1 /* 2 * Copyright (C) 2017 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_RANGE_H 18 #define MINIKIN_RANGE_H 19 20 #include <algorithm> 21 #include <limits> 22 #include <utility> 23 24 namespace minikin { 25 26 // An undirected range. 27 class Range { 28 public: 29 static constexpr uint32_t NOWHERE = std::numeric_limits<uint32_t>::max(); 30 31 // start must be smaller than or equal to end otherwise the behavior is undefined. 32 Range(uint32_t start, uint32_t end) : mStart(start), mEnd(end) {} 33 Range() : Range(NOWHERE, NOWHERE) {} 34 35 Range(const Range&) = default; 36 Range& operator=(const Range&) = default; 37 38 static Range invalidRange() { return Range(NOWHERE, NOWHERE); } 39 inline bool isValid() const { return mStart != NOWHERE && mEnd != NOWHERE; } 40 41 inline uint32_t getStart() const { return mStart; } // inclusive 42 inline void setStart(uint32_t start) { mStart = start; } // inclusive 43 44 inline uint32_t getEnd() const { return mEnd; } // exclusive 45 inline void setEnd(uint32_t end) { mEnd = end; } // exclusive 46 47 inline uint32_t getLength() const { return mEnd - mStart; } 48 49 inline bool isEmpty() const { return mStart == mEnd; } 50 51 inline uint32_t toRangeOffset(uint32_t globalPos) const { return globalPos - mStart; } 52 inline uint32_t toGlobalOffset(uint32_t rangePos) const { return mStart + rangePos; } 53 54 // The behavior is undefined if pos is out of range. 55 inline std::pair<Range, Range> split(uint32_t pos) const { 56 return std::make_pair(Range(mStart, pos), Range(pos, mEnd)); 57 } 58 59 inline bool contains(const Range& other) const { 60 return mStart <= other.mStart && other.mEnd <= mEnd; 61 } 62 63 // Returns true if the pos is in this range. 64 // For example, 65 // const Range range(1, 2); // 1 is inclusive, 2 is exclusive. 66 // range.contains(0); // false 67 // range.contains(1); // true 68 // range.contains(2); // false 69 inline bool contains(uint32_t pos) const { return mStart <= pos && pos < mEnd; } 70 71 // Returns true if left and right intersect. 72 inline static bool intersects(const Range& left, const Range& right) { 73 return left.isValid() && right.isValid() && left.mStart < right.mEnd && 74 right.mStart < left.mEnd; 75 } 76 inline static Range intersection(const Range& left, const Range& right) { 77 return Range(std::max(left.mStart, right.mStart), std::min(left.mEnd, right.mEnd)); 78 } 79 80 // Returns merged range. This method assumes left and right are not invalid ranges and they have 81 // an intersection. 82 static Range merge(const Range& left, const Range& right) { 83 return Range({std::min(left.mStart, right.mStart), std::max(left.mEnd, right.mEnd)}); 84 } 85 86 inline bool operator==(const Range& o) const { return mStart == o.mStart && mEnd == o.mEnd; } 87 88 inline bool operator!=(const Range& o) const { return !(*this == o); } 89 90 private: 91 // Helper class for "for (uint32_t i : range)" style for-loop. 92 class RangeIterator { 93 public: 94 RangeIterator(uint32_t pos) : mPos(pos) {} 95 96 inline bool operator!=(const RangeIterator& o) const { return o.mPos != mPos; } 97 inline uint32_t operator*() const { return mPos; } 98 inline RangeIterator& operator++() { 99 mPos++; 100 return *this; 101 } 102 103 private: 104 uint32_t mPos; 105 }; 106 107 public: 108 inline RangeIterator begin() const { return RangeIterator(mStart); } 109 inline RangeIterator end() const { return RangeIterator(mEnd); } 110 111 private: 112 uint32_t mStart; 113 uint32_t mEnd; 114 }; 115 116 } // namespace minikin 117 118 #endif // MINIKIN_RANGE_H 119
