148 lines
4.8 KiB
C++
148 lines
4.8 KiB
C++
#ifndef __CXXMPH_SEEDED_HASH_H__
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#define __CXXMPH_SEEDED_HASH_H__
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#include <stdint.h> // for uint32_t and friends
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#include <cstdlib>
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#include <cstring>
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#include <unordered_map> // for std::hash
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#include "MurmurHash3.h"
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#include "stringpiece.h"
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namespace cxxmph {
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struct h128 {
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const uint32_t& operator[](uint8_t i) const { return uint32[i]; }
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uint32_t& operator[](uint8_t i) { return uint32[i]; }
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uint64_t get64(bool second) const { return (static_cast<uint64_t>(uint32[second << 1]) << 32) | uint32[1 + (second << 1)]; }
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void set64(uint64_t v, bool second) { uint32[second << 1] = v >> 32; uint32[1+(second<<1)] = ((v << 32) >> 32); }
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bool operator==(const h128 rhs) const { return memcmp(uint32, rhs.uint32, sizeof(uint32)) == 0; }
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uint32_t uint32[4];
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struct hash32 { uint32_t operator()(const cxxmph::h128& h) const { return h[3]; } };
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};
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template <class HashFcn>
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struct seeded_hash_function {
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template <class Key>
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uint32_t operator()(const Key& k, uint32_t seed) const {
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uint32_t h;
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uint32_t h0 = HashFcn()(k);
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MurmurHash3_x86_32(reinterpret_cast<const void*>(&h0), 4, seed, &h);
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return h;
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}
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template <class Key>
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h128 hash128(const Key& k, uint32_t seed) const {
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h128 h;
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uint32_t h0 = HashFcn()(k);
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MurmurHash3_x64_128(reinterpret_cast<const void*>(&h0), 4, seed, &h);
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return h;
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}
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};
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struct Murmur3 {
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template<class Key>
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uint32_t operator()(const Key& k) const {
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uint32_t out;
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MurmurHash3_x86_32(reinterpret_cast<const void*>(&k), sizeof(Key), 1 /* seed */, &out);
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return out;
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}
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template <class Key>
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h128 hash128(const Key& k) const {
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h128 h;
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MurmurHash3_x64_128(reinterpret_cast<const void*>(&k), sizeof(Key), 1 /* seed */, &h);
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return h;
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}
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};
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struct Murmur3StringPiece {
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template <class Key>
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uint32_t operator()(const Key& k) const {
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StringPiece s(k);
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uint32_t out;
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MurmurHash3_x86_32(s.data(), s.length(), 1 /* seed */, &out);
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return out;
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}
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template <class Key>
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h128 hash128(const Key& k) const {
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h128 h;
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StringPiece s(k);
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MurmurHash3_x64_128(s.data(), s.length(), 1 /* seed */, &h);
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return h;
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}
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};
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template <>
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struct seeded_hash_function<Murmur3> {
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template <class Key>
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uint32_t operator()(const Key& k, uint32_t seed) const {
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uint32_t out;
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MurmurHash3_x86_32(reinterpret_cast<const void*>(&k), sizeof(Key), seed, &out);
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return out;
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}
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template <class Key>
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h128 hash128(const Key& k, uint32_t seed) const {
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h128 h;
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MurmurHash3_x64_128(reinterpret_cast<const void*>(&k), sizeof(Key), seed, &h);
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return h;
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}
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};
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template <>
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struct seeded_hash_function<Murmur3StringPiece> {
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template <class Key>
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uint32_t operator()(const Key& k, uint32_t seed) const {
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StringPiece s(k);
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uint32_t out;
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MurmurHash3_x86_32(s.data(), s.length(), seed, &out);
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return out;
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}
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template <class Key>
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h128 hash128(const Key& k, uint32_t seed) const {
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h128 h;
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StringPiece s(k);
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MurmurHash3_x64_128(s.data(), s.length(), seed, &h);
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return h;
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}
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};
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template <class HashFcn> struct seeded_hash
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{ typedef seeded_hash_function<HashFcn> hash_function; };
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// Use Murmur3 instead for all types defined in std::hash, plus
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// std::string which is commonly extended.
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template <> struct seeded_hash<std::hash<char*> >
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{ typedef seeded_hash_function<Murmur3StringPiece> hash_function; };
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template <> struct seeded_hash<std::hash<const char*> >
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{ typedef seeded_hash_function<Murmur3StringPiece> hash_function; };
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template <> struct seeded_hash<std::hash<std::string> >
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{ typedef seeded_hash_function<Murmur3StringPiece> hash_function; };
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template <> struct seeded_hash<std::hash<cxxmph::StringPiece> >
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{ typedef seeded_hash_function<Murmur3StringPiece> hash_function; };
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template <> struct seeded_hash<std::hash<char> >
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{ typedef seeded_hash_function<Murmur3> hash_function; };
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template <> struct seeded_hash<std::hash<unsigned char> >
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{ typedef seeded_hash_function<Murmur3> hash_function; };
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template <> struct seeded_hash<std::hash<short> >
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{ typedef seeded_hash_function<Murmur3> hash_function; };
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template <> struct seeded_hash<std::hash<unsigned short> >
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{ typedef seeded_hash_function<Murmur3> hash_function; };
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template <> struct seeded_hash<std::hash<int> >
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{ typedef seeded_hash_function<Murmur3> hash_function; };
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template <> struct seeded_hash<std::hash<unsigned int> >
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{ typedef seeded_hash_function<Murmur3> hash_function; };
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template <> struct seeded_hash<std::hash<long> >
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{ typedef seeded_hash_function<Murmur3> hash_function; };
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template <> struct seeded_hash<std::hash<unsigned long> >
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{ typedef seeded_hash_function<Murmur3> hash_function; };
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template <> struct seeded_hash<std::hash<long long> >
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{ typedef seeded_hash_function<Murmur3> hash_function; };
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template <> struct seeded_hash<std::hash<unsigned long long> >
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{ typedef seeded_hash_function<Murmur3> hash_function; };
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} // namespace cxxmph
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#endif // __CXXMPH_SEEDED_HASH_H__
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