base/utf_string_conversions.cc - platform/external/libchrome - Gitiles

 // 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/utf_string_conversions.h"

 #include <vector>

 #include "base/basictypes.h"
 #include "base/logging.h"
 #include "base/string_util.h"
 #include "base/third_party/icu/icu_utf.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);
 }

 // ReadUnicodeCharacter --------------------------------------------------------

 // Reads a UTF-8 stream, placing the next code point into the given output
 // |*code_point|. |src| represents the entire string to read, and |*char_index|
 // is the character offset within the string to start reading at. |*char_index|
 // will be updated to index the last character read, such that incrementing it
 // (as in a for loop) will take the reader to the next character.
 //
 // Returns true on success. On false, |*code_point| will be invalid.
 bool ReadUnicodeCharacter(const char* src, int32 src_len,
                           int32* char_index, uint32* code_point_out) {
   // U8_NEXT expects to be able to use -1 to signal an error, so we must
   // use a signed type for code_point.  But this function returns false
   // on error anyway, so code_point_out is unsigned.
   int32 code_point;
   CBU8_NEXT(src, *char_index, src_len, code_point);
   *code_point_out = static_cast<uint32>(code_point);

   // The ICU macro above moves to the next char, we want to point to the last
   // char consumed.
   (*char_index)--;

   // Validate the decoded value.
   return IsValidCodepoint(code_point);
 }

 // Reads a UTF-16 character. The usage is the same as the 8-bit version above.
 bool ReadUnicodeCharacter(const char16* src, int32 src_len,
                           int32* char_index, uint32* code_point) {
   if (CBU16_IS_SURROGATE(src[*char_index])) {
     if (!CBU16_IS_SURROGATE_LEAD(src[*char_index]) ||
         *char_index + 1 >= src_len ||
         !CBU16_IS_TRAIL(src[*char_index + 1])) {
       // Invalid surrogate pair.
       return false;
     }

     // Valid surrogate pair.
     *code_point = CBU16_GET_SUPPLEMENTARY(src[*char_index],
                                           src[*char_index + 1]);
     (*char_index)++;
   } else {
     // Not a surrogate, just one 16-bit word.
     *code_point = src[*char_index];
   }

   return IsValidCodepoint(*code_point);
 }

 #if defined(WCHAR_T_IS_UTF32)
 // Reads UTF-32 character. The usage is the same as the 8-bit version above.
 bool ReadUnicodeCharacter(const wchar_t* src, int32 src_len,
                           int32* char_index, uint32* code_point) {
   // Conversion is easy since the source is 32-bit.
   *code_point = src[*char_index];

   // Validate the value.
   return IsValidCodepoint(*code_point);
 }
 #endif  // defined(WCHAR_T_IS_UTF32)

 // WriteUnicodeCharacter -------------------------------------------------------

 // Appends a UTF-8 character to the given 8-bit string.  Returns the number of
 // bytes written.
 size_t WriteUnicodeCharacter(uint32 code_point, std::string* output) {
   if (code_point <= 0x7f) {
     // Fast path the common case of one byte.
     output->push_back(code_point);
     return 1;
   }

   // CBU8_APPEND_UNSAFE can append up to 4 bytes.
   size_t char_offset = output->length();
   size_t original_char_offset = char_offset;
   output->resize(char_offset + CBU8_MAX_LENGTH);

   CBU8_APPEND_UNSAFE(&(*output)[0], char_offset, code_point);

   // CBU8_APPEND_UNSAFE will advance our pointer past the inserted character, so
   // it will represent the new length of the string.
   output->resize(char_offset);
   return char_offset - original_char_offset;
 }

 // Appends the given code point as a UTF-16 character to the given 16-bit
 // string.  Returns the number of 16-bit values written.
 size_t WriteUnicodeCharacter(uint32 code_point, string16* output) {
   if (CBU16_LENGTH(code_point) == 1) {
     // Thie code point is in the Basic Multilingual Plane (BMP).
     output->push_back(static_cast<char16>(code_point));
     return 1;
   }
   // Non-BMP characters use a double-character encoding.
   size_t char_offset = output->length();
   output->resize(char_offset + CBU16_MAX_LENGTH);
   CBU16_APPEND_UNSAFE(&(*output)[0], char_offset, code_point);
   return CBU16_MAX_LENGTH;
 }

