72 lines
1.6 KiB
C++
72 lines
1.6 KiB
C++
#ifndef hash_hh_INCLUDED
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#define hash_hh_INCLUDED
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#include <type_traits>
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#include <utility>
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#include <cstddef>
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namespace Kakoune
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{
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size_t hash_data(const char* data, size_t len);
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template<typename Type> requires std::is_integral_v<Type>
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constexpr size_t hash_value(const Type& val)
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{
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return (size_t)val;
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}
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template<typename Type> requires std::is_enum_v<Type>
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constexpr size_t hash_value(const Type& val)
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{
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return hash_value((std::underlying_type_t<Type>)val);
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}
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template<typename Type>
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constexpr size_t hash_values(Type&& t)
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{
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return hash_value(std::forward<Type>(t));
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}
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constexpr size_t combine_hash(size_t lhs, size_t rhs)
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{
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return lhs ^ (rhs + 0x9e3779b9 + (lhs << 6) + (lhs >> 2));
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}
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template<typename Type, typename... RemainingTypes>
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constexpr size_t hash_values(Type&& t, RemainingTypes&&... rt)
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{
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size_t seed = hash_values(std::forward<RemainingTypes>(rt)...);
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return combine_hash(seed, hash_value(std::forward<Type>(t)));
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}
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template<typename T1, typename T2>
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constexpr size_t hash_value(const std::pair<T1, T2>& val)
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{
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return hash_values(val.first, val.second);
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}
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template<typename Type>
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struct Hash
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{
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constexpr size_t operator()(const Type& val) const
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{
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return hash_value(val);
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}
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};
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// Traits specifying if two types have compatible hashing, that is,
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// if lhs == rhs => hash_value(lhs) == hash_value(rhs)
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template<typename Lhs, typename Rhs>
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struct HashCompatible : std::false_type {};
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template<typename T> struct HashCompatible<T, T> : std::true_type {};
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template<typename Lhs, typename Rhs>
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constexpr bool IsHashCompatible = HashCompatible<Lhs, Rhs>::value;
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}
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#endif // hash_hh_INCLUDED
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