mirror of https://github.com/trapexit/mergerfs.git
295 lines
12 KiB
C
295 lines
12 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_2
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#define wyhash_final_version_4_2
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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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//The wyrand PRNG that pass BigCrush and PractRand
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static inline uint64_t wyrand(uint64_t *seed){ *seed+=0x2d358dccaa6c78a5ull; return _wymix(*seed,*seed^0x8bb84b93962eacc9ull);}
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//convert any 64 bit pseudo random numbers to uniform distribution [0,1). It can be combined with wyrand, wyhash64 or wyhash.
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static inline double wy2u01(uint64_t r){ const double _wynorm=1.0/(1ull<<52); return (r>>12)*_wynorm;}
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//convert any 64 bit pseudo random numbers to APPROXIMATE Gaussian distribution. It can be combined with wyrand, wyhash64 or wyhash.
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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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#ifdef WYTRNG
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#include <sys/time.h>
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//The wytrand true random number generator, passed BigCrush.
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static inline uint64_t wytrand(uint64_t *seed){
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struct timeval t; gettimeofday(&t,0);
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uint64_t teed=(((uint64_t)t.tv_sec)<<32)|t.tv_usec;
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teed=_wymix(teed^_wyp[0],*seed^_wyp[1]);
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*seed=_wymix(teed^_wyp[0],_wyp[2]);
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return _wymix(*seed,*seed^_wyp[3]);
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}
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#endif
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#if(!WYHASH_32BIT_MUM)
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//fast range integer random number generation on [0,k) credit to Daniel Lemire. May not work when WYHASH_32BIT_MUM=1. It can be combined with wyrand, wyhash64 or wyhash.
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static inline uint64_t wy2u0k(uint64_t r, uint64_t k){ _wymum(&r,&k); return k; }
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#endif
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// modified from https://github.com/going-digital/Prime64
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static inline unsigned long long mul_mod(unsigned long long a, unsigned long long b, unsigned long long m) {
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unsigned long long r=0;
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while (b) {
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if (b & 1) {
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unsigned long long r2 = r + a;
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if (r2 < r) r2 -= m;
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r = r2 % m;
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}
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b >>= 1;
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if (b) {
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unsigned long long a2 = a + a;
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if (a2 < a) a2 -= m;
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a = a2 % m;
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}
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}
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return r;
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}
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static inline unsigned long long pow_mod(unsigned long long a, unsigned long long b, unsigned long long m) {
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unsigned long long r=1;
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while (b) {
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if (b&1) r=mul_mod(r,a,m);
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b>>=1;
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if (b) a=mul_mod(a,a,m);
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}
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return r;
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}
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static inline unsigned sprp(unsigned long long n, unsigned long long a) {
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unsigned long long d=n-1;
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unsigned char s=0;
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while (!(d & 0xff)) { d>>=8; s+=8; }
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if (!(d & 0xf)) { d>>=4; s+=4; }
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if (!(d & 0x3)) { d>>=2; s+=2; }
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if (!(d & 0x1)) { d>>=1; s+=1; }
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unsigned long long b=pow_mod(a,d,n);
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if ((b==1) || (b==(n-1))) return 1;
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unsigned char r;
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for (r=1; r<s; r++) {
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b=mul_mod(b,b,n);
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if (b<=1) return 0;
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if (b==(n-1)) return 1;
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}
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return 0;
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}
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static inline unsigned is_prime(unsigned long long n) {
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if (n<2||!(n&1)) return 0;
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if (n<4) return 1;
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if (!sprp(n,2)) return 0;
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if (n<2047) return 1;
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if (!sprp(n,3)) return 0;
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if (!sprp(n,5)) return 0;
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if (!sprp(n,7)) return 0;
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if (!sprp(n,11)) return 0;
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if (!sprp(n,13)) return 0;
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if (!sprp(n,17)) return 0;
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if (!sprp(n,19)) return 0;
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if (!sprp(n,23)) return 0;
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if (!sprp(n,29)) return 0;
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if (!sprp(n,31)) return 0;
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if (!sprp(n,37)) return 0;
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return 1;
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}
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//make your own secret
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static inline void make_secret(uint64_t seed, uint64_t *secret){
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uint8_t c[] = {15, 23, 27, 29, 30, 39, 43, 45, 46, 51, 53, 54, 57, 58, 60, 71, 75, 77, 78, 83, 85, 86, 89, 90, 92, 99, 101, 102, 105, 106, 108, 113, 114, 116, 120, 135, 139, 141, 142, 147, 149, 150, 153, 154, 156, 163, 165, 166, 169, 170, 172, 177, 178, 180, 184, 195, 197, 198, 201, 202, 204, 209, 210, 212, 216, 225, 226, 228, 232, 240 };
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for(size_t i=0;i<4;i++){
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uint8_t ok;
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do{
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ok=1; secret[i]=0;
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for(size_t j=0;j<64;j+=8) secret[i]|=((uint64_t)c[wyrand(&seed)%sizeof(c)])<<j;
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if(secret[i]%2==0){ ok=0; continue; }
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for(size_t j=0;j<i;j++) {
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#if defined(__GNUC__) || defined(__INTEL_COMPILER) || defined(__clang__)
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if(__builtin_popcountll(secret[j]^secret[i])!=32){ ok=0; break; }
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#elif defined(_MSC_VER) && defined(_M_X64)
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if(_mm_popcnt_u64(secret[j]^secret[i])!=32){ ok=0; break; }
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#else
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//manual popcount
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uint64_t x = secret[j]^secret[i];
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x -= (x >> 1) & 0x5555555555555555;
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x = (x & 0x3333333333333333) + ((x >> 2) & 0x3333333333333333);
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x = (x + (x >> 4)) & 0x0f0f0f0f0f0f0f0f;
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x = (x * 0x0101010101010101) >> 56;
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if(x!=32){ ok=0; break; }
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#endif
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}
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if(ok&&!is_prime(secret[i])) ok=0;
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}while(!ok);
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}
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}
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#endif
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/* The Unlicense
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This is free and unencumbered software released into the public domain.
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Anyone is free to copy, modify, publish, use, compile, sell, or
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distribute this software, either in source code form or as a compiled
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binary, for any purpose, commercial or non-commercial, and by any
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means.
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In jurisdictions that recognize copyright laws, the author or authors
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of this software dedicate any and all copyright interest in the
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software to the public domain. We make this dedication for the benefit
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of the public at large and to the detriment of our heirs and
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successors. We intend this dedication to be an overt act of
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relinquishment in perpetuity of all present and future rights to this
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software under copyright law.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
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OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
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ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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OTHER DEALINGS IN THE SOFTWARE.
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For more information, please refer to <http://unlicense.org/>
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*/
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