fuzzer for third_party icu::UnicodeString::UnicodeString (invokes doCodepageCreate) implemented

testing/libfuzzer/fuzzers/unicode_string_codepage_create_fuzzer.cc

Index: testing/libfuzzer/fuzzers/unicode_string_codepage_create_fuzzer.cc
diff --git a/testing/libfuzzer/fuzzers/unicode_string_codepage_create_fuzzer.cc b/testing/libfuzzer/fuzzers/unicode_string_codepage_create_fuzzer.cc
new file mode 100644
index 0000000000000000000000000000000000000000..08806f2bf826bf413a19d2abe49075626f1ec6ad
--- /dev/null
+++ b/testing/libfuzzer/fuzzers/unicode_string_codepage_create_fuzzer.cc
@@ -0,0 +1,97 @@
+// Copyright (c) 2015 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 <algorithm>
+#include <array>
+#include <vector>
+
+#include "third_party/icu/source/common/unicode/unistr.h"
+
+// Taken from third_party/icu/source/data/mappings/convrtrs.txt file.
+static const std::array<const char*, 45> kConverters = {
+  {
+    "UTF-8",
+    "utf-16be",
+    "utf-16le",
+    "UTF-32",
+    "UTF-32BE",
+    "UTF-32LE",
+    "ibm866-html",
+    "iso-8859-2-html",
+    "iso-8859-3-html",
+    "iso-8859-4-html",
+    "iso-8859-5-html",
+    "iso-8859-6-html",
+    "iso-8859-7-html",
+    "iso-8859-8-html",
+    "ISO-8859-8-I",
+    "iso-8859-10-html",
+    "iso-8859-13-html",
+    "iso-8859-14-html",
+    "iso-8859-15-html",
+    "iso-8859-16-html",
+    "koi8-r-html",
+    "koi8-u-html",
+    "macintosh-html",
+    "windows-874-html",
+    "windows-1250-html",
+    "windows-1251-html",
+    "windows-1252-html",
+    "windows-1253-html",
+    "windows-1254-html",
+    "windows-1255-html",
+    "windows-1256-html",
+    "windows-1257-html",
+    "windows-1258-html",
+    "x-mac-cyrillic-html",
+    "windows-936-2000",
+    "gb18030",
+    "big5-html",
+    "euc-jp-html",
+    "ISO_2022,locale=ja,version=0",
+    "shift_jis-html",
+    "euc-kr-html",
+    "ISO-2022-KR",
+    "ISO-2022-CN",
+    "ISO-2022-CN-EXT",
+    "HZ-GB-2312"
+  }
+};
+
+// Entry point for LibFuzzer.
+extern "C" int LLVMFuzzerTestOneInput(const unsigned char *data, size_t size) {
+  if (size < 2)
+    return 0;
+
+  // Need null-terminated string.
+  std::vector<char> buffer(size, 0);
+  // First byte will be used for random decisions.
+  unsigned char selector = data[0];
+  size -= 1;
+  std::copy(data + 1, data + size, buffer.data());
+
+  // Pointer to a part of fuzzer's data or to some valid codepage value.
+  char* codepage;
+
+  if (selector & 1) {
+    // Use random codepage value provided by fuzzer (split data in two parts).
+    // Remove least significant bit because we already used it as input value.
+    size_t codepage_length = (selector >> 1) & 0xF;
+    if (size <= codepage_length)
+      size /= 2;
+    else
+      size -= codepage_length;
+
+    codepage = buffer.data() + size;
+  } else {
+    // Use one of valid codepage values.
+    // Remove least significant bit because we already used it as input value.
+    size_t index = (selector >> 1) % kConverters.size();
+    codepage = const_cast<char*>(kConverters[index]);
+  }
+
+  icu::UnicodeString unicode_string(buffer.data(), size, codepage);
+
+  return 0;
+}