77 lines
4.3 KiB
C
77 lines
4.3 KiB
C
// Author: Wang Yi <godspeed_china@yeah.net>
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#ifndef wyhash_version_4
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#define wyhash_version_4
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#include <stdint.h>
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#include <string.h>
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#if defined(_MSC_VER) && defined(_M_X64)
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#include <intrin.h>
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#pragma intrinsic(_umul128)
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#endif
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const uint64_t _wyp0=0xa0761d6478bd642full, _wyp1=0xe7037ed1a0b428dbull, _wyp2=0x8ebc6af09c88c6e3ull, _wyp3=0x589965cc75374cc3ull, _wyp4=0x1d8e4e27c47d124full;
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static inline uint64_t _wyrotr(uint64_t v, unsigned k) { return (v>>k)|(v<<(64-k)); }
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static inline uint64_t _wymum(uint64_t A, uint64_t B) {
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#ifdef WYHASH32
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uint64_t hh=(A>>32)*(B>>32), hl=(A>>32)*(unsigned)B, lh=(unsigned)A*(B>>32), ll=(uint64_t)(unsigned)A*(unsigned)B;
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return _wyrotr(hl,32)^_wyrotr(lh,32)^hh^ll;
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#else
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#ifdef __SIZEOF_INT128__
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__uint128_t r=A; r*=B; return (r>>64)^r;
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#elif defined(_MSC_VER) && defined(_M_X64)
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A=_umul128(A, B, &B); return A^B;
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#else
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uint64_t ha=A>>32, hb=B>>32, la=(uint32_t)A, lb=(uint32_t)B, hi, lo;
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uint64_t rh=ha*hb, rm0=ha*lb, rm1=hb*la, rl=la*lb, t=rl+(rm0<<32), c=t<rl;
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lo=t+(rm1<<32); c+=lo<t;hi=rh+(rm0>>32)+(rm1>>32)+c; return hi^lo;
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#endif
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#endif
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}
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#ifndef WYHASH_LITTLE_ENDIAN
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#if defined(_WIN32) || defined(__LITTLE_ENDIAN__) || (defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__)
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#define WYHASH_LITTLE_ENDIAN 1
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#elif defined(__BIG_ENDIAN__) || (defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
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#define WYHASH_LITTLE_ENDIAN 0
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#endif
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#endif
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#if(WYHASH_LITTLE_ENDIAN) || defined(__TINYC__)
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static inline uint64_t _wyr8(const uint8_t *p) { uint64_t v; memcpy(&v, p, 8); return v; }
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static inline uint64_t _wyr4(const uint8_t *p) { unsigned v; memcpy(&v, p, 4); return v; }
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#else
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#if defined(__GNUC__) || defined(__INTEL_COMPILER)
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static inline uint64_t _wyr8(const uint8_t *p) { uint64_t v; memcpy(&v, p, 8); return __builtin_bswap64(v); }
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static inline uint64_t _wyr4(const uint8_t *p) { unsigned v; memcpy(&v, p, 4); return __builtin_bswap32(v); }
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#elif defined(_MSC_VER)
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static inline uint64_t _wyr8(const uint8_t *p) { uint64_t v; memcpy(&v, p, 8); return _byteswap_uint64(v);}
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static inline uint64_t _wyr4(const uint8_t *p) { unsigned v; memcpy(&v, p, 4); return _byteswap_ulong(v); }
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#endif
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#endif
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static inline uint64_t _wyr3(const uint8_t *p, unsigned k) { return (((uint64_t)p[0])<<16)|(((uint64_t)p[k>>1])<<8)|p[k-1]; }
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static inline uint64_t wyhash(const void* key, uint64_t len, uint64_t seed) {
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const uint8_t *p=(const uint8_t*)key; uint64_t i=len&63;
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#if defined(__GNUC__) || defined(__INTEL_COMPILER)
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#define _like_(x) __builtin_expect(x,1)
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#define _unlike_(x) __builtin_expect(x,0)
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#else
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#define _like_(x) (x)
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#define _unlike_(x) (x)
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#endif
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if(_unlike_(!i)) { }
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else if(_unlike_(i<4)) seed=_wymum(_wyr3(p,i)^seed^_wyp0,seed^_wyp1);
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else if(_like_(i<=8)) seed=_wymum(_wyr4(p)^seed^_wyp0,_wyr4(p+i-4)^seed^_wyp1);
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else if(_like_(i<=16)) seed=_wymum(_wyr8(p)^seed^_wyp0,_wyr8(p+i-8)^seed^_wyp1);
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else if(_like_(i<=24)) seed=_wymum(_wyr8(p)^seed^_wyp0,_wyr8(p+8)^seed^_wyp1)^_wymum(_wyr8(p+i-8)^seed^_wyp2,seed^_wyp3);
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else if(_like_(i<=32)) seed=_wymum(_wyr8(p)^seed^_wyp0,_wyr8(p+8)^seed^_wyp1)^_wymum(_wyr8(p+16)^seed^_wyp2,_wyr8(p+i-8)^seed^_wyp3);
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else{ seed=_wymum(_wyr8(p)^seed^_wyp0,_wyr8(p+8)^seed^_wyp1)^_wymum(_wyr8(p+16)^seed^_wyp2,_wyr8(p+24)^seed^_wyp3)^_wymum(_wyr8(p+i-32)^seed^_wyp1,_wyr8(p+i-24)^seed^_wyp2)^_wymum(_wyr8(p+i-16)^seed^_wyp3,_wyr8(p+i-8)^seed^_wyp0); }
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if(_like_(i==len)) return _wymum(seed,len^_wyp4);
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uint64_t see1=seed, see2=seed, see3=seed;
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for(p+=i,i=len-i; _like_(i>=64); i-=64,p+=64) {
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seed=_wymum(_wyr8(p)^seed^_wyp0,_wyr8(p+8)^seed^_wyp1); see1=_wymum(_wyr8(p+16)^see1^_wyp2,_wyr8(p+24)^see1^_wyp3);
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see2=_wymum(_wyr8(p+32)^see2^_wyp1,_wyr8(p+40)^see2^_wyp2); see3=_wymum(_wyr8(p+48)^see3^_wyp3,_wyr8(p+56)^see3^_wyp0);
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}
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return _wymum(seed^see1^see2,see3^len^_wyp4);
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}
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static inline uint64_t wyhash64(uint64_t A, uint64_t B) { return _wymum(_wymum(A^_wyp0, B^_wyp1), _wyp2); }
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static inline uint64_t wyrand(uint64_t *seed) { *seed+=_wyp0; return _wymum(*seed^_wyp1,*seed); }
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static inline double wy2u01(uint64_t r) { const double _wynorm=1.0/(1ull<<52); return (r>>11)*_wynorm; }
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static inline double wy2gau(uint64_t r) { const double _wynorm=1.0/(1ull<<20); return ((r&0x1fffff)+((r>>21)&0x1fffff)+((r>>42)&0x1fffff))*_wynorm-3.0; }
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#endif
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