1 // Copyright 2019 the V8 project authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef V8_BASE_ENUM_SET_H_ 6 #define V8_BASE_ENUM_SET_H_ 7 8 #include <type_traits> 9 10 #include "src/base/logging.h" 11 12 namespace v8 { 13 namespace base { 14 15 // A poor man's version of STL's bitset: A bit set of enums E (without explicit 16 // values), fitting into an integral type T. 17 template <class E, class T = int> 18 class EnumSet { 19 static_assert(std::is_enum<E>::value, "EnumSet can only be used with enums"); 20 21 public: 22 constexpr EnumSet() = default; 23 EnumSet(std::initializer_list<E> init)24 explicit constexpr EnumSet(std::initializer_list<E> init) { 25 T bits = 0; 26 for (E e : init) bits |= Mask(e); 27 bits_ = bits; 28 } 29 empty()30 constexpr bool empty() const { return bits_ == 0; } contains(E element)31 constexpr bool contains(E element) const { 32 return (bits_ & Mask(element)) != 0; 33 } contains_any(EnumSet set)34 constexpr bool contains_any(EnumSet set) const { 35 return (bits_ & set.bits_) != 0; 36 } Add(E element)37 void Add(E element) { bits_ |= Mask(element); } Add(EnumSet set)38 void Add(EnumSet set) { bits_ |= set.bits_; } Remove(E element)39 void Remove(E element) { bits_ &= ~Mask(element); } Remove(EnumSet set)40 void Remove(EnumSet set) { bits_ &= ~set.bits_; } RemoveAll()41 void RemoveAll() { bits_ = 0; } Intersect(EnumSet set)42 void Intersect(EnumSet set) { bits_ &= set.bits_; } ToIntegral()43 constexpr T ToIntegral() const { return bits_; } 44 45 constexpr bool operator==(EnumSet set) const { return bits_ == set.bits_; } 46 constexpr bool operator!=(EnumSet set) const { return bits_ != set.bits_; } 47 48 constexpr EnumSet operator|(EnumSet set) const { 49 return EnumSet(bits_ | set.bits_); 50 } 51 constexpr EnumSet operator&(EnumSet set) const { 52 return EnumSet(bits_ & set.bits_); 53 } 54 constexpr EnumSet operator-(EnumSet set) const { 55 return EnumSet(bits_ & ~set.bits_); 56 } 57 58 EnumSet& operator|=(EnumSet set) { return *this = *this | set; } 59 EnumSet& operator&=(EnumSet set) { return *this = *this & set; } 60 EnumSet& operator-=(EnumSet set) { return *this = *this - set; } 61 62 constexpr EnumSet operator|(E element) const { 63 return EnumSet(bits_ | Mask(element)); 64 } 65 constexpr EnumSet operator&(E element) const { 66 return EnumSet(bits_ & Mask(element)); 67 } 68 constexpr EnumSet operator-(E element) const { 69 return EnumSet(bits_ & ~Mask(element)); 70 } 71 72 EnumSet& operator|=(E element) { return *this = *this | element; } 73 EnumSet& operator&=(E element) { return *this = *this & element; } 74 EnumSet& operator-=(E element) { return *this = *this - element; } 75 FromIntegral(T bits)76 static constexpr EnumSet FromIntegral(T bits) { return EnumSet{bits}; } 77 78 private: EnumSet(T bits)79 explicit constexpr EnumSet(T bits) : bits_(bits) {} 80 Mask(E element)81 static constexpr T Mask(E element) { 82 DCHECK_GT(sizeof(T) * 8, static_cast<size_t>(element)); 83 return T{1} << static_cast<typename std::underlying_type<E>::type>(element); 84 } 85 86 T bits_ = 0; 87 }; 88 89 } // namespace base 90 } // namespace v8 91 92 #endif // V8_BASE_ENUM_SET_H_ 93