wehub-resource-sync
151 lines
5.9 KiB
C
151 lines
5.9 KiB
C
// This is free and unencumbered software released into the public domain under The Unlicense (http://unlicense.org/)
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// main repo: https://github.com/wangyi-fudan/wyhash
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// author: 王一 Wang Yi <godspeed_china@yeah.net>
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// contributors: Reini Urban, Dietrich Epp, Joshua Haberman, Tommy Ettinger, Daniel Lemire, Otmar Ertl, cocowalla, leo-yuriev, Diego Barrios Romero, paulie-g, dumblob, Yann Collet, ivte-ms, hyb, James Z.M. Gao, easyaspi314 (Devin), TheOneric
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/* quick example:
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string s="fjsakfdsjkf";
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uint64_t hash=wyhash(s.c_str(), s.size(), 0, _wyp);
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*/
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#ifndef wyhash_final_version_4_3
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#define wyhash_final_version_4_3
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#ifndef WYHASH_CONDOM
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//protections that produce different results:
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//1: normal valid behavior
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//2: extra protection against entropy loss (probability=2^-63), aka. "blind multiplication"
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#define WYHASH_CONDOM 1
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#endif
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#ifndef WYHASH_32BIT_MUM
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//0: normal version, slow on 32 bit systems
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//1: faster on 32 bit systems but produces different results, incompatible with wy2u0k function
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#define WYHASH_32BIT_MUM 0
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#endif
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//includes
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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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//likely and unlikely macros
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#if defined(__GNUC__) || defined(__INTEL_COMPILER) || defined(__clang__)
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#define _likely_(x) __builtin_expect(x,1)
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#define _unlikely_(x) __builtin_expect(x,0)
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#else
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#define _likely_(x) (x)
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#define _unlikely_(x) (x)
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#endif
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//128bit multiply function
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static inline uint64_t _wyrot(uint64_t x) { return (x>>32)|(x<<32); }
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static inline void _wymum(uint64_t *A, uint64_t *B){
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#if(WYHASH_32BIT_MUM)
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uint64_t hh=(*A>>32)*(*B>>32), hl=(*A>>32)*(uint32_t)*B, lh=(uint32_t)*A*(*B>>32), ll=(uint64_t)(uint32_t)*A*(uint32_t)*B;
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#if(WYHASH_CONDOM>1)
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*A^=_wyrot(hl)^hh; *B^=_wyrot(lh)^ll;
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#else
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*A=_wyrot(hl)^hh; *B=_wyrot(lh)^ll;
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#endif
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#elif defined(__SIZEOF_INT128__)
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__uint128_t r=*A; r*=*B;
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#if(WYHASH_CONDOM>1)
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*A^=(uint64_t)r; *B^=(uint64_t)(r>>64);
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#else
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*A=(uint64_t)r; *B=(uint64_t)(r>>64);
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#endif
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#elif defined(_MSC_VER) && defined(_M_X64)
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#if(WYHASH_CONDOM>1)
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uint64_t a, b;
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a=_umul128(*A,*B,&b);
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*A^=a; *B^=b;
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#else
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*A=_umul128(*A,*B,B);
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#endif
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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;
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#if(WYHASH_CONDOM>1)
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*A^=lo; *B^=hi;
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#else
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*A=lo; *B=hi;
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#endif
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#endif
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}
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//multiply and xor mix function, aka MUM
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static inline uint64_t _wymix(uint64_t A, uint64_t B){ _wymum(&A,&B); return A^B; }
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//endian macros
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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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#else
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#warning could not determine endianness! Falling back to little endian.
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#define WYHASH_LITTLE_ENDIAN 1
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#endif
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#endif
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//read functions
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#if (WYHASH_LITTLE_ENDIAN)
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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) { uint32_t v; memcpy(&v, p, 4); return v;}
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#elif defined(__GNUC__) || defined(__INTEL_COMPILER) || defined(__clang__)
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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) { uint32_t 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) { uint32_t v; memcpy(&v, p, 4); return _byteswap_ulong(v);}
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#else
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static inline uint64_t _wyr8(const uint8_t *p) {
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uint64_t v; memcpy(&v, p, 8);
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return (((v >> 56) & 0xff)| ((v >> 40) & 0xff00)| ((v >> 24) & 0xff0000)| ((v >> 8) & 0xff000000)| ((v << 8) & 0xff00000000)| ((v << 24) & 0xff0000000000)| ((v << 40) & 0xff000000000000)| ((v << 56) & 0xff00000000000000));
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}
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static inline uint64_t _wyr4(const uint8_t *p) {
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uint32_t v; memcpy(&v, p, 4);
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return (((v >> 24) & 0xff)| ((v >> 8) & 0xff00)| ((v << 8) & 0xff0000)| ((v << 24) & 0xff000000));
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}
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#endif
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static inline uint64_t _wyr3(const uint8_t *p, size_t k) { return (((uint64_t)p[0])<<16)|(((uint64_t)p[k>>1])<<8)|p[k-1];}
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//wyhash main function
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static inline uint64_t wyhash(const void *key, size_t len, uint64_t seed, const uint64_t *secret){
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const uint8_t *p=(const uint8_t *)key; seed^=_wymix(seed^secret[0],secret[1]); uint64_t a, b;
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if(_likely_(len<=16)){
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if(_likely_(len>=4)){ a=(_wyr4(p)<<32)|_wyr4(p+((len>>3)<<2)); b=(_wyr4(p+len-4)<<32)|_wyr4(p+len-4-((len>>3)<<2)); }
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else if(_likely_(len>0)){ a=_wyr3(p,len); b=0;}
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else a=b=0;
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}
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else{
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size_t i=len;
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if(_unlikely_(i>=48)){
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uint64_t see1=seed, see2=seed;
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do{
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seed=_wymix(_wyr8(p)^secret[1],_wyr8(p+8)^seed);
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see1=_wymix(_wyr8(p+16)^secret[2],_wyr8(p+24)^see1);
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see2=_wymix(_wyr8(p+32)^secret[3],_wyr8(p+40)^see2);
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p+=48; i-=48;
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}while(_likely_(i>=48));
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seed^=see1^see2;
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}
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while(_unlikely_(i>16)){ seed=_wymix(_wyr8(p)^secret[1],_wyr8(p+8)^seed); i-=16; p+=16; }
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a=_wyr8(p+i-16); b=_wyr8(p+i-8);
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}
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a^=secret[1]; b^=seed; _wymum(&a,&b);
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return _wymix(a^secret[0]^len,b^secret[1]);
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}
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//the default secret parameters
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static const uint64_t _wyp[4] = {0x2d358dccaa6c78a5ull, 0x8bb84b93962eacc9ull, 0x4b33a62ed433d4a3ull, 0x4d5a2da51de1aa47ull};
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//a useful 64bit-64bit mix function to produce deterministic pseudo random numbers that can pass BigCrush and PractRand
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static inline uint64_t wyhash64(uint64_t A, uint64_t B){ A^=0x2d358dccaa6c78a5ull; B^=0x8bb84b93962eacc9ull; _wymum(&A,&B); return _wymix(A^0x2d358dccaa6c78a5ull,B^0x8bb84b93962eacc9ull);}
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#endif
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