 #if defined(WCHAR_T_IS_UTF32)
 // Appends the given UTF-32 character to the given 32-bit string.  Returns the
 // number of 32-bit values written.
 inline size_t WriteUnicodeCharacter(uint32 code_point, std::wstring* output) {
   // This is the easy case, just append the character.
   output->push_back(code_point);
   return 1;
 }
 #endif  // defined(WCHAR_T_IS_UTF32)

 // Generalized Unicode converter -----------------------------------------------

 // Converts the given source Unicode character type to the given destination
 // Unicode character type as a STL string. The given input buffer and size
 // determine the source, and the given output STL string will be replaced by
 // the result.
 template<typename SRC_CHAR, typename DEST_STRING>
 bool ConvertUnicode(const SRC_CHAR* src,
                     size_t src_len,
                     DEST_STRING* output,
                     size_t* offset_for_adjustment) {
   size_t output_offset =
       (offset_for_adjustment && *offset_for_adjustment < src_len) ?
           *offset_for_adjustment : DEST_STRING::npos;

   // ICU requires 32-bit numbers.
   bool success = true;
   int32 src_len32 = static_cast<int32>(src_len);
   for (int32 i = 0; i < src_len32; i++) {
     uint32 code_point;
     size_t original_i = i;
     size_t chars_written = 0;
     if (ReadUnicodeCharacter(src, src_len32, &i, &code_point)) {
       chars_written = WriteUnicodeCharacter(code_point, output);
     } else {
       // TODO(jungshik): consider adding 'Replacement character' (U+FFFD)
       // in place of an invalid codepoint.
       success = false;
     }
     if ((output_offset != DEST_STRING::npos) &&
         (*offset_for_adjustment > original_i)) {
       // NOTE: ReadUnicodeCharacter() adjusts |i| to point _at_ the last
       // character read, not after it (so that incrementing it in the loop
       // increment will place it at the right location), so we need to account
       // for that in determining the amount that was read.
       if (*offset_for_adjustment <= static_cast<size_t>(i))
         output_offset = DEST_STRING::npos;
       else
         output_offset += chars_written - (i - original_i + 1);
     }
   }

   if (offset_for_adjustment)
     *offset_for_adjustment = output_offset;
   return success;
 }

 // Guesses the length of the output in UTF-8 in bytes, clears that output
 // string, and reserves that amount of space.  We assume that the input
 // character types are unsigned, which will be true for UTF-16 and -32 on our
 // systems.
 template<typename CHAR>
 void PrepareForUTF8Output(const CHAR* src,
                           size_t src_len,
                           std::string* output) {
   output->clear();
   if (src_len == 0)
     return;
   if (src[0] < 0x80) {
     // Assume that the entire input will be ASCII.
     output->reserve(src_len);
   } else {
     // Assume that the entire input is non-ASCII and will have 3 bytes per char.
     output->reserve(src_len * 3);
   }
 }

 // Prepares an output buffer (containing either UTF-16 or -32 data) given some
 // UTF-8 input that will be converted to it.  See PrepareForUTF8Output().
 template<typename STRING>
 void PrepareForUTF16Or32Output(const char* src,
                                size_t src_len,
                                STRING* output) {
   output->clear();
   if (src_len == 0)
     return;
   if (static_cast<unsigned char>(src[0]) < 0x80) {
     // Assume the input is all ASCII, which means 1:1 correspondence.
     output->reserve(src_len);
   } else {
     // Otherwise assume that the UTF-8 sequences will have 2 bytes for each
     // character.
     output->reserve(src_len / 2);
   }
 }

 }  // namespace

 // UTF-8 <-> Wide --------------------------------------------------------------

 bool WideToUTF8(const wchar_t* src, size_t src_len, std::string* output) {
   PrepareForUTF8Output(src, src_len, output);
   return ConvertUnicode<wchar_t, std::string>(src, src_len, output, NULL);
 }

 std::string WideToUTF8(const std::wstring& wide) {
   std::string ret;
   // Ignore the success flag of this call, it will do the best it can for
   // invalid input, which is what we want here.
   WideToUTF8(wide.data(), wide.length(), &ret);
   return ret;
 }

 bool UTF8ToWideAndAdjustOffset(const char* src,
                                size_t src_len,
                                std::wstring* output,
                                size_t* offset_for_adjustment) {
   PrepareForUTF16Or32Output(src, src_len, output);
   return ConvertUnicode<char, std::wstring>(src, src_len, output,
                                             offset_for_adjustment);
 }

 std::wstring UTF8ToWideAndAdjustOffset(const base::StringPiece& utf8,
                                        size_t* offset_for_adjustment) {
   std::wstring ret;
   UTF8ToWideAndAdjustOffset(utf8.data(), utf8.length(), &ret,
                             offset_for_adjustment);
   return ret;
 }

