1 // Copyright (c) 2009 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 #ifndef BASE_UTF_STRING_CONVERSION_UTILS_H_ 6 #define BASE_UTF_STRING_CONVERSION_UTILS_H_ 7 8 // This should only be used by the various UTF string conversion files. 9 10 #include "base/string16.h" 11 12 namespace base { 13 14 inline bool IsValidCodepoint(uint32 code_point) { 15 // Excludes the surrogate code points ([0xD800, 0xDFFF]) and 16 // codepoints larger than 0x10FFFF (the highest codepoint allowed). 17 // Non-characters and unassigned codepoints are allowed. 18 return code_point < 0xD800u || 19 (code_point >= 0xE000u && code_point <= 0x10FFFFu); 20 } 21 22 // ReadUnicodeCharacter -------------------------------------------------------- 23 24 // Reads a UTF-8 stream, placing the next code point into the given output 25 // |*code_point|. |src| represents the entire string to read, and |*char_index| 26 // is the character offset within the string to start reading at. |*char_index| 27 // will be updated to index the last character read, such that incrementing it 28 // (as in a for loop) will take the reader to the next character. 29 // 30 // Returns true on success. On false, |*code_point| will be invalid. 31 bool ReadUnicodeCharacter(const char* src, 32 int32 src_len, 33 int32* char_index, 34 uint32* code_point_out); 35 36 // Reads a UTF-16 character. The usage is the same as the 8-bit version above. 37 bool ReadUnicodeCharacter(const char16* src, 38 int32 src_len, 39 int32* char_index, 40 uint32* code_point); 41 42 #if defined(WCHAR_T_IS_UTF32) 43 // Reads UTF-32 character. The usage is the same as the 8-bit version above. 44 bool ReadUnicodeCharacter(const wchar_t* src, 45 int32 src_len, 46 int32* char_index, 47 uint32* code_point); 48 #endif // defined(WCHAR_T_IS_UTF32) 49 50 // WriteUnicodeCharacter ------------------------------------------------------- 51 52 // Appends a UTF-8 character to the given 8-bit string. Returns the number of 53 // bytes written. 54 size_t WriteUnicodeCharacter(uint32 code_point, std::string* output); 55 56 // Appends the given code point as a UTF-16 character to the given 16-bit 57 // string. Returns the number of 16-bit values written. 58 size_t WriteUnicodeCharacter(uint32 code_point, string16* output); 59 60 #if defined(WCHAR_T_IS_UTF32) 61 // Appends the given UTF-32 character to the given 32-bit string. Returns the 62 // number of 32-bit values written. 63 inline size_t WriteUnicodeCharacter(uint32 code_point, std::wstring* output) { 64 // This is the easy case, just append the character. 65 output->push_back(code_point); 66 return 1; 67 } 68 #endif // defined(WCHAR_T_IS_UTF32) 69 70 // Generalized Unicode converter ----------------------------------------------- 71 72 // Guesses the length of the output in UTF-8 in bytes, clears that output 73 // string, and reserves that amount of space. We assume that the input 74 // character types are unsigned, which will be true for UTF-16 and -32 on our 75 // systems. 76 template<typename CHAR> 77 void PrepareForUTF8Output(const CHAR* src, size_t src_len, std::string* output); 78 79 // Prepares an output buffer (containing either UTF-16 or -32 data) given some 80 // UTF-8 input that will be converted to it. See PrepareForUTF8Output(). 81 template<typename STRING> 82 void PrepareForUTF16Or32Output(const char* src, size_t src_len, STRING* output); 83 84 } // namespace base 85 86 #endif // BASE_UTF_STRING_CONVERSION_UTILS_H_ 87
