// Copyright 2020 The Dawn & Tint Authors // // Redistribution and use in source and binary forms, with or without // modification, are permitted provided that the following conditions are met: // // 1. Redistributions of source code must retain the above copyright notice, this // list of conditions and the following disclaimer. // // 2. Redistributions in binary form must reproduce the above copyright notice, // this list of conditions and the following disclaimer in the documentation // and/or other materials provided with the distribution. // // 3. Neither the name of the copyright holder nor the names of its // contributors may be used to endorse or promote products derived from // this software without specific prior written permission. // // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE // FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL // DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR // SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER // CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, // OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. #ifndef SRC_DAWN_COMMON_TYPEDINTEGER_H_ #define SRC_DAWN_COMMON_TYPEDINTEGER_H_ #include <limits> #include <type_traits> #include <utility> #include "dawn/common/Assert.h" #include "dawn/common/UnderlyingType.h" namespace dawn { // TypedInteger is helper class that provides additional type safety in Debug. // - Integers of different (Tag, BaseIntegerType) may not be used interoperably // - Allows casts only to the underlying type. // - Integers of the same (Tag, BaseIntegerType) may be compared or assigned. // This class helps ensure that the many types of indices in Dawn aren't mixed up and used // interchangably. // In Release builds, when DAWN_ENABLE_ASSERTS is not defined, TypedInteger is a passthrough // typedef of the underlying type. // // Example: // using UintA = dawn::TypedInteger<struct TypeA, uint32_t>; // using UintB = dawn::TypedInteger<struct TypeB, uint32_t>; // // in Release: // using UintA = uint32_t; // using UintB = uint32_t; // // in Debug: // using UintA = detail::TypedIntegerImpl<struct TypeA, uint32_t>; // using UintB = detail::TypedIntegerImpl<struct TypeB, uint32_t>; // // Assignment, construction, comparison, and arithmetic with TypedIntegerImpl are allowed // only for typed integers of exactly the same type. Further, they must be // created / cast explicitly; there is no implicit conversion. // // UintA a(2); // uint32_t aValue = static_cast<uint32_t>(a); // namespace detail { template <typename Tag, typename T> class TypedIntegerImpl; } // namespace detail TypedInteger; #else using TypedInteger = T; #endif namespace detail { template <typename Tag, typename T> class alignas(T) TypedIntegerImpl { … }; } // namespace detail } // namespace dawn namespace std { numeric_limits<dawn::detail::TypedIntegerImpl<Tag, T>>; } // namespace std namespace dawn::ityp { // These helpers below are provided since the default arithmetic operators for small integer // types like uint8_t and uint16_t return integers, not their same type. To avoid lots of // casting or conditional code between Release/Debug. Callsites should use ityp::Add(a, b) and // ityp::Sub(a, b) instead. template <typename Tag, typename T> constexpr ::dawn::detail::TypedIntegerImpl<Tag, T> Add( ::dawn::detail::TypedIntegerImpl<Tag, T> lhs, ::dawn::detail::TypedIntegerImpl<Tag, T> rhs) { … } template <typename Tag, typename T> constexpr ::dawn::detail::TypedIntegerImpl<Tag, T> Sub( ::dawn::detail::TypedIntegerImpl<Tag, T> lhs, ::dawn::detail::TypedIntegerImpl<Tag, T> rhs) { … } template <typename Tag, typename T> constexpr ::dawn::detail::TypedIntegerImpl<Tag, T> PlusOne( ::dawn::detail::TypedIntegerImpl<Tag, T> value) { … } template <typename T> constexpr std::enable_if_t<std::is_integral<T>::value, T> Add(T lhs, T rhs) { … } template <typename T> constexpr std::enable_if_t<std::is_integral<T>::value, T> Sub(T lhs, T rhs) { … } template <typename T> constexpr std::enable_if_t<std::is_integral<T>::value, T> PlusOne(T value) { … } } // namespace dawn::ityp #endif // SRC_DAWN_COMMON_TYPEDINTEGER_H_