| /** |
| * Copyright 2010 Google Inc. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #ifndef UTIL_UTF8_PUBLIC_UNILIB_UTF8_UTILS_H_ |
| #define UTIL_UTF8_PUBLIC_UNILIB_UTF8_UTILS_H_ |
| |
| // These definitions are self-contained and have no dependencies. |
| // They are also exported from unilib.h for legacy reasons. |
| |
| #include "base/integral_types.h" // for char32, uint32 |
| |
| namespace UniLib { |
| |
| // Returns true if 'c' is in the range [0, 0xD800) or [0xE000, 0x10FFFF] |
| // (i.e., is not a surrogate codepoint). See also |
| // IsValidCodepoint(const char* src) in util/utf8/public/unilib.h. |
| inline bool IsValidCodepoint(char32 c) { |
| return (static_cast<uint32>(c) < 0xD800) |
| || (c >= 0xE000 && c <= 0x10FFFF); |
| } |
| |
| // Returns the length (number of bytes) of the Unicode code point |
| // starting at src, based on inspecting just that one byte. This |
| // requires that src point to a well-formed UTF-8 string; the result |
| // is undefined otherwise. |
| inline int OneCharLen(const char* src) { |
| return "\1\1\1\1\1\1\1\1\1\1\1\1\2\2\3\4"[(*src & 0xFF) >> 4]; |
| } |
| |
| // Returns true if this byte is a trailing UTF-8 byte (10xx xxxx) |
| inline bool IsTrailByte(char x) { |
| // return (x & 0xC0) == 0x80; |
| // Since trail bytes are always in [0x80, 0xBF], we can optimize: |
| return static_cast<signed char>(x) < -0x40; |
| } |
| |
| } // namespace UniLib |
| |
| #endif // UTIL_UTF8_PUBLIC_UNILIB_UTF8_UTILS_H_ |
