Copy the relevant parts of ICU to a new file base/third_party/icu/icu_utf.*

so we can do basic UTF8/16/32 conversions without linking all of ICU.

Change callers who used to call SysUTF8ToWide/SysWideToUTF8 in base to using
these new functions. I will remove the Sys versions of these functions in a
later patch.

TEST=none
BUG=none
Review URL: http://codereview.chromium.org/243102

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@28219 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 288 insertions, 0 deletions

diff --git a/base/i18n/icu_string_conversions.cc b/base/i18n/icu_string_conversions.cc
new file mode 100644
index 0000000..225fe0b
--- /dev/null
+++ b/base/i18n/icu_string_conversions.cc
@@ -0,0 +1,288 @@
+// 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/i18n/icu_string_conversions.h"
+
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/logging.h"
+#include "base/string_util.h"
+#include "unicode/ucnv.h"
+#include "unicode/ucnv_cb.h"
+#include "unicode/ucnv_err.h"
+#include "unicode/ustring.h"
+
+namespace {
+
+inline bool IsValidCodepoint(uint32 code_point) {
+  // Excludes the surrogate code points ([0xD800, 0xDFFF]) and
+  // codepoints larger than 0x10FFFF (the highest codepoint allowed).
+  // Non-characters and unassigned codepoints are allowed.
+  return code_point < 0xD800u ||
+         (code_point >= 0xE000u && code_point <= 0x10FFFFu);
+}
+
+// ToUnicodeCallbackSubstitute() is based on UCNV_TO_U_CALLBACK_SUSBSTITUTE
+// in source/common/ucnv_err.c.
+
+// Copyright (c) 1995-2006 International Business Machines Corporation
+// and others
+//
+// All rights reserved.
+//
+
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, and/or
+// sell copies of the Software, and to permit persons to whom the Software
+// is furnished to do so, provided that the above copyright notice(s) and
+// this permission notice appear in all copies of the Software and that
+// both the above copyright notice(s) and this permission notice appear in
+// supporting documentation.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT
+// OF THIRD PARTY RIGHTS. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR HOLDERS
+// INCLUDED IN THIS NOTICE BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL INDIRECT
+// OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
+// OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
+// OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE
+// OR PERFORMANCE OF THIS SOFTWARE.
+//
+// Except as contained in this notice, the name of a copyright holder
+// shall not be used in advertising or otherwise to promote the sale, use
+// or other dealings in this Software without prior written authorization
+// of the copyright holder.
+
+//  ___________________________________________________________________________
+//
+// All trademarks and registered trademarks mentioned herein are the property
+// of their respective owners.
+
+void ToUnicodeCallbackSubstitute(const void* context,
+                                 UConverterToUnicodeArgs *to_args,
+                                 const char* code_units,
+                                 int32_t length,
+                                 UConverterCallbackReason reason,
+                                 UErrorCode * err) {
+  static const UChar kReplacementChar = 0xFFFD;
+  if (reason <= UCNV_IRREGULAR) {
+      if (context == NULL ||
+          (*(reinterpret_cast<const char*>(context)) == 'i' &&
+           reason == UCNV_UNASSIGNED)) {
+        *err = U_ZERO_ERROR;
+        ucnv_cbToUWriteUChars(to_args, &kReplacementChar, 1, 0, err);
+      }
+      // else the caller must have set the error code accordingly.
+  }
+  // else ignore the reset, close and clone calls.
+}
+
+bool ConvertFromUTF16(UConverter* converter, const UChar* uchar_src,
