filename)
-    : fName("image_decode_")
+    SkipZeroesBench(const char* filename, bool skipZeroes)
+    : fName("SkipZeroes_")
+    , fDecoder(NULL)
     , fFilename(filename)
     , fStream()
+    , fSkipZeroes(skipZeroes)
     , fValid(false) {
         fName.append(SkOSPath::SkBasename(filename));
+        if (skipZeroes) {
+            fName.append("_skip_zeroes");
+        }
         fIsRendering = false;
     }
 
+    ~SkipZeroesBench() {
+        SkDELETE(fDecoder);
+    }
 protected:
     virtual const char* onGetName() SK_OVERRIDE {
         return fName.c_str();
     }
 
     virtual void onPreDraw() SK_OVERRIDE {
         SkFILEStream fileStream(fFilename.c_str());
         fValid = fileStream.isValid() && fileStream.getLength() > 0;
         if (fValid) {
             const size_t size = fileStream.getLength();
             void* data = sk_malloc_throw(size);
             if (fileStream.read(data, size) < size) {
                 fValid = false;
             } else {
                 SkAutoTUnref<SkData> skdata(SkData::NewFromMalloc(data, size));
                 fStream.setData(skdata.get());
+                fDecoder = SkImageDecoder::Factory(&fStream);
+                if (fDecoder) {
+                    fDecoder->setSkipWritingZeroes(fSkipZeroes);
+                } else {
+                    fValid = false;
+                }
             }
         }
     }
 
     virtual void onDraw(SkCanvas*) SK_OVERRIDE {
 #ifdef SK_DEBUG
         if (!fValid) {
             SkDebugf("stream was invalid: %s\n", fName.c_str());
             return;
         }
 #endif
         // Decode a bunch of times
         SkBitmap bm;
         for (int i = 0; i < this->getLoops(); ++i) {
-            SkDEBUGCODE(bool success =) SkImageDecoder::DecodeStream(&fStream, &bm);
+            SkDEBUGCODE(bool success =) fDecoder->decode(&fStream, &bm, SkImageDecoder::kDecodePixels_Mode);
 #ifdef SK_DEBUG
             if (!success) {
                 SkDebugf("failed to decode %s\n", fName.c_str());
                 return;
             }
 #endif
             SkDEBUGCODE(success =) fStream.rewind();
 #ifdef SK_DEBUG
             if (!success) {
                 SkDebugf("failed to rewind %s\n", fName.c_str());
                 return;
             }
 #endif
         }
     }
 
 private:
     SkString        fName;
+    SkImageDecoder* fDecoder;
     const SkString  fFilename;
     SkMemoryStream  fStream;
+    bool            fSkipZeroes;
     bool            fValid;
 
     typedef SkBenchmark INHERITED;
 };
 
-// These are files which call decodePalette
-//DEF_BENCH( return SkNEW_ARGS(ImageDecodeBench, ("/usr/local/google/home/scroggo/Downloads/images/hal_163x90.png")); )
-//DEF_BENCH( return SkNEW_ARGS(ImageDecodeBench, ("/usr/local/google/home/scroggo/Downloads/images/box_19_top-left.png")); )
+//DEF_BENCH( return SkNEW_ARGS(SkipZeroesBench, ("/sdcard/skia/images/arrow.png", true)));

[djsollen, 2013/09/19 19:41:17]

seems like we should be able to supply a resources directory as an arg to bench
so that we can enable this test if the resources are present.

[scroggo, 2013/09/19 21:07:21]

I can add this next week. Also as a note to myself, reed suggested I add the
benchmark before the change. On my local device, the benchmark runs in about the
same amount of time (as the false case, where we're not skipping zeroes).

+//DEF_BENCH( return SkNEW_ARGS(SkipZeroesBench, ("/sdcard/skia/images/arrow.png", false)));