luau/EqSat/include/Luau/LanguageHash.h
2024-08-01 16:26:06 -07:00

57 lines
1.3 KiB
C++

// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
#pragma once
#include <cstddef>
#include <functional>
namespace Luau::EqSat
{
template<typename T>
struct LanguageHash
{
size_t operator()(const T& t, decltype(std::hash<T>{}(std::declval<T>()))* = 0) const
{
return std::hash<T>{}(t);
}
};
template<typename T>
size_t languageHash(const T& lang)
{
return LanguageHash<T>{}(lang);
}
inline void hashCombine(size_t& seed, size_t hash)
{
// Golden Ratio constant used for better hash scattering
// See https://softwareengineering.stackexchange.com/a/402543
seed ^= hash + 0x9e3779b9 + (seed << 6) + (seed >> 2);
}
template<typename T, size_t I>
struct LanguageHash<std::array<T, I>>
{
size_t operator()(const std::array<T, I>& array) const
{
size_t seed = 0;
for (const T& t : array)
hashCombine(seed, languageHash(t));
return seed;
}
};
template<typename T>
struct LanguageHash<std::vector<T>>
{
size_t operator()(const std::vector<T>& vector) const
{
size_t seed = 0;
for (const T& t : vector)
hashCombine(seed, languageHash(t));
return seed;
}
};
} // namespace Luau::EqSat