1// Copyright (c) 2011 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_STRINGS_UTF_STRING_CONVERSION_UTILS_H_ 6#define BASE_STRINGS_UTF_STRING_CONVERSION_UTILS_H_ 7 8// This should only be used by the various UTF string conversion files. 9 10#include "base/base_export.h" 11#include "base/strings/string16.h" 12 13namespace base { 14 15inline 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 23inline 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. 40BASE_EXPORT 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. 46BASE_EXPORT 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. 53BASE_EXPORT 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// TODO(brettw) Bug 79631: This function should not be exposed. 64BASE_EXPORT size_t WriteUnicodeCharacter(uint32 code_point, 65 std::string* output); 66 67// Appends the given code point as a UTF-16 character to the given 16-bit 68// string. Returns the number of 16-bit values written. 69BASE_EXPORT size_t WriteUnicodeCharacter(uint32 code_point, string16* output); 70 71#if defined(WCHAR_T_IS_UTF32) 72// Appends the given UTF-32 character to the given 32-bit string. Returns the 73// number of 32-bit values written. 74inline size_t WriteUnicodeCharacter(uint32 code_point, std::wstring* output) { 75 // This is the easy case, just append the character. 76 output->push_back(code_point); 77 return 1; 78} 79#endif // defined(WCHAR_T_IS_UTF32) 80 81// Generalized Unicode converter ----------------------------------------------- 82 83// Guesses the length of the output in UTF-8 in bytes, clears that output 84// string, and reserves that amount of space. We assume that the input 85// character types are unsigned, which will be true for UTF-16 and -32 on our 86// systems. 87template<typename CHAR> 88void PrepareForUTF8Output(const CHAR* src, size_t src_len, std::string* output); 89 90// Prepares an output buffer (containing either UTF-16 or -32 data) given some 91// UTF-8 input that will be converted to it. See PrepareForUTF8Output(). 92template<typename STRING> 93void PrepareForUTF16Or32Output(const char* src, size_t src_len, STRING* output); 94 95} // namespace base 96 97#endif // BASE_STRINGS_UTF_STRING_CONVERSION_UTILS_H_ 98