43 lines
1.2 KiB
C++
43 lines
1.2 KiB
C++
/**
|
|
This file is a part of rexy's general purpose library
|
|
Copyright (C) 2020 rexy712
|
|
|
|
This program is free software: you can redistribute it and/or modify
|
|
it under the terms of the GNU Affero General Public License as published by
|
|
the Free Software Foundation, either version 3 of the License, or
|
|
(at your option) any later version.
|
|
|
|
This program is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
GNU Affero General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Affero General Public License
|
|
along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#ifndef REXY_CX_HASH_HPP
|
|
#define REXY_CX_HASH_HPP
|
|
|
|
#include <climits> //CHAR_BIT
|
|
|
|
namespace rexy::cx{
|
|
|
|
template<class T>
|
|
struct hash{
|
|
constexpr size_t operator()(const T& t, size_t salt = 0)const noexcept{
|
|
constexpr size_t bytes = sizeof(size_t);
|
|
size_t val = static_cast<size_t>(t);
|
|
size_t hash = 5381 + salt; //magic hash number
|
|
for(size_t i = 0;i < bytes;++i){
|
|
unsigned char c = static_cast<unsigned char>(val >> (i * CHAR_BIT));
|
|
hash = ((hash << 5) + hash) ^ c;
|
|
}
|
|
return hash;
|
|
}
|
|
};
|
|
|
|
}
|
|
|
|
#endif
|