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The DSI utilities are a mishmash of classes accumulated during the last twenty years in projects developed at the DSI (Dipartimento di Scienze dell'Informazione, i.e., Information Sciences Department), now DI (Dipartimento di Informatica, i.e., Informatics Department), of the Universita` degli Studi di Milano.

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/*
 * DSI utilities
 *
 * Copyright (C) 2003-2020 Paolo Boldi and Sebastiano Vigna
 *
 *  This library is free software; you can redistribute it and/or modify it
 *  under the terms of the GNU Lesser General Public License as published by the Free
 *  Software Foundation; either version 3 of the License, or (at your option)
 *  any later version.
 *
 *  This library is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 *  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
 *  for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this program; if not, see .
 *
 */

package it.unimi.dsi.util;

import java.util.Comparator;


/** A class providing static methods and objects that do useful things with intervals.
 *
 * @see LongInterval
 */

public class LongIntervals {

	private LongIntervals() {}

	public static final LongInterval[] EMPTY_ARRAY = {};

	/** An empty (singleton) interval. */
	public static final LongInterval EMPTY_INTERVAL = new LongInterval(1, 0);

	/** A singleton located at −∞. */
	public static final LongInterval MINUS_INFINITY = new LongInterval(Integer.MIN_VALUE, Integer.MIN_VALUE);

	/** A comparator between intervals defined as follows:
	 * [a..b] is less than [a'..b']
	 * iff the first interval starts after the second one, that is,
	 * iff a' < a.
	 */
	public static final Comparator STARTS_AFTER = (i1, i2) -> Long.compare(i2.left, i1.left);

	/** A comparator between intervals defined as follows:
	 * [a..b] is less than [a'..b']
	 * iff the first interval starts before the second one, that is,
	 * iff a < a'.
	 */
	public static final Comparator STARTS_BEFORE = (i1, i2) -> Long.compare(i1.left, i2.left);

	/** A comparator between intervals defined as follows:
	 * [a..b] is less than [a'..b']
	 * iff the first interval ends after the second one, that is,
	 * iff b' < b.
	 */
	public static final Comparator ENDS_AFTER = (i1, i2) -> Long.compare(i2.right, i1.right);

	/** A comparator between intervals defined as follows:
	 * [a..b] is less than [a'..b']
	 * iff the first interval ends before the second one, that is,
	 * iff b < b'.
	 */
	public static final Comparator ENDS_BEFORE = (i1, i2) -> Long.compare(i1.right, i2.right);

	/** A comparator between intervals based on their length. */
	public static final Comparator LENGTH_COMPARATOR = (i1, i2) -> Long.compare(i1.length(), i2.length());
}