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package it.unimi.dsi.util;

/*
 * DSI utilities
 *
 * Copyright (C) 2003-2017 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 .
 *
 */

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 final static LongInterval[] EMPTY_ARRAY = {};

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

	/** A singleton located at −∞. */
	public final static 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 final static 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 final static 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 final static 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 final static Comparator ENDS_BEFORE = (i1, i2) -> Long.compare(i1.right, i2.right);

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