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#ifndef CEPH_HASH_H
#define CEPH_HASH_H
#include "acconfig.h"
// Robert Jenkins' function for mixing 32-bit values
// http://burtleburtle.net/bob/hash/evahash.html
// a, b = random bits, c = input and output
#define hashmix(a,b,c) \
a=a-b; a=a-c; a=a^(c>>13); \
b=b-c; b=b-a; b=b^(a<<8); \
c=c-a; c=c-b; c=c^(b>>13); \
a=a-b; a=a-c; a=a^(c>>12); \
b=b-c; b=b-a; b=b^(a<<16); \
c=c-a; c=c-b; c=c^(b>>5); \
a=a-b; a=a-c; a=a^(c>>3); \
b=b-c; b=b-a; b=b^(a<<10); \
c=c-a; c=c-b; c=c^(b>>15);
//namespace ceph {
template <class _Key> struct rjhash { };
inline uint64_t rjhash64(uint64_t key) {
key = (~key) + (key << 21); // key = (key << 21) - key - 1;
key = key ^ (key >> 24);
key = (key + (key << 3)) + (key << 8); // key * 265
key = key ^ (key >> 14);
key = (key + (key << 2)) + (key << 4); // key * 21
key = key ^ (key >> 28);
key = key + (key << 31);
return key;
}
inline uint32_t rjhash32(uint32_t a) {
a = (a+0x7ed55d16) + (a<<12);
a = (a^0xc761c23c) ^ (a>>19);
a = (a+0x165667b1) + (a<<5);
a = (a+0xd3a2646c) ^ (a<<9);
a = (a+0xfd7046c5) + (a<<3);
a = (a^0xb55a4f09) ^ (a>>16);
return a;
}
template<> struct rjhash<uint32_t> {
inline size_t operator()(const uint32_t x) const {
return rjhash32(x);
}
};
template<> struct rjhash<uint64_t> {
inline size_t operator()(const uint64_t x) const {
return rjhash64(x);
}
};
//}
#endif
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