Switch public fuzz tests to fuzztest.

Change-Id: I75afb65058690585bbf2671c27d6a99a87bcaab7

tests/fuzzer/advanced_api_fuzzer.cc

@@ -0,0 +1,167 @@
+// Copyright 2018 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+////////////////////////////////////////////////////////////////////////////////
+
+#include <algorithm>
+#include <cstddef>
+#include <cstdint>
+#include <string_view>
+
+#include "./fuzz_utils.h"
+#include "src/utils/rescaler_utils.h"
+#include "src/webp/decode.h"
+
+namespace {
+
+void AdvancedApiTest(std::string_view blob, uint8_t factor_u8, bool flip,
+                     bool bypass_filtering, bool no_fancy_upsampling,
+                     bool use_threads, bool use_cropping, bool use_scaling,
+                     bool use_dithering, int colorspace, bool incremental) {
+  WebPDecoderConfig config;
+  if (!WebPInitDecoderConfig(&config)) return;
+  const uint8_t* const data = reinterpret_cast<const uint8_t*>(blob.data());
+  const size_t size = blob.size();
+  if (WebPGetFeatures(data, size, &config.input) != VP8_STATUS_OK) return;
+  if ((size_t)config.input.width * config.input.height >
+      fuzz_utils::kFuzzPxLimit) {
+    return;
+  }
+
+  // Using two independent criteria ensures that all combinations of options
+  // can reach each path at the decoding stage, with meaningful differences.
+
+  const uint8_t value = fuzz_utils::FuzzHash(data, size);
+  const float factor = factor_u8 / 255.f;  // 0-1
+
+  config.options.flip = flip;
+  config.options.bypass_filtering = bypass_filtering;
+  config.options.no_fancy_upsampling = no_fancy_upsampling;
+  config.options.use_threads = use_threads;
+  if (use_cropping) {
+    config.options.use_cropping = 1;
+    config.options.crop_width = (int)(config.input.width * (1 - factor));
+    config.options.crop_height = (int)(config.input.height * (1 - factor));
+    config.options.crop_left = config.input.width - config.options.crop_width;
+    config.options.crop_top = config.input.height - config.options.crop_height;
+  }
+  if (use_dithering) {
+    int strength = (int)(factor * 100);
+    config.options.dithering_strength = strength;
+    config.options.alpha_dithering_strength = 100 - strength;
+  }
+  if (use_scaling) {
+    config.options.use_scaling = 1;
+    config.options.scaled_width = (int)(config.input.width * factor * 2);
+    config.options.scaled_height = (int)(config.input.height * factor * 2);
+  }
+  config.output.colorspace = static_cast<WEBP_CSP_MODE>(colorspace);
+
+  for (int i = 0; i < 2; ++i) {
+    if (i == 1) {
+      // Use the bitstream data to generate extreme ranges for the options. An
+      // alternative approach would be to use a custom corpus containing webp
+      // files prepended with sizeof(config.options) zeroes to allow the fuzzer
+      // to modify these independently.
+      const int data_offset = 50;
+      if (data_offset + sizeof(config.options) >= size) break;
+      memcpy(&config.options, data + data_offset, sizeof(config.options));
+
+      // Skip easily avoidable out-of-memory fuzzing errors.
+      if (config.options.use_scaling) {
+        int scaled_width = config.options.scaled_width;
+        int scaled_height = config.options.scaled_height;
+        if (WebPRescalerGetScaledDimensions(config.input.width,
+                                            config.input.height, &scaled_width,
+                                            &scaled_height)) {
+          size_t fuzz_px_limit = fuzz_utils::kFuzzPxLimit;
+          if (scaled_width != config.input.width ||
+              scaled_height != config.input.height) {
+            // Using the WebPRescalerImport internally can significantly slow
+            // down the execution. Avoid timeouts due to that.
+            fuzz_px_limit /= 2;
+          }
+          // A big output canvas can lead to out-of-memory and timeout issues,
+          // but a big internal working buffer can too. Also, rescaling from a
+          // very wide input image to a very tall canvas can be as slow as
+          // decoding a huge number of pixels. Avoid timeouts due to these.
+          const uint64_t max_num_operations =
+              (uint64_t)std::max(scaled_width, config.input.width) *
+              std::max(scaled_height, config.input.height);
+          if (max_num_operations > fuzz_px_limit) {
+            break;
+          }
+        }
+      }
+    }
+    if (incremental) {
+      // Decodes incrementally in chunks of increasing size.
+      WebPIDecoder* idec = WebPIDecode(NULL, 0, &config);
+      if (!idec) return;
+      VP8StatusCode status;
+      if (size & 8) {
+        size_t available_size = value + 1;
+        while (1) {
+          if (available_size > size) available_size = size;
+          status = WebPIUpdate(idec, data, available_size);
+          if (status != VP8_STATUS_SUSPENDED || available_size == size) break;
+          available_size *= 2;
+        }
+      } else {
+        // WebPIAppend expects new data and its size with each call.
+        // Implemented here by simply advancing the pointer into data.
+        const uint8_t* new_data = data;
+        size_t new_size = value + 1;
+        while (1) {
+          if (new_data + new_size > data + size) {
+            new_size = data + size - new_data;
+          }
+          status = WebPIAppend(idec, new_data, new_size);
+          if (status != VP8_STATUS_SUSPENDED || new_size == 0) break;
+          new_data += new_size;
+          new_size *= 2;
+        }
+      }
+      WebPIDelete(idec);
+    } else {
+      (void)WebPDecode(data, size, &config);
+    }
+
+    WebPFreeDecBuffer(&config.output);
+  }
+}
+
+}  // namespace
+
+FUZZ_TEST(AdvancedApi, AdvancedApiTest)
+    .WithDomains(
+        fuzztest::String()
+            .WithMaxSize(fuzz_utils::kMaxWebPFileSize + 1),
+        /*factor_u8=*/fuzztest::Arbitrary<uint8_t>(),
+        /*flip=*/fuzztest::Arbitrary<bool>(),
+        /*bypass_filtering=*/fuzztest::Arbitrary<bool>(),
+        /*no_fancy_upsampling=*/fuzztest::Arbitrary<bool>(),
+        /*use_threads=*/fuzztest::Arbitrary<bool>(),
+        /*use_cropping=*/fuzztest::Arbitrary<bool>(),
+        /*use_scaling=*/fuzztest::Arbitrary<bool>(),
+        /*use_dithering=*/fuzztest::Arbitrary<bool>(),
+#if defined(WEBP_REDUCE_CSP)
+        fuzztest::ElementOf<int>({static_cast<int>(MODE_RGBA),
+                                  static_cast<int>(MODE_BGRA),
+                                  static_cast<int>(MODE_rgbA),
+                                  static_cast<int>(MODE_bgrA)}),
+#else
+        fuzztest::InRange<int>(0, static_cast<int>(MODE_LAST) - 1),
+#endif
+        /*incremental=*/fuzztest::Arbitrary<bool>());