Add --simpleCodec to nanobench flags to run a smaller set of benchmarks

bench/nanobench.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include <ctype.h>
 
 #include "nanobench.h"
@@ skipping 101 matching lines @@
 DEFINE_bool(bbh, true, "Build a BBH for SKPs?");
 DEFINE_bool(mpd, true, "Use MultiPictureDraw for the SKPs?");
 DEFINE_bool(loopSKP, true, "Loop SKPs like we do for micro benches?");
 DEFINE_int32(flushEvery, 10, "Flush --outResultsFile every Nth run.");
 DEFINE_bool(resetGpuContext, true, "Reset the GrContext before running each test.");
 DEFINE_bool(gpuStats, false, "Print GPU stats after each gpu benchmark?");
 DEFINE_bool(gpuStatsDump, false, "Dump GPU states after each benchmark to json");
 DEFINE_bool(keepAlive, false, "Print a message every so often so that we don't time out");
 DEFINE_string(useThermalManager, "0,1,10,1000", "enabled,threshold,sleepTimeMs,TimeoutMs for "
                                                 "thermalManager\n");
+DEFINE_bool(simpleCodec, false, "Only decode images to N32 opaque or premul");
 
 DEFINE_string(sourceType, "",
         "Apply usual --match rules to source type: bench, gm, skp, image, etc.");
 DEFINE_string(benchType,  "",
         "Apply usual --match rules to bench type: micro, recording, playback, skcodec, etc.");
 
 static double now_ms() { return SkTime::GetNSecs() * 1e-6; }
 
 static SkString humanize(double ms) {
     if (FLAGS_verbose) return SkStringPrintf("%llu", (uint64_t)(ms*1e6));
@@ skipping 480 matching lines @@
 
         // Prepare the images for decoding
         if (!CollectImages(FLAGS_images, &fImages)) {
             exit(1);
         }
         if (!CollectImages(FLAGS_colorImages, &fColorImages)) {
             exit(1);
         }
 
         // Choose the candidate color types for image decoding
-        const SkColorType colorTypes[] =
-            { kN32_SkColorType,
-              kRGB_565_SkColorType,
-              kAlpha_8_SkColorType,
-              kIndex_8_SkColorType,
-              kGray_8_SkColorType };
-        fColorTypes.reset(colorTypes, SK_ARRAY_COUNT(colorTypes));
+        if (FLAGS_simpleCodec) {

[scroggo, 2016/06/21 14:52:48]

Alternatively, you could always reset fColorTypes to kN32, and then append the
rest 

if (!FLAGS_simpleCodec)

That seems simpler/clearer to me, but maybe you like the existing code better.
The most awkward part to me is that you create an array of one just to copy it.

+            const SkColorType colorTypes[] = {
+                    kN32_SkColorType,
+            };
+
+            fColorTypes.reset(colorTypes, SK_ARRAY_COUNT(colorTypes));
+        } else {
+            const SkColorType colorTypes[] = {
+                    kN32_SkColorType,
+                    kRGB_565_SkColorType,
+                    kAlpha_8_SkColorType,
+                    kIndex_8_SkColorType,
+                    kGray_8_SkColorType,
+            };
+
+            fColorTypes.reset(colorTypes, SK_ARRAY_COUNT(colorTypes));
+        }
     }
 
     static sk_sp<SkPicture> ReadPicture(const char* path) {
         // Not strictly necessary, as it will be checked again later,
         // but helps to avoid a lot of pointless work if we're going to skip it.
         if (SkCommandLineFlags::ShouldSkip(FLAGS_match, SkOSPath::Basename(path).c_str())) {
             return nullptr;
         }
 
         SkAutoTDelete<SkStream> stream(SkStream::NewFromFile(path));
@@ skipping 117 matching lines @@
             if (!codec) {
                 // Nothing to time.
                 SkDebugf("Cannot find codec for %s\n", path.c_str());
                 continue;
             }
 
             while (fCurrentColorType < fColorTypes.count()) {
                 const SkColorType colorType = fColorTypes[fCurrentColorType];
 
                 SkAlphaType alphaType = codec->getInfo().alphaType();
-                switch (alphaType) {
-                    case kOpaque_SkAlphaType:
-                        // We only need to test one alpha type (opaque).
-                        fCurrentColorType++;
-                        break;
-                    case kUnpremul_SkAlphaType:
-                    case kPremul_SkAlphaType:
-                        if (0 == fCurrentAlphaType) {
-                            // Test unpremul first.
-                            alphaType = kUnpremul_SkAlphaType;
-                            fCurrentAlphaType++;
-                        } else {
-                            // Test premul.
-                            alphaType = kPremul_SkAlphaType;
-                            fCurrentAlphaType = 0;
+                if (FLAGS_simpleCodec) {
+                    if (kUnpremul_SkAlphaType == alphaType) {
+                        alphaType = kPremul_SkAlphaType;
+                    }
+
+                    fCurrentColorType++;
+                } else {
+                    switch (alphaType) {
+                        case kOpaque_SkAlphaType:
+                            // We only need to test one alpha type (opaque).
                             fCurrentColorType++;
-                        }
-                        break;
-                    default:
-                        SkASSERT(false);
-                        fCurrentColorType++;
-                        break;
+                            break;
+                        case kUnpremul_SkAlphaType:
+                        case kPremul_SkAlphaType:
+                            if (0 == fCurrentAlphaType) {
+                                // Test unpremul first.
+                                alphaType = kUnpremul_SkAlphaType;
+                                fCurrentAlphaType++;
+                            } else {
+                                // Test premul.
+                                alphaType = kPremul_SkAlphaType;
+                                fCurrentAlphaType = 0;
+                                fCurrentColorType++;
+                            }
+                            break;
+                        default:
+                            SkASSERT(false);
+                            fCurrentColorType++;
+                            break;
+                    }
                 }
 
                 // Make sure we can decode to this color type and alpha type.
                 SkImageInfo info =
                         codec->getInfo().makeColorType(colorType).makeAlphaType(alphaType);
                 const size_t rowBytes = info.minRowBytes();
                 SkAutoMalloc storage(info.getSafeSize(rowBytes));
 
                 // Used if fCurrentColorType is kIndex_8_SkColorType
                 int colorCount = 256;
@@ skipping 492 matching lines @@
 
     return 0;
 }
 
 #if !defined SK_BUILD_FOR_IOS
 int main(int argc, char** argv) {
     SkCommandLineFlags::Parse(argc, argv);
     return nanobench_main();
 }
 #endif