+                      int uchar_len, OnStringUtilConversionError::Type on_error,
+                      std::string* encoded) {
+  int encoded_max_length = UCNV_GET_MAX_BYTES_FOR_STRING(uchar_len,
+      ucnv_getMaxCharSize(converter));
+  encoded->resize(encoded_max_length);
+
+  UErrorCode status = U_ZERO_ERROR;
+
+  // Setup our error handler.
+  switch (on_error) {
+    case OnStringUtilConversionError::FAIL:
+      ucnv_setFromUCallBack(converter, UCNV_FROM_U_CALLBACK_STOP, 0,
+                            NULL, NULL, &status);
+      break;
+    case OnStringUtilConversionError::SKIP:
+    case OnStringUtilConversionError::SUBSTITUTE:
+      ucnv_setFromUCallBack(converter, UCNV_FROM_U_CALLBACK_SKIP, 0,
+                            NULL, NULL, &status);
+      break;
+    default:
+      NOTREACHED();
+  }
+
+  // ucnv_fromUChars returns size not including terminating null
+  int actual_size = ucnv_fromUChars(converter, &(*encoded)[0],
+      encoded_max_length, uchar_src, uchar_len, &status);
+  encoded->resize(actual_size);
+  ucnv_close(converter);
+  if (U_SUCCESS(status))
+    return true;
+  encoded->clear();  // Make sure the output is empty on error.
+  return false;
+}
+
+// Set up our error handler for ToUTF-16 converters
+void SetUpErrorHandlerForToUChars(OnStringUtilConversionError::Type on_error,
+                                  UConverter* converter, UErrorCode* status) {
+  switch (on_error) {
+    case OnStringUtilConversionError::FAIL:
+      ucnv_setToUCallBack(converter, UCNV_TO_U_CALLBACK_STOP, 0,
+                          NULL, NULL, status);
+      break;
+    case OnStringUtilConversionError::SKIP:
+      ucnv_setToUCallBack(converter, UCNV_TO_U_CALLBACK_SKIP, 0,
+                          NULL, NULL, status);
+      break;
+    case OnStringUtilConversionError::SUBSTITUTE:
+      ucnv_setToUCallBack(converter, ToUnicodeCallbackSubstitute, 0,
+                          NULL, NULL, status);
+      break;
+    default:
+      NOTREACHED();
+  }
+}
+
+inline UConverterType utf32_platform_endian() {
+#if U_IS_BIG_ENDIAN
+  return UCNV_UTF32_BigEndian;
+#else
+  return UCNV_UTF32_LittleEndian;
+#endif
+}
+
+}  // namespace
+
+// Codepage <-> Wide/UTF-16  ---------------------------------------------------
+
+// Convert a wstring into the specified codepage_name.  If the codepage
+// isn't found, return false.
+bool WideToCodepage(const std::wstring& wide,
+                    const char* codepage_name,
+                    OnStringUtilConversionError::Type on_error,
+                    std::string* encoded) {
+#if defined(WCHAR_T_IS_UTF16)
+  return UTF16ToCodepage(wide, codepage_name, on_error, encoded);
+#elif defined(WCHAR_T_IS_UTF32)
+  encoded->clear();
+
+  UErrorCode status = U_ZERO_ERROR;
+  UConverter* converter = ucnv_open(codepage_name, &status);
+  if (!U_SUCCESS(status))
+    return false;
+
+  int utf16_len;
+  // When wchar_t is wider than UChar (16 bits), transform |wide| into a
+  // UChar* string.  Size the UChar* buffer to be large enough to hold twice
+  // as many UTF-16 code units (UChar's) as there are Unicode code points,
+  // in case each code points translates to a UTF-16 surrogate pair,
+  // and leave room for a NUL terminator.
+  std::vector<UChar> utf16(wide.length() * 2 + 1);
+  u_strFromWCS(&utf16[0], utf16.size(), &utf16_len,
+               wide.c_str(), wide.length(), &status);
+  DCHECK(U_SUCCESS(status)) << "failed to convert wstring to UChar*";
+
+  return ConvertFromUTF16(converter, &utf16[0], utf16_len, on_error, encoded);
+#endif  // defined(WCHAR_T_IS_UTF32)
+}
+
+// Convert a UTF-16 string into the specified codepage_name.  If the codepage
+// isn't found, return false.
+bool UTF16ToCodepage(const string16& utf16,
+                    const char* codepage_name,
+                    OnStringUtilConversionError::Type on_error,
+                    std::string* encoded) {
