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Murmur3.java
308 lines (230 loc) · 7.76 KB
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Murmur3.java
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package com.hashfunctions.murmur;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
public class Murmur3 extends MurmurConstants {
private static final int X86_32_C1 = 0xcc9e2d51;
private static final int X86_32_C2 = 0x1b873593;
private static long X64_128_C1 = 0x87c37b91114253d5L;
private static long X64_128_C2 = 0x4cf5ad432745937fL;
public static long hash_32(final byte[] data, int length, long seed) {
final int nblocks = length >> 2;
long hash = seed;
//----------
// body
for(int i = 0; i < nblocks; i++) {
final int i4 = i << 2;
long k1 = (data[i4] & UNSIGNED_MASK);
k1 |= (data[i4 + 1] & UNSIGNED_MASK) << 8;
k1 |= (data[i4 + 2] & UNSIGNED_MASK) << 16;
k1 |= (data[i4 + 3] & UNSIGNED_MASK) << 24;
// int k1 = (data[i4] & 0xff) + ((data[i4 + 1] & 0xff) << 8) + ((data[i4 + 2] & 0xff) << 16) + ((data[i4 + 3] & 0xff) << 24);
k1 = (k1 * X86_32_C1) & UINT_MASK;
k1 = rotl32(k1, 15);
k1 = (k1 * X86_32_C2) & UINT_MASK;
hash ^= k1;
hash = rotl32(hash,13);
hash = (((hash * 5) & UINT_MASK) + 0xe6546b64l) & UINT_MASK;
}
//----------
// tail
// Advance offset to the unprocessed tail of the data.
int offset = (nblocks << 2); // nblocks * 2;
long k1 = 0;
switch (length & 3) {
case 3:
k1 ^= (data[offset + 2] << 16) & UINT_MASK;
case 2:
k1 ^= (data[offset + 1] << 8) & UINT_MASK;
case 1:
k1 ^= data[offset];
k1 = (k1 * X86_32_C1) & UINT_MASK;
k1 = rotl32(k1, 15);
k1 = (k1 * X86_32_C2) & UINT_MASK;
hash ^= k1;
}
// ----------
// finalization
hash ^= length;
hash = fmix32(hash);
return hash;
}
public static long hash_32(String data, long seed) {
int length = data.length();
final int nblocks = length >> 2;
long hash = seed;
//----------
// body
for(int i = 0; i < nblocks; i++) {
final int i4 = i << 2;
long k1 = (data.charAt(i4) & UNSIGNED_MASK);
k1 |= (data.charAt(i4 + 1) & UNSIGNED_MASK) << 8;
k1 |= (data.charAt(i4 + 2) & UNSIGNED_MASK) << 16;
k1 |= (data.charAt(i4 + 3) & UNSIGNED_MASK) << 24;
// int k1 = (data[i4] & 0xff) + ((data[i4 + 1] & 0xff) << 8) + ((data[i4 + 2] & 0xff) << 16) + ((data[i4 + 3] & 0xff) << 24);
k1 = (k1 * X86_32_C1) & UINT_MASK;
k1 = rotl32(k1, 15);
k1 = (k1 * X86_32_C2) & UINT_MASK;
hash ^= k1;
hash = rotl32(hash,13);
hash = (((hash * 5) & UINT_MASK) + 0xe6546b64l) & UINT_MASK;
}
//----------
// tail
// Advance offset to the unprocessed tail of the data.
int offset = (nblocks << 2); // nblocks * 2;
long k1 = 0;
switch (length & 3) {
case 3:
k1 ^= (data.charAt(offset + 2) << 16) & UINT_MASK;
case 2:
k1 ^= (data.charAt(offset + 1) << 8) & UINT_MASK;
case 1:
k1 ^= data.charAt(offset);
k1 = (k1 * X86_32_C1) & UINT_MASK;
k1 = rotl32(k1, 15);
k1 = (k1 * X86_32_C2) & UINT_MASK;
hash ^= k1;
}
// ----------
// finalization
hash ^= length;
hash = fmix32(hash);
return hash;
}
public static long[] hash_128(final byte[] data, final int length, final long seed) {
long h1 = seed;
long h2 = seed;
ByteBuffer buffer = ByteBuffer.wrap(data);
buffer.order(ByteOrder.LITTLE_ENDIAN);
while(buffer.remaining() >= 16) {
long k1 = buffer.getLong();
long k2 = buffer.getLong();
h1 ^= mixK1(k1);
h1 = Long.rotateLeft(h1, 27);
h1 += h2;
h1 = h1 * 5 + 0x52dce729;
h2 ^= mixK2(k2);
h2 = Long.rotateLeft(h2, 31);
h2 += h1;
h2 = h2 * 5 + 0x38495ab5;
}
// ----------
// tail
// Advance offset to the unprocessed tail of the data.
