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kakoune/src/hash.hh
Maxime Coste ebecd60eb8 Rework hashing, use a more extensible framework similar to n3876 proposal
std::hash specialization is a pain to work with, stop using that, and
just specialize a 'size_t hash_value(const T&)' free function.
2014-12-16 18:57:19 +00:00

58 lines
1.2 KiB
C++

#ifndef hash_hh_INCLUDED
#define hash_hh_INCLUDED
#include <type_traits>
#include <functional>
namespace Kakoune
{
size_t hash_data(const char* data, size_t len);
template<typename Type>
typename std::enable_if<not std::is_enum<Type>::value, size_t>::type
hash_value(const Type& val)
{
return std::hash<Type>()(val);
}
template<typename Type>
typename std::enable_if<std::is_enum<Type>::value, size_t>::type
hash_value(const Type& val)
{
return hash_value((typename std::underlying_type<Type>::type)val);
}
template<typename Type>
size_t hash_values(Type&& t)
{
return hash_value(std::forward<Type>(t));
}
template<typename Type, typename... RemainingTypes>
size_t hash_values(Type&& t, RemainingTypes&&... rt)
{
size_t seed = hash_values(std::forward<RemainingTypes>(rt)...);
return seed ^ (hash_value(std::forward<Type>(t)) + 0x9e3779b9 +
(seed << 6) + (seed >> 2));
}
template<typename T1, typename T2>
size_t hash_value(const std::pair<T1, T2>& val)
{
return hash_values(val.first, val.second);
}
template<typename Type>
struct Hash
{
size_t operator()(const Type& val) const
{
return hash_value(val);
}
};
}
#endif // hash_hh_INCLUDED