1 /* 2 * Copyright (C) 2024 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include "minikin/U16StringPiece.h" 18 19 #include <unicode/utf16.h> 20 21 #include "minikin/Characters.h" 22 23 namespace minikin { 24 codePointAt(uint32_t pos) const25uint32_t U16StringPiece::codePointAt(uint32_t pos) const { 26 const uint16_t c = mData[pos]; 27 if (!U16_IS_SURROGATE(c)) { 28 return c; // Not a surrogate pair. 29 } 30 31 if (U16_IS_SURROGATE_TRAIL(c)) { // isolated surrogate trail. 32 return CHAR_REPLACEMENT_CHARACTER; 33 } 34 35 if (pos == mLength - 1) { // isolated surrogate lead. 36 return CHAR_REPLACEMENT_CHARACTER; 37 } 38 39 const uint16_t c2 = mData[pos + 1]; 40 if (!(U16_IS_SURROGATE(c2) && U16_IS_SURROGATE_LEAD(c2))) { // isolated surrogate lead 41 return CHAR_REPLACEMENT_CHARACTER; 42 } 43 44 return U16_GET_SUPPLEMENTARY(c, c2); 45 } 46 47 } // namespace minikin 48