// Copyright (c) 2011 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. #ifndef BASE_STRINGS_UTF_STRING_CONVERSION_UTILS_H_ #define BASE_STRINGS_UTF_STRING_CONVERSION_UTILS_H_ // Low-level UTF handling functions. Most code will want to use the functions // in utf_string_conversions.h #include #include #include #include "base/base_export.h" #include "base/third_party/icu/icu_utf.h" #include "build/build_config.h" namespace base { inline bool IsValidCodepoint(base_icu::UChar32 code_point) { // Excludes code points that are not Unicode scalar values, i.e. // surrogate code points ([0xD800, 0xDFFF]). Additionally, excludes // code points larger than 0x10FFFF (the highest codepoint allowed). // Non-characters and unassigned code points are allowed. // https://unicode.org/glossary/#unicode_scalar_value return (code_point >= 0 && code_point < 0xD800) || (code_point >= 0xE000 && code_point <= 0x10FFFF); } inline bool IsValidCharacter(base_icu::UChar32 code_point) { // Excludes non-characters (U+FDD0..U+FDEF, and all code points // ending in 0xFFFE or 0xFFFF) from the set of valid code points. // https://unicode.org/faq/private_use.html#nonchar1 return (code_point >= 0 && code_point < 0xD800) || (code_point >= 0xE000 && code_point < 0xFDD0) || (code_point > 0xFDEF && code_point <= 0x10FFFF && (code_point & 0xFFFE) != 0xFFFE); } // 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. BASE_EXPORT bool ReadUnicodeCharacter(const char* src, size_t src_len, size_t* char_index, base_icu::UChar32* code_point_out); // Reads a UTF-16 character. The usage is the same as the 8-bit version above. BASE_EXPORT bool ReadUnicodeCharacter(const char16_t* src, size_t src_len, size_t* char_index, base_icu::UChar32* code_point); #if defined(WCHAR_T_IS_UTF32) // Reads UTF-32 character. The usage is the same as the 8-bit version above. BASE_EXPORT bool ReadUnicodeCharacter(const wchar_t* src, size_t src_len, size_t* char_index, base_icu::UChar32* 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. BASE_EXPORT size_t WriteUnicodeCharacter(base_icu::UChar32 code_point, std::string* output); // Appends the given code point as a UTF-16 character to the given 16-bit // string. Returns the number of 16-bit values written. BASE_EXPORT size_t WriteUnicodeCharacter(base_icu::UChar32 code_point, std::u16string* output); #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(base_icu::UChar32 code_point, std::wstring* output) { // This is the easy case, just append the character. output->push_back(static_cast(code_point)); return 1; } #endif // defined(WCHAR_T_IS_UTF32) // Generalized Unicode converter ----------------------------------------------- // 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 void PrepareForUTF8Output(const CHAR* src, size_t src_len, std::string* output); // 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 void PrepareForUTF16Or32Output(const char* src, size_t src_len, STRING* output); } // namespace base #endif // BASE_STRINGS_UTF_STRING_CONVERSION_UTILS_H_