 // UTF-16 <-> Wide -------------------------------------------------------------

 #if defined(WCHAR_T_IS_UTF16)

 // When wide == UTF-16, then conversions are a NOP.
 bool WideToUTF16(const wchar_t* src, size_t src_len, string16* output) {
   output->assign(src, src_len);
   return true;
 }

 string16 WideToUTF16(const std::wstring& wide) {
   return wide;
 }

 bool UTF16ToWideAndAdjustOffset(const char16* src,
                                 size_t src_len,
                                 std::wstring* output,
                                 size_t* offset_for_adjustment) {
   output->assign(src, src_len);
   if (offset_for_adjustment && (*offset_for_adjustment >= src_len))
     *offset_for_adjustment = std::wstring::npos;
   return true;
 }

 std::wstring UTF16ToWideAndAdjustOffset(const string16& utf16,
                                         size_t* offset_for_adjustment) {
   if (offset_for_adjustment && (*offset_for_adjustment >= utf16.length()))
     *offset_for_adjustment = std::wstring::npos;
   return utf16;
 }

 #elif defined(WCHAR_T_IS_UTF32)

 bool WideToUTF16(const wchar_t* src, size_t src_len, string16* output) {
   output->clear();
   // Assume that normally we won't have any non-BMP characters so the counts
   // will be the same.
   output->reserve(src_len);
   return ConvertUnicode<wchar_t, string16>(src, src_len, output, NULL);
 }

 string16 WideToUTF16(const std::wstring& wide) {
   string16 ret;
   WideToUTF16(wide.data(), wide.length(), &ret);
   return ret;
 }

 bool UTF16ToWideAndAdjustOffset(const char16* src,
                                 size_t src_len,
                                 std::wstring* output,
                                 size_t* offset_for_adjustment) {
   output->clear();
   // Assume that normally we won't have any non-BMP characters so the counts
   // will be the same.
   output->reserve(src_len);
   return ConvertUnicode<char16, std::wstring>(src, src_len, output,
                                               offset_for_adjustment);
 }

 std::wstring UTF16ToWideAndAdjustOffset(const string16& utf16,
                                         size_t* offset_for_adjustment) {
   std::wstring ret;
   UTF16ToWideAndAdjustOffset(utf16.data(), utf16.length(), &ret,
                              offset_for_adjustment);
   return ret;
 }

 #endif  // defined(WCHAR_T_IS_UTF32)

 // UTF16 <-> UTF8 --------------------------------------------------------------

 #if defined(WCHAR_T_IS_UTF32)

 bool UTF8ToUTF16(const char* src, size_t src_len, string16* output) {
   PrepareForUTF16Or32Output(src, src_len, output);
   return ConvertUnicode<char, string16>(src, src_len, output, NULL);
 }

 string16 UTF8ToUTF16(const std::string& utf8) {
   string16 ret;
   // Ignore the success flag of this call, it will do the best it can for
   // invalid input, which is what we want here.
   UTF8ToUTF16(utf8.data(), utf8.length(), &ret);
   return ret;
 }

 bool UTF16ToUTF8(const char16* src, size_t src_len, std::string* output) {
   PrepareForUTF8Output(src, src_len, output);
   return ConvertUnicode<char16, std::string>(src, src_len, output, NULL);
 }

 std::string UTF16ToUTF8(const string16& utf16) {
   std::string ret;
   // Ignore the success flag of this call, it will do the best it can for
   // invalid input, which is what we want here.
   UTF16ToUTF8(utf16.data(), utf16.length(), &ret);
   return ret;
 }

 #elif defined(WCHAR_T_IS_UTF16)
 // Easy case since we can use the "wide" versions we already wrote above.

 bool UTF8ToUTF16(const char* src, size_t src_len, string16* output) {
   return UTF8ToWide(src, src_len, output);
 }

 string16 UTF8ToUTF16(const std::string& utf8) {
   return UTF8ToWide(utf8);
 }

 bool UTF16ToUTF8(const char16* src, size_t src_len, std::string* output) {
   return WideToUTF8(src, src_len, output);
 }

 std::string UTF16ToUTF8(const string16& utf16) {
   return WideToUTF8(utf16);
 }

 #endif
	// 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/utf_string_conversions.h"

