263 lines
8.1 KiB
C++
263 lines
8.1 KiB
C++
/*
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* Copyright (C) 2016-2020 Apple Inc. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
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* THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#pragma once
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#include <initializer_list>
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#include <iterator>
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#include <optional>
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#include <type_traits>
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#include <wtf/Assertions.h>
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#include <wtf/EnumTraits.h>
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#include <wtf/MathExtras.h>
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#include <wtf/StdLibExtras.h>
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namespace WTF {
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template<typename E> class OptionSet;
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template<typename T, typename E> struct OptionSetValueChecker;
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template<typename T, typename E, E e, E... es>
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struct OptionSetValueChecker<T, EnumValues<E, e, es...>> {
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static constexpr T allValidBits()
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{
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return static_cast<T>(e) | OptionSetValueChecker<T, EnumValues<E, es...>>::allValidBits();
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}
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static constexpr bool isValidOptionSetEnum(T t)
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{
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return (static_cast<T>(e) == t) ? true : OptionSetValueChecker<T, EnumValues<E, es...>>::isValidOptionSetEnum(t);
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}
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};
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template<typename T, typename E>
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struct OptionSetValueChecker<T, EnumValues<E>> {
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static constexpr T allValidBits()
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{
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return 0;
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}
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static constexpr bool isValidOptionSetEnum(T)
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{
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return false;
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}
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};
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template<typename E, std::enable_if_t<std::is_enum<E>::value && IsTypeComplete<EnumTraits<E>>>* = nullptr>
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constexpr bool isValidOptionSetEnum(E e)
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{
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return OptionSetValueChecker<std::underlying_type_t<E>, typename EnumTraits<E>::values>::isValidOptionSetEnum(static_cast<std::underlying_type_t<E>>(e));
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}
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template<typename E, std::enable_if_t<std::is_enum<E>::value && !IsTypeComplete<EnumTraits<E>>>* = nullptr>
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constexpr bool isValidOptionSetEnum(E e)
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{
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// FIXME: Remove once all OptionSet<> enums have EnumTraits<> defined.
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return hasOneBitSet(static_cast<typename OptionSet<E>::StorageType>(e));
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}
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template<typename E, std::enable_if_t<std::is_enum<E>::value && IsTypeComplete<EnumTraits<E>>>* = nullptr>
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constexpr typename OptionSet<E>::StorageType maskRawValue(typename OptionSet<E>::StorageType rawValue)
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{
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auto allValidBitsValue = OptionSetValueChecker<std::underlying_type_t<E>, typename EnumTraits<E>::values>::allValidBits();
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return rawValue & allValidBitsValue;
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}
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template<typename E, std::enable_if_t<std::is_enum<E>::value && !IsTypeComplete<EnumTraits<E>>>* = nullptr>
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constexpr typename OptionSet<E>::StorageType maskRawValue(typename OptionSet<E>::StorageType rawValue)
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{
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// FIXME: Remove once all OptionSet<> enums have EnumTraits<> defined.
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return rawValue;
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}
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// OptionSet is a class that represents a set of enumerators in a space-efficient manner. The enumerators
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// must be powers of two greater than 0. This class is useful as a replacement for passing a bitmask of
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// enumerators around.
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template<typename E> class OptionSet {
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WTF_MAKE_FAST_ALLOCATED;
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static_assert(std::is_enum<E>::value, "T is not an enum type");
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public:
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using StorageType = std::make_unsigned_t<std::underlying_type_t<E>>;
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template<typename StorageType> class Iterator {
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WTF_MAKE_FAST_ALLOCATED;
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public:
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// Isolate the rightmost set bit.
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E operator*() const { return static_cast<E>(m_value & -m_value); }
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// Iterates from smallest to largest enum value by turning off the rightmost set bit.
