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 #pragma once 8 9 // This should only be used by the various UTF string conversion files. 10 11 #include "base/string16.h" 12 13 namespace base { 14 15 inline bool IsValidCodepoint(uint32 code_point) { 16 // Excludes the surrogate code points ([0xD800, 0xDFFF]) and 17 // codepoints larger than 0x10FFFF (the highest codepoint allowed). 18 // Non-characters and unassigned codepoints are allowed. 19 return code_point < 0xD800u || 20 (code_point >= 0xE000u && code_point <= 0x10FFFFu); 21 } 22 23 inline bool IsValidCharacter(uint32 code_point) { 24 // Excludes non-characters (U+FDD0..U+FDEF, and all codepoints ending in 25 // 0xFFFE or 0xFFFF) from the set of valid code points. 26 return code_point < 0xD800u || (code_point >= 0xE000u && 27 code_point < 0xFDD0u) || (code_point > 0xFDEFu && 28 code_point <= 0x10FFFFu && (code_point & 0xFFFEu) != 0xFFFEu); 29 } 30 31 // ReadUnicodeCharacter -------------------------------------------------------- 32 33 // Reads a UTF-8 stream, placing the next code point into the given output 34 // |*code_point|. |src| represents the entire string to read, and |*char_index| 35 // is the character offset within the string to start reading at. |*char_index| 36 // will be updated to index the last character read, such that incrementing it 37 // (as in a for loop) will take the reader to the next character. 38 // 39 // Returns true on success. On false, |*code_point| will be invalid. 40 bool ReadUnicodeCharacter(const char* src, 41 int32 src_len, 42 int32* char_index, 43 uint32* code_point_out); 44 45 // Reads a UTF-16 character. The usage is the same as the 8-bit version above. 46 bool ReadUnicodeCharacter(const char16* src, 47 int32 src_len, 48 int32* char_index, 49 uint32* code_point); 50 51 #if defined(WCHAR_T_IS_UTF32) 52 // Reads UTF-32 character. The usage is the same as the 8-bit version above. 53 bool ReadUnicodeCharacter(const wchar_t* src, 54 int32 src_len, 55 int32* char_index, 56 uint32* code_point); 57 #endif // defined(WCHAR_T_IS_UTF32) 58 59 // WriteUnicodeCharacter ------------------------------------------------------- 60 61 // Appends a UTF-8 character to the given 8-bit string. Returns the number of 62 // bytes written. 63 size_t WriteUnicodeCharacter(uint32 code_point, std::string* output); 64 65 // Appends the given code point as a UTF-16 character to the given 16-bit 66 // string. Returns the number of 16-bit values written. 67 size_t WriteUnicodeCharacter(uint32 code_point, string16* output); 68 69 #if defined(WCHAR_T_IS_UTF32) 70 // Appends the given UTF-32 character to the given 32-bit string. Returns the 71 // number of 32-bit values written. 72 inline size_t WriteUnicodeCharacter(uint32 code_point, std::wstring* output) { 73 // This is the easy case, just append the character. 74 output->push_back(code_point); 75 return 1; 76 } 77 #endif // defined(WCHAR_T_IS_UTF32) 78 79 // Generalized Unicode converter ----------------------------------------------- 80 81 // Guesses the length of the output in UTF-8 in bytes, clears that output 82 // string, and reserves that amount of space. We assume that the input 83 // character types are unsigned, which will be true for UTF-16 and -32 on our 84 // systems. 85 template<typename CHAR> 86 void PrepareForUTF8Output(const CHAR* src, size_t src_len, std::string* output); 87 88 // Prepares an output buffer (containing either UTF-16 or -32 data) given some 89 // UTF-8 input that will be converted to it. See PrepareForUTF8Output(). 90 template<typename STRING> 91 void PrepareForUTF16Or32Output(const char* src, size_t src_len, STRING* output); 92 93 } // namespace base 94 95 #endif // BASE_UTF_STRING_CONVERSION_UTILS_H_ 96
