fasthash-sys-fork 0.4.2

A suite of non-cryptographic hash functions for Rust.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142

//Author: Wang Yi <godspeed_china@yeah.net>
#ifndef wyhash_version_gamma
#define wyhash_version_gamma
//defines that change behavior
#define WYHASH_SAFE_READ 0	//may read up to 8 bytes before/after
#define WYHASH_SAFE_MUM  0	//loss of entroy every 2^66 bytes
#define WYHASH_32BIT_MUM 0	//faster on 32 bit system
//includes
#include <stdint.h>
#include <string.h>
#if defined(_MSC_VER) && defined(_M_X64)
  #include <intrin.h>
  #pragma intrinsic(_umul128)
#endif
#if defined(__GNUC__) || defined(__INTEL_COMPILER) || defined(__clang__)
  #define _likely_(x)	__builtin_expect(x,1)
#else
  #define _likely_(x) (x)
#endif
//mum function
static inline uint64_t _wyrot(uint64_t x) { return (x>>32)|(x<<32); }
static inline void _wymum(uint64_t *A, uint64_t *B){
#if(WYHASH_32BIT_MUM)
  uint64_t hh=(*A>>32)*(*B>>32), hl=(*A>>32)*(unsigned)*B, lh=(unsigned)*A*(*B>>32), ll=(uint64_t)(unsigned)*A*(unsigned)*B;
  #if(WYHASH_SAFE_MUM)
  *A|=_wyrot(hl)^hh; *B|=_wyrot(lh)^ll;
  #else
  *A=_wyrot(hl)^hh; *B=_wyrot(lh)^ll;
  #endif
#elif defined(__SIZEOF_INT128__)
  __uint128_t r=*A; r*=*B; 
  #if(WYHASH_SAFE_MUM)
  *A|=(uint64_t)r; *B|=(uint64_t)(r>>64);
  #else
  *A=(uint64_t)r; *B=(uint64_t)(r>>64);
  #endif
#elif defined(_MSC_VER) && defined(_M_X64)
  #if(WYHASH_SAFE_MUM)
  uint64_t  a,  b;
  a=_umul128(*A,*B,&b);
  *A|=a;  *B|=b;
  #else
  *A=_umul128(*A,*B,B);
  #endif
#else
  uint64_t ha=*A>>32, hb=*B>>32, la=(uint32_t)*A, lb=(uint32_t)*B, hi, lo;
  uint64_t rh=ha*hb, rm0=ha*lb, rm1=hb*la, rl=la*lb, t=rl+(rm0<<32), c=t<rl;
  lo=t+(rm1<<32); c+=lo<t; hi=rh+(rm0>>32)+(rm1>>32)+c;
  #if(WYHASH_SAFE_MUM)
  *A|=lo;  *B|=hi;
  #else
  *A=lo;  *B=hi;
  #endif
#endif
}
static inline uint64_t _wymix(uint64_t A, uint64_t B){ _wymum(&A,&B); return A^B; }
//read functions
#ifndef WYHASH_LITTLE_ENDIAN
  #if defined(_WIN32) || defined(__LITTLE_ENDIAN__) || (defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__)
    #define WYHASH_LITTLE_ENDIAN 1
  #elif defined(__BIG_ENDIAN__) || (defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__)
    #define WYHASH_LITTLE_ENDIAN 0
  #endif
#endif
#if (WYHASH_LITTLE_ENDIAN)
static inline uint64_t _wyr8(const uint8_t *p) { uint64_t v; memcpy(&v, p, 8); return v;}
static inline uint64_t _wyr4(const uint8_t *p) { unsigned v; memcpy(&v, p, 4); return v;}
#elif defined(__GNUC__) || defined(__INTEL_COMPILER) || defined(__clang__)
static inline uint64_t _wyr8(const uint8_t *p) { uint64_t v; memcpy(&v, p, 8); return __builtin_bswap64(v);}
static inline uint64_t _wyr4(const uint8_t *p) { unsigned v; memcpy(&v, p, 4); return __builtin_bswap32(v);}
#elif defined(_MSC_VER)
static inline uint64_t _wyr8(const uint8_t *p) { uint64_t v; memcpy(&v, p, 8); return _byteswap_uint64(v);}
