import fuzzers from oss-fuzz/chromium

+ a simple makefile + README

these were mostly equivalent, chromium added support for
WEBP_REDUCE_CSP.

the file names were normalized as follows:

fuzz_advanced_api.{c,cc} -> advanced_api_fuzzer.c
fuzz_animation_api.{c,cc} -> animation_api_fuzzer.c
fuzz_webp_animencoder.cc -> animencoder_fuzzer.cc
fuzz_demux_api.{c,cc} -> demux_api_fuzzer.c
fuzz_webp_enc_dec.cc -> enc_dec_fuzzer.cc
fuzz.h -> fuzz_utils.h
fuzz_simple_api.{c,cc} -> simple_api_fuzzer.c

Bug: webp:409
Change-Id: Ib997f0c92f25f8a1f91da83790298cd848b61a5d

tests/fuzzer/enc_dec_fuzzer.cc

@@ -0,0 +1,134 @@
+// 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 <stdio.h>
+#include <stdlib.h>
+
+#include "./fuzz_utils.h"
+#include "webp/decode.h"
+#include "webp/encode.h"
+
+namespace {
+
+const VP8CPUInfo default_VP8GetCPUInfo = VP8GetCPUInfo;
+
+}  // namespace
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* const data, size_t size) {
+  uint32_t bit_pos = 0;
+
+  ExtractAndDisableOptimizations(default_VP8GetCPUInfo, data, size, &bit_pos);
+
+  // Init the source picture.
+  WebPPicture pic;
+  if (!WebPPictureInit(&pic)) {
+    fprintf(stderr, "WebPPictureInit failed.\n");
+    abort();
+  }
+  pic.use_argb = Extract(1, data, size, &bit_pos);
+
+  // Read the source picture.
+  if (!ExtractSourcePicture(&pic, data, size, &bit_pos)) {
+    fprintf(stderr, "Can't read input image.\n");
+    WebPPictureFree(&pic);
+    abort();
+  }
+
+  // Crop and scale.
+  if (!ExtractAndCropOrScale(&pic, data, size, &bit_pos)) {
+    fprintf(stderr, "ExtractAndCropOrScale failed.");
+    WebPPictureFree(&pic);
+    abort();
+  }
+
+  // Extract a configuration from the packed bits.
+  WebPConfig config;
+  if (!ExtractWebPConfig(&config, data, size, &bit_pos)) {
+    fprintf(stderr, "ExtractWebPConfig failed.\n");
+    abort();
+  }
+  // Skip slow settings on big images, it's likely to timeout.
+  if (pic.width * pic.height > 32 * 32) {
+    if (config.lossless) {
+      if (config.quality > 99.0f && config.method >= 5) {
+        config.quality = 99.0f;
+        config.method = 5;
+      }
+    } else {
+      if (config.quality > 99.0f && config.method == 6) {
+        config.quality = 99.0f;
+      }
+    }
+    if (config.alpha_quality == 100 && config.method == 6) {
+      config.alpha_quality = 99;
+    }
+  }
+
+  // Encode.
+  WebPMemoryWriter memory_writer;
+  WebPMemoryWriterInit(&memory_writer);
+  pic.writer = WebPMemoryWrite;
+  pic.custom_ptr = &memory_writer;
+  if (!WebPEncode(&config, &pic)) {
+    fprintf(stderr, "WebPEncode failed. Error code: %d\n", pic.error_code);
+    WebPMemoryWriterClear(&memory_writer);
+    WebPPictureFree(&pic);
+    abort();
+  }
+
+  // Try decoding the result.
+  int w, h;
+  const uint8_t* const out_data = memory_writer.mem;
+  const size_t out_size = memory_writer.size;
+  uint8_t* const rgba = WebPDecodeBGRA(out_data, out_size, &w, &h);
+  if (rgba == nullptr || w != pic.width || h != pic.height) {
+    fprintf(stderr, "WebPDecodeBGRA failed.\n");
+    WebPFree(rgba);
+    WebPMemoryWriterClear(&memory_writer);
+    WebPPictureFree(&pic);
+    abort();
+  }
+
+  // Compare the results if exact encoding.
+  if (pic.use_argb && config.lossless && config.near_lossless == 100) {
+    const uint32_t* src1 = (const uint32_t*)rgba;
+    const uint32_t* src2 = pic.argb;
+    for (int y = 0; y < h; ++y, src1 += w, src2 += pic.argb_stride) {
+      for (int x = 0; x < w; ++x) {
+        uint32_t v1 = src1[x], v2 = src2[x];
+        if (!config.exact) {
+          if ((v1 & 0xff000000u) == 0 || (v2 & 0xff000000u) == 0) {
+            // Only keep alpha for comparison of fully transparent area.
+            v1 &= 0xff000000u;
+            v2 &= 0xff000000u;
+          }
+        }
+        if (v1 != v2) {
+          fprintf(stderr, "Lossless compression failed pixel-exactness.\n");
+          WebPFree(rgba);
+          WebPMemoryWriterClear(&memory_writer);
+          WebPPictureFree(&pic);
+          abort();
+        }
+      }
+    }
+  }
+
+  WebPFree(rgba);
+  WebPMemoryWriterClear(&memory_writer);
+  WebPPictureFree(&pic);
+  return 0;
+}