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Iterator& operator++()
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{
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m_value &= m_value - 1;
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return *this;
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}
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Iterator& operator++(int) = delete;
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bool operator==(const Iterator& other) const { return m_value == other.m_value; }
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bool operator!=(const Iterator& other) const { return m_value != other.m_value; }
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private:
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Iterator(StorageType value) : m_value(value) { }
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friend OptionSet;
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StorageType m_value;
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};
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using iterator = Iterator<StorageType>;
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static constexpr OptionSet fromRaw(StorageType rawValue)
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{
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return OptionSet(static_cast<E>(maskRawValue<E>(rawValue)), FromRawValue);
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}
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constexpr OptionSet() = default;
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constexpr OptionSet(E e)
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: m_storage(static_cast<StorageType>(e))
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{
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ASSERT(!m_storage || isValidOptionSetEnum(e));
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}
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constexpr OptionSet(std::initializer_list<E> initializerList)
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{
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for (auto& option : initializerList) {
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ASSERT(isValidOptionSetEnum(option));
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m_storage |= static_cast<StorageType>(option);
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}
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}
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constexpr OptionSet(std::optional<E> optional)
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: m_storage(optional ? static_cast<StorageType>(*optional) : 0)
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{
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}
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constexpr StorageType toRaw() const { return m_storage; }
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constexpr bool isEmpty() const { return !m_storage; }
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constexpr iterator begin() const { return m_storage; }
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constexpr iterator end() const { return 0; }
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constexpr explicit operator bool() { return !isEmpty(); }
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constexpr bool contains(E option) const
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{
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return containsAny(option);
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}
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constexpr bool containsAny(OptionSet optionSet) const
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{
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return !!(*this & optionSet);
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}
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constexpr bool containsAll(OptionSet optionSet) const
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{
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return (*this & optionSet) == optionSet;
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}
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constexpr void add(OptionSet optionSet)
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{
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m_storage |= optionSet.m_storage;
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}
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constexpr void remove(OptionSet optionSet)
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{
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m_storage &= ~optionSet.m_storage;
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}
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constexpr void set(OptionSet optionSet, bool value)
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{
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if (value)
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add(optionSet);
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else
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remove(optionSet);
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}
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constexpr bool hasExactlyOneBitSet() const
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{
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return m_storage && !(m_storage & (m_storage - 1));
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}
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constexpr std::optional<E> toSingleValue() const
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{
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return hasExactlyOneBitSet() ? std::optional<E>(static_cast<E>(m_storage)) : std::nullopt;
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}
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constexpr friend bool operator==(OptionSet lhs, OptionSet rhs)
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{
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return lhs.m_storage == rhs.m_storage;
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}
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constexpr friend bool operator!=(OptionSet lhs, OptionSet rhs)
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{
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return lhs.m_storage != rhs.m_storage;
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}
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constexpr friend OptionSet operator|(OptionSet lhs, OptionSet rhs)
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{
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return fromRaw(lhs.m_storage | rhs.m_storage);
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}
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constexpr friend OptionSet operator&(OptionSet lhs, OptionSet rhs)
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{
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return fromRaw(lhs.m_storage & rhs.m_storage);
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}
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constexpr friend OptionSet operator-(OptionSet lhs, OptionSet rhs)
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{
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return fromRaw(lhs.m_storage & ~rhs.m_storage);
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}
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constexpr friend OptionSet operator^(OptionSet lhs, OptionSet rhs)
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{
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return fromRaw(lhs.m_storage ^ rhs.m_storage);
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}
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private:
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enum InitializationTag { FromRawValue };
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constexpr OptionSet(E e, InitializationTag)
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: m_storage(static_cast<StorageType>(e))
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{
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}
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StorageType m_storage { 0 };
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};
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template<typename E>
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WARN_UNUSED_RETURN constexpr bool isValidOptionSet(OptionSet<E> optionSet)
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{
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auto allValidBitsValue = OptionSetValueChecker<std::make_unsigned_t<std::underlying_type_t<E>>, typename EnumTraits<E>::values>::allValidBits();
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return (optionSet.toRaw() | allValidBitsValue) == allValidBitsValue;
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}
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} // namespace WTF
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using WTF::OptionSet;
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