com.facebook.presto.jdbc.internal.io.airlift.slice.FnvHash Maven / Gradle / Ivy
/*
* 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 com.facebook.presto.jdbc.internal.io.airlift.slice;
/**
* Reference implementation: https://tools.ietf.org/html/draft-eastlake-fnv-17#section-6
*/
public class FnvHash
{
private static final long FNV_64_OFFSET_BASIS = 0xcbf29ce484222325L;
private static final long FNV_64_PRIME = 0x100000001b3L;
private static final int FNV_32_OFFSET_BASIS = 0x811c9dc5;
private static final int FNV_32_PRIME = 0x01000193;
private FnvHash()
{
}
public static int hash32(Slice data)
{
int hash = FNV_32_OFFSET_BASIS;
for (int i = 0; i < data.length(); ++i) {
byte dataByte = data.getByte(i);
hash ^= dataByte;
hash *= FNV_32_PRIME;
}
return hash;
}
public static long hash64(Slice data)
{
long hash = FNV_64_OFFSET_BASIS;
for (int i = 0; i < data.length(); ++i) {
byte dataByte = data.getByte(i);
hash ^= dataByte;
hash *= FNV_64_PRIME;
}
return hash;
}
}