+  encoded->clear();
+
+  UErrorCode status = U_ZERO_ERROR;
+  UConverter* converter = ucnv_open(codepage_name, &status);
+  if (!U_SUCCESS(status))
+    return false;
+
+  return ConvertFromUTF16(converter, utf16.c_str(),
+                          static_cast<int>(utf16.length()), on_error, encoded);
+}
+
+// Converts a string of the given codepage into wstring.
+// If the codepage isn't found, return false.
+bool CodepageToWide(const std::string& encoded,
+                    const char* codepage_name,
+                    OnStringUtilConversionError::Type on_error,
+                    std::wstring* wide) {
+#if defined(WCHAR_T_IS_UTF16)
+  return CodepageToUTF16(encoded, codepage_name, on_error, wide);
+#elif defined(WCHAR_T_IS_UTF32)
+  wide->clear();
+
+  UErrorCode status = U_ZERO_ERROR;
+  UConverter* converter = ucnv_open(codepage_name, &status);
+  if (!U_SUCCESS(status))
+    return false;
+
+  // The maximum length in 4 byte unit of UTF-32 output would be
+  // at most the same as the number of bytes in input. In the worst
+  // case of GB18030 (excluding escaped-based encodings like ISO-2022-JP),
+  // this can be 4 times larger than actually needed.
+  size_t wchar_max_length = encoded.length() + 1;
+
+  // The byte buffer and its length to pass to ucnv_toAlgorithimic.
+  char* byte_buffer = reinterpret_cast<char*>(
+      WriteInto(wide, wchar_max_length));
+  int byte_buffer_length = static_cast<int>(wchar_max_length) * 4;
+
+  SetUpErrorHandlerForToUChars(on_error, converter, &status);
+  int actual_size = ucnv_toAlgorithmic(utf32_platform_endian(),
+                                       converter,
+                                       byte_buffer,
+                                       byte_buffer_length,
+                                       encoded.data(),
+                                       static_cast<int>(encoded.length()),
+                                       &status);
+  ucnv_close(converter);
+
+  if (!U_SUCCESS(status)) {
+    wide->clear();  // Make sure the output is empty on error.
+    return false;
+  }
+
+  // actual_size is # of bytes.
+  wide->resize(actual_size / 4);
+  return true;
+#endif  // defined(WCHAR_T_IS_UTF32)
+}
+
+// Converts a string of the given codepage into UTF-16.
+// If the codepage isn't found, return false.
+bool CodepageToUTF16(const std::string& encoded,
+                     const char* codepage_name,
+                     OnStringUtilConversionError::Type on_error,
+                     string16* utf16) {
+  utf16->clear();
+
+  UErrorCode status = U_ZERO_ERROR;
+  UConverter* converter = ucnv_open(codepage_name, &status);
+  if (!U_SUCCESS(status))
+    return false;
+
+  // Even in the worst case, the maximum length in 2-byte units of UTF-16
+  // output would be at most the same as the number of bytes in input. There
+  // is no single-byte encoding in which a character is mapped to a
+  // non-BMP character requiring two 2-byte units.
+  //
+  // Moreover, non-BMP characters in legacy multibyte encodings
+  // (e.g. EUC-JP, GB18030) take at least 2 bytes. The only exceptions are
+  // BOCU and SCSU, but we don't care about them.
+  size_t uchar_max_length = encoded.length() + 1;
+
+  SetUpErrorHandlerForToUChars(on_error, converter, &status);
+  int actual_size = ucnv_toUChars(converter,
+                                  WriteInto(utf16, uchar_max_length),
+                                  static_cast<int>(uchar_max_length),
+                                  encoded.data(),
+                                  static_cast<int>(encoded.length()),
+                                  &status);
+  ucnv_close(converter);
+  if (!U_SUCCESS(status)) {
+    utf16->clear();  // Make sure the output is empty on error.
+    return false;
+  }
+
+  utf16->resize(actual_size);
+  return true;
+}
+