private static unsafe uint Hash32Len5to12(byte *s, uint len, uint seed = 0)
{
uint a = len, b = len * 5, c = 9, d = b + seed;
a += Utilities.Fetch32(s);
b += Utilities.Fetch32(s + len - 4);
c += Utilities.Fetch32(s + ((len >> 1) & 4));
return(Utilities.FMix(seed ^ FarmHash.Mur(c, FarmHash.Mur(b, FarmHash.Mur(a, d)))));
}
private static unsafe uint Hash32Len0to4(byte *s, uint len, uint seed = 0)
{
uint b = seed;
uint c = 9;
for (int i = 0; i < len; i++)
{
b = b * FarmHashConstants.c1 + *(s + i);
c ^= b;
}
return(Utilities.FMix(FarmHash.Mur(b, FarmHash.Mur(len, c))));
}
private static uint Hash32Len0to4(byte[] s, uint len, uint seed = 0)
{
uint b = seed;
uint c = 9;
for (int i = 0; i < len; i++)
{
byte v = s[i];
b = b * FarmHashConstants.c1 + v;
c ^= b;
}
return(Utilities.FMix(FarmHash.Mur(b, FarmHash.Mur(len, c))));
}
private static unsafe uint Hash32Len13to24(byte *s, uint len, uint seed = 0)
{
uint a = Utilities.Fetch32(s - 4 + (len >> 1));
uint b = Utilities.Fetch32(s + 4);
uint c = Utilities.Fetch32(s + len - 8);
uint d = Utilities.Fetch32(s + (len >> 1));
uint e = Utilities.Fetch32(s);
uint f = Utilities.Fetch32(s + len - 4);
uint h = d * FarmHashConstants.c1 + len + seed;
a = Utilities.RotateWithCheck(a, 12) + f;
h = FarmHash.Mur(c, h) + a;
a = Utilities.RotateWithCheck(a, 3) + c;
h = FarmHash.Mur(e, h) + a;
a = Utilities.RotateWithCheck(a + f, 12) + d;
h = FarmHash.Mur(b ^ seed, h) + a;
return(Utilities.FMix(h));
}
public static unsafe uint ComputeHash(byte *s, int len)
{
if (len <= 4)
{
return(Hash32Len0to4(s, (uint)len));
}
if (len <= 24)
{
return(len <= 12 ? Hash32Len5to12(s, (uint)len) : Hash32Len13to24(s, (uint)len));
}
uint h = (uint)len, g = FarmHashConstants.c1 * (uint)len, f = g;
uint a0 = Utilities.RotateWithCheck(Utilities.Fetch32(s + len - 4) * FarmHashConstants.c1, 17) * FarmHashConstants.c2;
uint a1 = Utilities.RotateWithCheck(Utilities.Fetch32(s + len - 8) * FarmHashConstants.c1, 17) * FarmHashConstants.c2;
uint a2 = Utilities.RotateWithCheck(Utilities.Fetch32(s + len - 16) * FarmHashConstants.c1, 17) * FarmHashConstants.c2;
uint a3 = Utilities.RotateWithCheck(Utilities.Fetch32(s + len - 12) * FarmHashConstants.c1, 17) * FarmHashConstants.c2;
uint a4 = Utilities.RotateWithCheck(Utilities.Fetch32(s + len - 20) * FarmHashConstants.c1, 17) * FarmHashConstants.c2;
h ^= a0;
h = Utilities.RotateWithCheck(h, 19);
h = h * 5 + 0xe6546b64;
h ^= a2;
h = Utilities.RotateWithCheck(h, 19);
h = h * 5 + 0xe6546b64;
g ^= a1;
g = Utilities.RotateWithCheck(g, 19);
g = g * 5 + 0xe6546b64;
g ^= a3;
g = Utilities.RotateWithCheck(g, 19);
g = g * 5 + 0xe6546b64;
f += a4;
f = Utilities.RotateWithCheck(f, 19) + 113;
uint iters = ((uint)len - 1) / 20;
do
{
uint a = Utilities.Fetch32(s);
uint b = Utilities.Fetch32(s + 4);
uint c = Utilities.Fetch32(s + 8);
uint d = Utilities.Fetch32(s + 12);
uint e = Utilities.Fetch32(s + 16);
