Add LLVM fuzzer: QCMS color space and color transform

third_party/qcms/qcms_color_space_fuzzer.cc

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <cstddef>
+#include <cstdint>
+#include <random>
+
+#include "base/logging.h"
+#include "base/strings/string_piece.h"
+#include "testing/libfuzzer/fuzzers/color_space_data.h"
+#include "third_party/qcms/src/qcms.h"
+
+static constexpr size_t kPixels = 2048 / 4;
+
+static uint32_t pixels[kPixels];
+
+static void GeneratePixels(size_t hash) {
+  static std::uniform_int_distribution<uint32_t> uniform(0u, ~0u);
+
+  std::mt19937_64 random(hash);
+  for (size_t i = 0; i < arraysize(pixels); ++i)
+    pixels[i] = uniform(random);
+}
+
+static qcms_profile* test;
+static qcms_profile* srgb;
+
+static void ColorTransform(bool input) {
+  if (!test)
+    return;
+
+  const qcms_intent intent = QCMS_INTENT_DEFAULT;
+  const qcms_data_type format = QCMS_DATA_RGBA_8;
+
+  auto transform =

[dcheng, 2017/04/12 07:19:23]

Nit: auto*

[Noel Gordon, 2017/04/12 12:09:47]

Done.

+      input ? qcms_transform_create(test, format, srgb, format, intent)
+            : qcms_transform_create(srgb, format, test, format, intent);
+  if (!transform)
+    return;
+
+  static uint32_t output[kPixels];
+
+  qcms_transform_data(transform, pixels, output, kPixels);
+  qcms_transform_release(transform);
+}
+
+static qcms_profile* SelectProfile(size_t hash) {
+  static qcms_profile* profiles[4] = {
+      qcms_profile_from_memory(kSRGBData, arraysize(kSRGBData)),
+      qcms_profile_from_memory(kSRGBPara, arraysize(kSRGBPara)),
+      qcms_profile_from_memory(kAdobeData, arraysize(kAdobeData)),
+      qcms_profile_sRGB(),
+  };
+
+  return profiles[hash & 3];
+}
+
+inline size_t Hash(const char* data, size_t size) {
+  return base::StringPieceHash()(base::StringPiece(data, size));
+}
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  constexpr size_t kSizeLimit = 4 * 1024 * 1024;
+  if (size < 128 || size > kSizeLimit)
+    return 0;
+
+  test = qcms_profile_from_memory(data, size);
+  if (!test)
+    return 0;
+
+  const size_t hash = Hash(reinterpret_cast<const char*>(data), size);

[dcheng, 2017/04/12 07:19:23]

How about just running this through base::SHA1HashBytes?

https://cs.chromium.org/chromium/src/base/sha1.h?rcl=d7eaf476075d774e835fc031...

I don't think there's any guarantee that StringPieceHash is stable over time,
and I could see this theoretically causing issues with reproducibility.

[Noel Gordon, 2017/04/12 12:09:47]

Too slow: need a good and fast hash.
 
OK, used StringPieceHash's hash in-situ, and removed the StringPiece dependency.

[dcheng, 2017/04/12 20:21:10]

Hmm... how about just use one byte of the test input for this then? I think that
would be the simplest of all.

+  srgb = SelectProfile(hash);
+  GeneratePixels(hash);
+
+  qcms_profile_precache_output_transform(srgb);
+  ColorTransform(true);
+
+  qcms_profile_precache_output_transform(test);
+  ColorTransform(false);
+
+  qcms_profile_release(test);
+  return 0;
+}