52 lines
1.8 KiB
C++
52 lines
1.8 KiB
C++
// Copyright 2020 The Dawn Authors
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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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#ifndef COMMON_UNDERLYINGTYPE_H_
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#define COMMON_UNDERLYINGTYPE_H_
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#include <type_traits>
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// UnderlyingType is similar to std::underlying_type_t. It is a passthrough for already
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// integer types which simplifies getting the underlying primitive type for an arbitrary
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// template parameter. It includes a specialization for detail::TypedIntegerImpl which yields
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// the wrapped integer type.
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namespace detail {
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template <typename T, typename Enable = void>
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struct UnderlyingTypeImpl;
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template <typename I>
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struct UnderlyingTypeImpl<I, typename std::enable_if_t<std::is_integral<I>::value>> {
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using type = I;
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};
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template <typename E>
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struct UnderlyingTypeImpl<E, typename std::enable_if_t<std::is_enum<E>::value>> {
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using type = std::underlying_type_t<E>;
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};
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// Forward declare the TypedInteger impl.
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template <typename Tag, typename T>
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class TypedIntegerImpl;
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template <typename Tag, typename I>
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struct UnderlyingTypeImpl<TypedIntegerImpl<Tag, I>> {
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using type = typename UnderlyingTypeImpl<I>::type;
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};
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} // namespace detail
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template <typename T>
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using UnderlyingType = typename detail::UnderlyingTypeImpl<T>::type;
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#endif // COMMON_UNDERLYINGTYPE_H_
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