Subset decoding benchmarks

bench/subset/SubsetSingleBench.cpp

Index: bench/subset/SubsetSingleBench.cpp
diff --git a/bench/subset/SubsetSingleBench.cpp b/bench/subset/SubsetSingleBench.cpp
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+++ b/bench/subset/SubsetSingleBench.cpp
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+/*
+ * 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 "SubsetSingleBench.h"
+#include "SubsetBenchPriv.h"
+#include "SkData.h"
+#include "SkCodec.h"
+#include "SkImageDecoder.h"
+#include "SkOSFile.h"
+#include "SkStream.h"
+
+/*
+ *
+ * This benchmark is designed to test the performance of subset decoding.
+ * It uses an input width, height, left, and top to decode a single subset.
+ *
+ */
+
+SubsetSingleBench::SubsetSingleBench(const SkString& path,
+                                     SkColorType colorType,
+                                     uint32_t subsetWidth,
+                                     uint32_t subsetHeight,
+                                     uint32_t offsetLeft,
+                                     uint32_t offsetTop,
+                                     bool useCodec)
+    : fColorType(colorType)
+    , fSubsetWidth(subsetWidth)
+    , fSubsetHeight(subsetHeight)
+    , fOffsetLeft(offsetLeft)
+    , fOffsetTop(offsetTop)
+    , fUseCodec(useCodec)
+{
+    // Parse the filename
+    SkString baseName = SkOSPath::Basename(path.c_str());
+
+    // Choose an informative color name
+    const char* colorName = get_color_name(fColorType);
+
+    fName.printf("%sSubsetSingle_%dx%d +%d_+%d_%s_%s", fUseCodec ? "Codec" : "Image", fSubsetWidth,
+            fSubsetHeight, fOffsetLeft, fOffsetTop, baseName.c_str(), colorName);
+
+    // Perform the decode setup
+    SkAutoTUnref<SkData> encoded(SkData::NewFromFileName(path.c_str()));
+    fStream.reset(new SkMemoryStream(encoded));
+}
+
+const char* SubsetSingleBench::onGetName() {
+    return fName.c_str();
+}
+
+bool SubsetSingleBench::isSuitableFor(Backend backend) {
+    return kNonRendering_Backend == backend;
+}
+
+void SubsetSingleBench::onDraw(const int n, SkCanvas* canvas) {
+    // When the color type is kIndex8, we will need to store the color table.  If it is
+    // used, it will be initialized by the codec.
+    int colorCount;
+    SkPMColor colors[256];
+    if (fUseCodec) {
+        for (int count = 0; count < n; count++) {
+            SkAutoTDelete<SkCodec> codec(SkCodec::NewFromStream(fStream->duplicate()));
+            const SkImageInfo info = codec->getInfo().makeColorType(fColorType);
+            SkAutoTDeleteArray<uint8_t> row(SkNEW_ARRAY(uint8_t, info.minRowBytes()));
+            SkScanlineDecoder* scanlineDecoder = codec->getScanlineDecoder(
+                    info, NULL, colors, &colorCount);
+
+            SkBitmap bitmap;
+            bitmap.allocPixels(info.makeWH(fSubsetWidth, fSubsetHeight));
+
+            scanlineDecoder->skipScanlines(fOffsetTop);
+            uint32_t bpp = info.bytesPerPixel();
+            for (uint32_t y = 0; y < fSubsetHeight; y++) {
+                scanlineDecoder->getScanlines(row.get(), 1, 0);
+                memcpy(bitmap.getAddr(0, y), row.get() + fOffsetLeft * bpp,
+                        fSubsetWidth * bpp);
+            }
+        }
+    } else {
+        for (int count = 0; count < n; count++) {
+            SkAutoTDelete<SkImageDecoder> decoder(SkImageDecoder::Factory(fStream));
+            int width, height;
+            decoder->buildTileIndex(fStream->duplicate(), &width, &height);
+            SkBitmap bitmap;
+            SkIRect rect = SkIRect::MakeXYWH(fOffsetLeft, fOffsetTop, fSubsetWidth,
+                    fSubsetHeight);
+            decoder->decodeSubset(&bitmap, rect, fColorType);
+        }
+    }
+}