// offset += (nblocks << 4); // nblocks * 16;
buffer.compact();
buffer.flip();
final int remaining = buffer.remaining();
if(remaining > 0) {
long k1 = 0;
long k2 = 0;
switch (buffer.remaining()) {
case 15:
k2 ^= (long) (buffer.get(14) & UNSIGNED_MASK) << 48;
case 14:
k2 ^= (long) (buffer.get(13) & UNSIGNED_MASK) << 40;
case 13:
k2 ^= (long) (buffer.get(12) & UNSIGNED_MASK) << 32;
case 12:
k2 ^= (long) (buffer.get(11) & UNSIGNED_MASK) << 24;
case 11:
k2 ^= (long) (buffer.get(10) & UNSIGNED_MASK) << 16;
case 10:
k2 ^= (long) (buffer.get(9) & UNSIGNED_MASK) << 8;
case 9:
k2 ^= (long) (buffer.get(8) & UNSIGNED_MASK);
case 8:
k1 ^= buffer.getLong();
break;
case 7:
k1 ^= (long) (buffer.get(6) & UNSIGNED_MASK) << 48;
case 6:
k1 ^= (long) (buffer.get(5) & UNSIGNED_MASK) << 40;
case 5:
k1 ^= (long) (buffer.get(4) & UNSIGNED_MASK) << 32;
case 4:
k1 ^= (long) (buffer.get(3) & UNSIGNED_MASK) << 24;
case 3:
k1 ^= (long) (buffer.get(2) & UNSIGNED_MASK) << 16;
case 2:
k1 ^= (long) (buffer.get(1) & UNSIGNED_MASK) << 8;
case 1:
k1 ^= (long) (buffer.get(0) & UNSIGNED_MASK);
break;
default:
throw new AssertionError("Code should not reach here!");
}
// mix
h1 ^= mixK1(k1);
h2 ^= mixK2(k2);
}
// ----------
// finalization
h1 ^= length;
h2 ^= length;
h1 += h2;
h2 += h1;
h1 = fmix64(h1);
h2 = fmix64(h2);
h1 += h2;
h2 += h1;
return (new long[] { h1, h2 });
}
private static long mixK1(long k1) {
k1 *= X64_128_C1;
k1 = Long.rotateLeft(k1, 31);
k1 *= X64_128_C2;
return k1;
}
private static long mixK2(long k2) {
k2 *= X64_128_C2;
k2 = Long.rotateLeft(k2, 33);
k2 *= X64_128_C1;
return k2;
}
/**
* Rotate left for 32 bits.
*
* @param original
* @param shift
* @return
*/
private static long rotl32(long original, int shift) {
return ((original << shift) & UINT_MASK) | ((original >>> (32 - shift)) & UINT_MASK);
}
/**
* Rotate left for 64 bits.
*
* @param original
* @param shift
* @return
*/
/**
* fmix function for 32 bits.
*
* @param h
* @return
*/
private static long fmix32(long h) {
h ^= (h >> 16) & UINT_MASK;
h = (h * 0x85ebca6bl) & UINT_MASK;
h ^= (h >> 13) & UINT_MASK;
h = (h * 0xc2b2ae35) & UINT_MASK;
h ^= (h >> 16) & UINT_MASK;
return h;
}
/**
* fmix function for 64 bits.
*
* @param k
* @return
*/
private static long fmix64(long k) {
k ^= k >>> 33;
k *= 0xff51afd7ed558ccdL;
k ^= k >>> 33;
k *= 0xc4ceb9fe1a85ec53L;
k ^= k >>> 33;
return k;
}
}