[libfuzzer] moving icu fuzzers to //third_party/icu, additional fuzzers.

fuzzers/icu_ucasemap_fuzzer.cc

+// Copyright 2016 The Chromium Authors. All rights reserved.
+
+// Fuzzer for ucasemap.
+
+#include <stddef.h>
+#include <stdint.h>
+#include <memory>
+#include "third_party/icu/fuzzers/fuzzer_utils.h"
+#include "third_party/icu/source/common/unicode/ucasemap.h"
+
+IcuEnvironment* env = new IcuEnvironment();
+
+template<typename T>
+using deleted_unique_ptr = std::unique_ptr<T,std::function<void(T*)>>;
+
+
+// Entry point for LibFuzzer.
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  UErrorCode status = U_ZERO_ERROR;
+
+  auto rng = CreateRng(data, size);
+  const icu::Locale& locale = GetRandomLocale(&rng);
+  uint32_t open_flags = static_cast<uint32_t>(rng());
+
+  deleted_unique_ptr<UCaseMap> csm(
+      ucasemap_open(locale.getName(), open_flags, &status),
+      [](UCaseMap* map) { ucasemap_close(map); });
+
+  if (U_FAILURE(status))
+    return 0;
+
+  int32_t dst_size = size * 2;
+  std::unique_ptr<char[]> dst(new char[dst_size]);
+  auto src = reinterpret_cast<const char*>(data);
+
+  switch (rng() % 4) {
+    case 0: ucasemap_utf8ToLower(csm.get(), dst.get(), dst_size, src, size,

[jungshik at Google, 2016/05/19 07:21:54]

This will test how well ucasemap_utf8Foo can deal with invalid UTF-8 input (most
 of input will be invalid UTF-8), but will not test the code path for valid
input strings (much). 

You may as well consider testing ucase_* APIs accepting UTF-16 input
(reintepret_casting |data| to UChar*). 

+                &status);
+            break;
+    case 1: ucasemap_utf8ToUpper(csm.get(), dst.get(), dst_size, src, size,
+                &status);
+            break;
+    case 2: ucasemap_utf8ToTitle(csm.get(), dst.get(), dst_size, src, size,
+                &status);
+            break;
+    case 3: ucasemap_utf8FoldCase(csm.get(), dst.get(), dst_size, src, size,
+                &status);
+            break;
+  }
+
+  return 0;
+}
+