| // Copyright 2018 The Amber Authors. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| #ifndef SRC_CAST_HASH_H_ |
| #define SRC_CAST_HASH_H_ |
| |
| namespace amber { |
| |
| /// A hash implementation for types that can trivially be up-cast to a size_t. |
| /// For example, use this as a hasher for an enum whose underlying type is |
| /// an integer no wider than size_t. |
| /// |
| /// The need for this was a defect in the C++11 library, and has been fixed |
| /// in C++14. http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2148 |
| template <typename T> |
| struct CastHash { |
| size_t operator()(const T& value) const { return static_cast<size_t>(value); } |
| }; |
| |
| } // namespace amber |
| |
| #endif // SRC_CAST_HASH_H_ |
