1 /* 2 * Copyright (C) 2023 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 #ifndef MINIKIN_SCRIPT_UTILS_H 18 #define MINIKIN_SCRIPT_UTILS_H 19 20 #define LOG_TAG "Minikin" 21 22 #include <unicode/ubidi.h> 23 24 #include <memory> 25 26 #include "minikin/Layout.h" 27 #include "minikin/Macros.h" 28 #include "minikin/U16StringPiece.h" 29 30 namespace minikin { 31 32 // A helper class for iterating the bidi run transitions. 33 class ScriptText { 34 public: 35 struct RunInfo { 36 Range range; 37 hb_script_t script; 38 }; 39 ScriptText(const U16StringPiece & textBuf,uint32_t start,uint32_t end)40 ScriptText(const U16StringPiece& textBuf, uint32_t start, uint32_t end) 41 : mTextBuf(textBuf), mRange(start, end) {} 42 ScriptText(const U16StringPiece & textBuf)43 explicit ScriptText(const U16StringPiece& textBuf) 44 : mTextBuf(textBuf), mRange(0, textBuf.size()) {} 45 46 class iterator { 47 public: 48 inline bool operator==(const iterator& o) const { 49 return mStart == o.mStart && mParent == o.mParent; 50 } 51 52 inline bool operator!=(const iterator& o) const { return !(*this == o); } 53 54 inline std::pair<Range, hb_script_t> operator*() const { 55 return std::make_pair(Range(mStart, mEnd), mScript); 56 } 57 58 inline iterator& operator++() { 59 mStart = mEnd; 60 std::tie(mEnd, mScript) = getScriptRun(mParent->mTextBuf, mParent->mRange, mStart); 61 return *this; 62 } 63 64 private: 65 friend class ScriptText; 66 iterator(const ScriptText * parent,uint32_t start)67 iterator(const ScriptText* parent, uint32_t start) : mParent(parent), mStart(start) { 68 std::tie(mEnd, mScript) = getScriptRun(mParent->mTextBuf, mParent->mRange, mStart); 69 } 70 71 const ScriptText* mParent; 72 uint32_t mStart; 73 uint32_t mEnd; 74 hb_script_t mScript; 75 }; 76 begin()77 inline iterator begin() const { return iterator(this, mRange.getStart()); } end()78 inline iterator end() const { return iterator(this, mRange.getEnd()); } 79 80 private: 81 U16StringPiece mTextBuf; 82 Range mRange; 83 84 static std::pair<uint32_t, hb_script_t> getScriptRun(U16StringPiece text, Range range, 85 uint32_t pos); 86 87 MINIKIN_PREVENT_COPY_AND_ASSIGN(ScriptText); 88 }; 89 90 } // namespace minikin 91 92 #endif // MINIKIN_SCRIPT_UTILS_H 93