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CityHashのJava実装。
/*
* Copyright (C) 2012 tamtam180
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package at.orz.hash;
/**
* @author tamtam180 - kirscheless at gmail.com
* @see http://google-opensource.blogspot.jp/2011/04/introducing-cityhash.html
* @see http://code.google.com/p/cityhash/
*
*/
public class CityHash {
private static final long k0 = 0xc3a5c85c97cb3127L;
private static final long k1 = 0xb492b66fbe98f273L;
private static final long k2 = 0x9ae16a3b2f90404fL;
private static final long k3 = 0xc949d7c7509e6557L;
private static long toLongLE(byte[] b, int i) {
return (((long)b[i+7] << 56) +
((long)(b[i+6] & 255) << 48) +
((long)(b[i+5] & 255) << 40) +
((long)(b[i+4] & 255) << 32) +
((long)(b[i+3] & 255) << 24) +
((b[i+2] & 255) << 16) +
((b[i+1] & 255) << 8) +
((b[i+0] & 255) << 0));
}
private static int toIntLE(byte[] b, int i) {
return (((b[i+3] & 255) << 24) + ((b[i+2] & 255) << 16) + ((b[i+1] & 255) << 8) + ((b[i+0] & 255) << 0));
}
private static long fetch64(byte[] s, int pos) {
return toLongLE(s, pos);
}
private static int fetch32(byte[] s, int pos) {
return toIntLE(s, pos);
}
private static long rotate(long val, int shift) {
return shift == 0 ? val : (val >>> shift) | (val << (64 - shift));
}
private static long rotateByAtLeast1(long val, int shift) {
return (val >>> shift) | (val << (64 - shift));
}
private static long shiftMix(long val) {
return val ^ (val >>> 47);
}
private static final long kMul = 0x9ddfea08eb382d69L;
private static long hash128to64(long u, long v) {
long a = (u ^ v) * kMul;
a ^= (a >>> 47);
long b = (v ^ a) * kMul;
b ^= (b >>> 47);
b *= kMul;
return b;
}
private static long hashLen16(long u, long v) {
return hash128to64(u, v);
}
private static long hashLen0to16(byte[] s, int pos, int len) {
if (len > 8) {
long a = fetch64(s, pos + 0);
long b = fetch64(s, pos + len - 8);
return hashLen16(a, rotateByAtLeast1(b + len, len)) ^ b;
}
if (len >= 4) {
long a = 0xffffffffL & fetch32(s, pos + 0);
return hashLen16((a << 3) + len, 0xffffffffL & fetch32(s, pos + len - 4));
}
if (len > 0) {
int a = s[pos + 0] & 0xFF;
int b = s[pos + (len >>> 1)] & 0xFF;
int c = s[pos + len - 1] & 0xFF;
int y = a + (b << 8);
int z = len + (c << 2);
return shiftMix(y * k2 ^ z * k3) * k2;
}
return k2;
}
private static long hashLen17to32(byte[] s, int pos, int len) {
long a = fetch64(s, pos + 0) * k1;
long b = fetch64(s, pos + 8);
long c = fetch64(s, pos + len - 8) * k2;
long d = fetch64(s, pos + len - 16) * k0;
return hashLen16(
rotate(a - b, 43) + rotate(c, 30) + d,
a + rotate(b ^ k3, 20) - c + len
);
}
private static long[] weakHashLen32WithSeeds(
long w, long x, long y, long z,
long a, long b) {
a += w;
b = rotate(b + a + z, 21);
long c = a;
a += x;
a += y;
b += rotate(a, 44);
return new long[]{ a + z, b + c };
}
private static long[] weakHashLen32WithSeeds(byte[] s, int pos, long a, long b) {
return weakHashLen32WithSeeds(
fetch64(s, pos + 0),
fetch64(s, pos + 8),
fetch64(s, pos + 16),
fetch64(s, pos + 24),
a,
b
);
}
private static long hashLen33to64(byte[] s, int pos, int len) {
long z = fetch64(s, pos + 24);
long a = fetch64(s, pos + 0) + (fetch64(s, pos + len - 16) + len) * k0;
long b = rotate(a + z, 52);
long c = rotate(a, 37);
a += fetch64(s, pos + 8);
c += rotate(a, 7);
a += fetch64(s, pos + 16);
long vf = a + z;
long vs = b + rotate(a, 31) + c;
a = fetch64(s, pos + 16) + fetch64(s, pos + len - 32);
z = fetch64(s, pos + len - 8);
b = rotate(a + z, 52);
c = rotate(a, 37);
a += fetch64(s, pos + len - 24);
c += rotate(a, 7);
a += fetch64(s, pos + len -16);
long wf = a + z;
long ws = b + rotate(a, 31) + c;
long r = shiftMix((vf + ws) * k2 + (wf + vs) * k0);
return shiftMix(r * k0 + vs) * k2;
}
public static long cityHash64(byte[] s, int pos, int len) {
if (len <= 32) {
if (len <= 16) {
return hashLen0to16(s, pos, len);
} else {
return hashLen17to32(s, pos, len);
}
} else if (len <= 64) {
return hashLen33to64(s, pos, len);
}
long x = fetch64(s, pos + len - 40);
long y = fetch64(s, pos + len - 16) + fetch64(s, pos + len - 56);
