7b200ec85e
This prevents values like NONE or COLOR which are very generic
names to collide with other classic enums. It also forces us to be
specific about what we're doing when converting to bitfields.
Also added a utility to easily enable any enum or enum class to
support binary operation (i.e. Bitmask contract), e.g.:
template<> struct utils::EnableBitMaskOperators<Foo> : public std::true_type{};
gives all binary operators to 'Foo'. Foo must be an enum.
Also added any() and none() convenience to convert an enum to a boolean.
100 lines
3.5 KiB
C++
100 lines
3.5 KiB
C++
/*
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* Copyright (C) 2019 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef TNT_UTILS_BITMASKENUM_H
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#define TNT_UTILS_BITMASKENUM_H
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#include <utils/compiler.h>
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#include <type_traits> // for std::false_type
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#include <assert.h>
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#include <stddef.h>
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#include <stdint.h>
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namespace utils {
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template<typename Enum>
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struct EnableBitMaskOperators : public std::false_type { };
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} // namespace utils
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template<typename Enum, typename std::enable_if_t<
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std::is_enum<Enum>::value && utils::EnableBitMaskOperators<Enum>::value, int> = 0>
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inline constexpr bool operator!(Enum rhs) noexcept {
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using underlying = std::underlying_type_t<Enum>;
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return underlying(rhs) == 0;
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}
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template<typename Enum, typename std::enable_if_t<
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std::is_enum<Enum>::value && utils::EnableBitMaskOperators<Enum>::value, int> = 0>
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inline constexpr Enum operator~(Enum rhs) noexcept {
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using underlying = std::underlying_type_t<Enum>;
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return Enum(~underlying(rhs));
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}
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template<typename Enum, typename std::enable_if_t<
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std::is_enum<Enum>::value && utils::EnableBitMaskOperators<Enum>::value, int> = 0>
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inline constexpr Enum operator|(Enum lhs, Enum rhs) noexcept {
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using underlying = std::underlying_type_t<Enum>;
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return Enum(underlying(lhs) | underlying(rhs));
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}
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template<typename Enum, typename std::enable_if_t<
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std::is_enum<Enum>::value && utils::EnableBitMaskOperators<Enum>::value, int> = 0>
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inline constexpr Enum operator&(Enum lhs, Enum rhs) noexcept {
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using underlying = std::underlying_type_t<Enum>;
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return Enum(underlying(lhs) & underlying(rhs));
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}
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template<typename Enum, typename std::enable_if_t<
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std::is_enum<Enum>::value && utils::EnableBitMaskOperators<Enum>::value, int> = 0>
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inline constexpr Enum operator^(Enum lhs, Enum rhs) noexcept {
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using underlying = std::underlying_type_t<Enum>;
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return Enum(underlying(lhs) ^ underlying(rhs));
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}
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template<typename Enum, typename std::enable_if_t<
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std::is_enum<Enum>::value && utils::EnableBitMaskOperators<Enum>::value, int> = 0>
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inline constexpr Enum operator|=(Enum& lhs, Enum rhs) noexcept {
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return lhs = lhs | rhs;
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}
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template<typename Enum, typename std::enable_if_t<
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std::is_enum<Enum>::value && utils::EnableBitMaskOperators<Enum>::value, int> = 0>
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inline constexpr Enum operator&=(Enum& lhs, Enum rhs) noexcept {
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return lhs = lhs & rhs;
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}
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template<typename Enum, typename std::enable_if_t<
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std::is_enum<Enum>::value && utils::EnableBitMaskOperators<Enum>::value, int> = 0>
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inline constexpr Enum operator^=(Enum& lhs, Enum rhs) noexcept {
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return lhs = lhs ^ rhs;
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}
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template<typename Enum, typename std::enable_if_t<
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std::is_enum<Enum>::value && utils::EnableBitMaskOperators<Enum>::value, int> = 0>
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inline constexpr bool none(Enum lhs) noexcept {
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return !lhs;
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}
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template<typename Enum, typename std::enable_if_t<
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std::is_enum<Enum>::value && utils::EnableBitMaskOperators<Enum>::value, int> = 0>
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inline constexpr bool any(Enum lhs) noexcept {
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return !none(lhs);
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}
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#endif // TNT_UTILS_BITMASKENUM_H
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