	#include <vector>

	#include "base/basictypes.h"
	#include "base/logging.h"
	#include "base/string_util.h"
	#include "base/third_party/icu/icu_utf.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);
	}

	// ReadUnicodeCharacter --------------------------------------------------------

	// Reads a UTF-8 stream, placing the next code point into the given output
	// \|code_point\|. \|src\| represents the entire string to read, and \|char_index\|
	// is the character offset within the string to start reading at. \|*char_index\|
	// will be updated to index the last character read, such that incrementing it
	// (as in a for loop) will take the reader to the next character.
	//
	// Returns true on success. On false, \|*code_point\| will be invalid.
	bool ReadUnicodeCharacter(const char* src, int32 src_len,
	int32* char_index, uint32* code_point_out) {
	// U8_NEXT expects to be able to use -1 to signal an error, so we must
	// use a signed type for code_point. But this function returns false
	// on error anyway, so code_point_out is unsigned.
	int32 code_point;
	CBU8_NEXT(src, *char_index, src_len, code_point);
	*code_point_out = static_cast<uint32>(code_point);

	// The ICU macro above moves to the next char, we want to point to the last
	// char consumed.
	(*char_index)--;

	// Validate the decoded value.
	return IsValidCodepoint(code_point);
	}

	// Reads a UTF-16 character. The usage is the same as the 8-bit version above.
	bool ReadUnicodeCharacter(const char16* src, int32 src_len,
	int32* char_index, uint32* code_point) {
	if (CBU16_IS_SURROGATE(src[*char_index])) {
	if (!CBU16_IS_SURROGATE_LEAD(src[*char_index]) \|\|
	*char_index + 1 >= src_len \|\|
	!CBU16_IS_TRAIL(src[*char_index + 1])) {
	// Invalid surrogate pair.
	return false;
	}

	// Valid surrogate pair.
	code_point = CBU16_GET_SUPPLEMENTARY(src[char_index],
	src[*char_index + 1]);
	(*char_index)++;
	} else {
	// Not a surrogate, just one 16-bit word.
	code_point = src[char_index];
	}

	return IsValidCodepoint(*code_point);
	}

	#if defined(WCHAR_T_IS_UTF32)
	// Reads UTF-32 character. The usage is the same as the 8-bit version above.
	bool ReadUnicodeCharacter(const wchar_t* src, int32 src_len,
	int32* char_index, uint32* code_point) {
	// Conversion is easy since the source is 32-bit.
	code_point = src[char_index];

	// Validate the value.
	return IsValidCodepoint(*code_point);
	}
	#endif // defined(WCHAR_T_IS_UTF32)

	// WriteUnicodeCharacter -------------------------------------------------------

	// Appends a UTF-8 character to the given 8-bit string. Returns the number of
	// bytes written.
	size_t WriteUnicodeCharacter(uint32 code_point, std::string* output) {
	if (code_point <= 0x7f) {
	// Fast path the common case of one byte.
	output->push_back(code_point);
	return 1;
	}

	// CBU8_APPEND_UNSAFE can append up to 4 bytes.
	size_t char_offset = output->length();
	size_t original_char_offset = char_offset;
	output->resize(char_offset + CBU8_MAX_LENGTH);

	CBU8_APPEND_UNSAFE(&(*output)[0], char_offset, code_point);

	// CBU8_APPEND_UNSAFE will advance our pointer past the inserted character, so
	// it will represent the new length of the string.
	output->resize(char_offset);
	return char_offset - original_char_offset;
	}

	// Appends the given code point as a UTF-16 character to the given 16-bit
	// string. Returns the number of 16-bit values written.
	size_t WriteUnicodeCharacter(uint32 code_point, string16* output) {
	if (CBU16_LENGTH(code_point) == 1) {
	// Thie code point is in the Basic Multilingual Plane (BMP).
	output->push_back(static_cast<char16>(code_point));
	return 1;
	}
	// Non-BMP characters use a double-character encoding.
	size_t char_offset = output->length();
	output->resize(char_offset + CBU16_MAX_LENGTH);
	CBU16_APPEND_UNSAFE(&(*output)[0], char_offset, code_point);
	return CBU16_MAX_LENGTH;
	}

