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Library for efficiently working with heap and off-heap memory
/*
* 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 io.airlift.slice;
public class Murmur3Hash128
{
private static final long C1 = 0x87c37b91114253d5L;
private static final long C2 = 0x4cf5ad432745937fL;
private final static long DEFAULT_SEED = 0;
public static Slice hash(Slice data)
{
return hash(data, 0, data.length());
}
public static Slice hash(Slice data, int offset, int length)
{
return hash(DEFAULT_SEED, data, offset, length);
}
public static Slice hash(long seed, Slice data, int offset, int length)
{
final int fastLimit = offset + length - (2 * SizeOf.SIZE_OF_LONG) + 1;
long h1 = seed;
long h2 = seed;
int current = offset;
while (current < fastLimit) {
long k1 = data.getLong(current);
current += SizeOf.SIZE_OF_LONG;
long k2 = data.getLong(current);
current += SizeOf.SIZE_OF_LONG;
k1 *= C1;
k1 = Long.rotateLeft(k1, 31);
k1 *= C2;
h1 ^= k1;
h1 = Long.rotateLeft(h1, 27);
h1 += h2;
h1 = h1 * 5 + 0x52dce729L;
k2 *= C2;
k2 = Long.rotateLeft(k2, 33);
k2 *= C1;
h2 ^= k2;
h2 = Long.rotateLeft(h2, 31);
h2 += h1;
h2 = h2 * 5 + 0x38495ab5L;
}
long k1 = 0;
long k2 = 0;
switch (length & 15) {
case 15:
k2 ^= ((long) data.getUnsignedByte(current + 14)) << 48;
case 14:
k2 ^= ((long) data.getUnsignedByte(current + 13)) << 40;
case 13:
k2 ^= ((long) data.getUnsignedByte(current + 12)) << 32;
case 12:
k2 ^= ((long) data.getUnsignedByte(current + 11)) << 24;
case 11:
k2 ^= ((long) data.getUnsignedByte(current + 10)) << 16;
case 10:
k2 ^= ((long) data.getUnsignedByte(current + 9)) << 8;
case 9:
k2 ^= ((long) data.getUnsignedByte(current + 8)) << 0;
k2 *= C2;
k2 = Long.rotateLeft(k2, 33);
k2 *= C1;
h2 ^= k2;
case 8:
k1 ^= ((long) data.getUnsignedByte(current + 7)) << 56;
case 7:
k1 ^= ((long) data.getUnsignedByte(current + 6)) << 48;
case 6:
k1 ^= ((long) data.getUnsignedByte(current + 5)) << 40;
case 5:
k1 ^= ((long) data.getUnsignedByte(current + 4)) << 32;
case 4:
k1 ^= ((long) data.getUnsignedByte(current + 3)) << 24;
case 3:
k1 ^= ((long) data.getUnsignedByte(current + 2)) << 16;
case 2:
k1 ^= ((long) data.getUnsignedByte(current + 1)) << 8;
case 1:
k1 ^= ((long) data.getUnsignedByte(current + 0)) << 0;
k1 *= C1;
k1 = Long.rotateLeft(k1, 31);
k1 *= C2;
h1 ^= k1;
}
h1 ^= length;
h2 ^= length;
h1 += h2;
h2 += h1;
h1 = mix64(h1);
h2 = mix64(h2);
h1 += h2;
h2 += h1;
Slice result = Slices.allocate(16);
result.setLong(0, h1);
result.setLong(8, h2);
return result;
}
/**
* Returns the 64 most significant bits of the Murmur128 hash of the provided value
*/
public static long hash64(Slice data)
{
return hash64(data, 0, data.length());
}
public static long hash64(Slice data, int offset, int length)
{
return hash64(DEFAULT_SEED, data, offset, length);
}
public static long hash64(long seed, Slice data, int offset, int length)
{
final int fastLimit = offset + length - (2 * SizeOf.SIZE_OF_LONG) + 1;
long h1 = seed;
long h2 = seed;
int current = offset;
while (current < fastLimit) {
long k1 = data.getLong(current);
current += SizeOf.SIZE_OF_LONG;
long k2 = data.getLong(current);
current += SizeOf.SIZE_OF_LONG;
k1 *= C1;
k1 = Long.rotateLeft(k1, 31);
k1 *= C2;
h1 ^= k1;
h1 = Long.rotateLeft(h1, 27);
h1 += h2;
h1 = h1 * 5 + 0x52dce729L;
k2 *= C2;
k2 = Long.rotateLeft(k2, 33);
k2 *= C1;
h2 ^= k2;
h2 = Long.rotateLeft(h2, 31);
h2 += h1;
h2 = h2 * 5 + 0x38495ab5L;
}
long k1 = 0;
long k2 = 0;
switch (length & 15) {
case 15:
k2 ^= ((long) data.getUnsignedByte(current + 14)) << 48;
case 14:
k2 ^= ((long) data.getUnsignedByte(current + 13)) << 40;
case 13:
k2 ^= ((long) data.getUnsignedByte(current + 12)) << 32;
case 12:
k2 ^= ((long) data.getUnsignedByte(current + 11)) << 24;
case 11:
k2 ^= ((long) data.getUnsignedByte(current + 10)) << 16;
case 10:
k2 ^= ((long) data.getUnsignedByte(current + 9)) << 8;
case 9:
k2 ^= ((long) data.getUnsignedByte(current + 8)) << 0;
k2 *= C2;
k2 = Long.rotateLeft(k2, 33);
k2 *= C1;
h2 ^= k2;
case 8:
k1 ^= ((long) data.getUnsignedByte(current + 7)) << 56;
case 7:
k1 ^= ((long) data.getUnsignedByte(current + 6)) << 48;
case 6:
k1 ^= ((long) data.getUnsignedByte(current + 5)) << 40;
case 5:
k1 ^= ((long) data.getUnsignedByte(current + 4)) << 32;
case 4:
k1 ^= ((long) data.getUnsignedByte(current + 3)) << 24;
case 3:
k1 ^= ((long) data.getUnsignedByte(current + 2)) << 16;
case 2:
k1 ^= ((long) data.getUnsignedByte(current + 1)) << 8;
case 1:
k1 ^= ((long) data.getUnsignedByte(current + 0)) << 0;
k1 *= C1;
k1 = Long.rotateLeft(k1, 31);
k1 *= C2;
h1 ^= k1;
}
h1 ^= length;
h2 ^= length;
h1 += h2;
h2 += h1;
h1 = mix64(h1);
h2 = mix64(h2);
return h1 + h2;
}
/**
* Special-purpose version for hashing a single long value. Value is treated as little-endian
*/
public static long hash64(long value)
{
long h2 = DEFAULT_SEED ^ SizeOf.SIZE_OF_LONG;
long h1 = h2 + (h2 ^ (Long.rotateLeft(value * C1, 31) * C2));
return mix64(h1) + mix64(h1 + h2);
}
private static long mix64(long k)
{
k ^= k >>> 33;
k *= 0xff51afd7ed558ccdL;
k ^= k >>> 33;
k *= 0xc4ceb9fe1a85ec53L;
k ^= k >>> 33;
return k;
}
}
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