static inline uint64_t _wyr4(const uint8_t *p) { unsigned v; memcpy(&v, p, 4); return _byteswap_ulong(v);}
#endif
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];}
//wyhash function
static inline uint64_t wyhash(const void *key, uint64_t len, uint64_t seed, const uint64_t *secret){
  const uint8_t *p=(const uint8_t *)key;
  uint64_t i=len, see1=seed; 
  if(_likely_(i<=64)){
    start:
    if(_likely_(i<=16)){
      uint64_t a,b;
      #if(WYHASH_SAFE_READ)
      if(_likely_(i<=8)){
        if(_likely_(i>=4)){ a=_wyr4(p); b=_wyr4(p+i-4);}
        else if (_likely_(i)){ a=_wyr3(p,i); b=0;}
        else a=b=0;
      } 
      else{ a=_wyr8(p); b=_wyr8(p+i-8);}
      #else
      uint64_t shift=(i<8)*((8-i)<<3);  
      a=_wyr8(p)<<shift; b=_wyr8(p+i-8)>>shift;
      #endif
      seed^=a^secret[0]; see1^=b^secret[1]; 
      _wymum(&seed, &see1); 
      return _wymix(seed^len,see1);
    }
    seed^=_wyr8(p)^secret[0]; 
    see1^=_wyr8(p+8)^secret[1];
    _wymum(&seed, &see1);
    i-=16; p+=16; 
    goto start;
  }
  const uint64_t secret2=secret[0]^secret[1];
  const uint64_t secret3=secret[0]+secret[1];
  uint64_t see2,see3;  
  seed=see1=see2=see3=seed^(secret[0]-secret[1]);
  for(;_likely_(i>64);i-=64,p+=64){
   seed=_wymix(_wyr8(p)^seed,_wyr8(p+8)^*secret);
   see1=_wymix(_wyr8(p+16)^see1,_wyr8(p+24)^secret[1]);
   see2=_wymix(_wyr8(p+32)^see2,_wyr8(p+40)^secret2);
   see3=_wymix(_wyr8(p+48)^see3,_wyr8(p+56)^secret3);
  }
  seed^=see2; see1^=see3; goto start;
}
//utility functions
const uint64_t _wyp[2]={0xf0b21d699cd8c593ull, 0x8be22b55d84e1b55ull};
static inline uint64_t wyhash64(uint64_t A, uint64_t B){  A^=_wyp[0]; B^=_wyp[1];  _wymum(&A,&B);  return _wymix(A^_wyp[0],B^_wyp[1]);}
static inline uint64_t wyrand(uint64_t *seed){  *seed+=_wyp[0]; return _wymix(*seed,*seed^_wyp[1]);}
static inline double wy2u01(uint64_t r){ const double _wynorm=1.0/(1ull<<52); return (r>>12)*_wynorm;}
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;}
static inline void make_secret(uint64_t seed, uint64_t secret[2]){
  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 };
  for(size_t i=0;i<2;i++){
    uint8_t ok;
    do{
      ok=1; secret[i]=0;
      for(size_t j=0;j<64;j+=8) secret[i]|=((uint64_t)c[wyrand(&seed)%sizeof(c)])<<j;
      if(secret[i]%2==0){ ok=0; continue; }
      for(size_t j=0;j<i;j++)
#if defined(__GNUC__) || defined(__INTEL_COMPILER) || defined(__clang__)
        if(__builtin_popcountll(secret[j]^secret[i])!=32||__builtin_popcountll(secret[j]+secret[i])!=32||__builtin_popcountll(secret[j]-secret[i])!=32){ ok=0; break; }
#elif defined(_MSC_VER)
        if(_mm_popcnt_u64(secret[j]^secret[i])!=32||_mm_popcnt_u64(secret[j]-secret[i])!=32||_mm_popcnt_u64(secret[j]+secret[i])!=32){ ok=0; break; }
#endif
       if(!ok)continue;
       for(uint64_t j=3;j<0x100000000ull;j+=2) if(secret[i]%j==0){ ok=0; break; }
    }while(!ok);
  }
}
#endif