/*
* Copyright (c) 2009-2015
* IT-Consulting Stephan Schloepke (http://www.schloepke.de/)
* klemm software consulting Mirko Klemm (http://www.klemm-scs.com/)
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package org.jbasics.arrays;
import org.jbasics.annotation.ImmutableState;
import org.jbasics.annotation.ThreadSafe;
import java.util.Comparator;
/**
* Implements the {@link Comparator} interface for long arrays and offers static compare methods. <p> This small helper
* class offers compare functionality for long arrays. Mostly the static methods are used in order to compare two given
* arrays. Additionally it is possible to instantiate this class in order to use it as a comparator. </p> <p> It is
* important to know that there is no null check. Meaning that if any of given x or y is null it is considered to be
* like a zero length array. So a zero length array and a null array are considered to be equal. However a zero length
* or null array compared to a not null and not zero length array is always considered to be less than even the not zero
* length array may contain only zero values. </p>
*
* @author Stephan Schloepke
* @since 1.0
*/
@ThreadSafe
@ImmutableState
public final class LongArrayComparator implements Comparator<long[]> {
/**
* The singleton comparator to use as comparator. Use this instead of creating a new instance since the comparator
* does not have any state and multiple instances do not make sense unless the api of the usage requires it.
*
* @since 1.0
*/
public static final Comparator<long[]> COMPARATOR = new LongArrayComparator();
/**
* Do not instantiate this comparator but use {@link LongArrayComparator#COMPARATOR} instead.
*/
private LongArrayComparator() {
// to hinder instantiation
}
/**
* Returns true if the given array is null, zero length or contains only zero values.
*
* @param x The array to check for zero or null
*
* @return True if the array is null, zero length or contains only zero.
*
* @since 1.0
*/
public static boolean isZeroOrNull(final long[] x) {
if (x != null && x.length > 0) {
int i = x.length;
while (--i >= 0) {
if (x[i] != 0) {
return false;
}
}
}
return true;
}
/**
* Returns true if the x array is greater than the y array.
*
* @param x The left array
* @param y The right array
*
* @return True if x > y
*
* @since 1.0
*/
public static boolean isGreaterThan(final long[] x, final long[] y) {
return LongArrayComparator.compareArrays(x, y) > 0;
}
/**
* Compare the two given arrays and return a value suitable by to the {@link Comparator} interface.
*
* @param x The left array to compare
* @param y The right array to compare
*
* @return 0 if the two arrays are equal, -1 if x is less than y and 1 if x is greater than y.
*
* @see #compare(long[], long[])
* @since 1.0
*/
public static int compareArrays(final long[] x, final long[] y) {
if (x == null) {
return y == null || y.length == 0 ? 0 : -1;
} else if (y == null) {
return 1;
} else if (x.length < y.length) {
return -1;
} else if (x.length > y.length) {
return 1;
} else if (x.length == 1) {
return x[0] == y[0] ? 0 : x[0] < y[0] ? -1 : 1;
} else {
final int k = x.length - 1;
int i = 0;
while (i < k && x[i] == y[i]) {
i++;
}
long tempA = x[i] >>> 1;
long tempB = y[i] >>> 1;
if (tempA == tempB) {
tempA = x[i] & 0x01;
tempB = y[i] & 0x01;
}
return tempA == tempB ? 0 : tempA < tempB ? -1 : 1;
}
}
/**
* Returns true if the x array is greater than or equal the y array.
*
* @param x The left array
* @param y The right array
*
* @return True if x >= y
*
* @since 1.0
*/
public static boolean isGreaterThanOrEqual(final long[] x, final long[] y) {
return LongArrayComparator.compareArrays(x, y) >= 0;
}
/**
* Returns true if the x array is equal to the y array.
*
* @param x The left array
* @param y The right array
*
* @return True if x == y
*
* @since 1.0
*/
public static boolean isEqual(final long[] x, final long[] y) {
return LongArrayComparator.compareArrays(x, y) == 0;
}
/**
* Returns true if the x array is less than the y array.
*
* @param x The left array
* @param y The right array
*
* @return True if x < y
*
* @since 1.0
*/
public static boolean isLessThan(final long[] x, final long[] y) {
return LongArrayComparator.compareArrays(x, y) < 0;
}
/**
* Returns true if the x array is less than or equal the y array.
*
* @param x The left array
* @param y The right array
*
* @return True if x <= y
*
* @since 1.0
*/
public static boolean isLessThanOrEqual(final long[] x, final long[] y) {
return LongArrayComparator.compareArrays(x, y) <= 0;
}
/**
* Returns true if the x array is not equal to the y array.
*
* @param x The left array
* @param y The right array
*
* @return True if x <> y
*
* @since 1.0
*/
public static boolean isNotEqual(final long[] x, final long[] y) {
return LongArrayComparator.compareArrays(x, y) != 0;
}
/**
* Compare the two given arrays and return a value suitable by to the {@link Comparator} interface.
*
* @param x The left array to compare
* @param y The right array to compare
*
* @return 0 if the two arrays are equal, -1 if x is less than y and 1 if x is greater than y.
*
* @see #compareArrays(long[], long[])
* @since 1.0
*/
@Override
public int compare(final long[] x, final long[] y) {
return LongArrayComparator.compareArrays(x, y);
}
}