1 /* A hasher for enums. 2 3 Copyright (C) 2017-2020 Free Software Foundation, Inc. 4 5 This file is part of GDB. 6 7 This program is free software; you can redistribute it and/or modify 8 it under the terms of the GNU General Public License as published by 9 the Free Software Foundation; either version 3 of the License, or 10 (at your option) any later version. 11 12 This program is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 GNU General Public License for more details. 16 17 You should have received a copy of the GNU General Public License 18 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 19 20 #ifndef COMMON_HASH_ENUM_H 21 #define COMMON_HASH_ENUM_H 22 23 /* A hasher for enums, which was missing in C++11: 24 http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2148 25 */ 26 27 namespace gdb { 28 29 /* Helper struct for hashing enum types. */ 30 template<typename T> 31 struct hash_enum 32 { 33 typedef size_t result_type; 34 typedef T argument_type; 35 36 size_t operator() (T val) const noexcept 37 { 38 using underlying = typename std::underlying_type<T>::type; 39 return std::hash<underlying> () (static_cast<underlying> (val)); 40 } 41 }; 42 43 } /* namespace gdb */ 44 45 #endif /* COMMON_HASH_ENUM_H */ 46