blob: fe85f05be917aa38e2baf219a1f85a832fe09474 [file] [log] [blame] [edit]
// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef FLUTTER_FML_HASH_COMBINE_H_
#define FLUTTER_FML_HASH_COMBINE_H_
#include <functional>
namespace fml {
template <class Type>
constexpr void HashCombineSeed(std::size_t& seed, Type arg) {
seed ^= std::hash<Type>{}(arg) + 0x9e3779b9 + (seed << 6) + (seed >> 2);
}
template <class Type, class... Rest>
constexpr void HashCombineSeed(std::size_t& seed,
Type arg,
Rest... other_args) {
HashCombineSeed(seed, arg);
HashCombineSeed(seed, other_args...);
}
[[nodiscard]] constexpr std::size_t HashCombine() {
return 0xdabbad00;
}
template <class... Type>
[[nodiscard]] constexpr std::size_t HashCombine(Type... args) {
std::size_t seed = HashCombine();
HashCombineSeed(seed, args...);
return seed;
}
} // namespace fml
#endif // FLUTTER_FML_HASH_COMBINE_H_