base/utf_string_conversions.cc

   1 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/utf_string_conversions.h"
   6
   7 #include "base/string_piece.h"
   8 #include "base/string_util.h"
   9 #include "base/utf_string_conversion_utils.h"
  10
  11 using base::PrepareForUTF8Output;
  12 using base::PrepareForUTF16Or32Output;
  13 using base::ReadUnicodeCharacter;
  14 using base::WriteUnicodeCharacter;
  15
  16 namespace {
  17
  18 // Generalized Unicode converter -----------------------------------------------
  19
  20 // Converts the given source Unicode character type to the given destination
  21 // Unicode character type as a STL string. The given input buffer and size
  22 // determine the source, and the given output STL string will be replaced by
  23 // the result.
  24 template<typename SRC_CHAR, typename DEST_STRING>
  25 bool ConvertUnicode(const SRC_CHAR* src,
  26                     size_t src_len,
  27                     DEST_STRING* output) {
  28   // ICU requires 32-bit numbers.
  29   bool success = true;
  30   int32 src_len32 = static_cast<int32>(src_len);
  31   for (int32 i = 0; i < src_len32; i++) {
  32     uint32 code_point;
  33     if (ReadUnicodeCharacter(src, src_len32, &i, &code_point)) {
  34       WriteUnicodeCharacter(code_point, output);
  35     } else {
  36       WriteUnicodeCharacter(0xFFFD, output);
  37       success = false;
  38     }
  39   }
  40
  41   return success;
  42 }
  43
  44 }  // namespace
  45
  46 // UTF-8 <-> Wide --------------------------------------------------------------
  47
  48 bool WideToUTF8(const wchar_t* src, size_t src_len, std::string* output) {
  49   PrepareForUTF8Output(src, src_len, output);
  50   return ConvertUnicode(src, src_len, output);
  51 }
  52
  53 std::string WideToUTF8(const std::wstring& wide) {
  54   std::string ret;
  55   // Ignore the success flag of this call, it will do the best it can for
  56   // invalid input, which is what we want here.
  57   WideToUTF8(wide.data(), wide.length(), &ret);
  58   return ret;
  59 }
  60
  61 bool UTF8ToWide(const char* src, size_t src_len, std::wstring* output) {
  62   PrepareForUTF16Or32Output(src, src_len, output);
  63   return ConvertUnicode(src, src_len, output);
  64 }
  65
  66 std::wstring UTF8ToWide(const base::StringPiece& utf8) {
  67   std::wstring ret;
  68   UTF8ToWide(utf8.data(), utf8.length(), &ret);
  69   return ret;
  70 }
  71
  72 // UTF-16 <-> Wide -------------------------------------------------------------
  73
  74 #if defined(WCHAR_T_IS_UTF16)
  75
  76 // When wide == UTF-16, then conversions are a NOP.
  77 bool WideToUTF16(const wchar_t* src, size_t src_len, string16* output) {
  78   output->assign(src, src_len);
  79   return true;
  80 }
  81
  82 string16 WideToUTF16(const std::wstring& wide) {
  83   return wide;
  84 }
  85
  86 bool UTF16ToWide(const char16* src, size_t src_len, std::wstring* output) {
  87   output->assign(src, src_len);
  88   return true;
  89 }
  90
  91 std::wstring UTF16ToWide(const string16& utf16) {
  92   return utf16;
  93 }
  94
  95 #elif defined(WCHAR_T_IS_UTF32)
  96
  97 bool WideToUTF16(const wchar_t* src, size_t src_len, string16* output) {
  98   output->clear();
  99   // Assume that normally we won't have any non-BMP characters so the counts
 100   // will be the same.
 101   output->reserve(src_len);
 102   return ConvertUnicode(src, src_len, output);
 103 }
 104
 105 string16 WideToUTF16(const std::wstring& wide) {
 106   string16 ret;
 107   WideToUTF16(wide.data(), wide.length(), &ret);
 108   return ret;
 109 }
 110
 111 bool UTF16ToWide(const char16* src, size_t src_len, std::wstring* output) {
 112   output->clear();
 113   // Assume that normally we won't have any non-BMP characters so the counts
 114   // will be the same.
 115   output->reserve(src_len);
 116   return ConvertUnicode(src, src_len, output);
 117 }
 118
 119 std::wstring UTF16ToWide(const string16& utf16) {
 120   std::wstring ret;
 121   UTF16ToWide(utf16.data(), utf16.length(), &ret);
 122   return ret;
 123 }
 124
 125 #endif  // defined(WCHAR_T_IS_UTF32)
 126
 127 // UTF16 <-> UTF8 --------------------------------------------------------------
 128
 129 #if defined(WCHAR_T_IS_UTF32)
 130
 131 bool UTF8ToUTF16(const char* src, size_t src_len, string16* output) {
 132   PrepareForUTF16Or32Output(src, src_len, output);
 133   return ConvertUnicode(src, src_len, output);
 134 }
 135
 136 string16 UTF8ToUTF16(const base::StringPiece& utf8) {
 137   string16 ret;
 138   // Ignore the success flag of this call, it will do the best it can for
 139   // invalid input, which is what we want here.
 140   UTF8ToUTF16(utf8.data(), utf8.length(), &ret);
 141   return ret;
 142 }
 143
 144 bool UTF16ToUTF8(const char16* src, size_t src_len, std::string* output) {
 145   PrepareForUTF8Output(src, src_len, output);
 146   return ConvertUnicode(src, src_len, output);
 147 }
 148
 149 std::string UTF16ToUTF8(const string16& utf16) {
 150   std::string ret;
 151   // Ignore the success flag of this call, it will do the best it can for
 152   // invalid input, which is what we want here.
 153   UTF16ToUTF8(utf16.data(), utf16.length(), &ret);
 154   return ret;
 155 }
 156
 157 #elif defined(WCHAR_T_IS_UTF16)
 158 // Easy case since we can use the "wide" versions we already wrote above.
 159
 160 bool UTF8ToUTF16(const char* src, size_t src_len, string16* output) {
 161   return UTF8ToWide(src, src_len, output);
 162 }
 163
 164 string16 UTF8ToUTF16(const base::StringPiece& utf8) {
 165   return UTF8ToWide(utf8);
 166 }
 167
 168 bool UTF16ToUTF8(const char16* src, size_t src_len, std::string* output) {
 169   return WideToUTF8(src, src_len, output);
 170 }
 171
 172 std::string UTF16ToUTF8(const string16& utf16) {
 173   return WideToUTF8(utf16);
 174 }
 175
 176 #endif
 177
 178 std::wstring ASCIIToWide(const base::StringPiece& ascii) {
 179   DCHECK(IsStringASCII(ascii)) << ascii;
 180   return std::wstring(ascii.begin(), ascii.end());
 181 }
 182
 183 string16 ASCIIToUTF16(const base::StringPiece& ascii) {
 184   DCHECK(IsStringASCII(ascii)) << ascii;
 185   return string16(ascii.begin(), ascii.end());
 186 }