	#if defined(WCHAR_T_IS_UTF32)
	// Appends the given UTF-32 character to the given 32-bit string. Returns the
	// number of 32-bit values written.
	inline size_t WriteUnicodeCharacter(uint32 code_point, std::wstring* output) {
	// This is the easy case, just append the character.
	output->push_back(code_point);
	return 1;
	}
	#endif // defined(WCHAR_T_IS_UTF32)

	// Generalized Unicode converter -----------------------------------------------

	// Converts the given source Unicode character type to the given destination
	// Unicode character type as a STL string. The given input buffer and size
	// determine the source, and the given output STL string will be replaced by
	// the result.
	template<typename SRC_CHAR, typename DEST_STRING>
	bool ConvertUnicode(const SRC_CHAR* src,
	size_t src_len,
	DEST_STRING* output,
	size_t* offset_for_adjustment) {
	size_t output_offset =
	(offset_for_adjustment && *offset_for_adjustment < src_len) ?
	*offset_for_adjustment : DEST_STRING::npos;

	// ICU requires 32-bit numbers.
	bool success = true;
	int32 src_len32 = static_cast<int32>(src_len);
	for (int32 i = 0; i < src_len32; i++) {
	uint32 code_point;
	size_t original_i = i;
	size_t chars_written = 0;
	if (ReadUnicodeCharacter(src, src_len32, &i, &code_point)) {
	chars_written = WriteUnicodeCharacter(code_point, output);
	} else {
	// TODO(jungshik): consider adding 'Replacement character' (U+FFFD)
	// in place of an invalid codepoint.
	success = false;
	}
	if ((output_offset != DEST_STRING::npos) &&
	(*offset_for_adjustment > original_i)) {
	// NOTE: ReadUnicodeCharacter() adjusts \|i\| to point _at_ the last
	// character read, not after it (so that incrementing it in the loop
	// increment will place it at the right location), so we need to account
	// for that in determining the amount that was read.
	if (*offset_for_adjustment <= static_cast<size_t>(i))
	output_offset = DEST_STRING::npos;
	else
	output_offset += chars_written - (i - original_i + 1);
	}
	}

	if (offset_for_adjustment)
	*offset_for_adjustment = output_offset;
	return success;
	}

	// Guesses the length of the output in UTF-8 in bytes, clears that output
	// string, and reserves that amount of space. We assume that the input
	// character types are unsigned, which will be true for UTF-16 and -32 on our
	// systems.
	template<typename CHAR>
	void PrepareForUTF8Output(const CHAR* src,
	size_t src_len,
	std::string* output) {
	output->clear();
	if (src_len == 0)
	return;
	if (src[0] < 0x80) {
	// Assume that the entire input will be ASCII.
	output->reserve(src_len);
	} else {
	// Assume that the entire input is non-ASCII and will have 3 bytes per char.
	output->reserve(src_len * 3);
	}
	}

	// Prepares an output buffer (containing either UTF-16 or -32 data) given some
	// UTF-8 input that will be converted to it. See PrepareForUTF8Output().
	template<typename STRING>
	void PrepareForUTF16Or32Output(const char* src,
	size_t src_len,
	STRING* output) {
	output->clear();
	if (src_len == 0)
	return;
	if (static_cast<unsigned char>(src[0]) < 0x80) {
	// Assume the input is all ASCII, which means 1:1 correspondence.
	output->reserve(src_len);
	} else {
	// Otherwise assume that the UTF-8 sequences will have 2 bytes for each
	// character.
	output->reserve(src_len / 2);
	}
	}

	} // namespace

	// UTF-8 <-> Wide --------------------------------------------------------------

	bool WideToUTF8(const wchar_t* src, size_t src_len, std::string* output) {
	PrepareForUTF8Output(src, src_len, output);
	return ConvertUnicode<wchar_t, std::string>(src, src_len, output, NULL);
	}

	std::string WideToUTF8(const std::wstring& wide) {
	std::string ret;
	// Ignore the success flag of this call, it will do the best it can for
	// invalid input, which is what we want here.
	WideToUTF8(wide.data(), wide.length(), &ret);
	return ret;
	}

	bool UTF8ToWideAndAdjustOffset(const char* src,
	size_t src_len,
	std::wstring* output,
	size_t* offset_for_adjustment) {
	PrepareForUTF16Or32Output(src, src_len, output);
	return ConvertUnicode<char, std::wstring>(src, src_len, output,
	offset_for_adjustment);
	}

	std::wstring UTF8ToWideAndAdjustOffset(const base::StringPiece& utf8,
	size_t* offset_for_adjustment) {
	std::wstring ret;
	UTF8ToWideAndAdjustOffset(utf8.data(), utf8.length(), &ret,
	offset_for_adjustment);
	return ret;
	}

