com.github.housepower.misc.ClickHouseCityHash Maven / Gradle / Ivy
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/*
* 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.
*
* Copyright 2017 YANDEX LLC
* Copyright (C) 2012 tamtam180
*/
package com.github.housepower.misc;
/**
* @author tamtam180 - kirscheless at gmail.com
* @see
* @see
*
* NOTE: The code is modified to be compatible with CityHash128 used in ClickHouse
*/
public class ClickHouseCityHash {
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 final long kMul = 0x9ddfea08eb382d69L;
private static long toLongLE(byte[] bytes, int offset) {
return (((long) (bytes[offset + 7] & 255) << 56) +
((long) (bytes[offset + 6] & 255) << 48) +
((long) (bytes[offset + 5] & 255) << 40) +
((long) (bytes[offset + 4] & 255) << 32) +
((long) (bytes[offset + 3] & 255) << 24) +
((long) (bytes[offset + 2] & 255) << 16) +
((long) (bytes[offset + 1] & 255) << 8) +
((long) (bytes[offset + 0] & 255) << 0));
}
private static long toIntLE(byte[] bytes, int offset) {
return (((bytes[offset + 0] & 255L) << 0) +
((bytes[offset + 1] & 255L) << 8) +
((bytes[offset + 2] & 255L) << 16) +
((bytes[offset + 3] & 255L) << 24));
}
private static long fetch32(byte[] s, int pos) {
return toIntLE(s, pos);
}
private static long fetch64(byte[] s, int pos) {
return toLongLE(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 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);
long b = fetch64(s, pos + len - 8);
return hashLen16(a, rotateByAtLeast1(b + len, len)) ^ b;
}
if (len >= 4) {
long a = fetch32(s, pos);
return hashLen16((a << 3) + len, fetch32(s, pos + len - 4));
}
if (len > 0) {
byte a = s[pos];
byte b = s[pos + (len >>> 1)];
byte c = s[pos + len - 1];
int y = (int) a + (((int) b) << 8);
int z = len + (((int) c) << 2);
return shiftMix(y * k2 ^ z * k3) * k2;
}
return k2;
}
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[] 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)};
}
private 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;
// This is the same inner loop as CityHash64(), manually unrolled.
do {
x = rotate(x + y + v[0] + fetch64(s, pos + 16), 37) * k1;
y = rotate(y + v[1] + fetch64(s, pos + 48), 42) * k1;
x ^= w[1];
y ^= v[0];
z = rotate(z ^ w[0], 33);
v = weakHashLen32WithSeeds(s, pos, v[1] * k1, x + w[0]);
w = weakHashLen32WithSeeds(s, pos + 32, z + w[1], y);
{
long swap = z;
z = x;
x = swap;
}
pos += 64;
x = rotate(x + y + v[0] + fetch64(s, pos + 16), 37) * k1;
y = rotate(y + v[1] + fetch64(s, pos + 48), 42) * k1;
x ^= w[1];
y ^= v[0];
z = rotate(z ^ w[0], 33);
v = weakHashLen32WithSeeds(s, pos, v[1] * k1, x + w[0]);
w = weakHashLen32WithSeeds(s, pos + 32, z + w[1], y);
{
long swap = z;
z = x;
x = swap;
}
pos += 64;
len -= 128;
} while (len >= 128);
y += rotate(w[0], 37) * k0 + z;
x += rotate(v[0] + z, 49) * k0;
// If 0 < len < 128, hash up to 4 chunks of 32 bytes each from the end of s.
for (int tail_done = 0; tail_done < len; ) {
tail_done += 32;
y = rotate(y - x, 42) * k0 + v[1];
w[0] += fetch64(s, pos + len - tail_done + 16);
x = rotate(x, 49) * k0 + w[0];
w[0] += v[0];
v = weakHashLen32WithSeeds(s, pos + len - tail_done, v[0], v[1]);
}
// At this point our 48 bytes of state should contain more than
// enough information for a strong 128-bit hash. We use two
// different 48-byte-to-8-byte hashes to get a 16-byte final result.
x = hashLen16(x, v[0]);
y = hashLen16(y, 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) ^ k3,
fetch64(s, pos + 8));
}
if (len >= 8) {
return cityHash128WithSeed(
new byte[0], 0, 0,
fetch64(s, pos) ^ (len * k0),
fetch64(s, pos + len - 8) ^ k1);
}
return cityHash128WithSeed(s, pos, len, k0, k1);
}
}