Kernel/include_std/functional
2024-01-19 06:47:42 +02:00

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/*
This file is part of Fennix Kernel.
Fennix Kernel is free software: you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation, either version 3 of
the License, or (at your option) any later version.
Fennix Kernel 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with Fennix Kernel. If not, see <https://www.gnu.org/licenses/>.
*/
#pragma once
namespace std
{
template <typename T>
struct equal_to
{
bool operator()(const T &lhs, const T &rhs) const
{
return lhs == rhs;
}
};
template <typename Key>
struct hash
{
size_t operator()(const Key &key) const
{
#if defined(a64)
static_assert(sizeof(uintptr_t) == sizeof(uint64_t));
const uint64_t FNV_OFFSET_BASIS = 14695981039346656037ull;
const uint64_t FNV_PRIME = 1099511628211ull;
#elif defined(a32)
static_assert(sizeof(uintptr_t) == sizeof(uint32_t));
const uint32_t FNV_OFFSET_BASIS = 2166136261u;
const uint32_t FNV_PRIME = 16777619u;
#else
#error "Unsupported architecture"
#endif
const uint8_t *data = reinterpret_cast<const uint8_t *>(&key);
const size_t size = sizeof(Key);
uintptr_t hash = FNV_OFFSET_BASIS;
for (size_t i = 0; i < size; ++i)
{
hash ^= static_cast<uintptr_t>(data[i]);
hash *= FNV_PRIME;
}
return static_cast<size_t>(hash);
}
};
}