long z = hashLen16(fetch64(s, pos + len - 48) + len, fetch64(s, pos + len - 24));
long [] v = weakHashLen32WithSeeds(s, pos + len - 64, len, z);
long [] w = weakHashLen32WithSeeds(s, pos + len - 32, y + k1, x);
x = x * k1 + fetch64(s, pos + 0);
len = (len - 1) & (~63);
do {
x = rotate(x + y + v[0] + fetch64(s, pos + 8), 37) * k1;
y = rotate(y + v[1] + fetch64(s, pos + 48), 42) * k1;
x ^= w[1];
y += v[0] + fetch64(s, pos + 40);
z = rotate(z + w[0], 33) * k1;
v = weakHashLen32WithSeeds(s, pos + 0, v[1] * k1, x + w[0]);
w = weakHashLen32WithSeeds(s, pos + 32, z + w[1], y + fetch64(s, pos + 16));
{ long swap = z; z = x; x = swap; }
pos += 64;
len -= 64;
} while (len != 0);
return hashLen16(
hashLen16(v[0], w[0]) + shiftMix(y) * k1 + z,
hashLen16(v[1], w[1]) + x
);
}
public static long cityHash64WithSeed(byte[] s, int pos, int len, long seed) {
return cityHash64WithSeeds(s, pos, len, k2, seed);
}
public static long cityHash64WithSeeds(byte[] s, int pos, int len, long seed0, long seed1) {
return hashLen16(cityHash64(s, pos, len) - seed0, seed1);
}
public static long[] cityMurmur(byte[] s, int pos, int len, long seed0, long seed1) {
long a = seed0;
long b = seed1;
long c = 0;
long d = 0;
int l = len - 16;
if (l <= 0) {
a = shiftMix(a * k1) * k1;
c = b * k1 + hashLen0to16(s, pos, len);
d = shiftMix(a + (len >= 8 ? fetch64(s, pos + 0) : c));
} else {
c = hashLen16(fetch64(s, pos + len - 8) + k1, a);
d = hashLen16(b + len, c + fetch64(s, pos + len - 16));
a += d;
do {
a ^= shiftMix(fetch64(s, pos + 0) * k1) * k1;
a *= k1;
b ^= a;
c ^= shiftMix(fetch64(s, pos + 8) * k1) * k1;
c *= k1;
d ^= c;
pos += 16;
l -= 16;
} while (l > 0);
}
a = hashLen16(a, c);
b = hashLen16(d, b);
return new long[]{ a ^ b, hashLen16(b, a) };
}
public static long[] cityHash128WithSeed(byte[] s, int pos, int len, long seed0, long seed1) {
if (len < 128) {
return cityMurmur(s, pos, len, seed0, seed1);
}
long[] v = new long[2], w = new long[2];
long x = seed0;
long y = seed1;
long z = k1 * len;
v[0] = rotate(y ^ k1, 49) * k1 + fetch64(s, pos);
v[1] = rotate(v[0], 42) * k1 + fetch64(s, pos + 8);
w[0] = rotate(y + z, 35) * k1 + x;
w[1] = rotate(x + fetch64(s, pos + 88), 53) * k1;
do {
x = rotate(x + y + v[0] + fetch64(s, pos + 8), 37) * k1;
y = rotate(y + v[1] + fetch64(s, pos + 48), 42) * k1;
x ^= w[1];
y += v[0] + fetch64(s, pos + 40);
z = rotate(z + w[0], 33) * k1;
v = weakHashLen32WithSeeds(s, pos + 0, v[1] * k1, x + w[0]);
w = weakHashLen32WithSeeds(s, pos + 32, z + w[1], y + fetch64(s, pos + 16));
{ long swap = z; z = x; x = swap; }
pos += 64;
x = rotate(x + y + v[0] + fetch64(s, pos + 8), 37) * k1;
y = rotate(y + v[1] + fetch64(s, pos + 48), 42) * k1;
x ^= w[1];
y += v[0] + fetch64(s, pos + 40);
z = rotate(z + w[0], 33) * k1;
v = weakHashLen32WithSeeds(s, pos, v[1] * k1, x + w[0]);
w = weakHashLen32WithSeeds(s, pos + 32, z + w[1], y + fetch64(s, pos + 16));
{ long swap = z; z = x; x = swap; }
pos += 64;
len -= 128;
} while (len >= 128);
x += rotate(v[0] + z, 49) * k0;
z += rotate(w[0], 37) * k0;
for (int tail_done = 0; tail_done < len; ) {
tail_done += 32;
y = rotate(x + y, 42) * k0 + v[1];
w[0] += fetch64(s, pos + len - tail_done + 16);
x = x * k0 + w[0];
z += w[1] + fetch64(s, pos + len - tail_done);
w[1] += v[0];
v = weakHashLen32WithSeeds(s, pos + len - tail_done, v[0] + z, v[1]);
}
x = hashLen16(x, v[0]);
y = hashLen16(y + z, w[0]);
return new long[]{
hashLen16(x + v[1], w[1]) + y,
hashLen16(x + w[1], y + v[1])
};
}
public static long[] cityHash128(byte[] s, int pos, int len) {
if (len >= 16) {
return cityHash128WithSeed(
s, pos + 16,
len - 16,
fetch64(s, pos + 0) ^ k3,
fetch64(s, pos + 8)
);
} else if (len >= 8) {
return cityHash128WithSeed(
new byte[0], 0, 0,
fetch64(s, pos + 0) ^ (len * k0),
fetch64(s, pos + len -8) ^ k1
);
} else {
return cityHash128WithSeed(s, pos, len, k0, k1);
}
}
}
@tamtam180

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Owner Author

commented Apr 6, 2012

CRCの方は_mm_crc32_u32|64の結果がnaitiveと一致しないので載せてません。
しょぼーん。。

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