97 lines
3.3 KiB
C++
97 lines
3.3 KiB
C++
#ifndef __CXXMPH_SEEDED_HASH_H__
|
|
#define __CXXMPH_SEEDED_HASH_H__
|
|
|
|
#include <stdint.h> // for uint32_t and friends
|
|
|
|
#include <cstdlib>
|
|
#include <tr1/unordered_map> // for std::tr1::hash
|
|
|
|
#include "MurmurHash2.h"
|
|
#include "stringpiece.h"
|
|
|
|
namespace cxxmph {
|
|
|
|
template <class HashFcn>
|
|
struct seeded_hash_function {
|
|
template <class Key>
|
|
uint32_t operator()(const Key& k, uint32_t seed) const {
|
|
return HashFcn()(k) ^ seed;
|
|
}
|
|
};
|
|
|
|
struct seeded_identity_function {
|
|
template <class Key>
|
|
uint32_t operator()(const Key& k, uint32_t seed) const {
|
|
return k ^ seed;
|
|
}
|
|
};
|
|
|
|
struct Murmur2 {
|
|
template<class Key>
|
|
uint32_t operator()(const Key& k) const {
|
|
return MurmurHash2(reinterpret_cast<const void*>(&k), sizeof(Key), 1 /* seed */);
|
|
}
|
|
};
|
|
struct Murmur2StringPiece {
|
|
template <class Key>
|
|
uint32_t operator()(const Key& k) const {
|
|
StringPiece s(k);
|
|
return MurmurHash2(s.data(), s.length(), 1 /* seed */);
|
|
}
|
|
};
|
|
|
|
template <>
|
|
struct seeded_hash_function<Murmur2> {
|
|
template <class Key>
|
|
uint32_t operator()(const Key& k, uint32_t seed) const {
|
|
return MurmurHash2(reinterpret_cast<const void*>(&k), sizeof(Key), seed);
|
|
}
|
|
};
|
|
|
|
template <>
|
|
struct seeded_hash_function<Murmur2StringPiece> {
|
|
template <class Key>
|
|
uint32_t operator()(const Key& k, uint32_t seed) const {
|
|
StringPiece s(k);
|
|
return MurmurHash2(s.data(), s.length(), seed);
|
|
}
|
|
};
|
|
|
|
template <class HashFcn> struct seeded_hash
|
|
{ typedef seeded_hash_function<HashFcn> hash_function; };
|
|
// Use Murmur2 instead for all types defined in std::tr1::hash, plus
|
|
// std::string which is commonly extended.
|
|
template <> struct seeded_hash<std::tr1::hash<char*> >
|
|
{ typedef seeded_hash_function<Murmur2StringPiece> hash_function; };
|
|
template <> struct seeded_hash<std::tr1::hash<const char*> >
|
|
{ typedef seeded_hash_function<Murmur2StringPiece> hash_function; };
|
|
template <> struct seeded_hash<std::tr1::hash<std::string> >
|
|
{ typedef seeded_hash_function<Murmur2StringPiece> hash_function; };
|
|
template <> struct seeded_hash<std::tr1::hash<cxxmph::StringPiece> >
|
|
{ typedef seeded_hash_function<Murmur2StringPiece> hash_function; };
|
|
|
|
template <> struct seeded_hash<std::tr1::hash<char> >
|
|
{ typedef seeded_hash_function<Murmur2> hash_function; };
|
|
template <> struct seeded_hash<std::tr1::hash<unsigned char> >
|
|
{ typedef seeded_hash_function<Murmur2> hash_function; };
|
|
template <> struct seeded_hash<std::tr1::hash<short> >
|
|
{ typedef seeded_hash_function<Murmur2> hash_function; };
|
|
template <> struct seeded_hash<std::tr1::hash<unsigned short> >
|
|
{ typedef seeded_hash_function<Murmur2> hash_function; };
|
|
template <> struct seeded_hash<std::tr1::hash<int> >
|
|
{ typedef seeded_hash_function<Murmur2> hash_function; };
|
|
template <> struct seeded_hash<std::tr1::hash<unsigned int> >
|
|
{ typedef seeded_hash_function<Murmur2> hash_function; };
|
|
template <> struct seeded_hash<std::tr1::hash<long> >
|
|
{ typedef seeded_hash_function<Murmur2> hash_function; };
|
|
template <> struct seeded_hash<std::tr1::hash<unsigned long> >
|
|
{ typedef seeded_hash_function<Murmur2> hash_function; };
|
|
template <> struct seeded_hash<std::tr1::hash<long long> >
|
|
{ typedef seeded_hash_function<Murmur2> hash_function; };
|
|
template <> struct seeded_hash<std::tr1::hash<unsigned long long> >
|
|
{ typedef seeded_hash_function<Murmur2> hash_function; };
|
|
|
|
} // namespace cxxmph
|
|
|
|
#endif // __CXXMPH_SEEDED_HASH_H__
|