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#ifndef _DEFAULT_HASHER_HH
#define _DEFAULT_HASHER_HH
#include <string>
#include <type_traits>
/*! DefaultHasher is the default hash class used in the table. It overloads a
* few types that std::hash does badly on (namely integers), and falls back to
* std::hash for anything else. */
template <class Key>
class DefaultHasher {
std::hash<Key> fallback;
public:
template <class T = Key>
typename std::enable_if<std::is_integral<T>::value, size_t>::type
operator()(const Key& k) const {
// This constant is found in the CityHash code
return k * 0x9ddfea08eb382d69ULL;
}
template <class T = Key>
typename std::enable_if<!std::is_integral<T>::value, size_t>::type
operator()(const Key& k) const {
return fallback(k);
}
};
#endif // _DEFAULT_HASHER_HH
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