	// UTF-16 <-> Wide -------------------------------------------------------------

	#if defined(WCHAR_T_IS_UTF16)

	// When wide == UTF-16, then conversions are a NOP.
	bool WideToUTF16(const wchar_t* src, size_t src_len, string16* output) {
	output->assign(src, src_len);
	return true;
	}

	string16 WideToUTF16(const std::wstring& wide) {
	return wide;
	}

	bool UTF16ToWideAndAdjustOffset(const char16* src,
	size_t src_len,
	std::wstring* output,
	size_t* offset_for_adjustment) {
	output->assign(src, src_len);
	if (offset_for_adjustment && (*offset_for_adjustment >= src_len))
	*offset_for_adjustment = std::wstring::npos;
	return true;
	}

	std::wstring UTF16ToWideAndAdjustOffset(const string16& utf16,
	size_t* offset_for_adjustment) {
	if (offset_for_adjustment && (*offset_for_adjustment >= utf16.length()))
	*offset_for_adjustment = std::wstring::npos;
	return utf16;
	}

	#elif defined(WCHAR_T_IS_UTF32)

	bool WideToUTF16(const wchar_t* src, size_t src_len, string16* output) {
	output->clear();
	// Assume that normally we won't have any non-BMP characters so the counts
	// will be the same.
	output->reserve(src_len);
	return ConvertUnicode<wchar_t, string16>(src, src_len, output, NULL);
	}

	string16 WideToUTF16(const std::wstring& wide) {
	string16 ret;
	WideToUTF16(wide.data(), wide.length(), &ret);
	return ret;
	}

	bool UTF16ToWideAndAdjustOffset(const char16* src,
	size_t src_len,
	std::wstring* output,
	size_t* offset_for_adjustment) {
	output->clear();
	// Assume that normally we won't have any non-BMP characters so the counts
	// will be the same.
	output->reserve(src_len);
	return ConvertUnicode<char16, std::wstring>(src, src_len, output,
	offset_for_adjustment);
	}

	std::wstring UTF16ToWideAndAdjustOffset(const string16& utf16,
	size_t* offset_for_adjustment) {
	std::wstring ret;
	UTF16ToWideAndAdjustOffset(utf16.data(), utf16.length(), &ret,
	offset_for_adjustment);
	return ret;
	}

	#endif // defined(WCHAR_T_IS_UTF32)

	// UTF16 <-> UTF8 --------------------------------------------------------------

	#if defined(WCHAR_T_IS_UTF32)

	bool UTF8ToUTF16(const char* src, size_t src_len, string16* output) {
	PrepareForUTF16Or32Output(src, src_len, output);
	return ConvertUnicode<char, string16>(src, src_len, output, NULL);
	}

	string16 UTF8ToUTF16(const std::string& utf8) {
	string16 ret;
	// Ignore the success flag of this call, it will do the best it can for
	// invalid input, which is what we want here.
	UTF8ToUTF16(utf8.data(), utf8.length(), &ret);
	return ret;
	}

	bool UTF16ToUTF8(const char16* src, size_t src_len, std::string* output) {
	PrepareForUTF8Output(src, src_len, output);
	return ConvertUnicode<char16, std::string>(src, src_len, output, NULL);
	}

	std::string UTF16ToUTF8(const string16& utf16) {
	std::string ret;
	// Ignore the success flag of this call, it will do the best it can for
	// invalid input, which is what we want here.
	UTF16ToUTF8(utf16.data(), utf16.length(), &ret);
	return ret;
	}

	#elif defined(WCHAR_T_IS_UTF16)
	// Easy case since we can use the "wide" versions we already wrote above.

	bool UTF8ToUTF16(const char* src, size_t src_len, string16* output) {
	return UTF8ToWide(src, src_len, output);
	}

	string16 UTF8ToUTF16(const std::string& utf8) {
	return UTF8ToWide(utf8);
	}

	bool UTF16ToUTF8(const char16* src, size_t src_len, std::string* output) {
	return WideToUTF8(src, src_len, output);
	}

	std::string UTF16ToUTF8(const string16& utf16) {
	return WideToUTF8(utf16);
	}

	#endif