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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.datasketches.memory;
import static org.apache.datasketches.memory.internal.XxHash64.hash;
import static org.apache.datasketches.memory.internal.XxHash64.hashBytes;
import static org.apache.datasketches.memory.internal.XxHash64.hashChars;
import static org.apache.datasketches.memory.internal.XxHash64.hashDoubles;
import static org.apache.datasketches.memory.internal.XxHash64.hashFloats;
import static org.apache.datasketches.memory.internal.XxHash64.hashInts;
import static org.apache.datasketches.memory.internal.XxHash64.hashLongs;
import static org.apache.datasketches.memory.internal.XxHash64.hashShorts;
/**
* The XxHash is a fast, non-cryptographic, 64-bit hash function that has
* excellent avalanche and 2-way bit independence properties.
* This java version adapted the C++ version and the OpenHFT/Zero-Allocation-Hashing implementation
* referenced below as inspiration.
*
* The C++ source repository:
*
* https://github.com/Cyan4973/xxHash. It has a BSD 2-Clause License:
*
* http://www.opensource.org/licenses/bsd-license.php. See LICENSE.
*
*
Portions of this code were adapted from
*
* OpenHFT/Zero-Allocation-Hashing, which has an Apache 2 license as does this site. See LICENSE.
*
* @author Lee Rhodes
*/
public final class XxHash {
private XxHash() { /* singleton */ }
/**
* Hash the given arr starting at the given offset and continuing for the given length using the
* given seed.
* @param arr the given array
* @param offsetBytes starting at this offset
* @param lengthBytes continuing for this length
* @param seed the given seed
* @return the hash
*/
public static long hashByteArr(
final byte[] arr,
final int offsetBytes,
final int lengthBytes,
final long seed) {
return hashBytes(arr, offsetBytes, lengthBytes, seed);
}
/**
* Hash the given arr starting at the given offset and continuing for the given length using the
* given seed.
* @param arr the given array
* @param offsetShorts starting at this offset
* @param lengthShorts continuing for this length
* @param seed the given seed
* @return the hash
*/
public static long hashShortArr(
final short[] arr,
final int offsetShorts,
final int lengthShorts,
final long seed) {
return hashShorts(arr, offsetShorts, lengthShorts, seed);
}
/**
* Hash the given arr starting at the given offset and continuing for the given length using the
* given seed.
* @param arr the given array
* @param offsetChars starting at this offset
* @param lengthChars continuing for this length
* @param seed the given seed
* @return the hash
*/
public static long hashCharArr(
final char[] arr,
final int offsetChars,
final int lengthChars,
final long seed) {
return hashChars(arr, offsetChars, lengthChars, seed);
}
/**
* Hash the given arr starting at the given offset and continuing for the given length using the
* given seed.
* @param arr the given array
* @param offsetInts starting at this offset
* @param lengthInts continuing for this length
* @param seed the given seed
* @return the hash
*/
public static long hashIntArr(
final int[] arr,
final int offsetInts,
final int lengthInts,
final long seed) {
return hashInts(arr, offsetInts, lengthInts, seed);
}
/**
* Hash the given arr starting at the given offset and continuing for the given length using the
* given seed.
* @param arr the given array
* @param offsetLongs starting at this offset
* @param lengthLongs continuing for this length
* @param seed the given seed
* @return the hash
*/
public static long hashLongArr(
final long[] arr,
final int offsetLongs,
final int lengthLongs,
final long seed) {
return hashLongs(arr, offsetLongs, lengthLongs, seed);
}
/**
* Returns a 64-bit hash from a single long. This method has been optimized for speed when only
* a single hash of a long is required.
* @param in A long.
* @param seed A long valued seed.
* @return the hash.
*/
public static long hashLong(
final long in,
final long seed) {
return hash(in, seed);
}
/**
* Hash the given arr starting at the given offset and continuing for the given length using the
* given seed.
* @param arr the given array
* @param offsetFloats starting at this offset
* @param lengthFloats continuing for this length
* @param seed the given seed
* @return the hash
*/
public static long hashFloatArr(
final float[] arr,
final int offsetFloats,
final int lengthFloats,
final long seed) {
return hashFloats(arr, offsetFloats, lengthFloats, seed);
}
/**
* Hash the given arr starting at the given offset and continuing for the given length using the
* given seed.
* @param arr the given array
* @param offsetDoubles starting at this offset
* @param lengthDoubles continuing for this length
* @param seed the given seed
* @return the hash
*/
public static long hashDoubleArr(
final double[] arr,
final int offsetDoubles,
final int lengthDoubles,
final long seed) {
return hashDoubles(arr, offsetDoubles, lengthDoubles, seed);
}
/**
* Hash the given arr starting at the given offset and continuing for the given length using the
* given seed.
* @param str the given string
* @param offsetChars starting at this offset
* @param lengthChars continuing for this length
* @param seed the given seed
* @return the hash
*/
public static long hashString(
final String str,
final int offsetChars,
final int lengthChars,
final long seed) {
return org.apache.datasketches.memory.internal.XxHash64.hashString(str, offsetChars, lengthChars, seed);
}
}