Split *AndAdjustOffset() functions into their own header, to restore utf_string_conversions.h to a simple, readable state.

BUG=4010
TEST=none
Review URL: http://codereview.chromium.org/387012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@31928 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 80 insertions, 0 deletions

diff --git a/base/utf_offset_string_conversions_unittest.cc b/base/utf_offset_string_conversions_unittest.cc
new file mode 100644
index 0000000..00d87d3
--- /dev/null
+++ b/base/utf_offset_string_conversions_unittest.cc
@@ -0,0 +1,80 @@
+// Copyright (c) 2009 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 "base/logging.h"
+#include "base/string_piece.h"
+#include "base/utf_offset_string_conversions.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace base {
+
+namespace {
+
+// Given a null-terminated string of wchar_t with each wchar_t representing
+// a UTF-16 code unit, returns a string16 made up of wchar_t's in the input.
+// Each wchar_t should be <= 0xFFFF and a non-BMP character (> U+FFFF)
+// should be represented as a surrogate pair (two UTF-16 units)
+// *even* where wchar_t is 32-bit (Linux and Mac).
+//
+// This is to help write tests for functions with string16 params until
+// the C++ 0x UTF-16 literal is well-supported by compilers.
+string16 BuildString16(const wchar_t* s) {
+#if defined(WCHAR_T_IS_UTF16)
+  return string16(s);
+#elif defined(WCHAR_T_IS_UTF32)
+  string16 u16;
+  while (*s != 0) {
+    DCHECK(static_cast<unsigned int>(*s) <= 0xFFFFu);
+    u16.push_back(*s++);
+  }
+  return u16;
+#endif
+}
+
+}  // namespace
+
+TEST(UTFOffsetStringConversionsTest, AdjustOffset) {
+  struct UTF8ToWideCase {
+    const char* utf8;
+    size_t input_offset;
+    size_t output_offset;
+  } utf8_to_wide_cases[] = {
+    {"", 0, std::wstring::npos},
+    {"\xe4\xbd\xa0\xe5\xa5\xbd", 1, std::wstring::npos},
+    {"\xe4\xbd\xa0\xe5\xa5\xbd", 3, 1},
+    {"\xed\xb0\x80z", 3, 0},
+    {"A\xF0\x90\x8C\x80z", 1, 1},
+    {"A\xF0\x90\x8C\x80z", 2, std::wstring::npos},
+#if defined(WCHAR_T_IS_UTF16)
+    {"A\xF0\x90\x8C\x80z", 5, 3},
+#elif defined(WCHAR_T_IS_UTF32)
+    {"A\xF0\x90\x8C\x80z", 5, 2},
+#endif
+  };
+  for (size_t i = 0; i < ARRAYSIZE_UNSAFE(utf8_to_wide_cases); ++i) {
+    size_t offset = utf8_to_wide_cases[i].input_offset;
+    UTF8ToWideAndAdjustOffset(utf8_to_wide_cases[i].utf8, &offset);
+    EXPECT_EQ(utf8_to_wide_cases[i].output_offset, offset);
+  }
+
+#if defined(WCHAR_T_IS_UTF32)
+  struct UTF16ToWideCase {
+    const wchar_t* wide;
+    size_t input_offset;
+    size_t output_offset;
+  } utf16_to_wide_cases[] = {
+    {L"\xD840\xDC00\x4E00", 0, 0},
+    {L"\xD840\xDC00\x4E00", 1, std::wstring::npos},
+    {L"\xD840\xDC00\x4E00", 2, 1},
+  };
+  for (size_t i = 0; i < ARRAYSIZE_UNSAFE(utf16_to_wide_cases); ++i) {
+    size_t offset = utf16_to_wide_cases[i].input_offset;
+    UTF16ToWideAndAdjustOffset(BuildString16(utf16_to_wide_cases[i].wide),
+                               &offset);
+    EXPECT_EQ(utf16_to_wide_cases[i].output_offset, offset);
+  }
+#endif
+}
+
+}  // namaspace base