h += a;
g += b;
f += c;
h = FarmHash.Mur(d, h) + e;
g = FarmHash.Mur(c, g) + a;
f = FarmHash.Mur(b + e * FarmHashConstants.c1, f) + d;
f += g;
g += f;
s += 20;
} while (--iters != 0);
g = Utilities.RotateWithCheck(g, 11) * FarmHashConstants.c1;
g = Utilities.RotateWithCheck(g, 17) * FarmHashConstants.c1;
f = Utilities.RotateWithCheck(f, 11) * FarmHashConstants.c1;
f = Utilities.RotateWithCheck(f, 17) * FarmHashConstants.c1;
h = Utilities.RotateWithCheck(h + g, 19);
h = h * 5 + 0xe6546b64;
h = Utilities.RotateWithCheck(h, 17) * FarmHashConstants.c1;
h = Utilities.RotateWithCheck(h + f, 19);
h = h * 5 + 0xe6546b64;
h = Utilities.RotateWithCheck(h, 17) * FarmHashConstants.c1;
return(h);
}
public static uint ComputeHash(byte[] s)
{
uint len = (uint)s.Length;
if (len <= 24)
{
return(len <= 12 ? (len <= 4 ? Hash32Len0to4(s, len) : Hash32Len5to12(s, len)) : Hash32Len13to24(s, len));
}
// len > 24
uint h = len, g = FarmHashConstants.c1 * len, f = g;
uint a0 = Utilities.RotateWithCheck(Utilities.Fetch32(s, len - 4) * FarmHashConstants.c1, 17) * FarmHashConstants.c2;
uint a1 = Utilities.RotateWithCheck(Utilities.Fetch32(s, len - 8) * FarmHashConstants.c1, 17) * FarmHashConstants.c2;
uint a2 = Utilities.RotateWithCheck(Utilities.Fetch32(s, len - 16) * FarmHashConstants.c1, 17) * FarmHashConstants.c2;
uint a3 = Utilities.RotateWithCheck(Utilities.Fetch32(s, len - 12) * FarmHashConstants.c1, 17) * FarmHashConstants.c2;
uint a4 = Utilities.RotateWithCheck(Utilities.Fetch32(s, len - 20) * FarmHashConstants.c1, 17) * FarmHashConstants.c2;
h ^= a0;
h = Utilities.RotateWithCheck(h, 19);
h = h * 5 + 0xe6546b64;
h ^= a2;
h = Utilities.RotateWithCheck(h, 19);
h = h * 5 + 0xe6546b64;
g ^= a1;
g = Utilities.RotateWithCheck(g, 19);
g = g * 5 + 0xe6546b64;
g ^= a3;
g = Utilities.RotateWithCheck(g, 19);
g = g * 5 + 0xe6546b64;
f += a4;
f = Utilities.RotateWithCheck(f, 19) + 113;
uint iters = (len - 1) / 20;
int index = 0;
do
{
uint a = Utilities.Fetch32(s, index);
uint b = Utilities.Fetch32(s, index + 4);
uint c = Utilities.Fetch32(s, index + 8);
uint d = Utilities.Fetch32(s, index + 12);
uint e = Utilities.Fetch32(s, index + 16);
h += a;
g += b;
f += c;
h = FarmHash.Mur(d, h) + e;
g = FarmHash.Mur(c, g) + a;
f = FarmHash.Mur(b + e * FarmHashConstants.c1, f) + d;
f += g;
g += f;
index += 20;
} while (--iters != 0);
g = Utilities.RotateWithCheck(g, 11) * FarmHashConstants.c1;
g = Utilities.RotateWithCheck(g, 17) * FarmHashConstants.c1;
f = Utilities.RotateWithCheck(f, 11) * FarmHashConstants.c1;
f = Utilities.RotateWithCheck(f, 17) * FarmHashConstants.c1;
h = Utilities.RotateWithCheck(h + g, 19);
h = h * 5 + 0xe6546b64;
h = Utilities.RotateWithCheck(h, 17) * FarmHashConstants.c1;
h = Utilities.RotateWithCheck(h + f, 19);
h = h * 5 + 0xe6546b64;
h = Utilities.RotateWithCheck(h, 17) * FarmHashConstants.c1;
return(h);
}
