1e5c31af7Sopenharmony_ci// Copyright 2018 The Amber Authors. 2e5c31af7Sopenharmony_ci// 3e5c31af7Sopenharmony_ci// Licensed under the Apache License, Version 2.0 (the "License"); 4e5c31af7Sopenharmony_ci// you may not use this file except in compliance with the License. 5e5c31af7Sopenharmony_ci// You may obtain a copy of the License at 6e5c31af7Sopenharmony_ci// 7e5c31af7Sopenharmony_ci// http://www.apache.org/licenses/LICENSE-2.0 8e5c31af7Sopenharmony_ci// 9e5c31af7Sopenharmony_ci// Unless required by applicable law or agreed to in writing, software 10e5c31af7Sopenharmony_ci// distributed under the License is distributed on an "AS IS" BASIS, 11e5c31af7Sopenharmony_ci// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12e5c31af7Sopenharmony_ci// See the License for the specific language governing permissions and 13e5c31af7Sopenharmony_ci// limitations under the License. 14e5c31af7Sopenharmony_ci 15e5c31af7Sopenharmony_ci#ifndef SRC_CAST_HASH_H_ 16e5c31af7Sopenharmony_ci#define SRC_CAST_HASH_H_ 17e5c31af7Sopenharmony_ci 18e5c31af7Sopenharmony_ci#include <cstddef> 19e5c31af7Sopenharmony_ci 20e5c31af7Sopenharmony_cinamespace amber { 21e5c31af7Sopenharmony_ci 22e5c31af7Sopenharmony_ci/// A hash implementation for types that can trivially be up-cast to a size_t. 23e5c31af7Sopenharmony_ci/// For example, use this as a hasher for an enum whose underlying type is 24e5c31af7Sopenharmony_ci/// an integer no wider than size_t. 25e5c31af7Sopenharmony_ci/// 26e5c31af7Sopenharmony_ci/// The need for this was a defect in the C++11 library, and has been fixed 27e5c31af7Sopenharmony_ci/// in C++14. http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2148 28e5c31af7Sopenharmony_citemplate <typename T> 29e5c31af7Sopenharmony_cistruct CastHash { 30e5c31af7Sopenharmony_ci size_t operator()(const T& value) const { return static_cast<size_t>(value); } 31e5c31af7Sopenharmony_ci}; 32e5c31af7Sopenharmony_ci 33e5c31af7Sopenharmony_ci} // namespace amber 34e5c31af7Sopenharmony_ci 35e5c31af7Sopenharmony_ci#endif // SRC_CAST_HASH_H_ 36