package it.unimi.dsi.util; /* * DSI utilities * * Copyright (C) 2003-2009 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 2.1 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, write to the Free Software * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. * */ import java.util.Comparator; /** A class providing static methods and objects that do useful things with intervals. * * @see Interval */ public class Intervals { private Intervals() {} public final static Interval[] EMPTY_ARRAY = {}; /** An empty (singleton) interval. */ public final static Interval EMPTY_INTERVAL = new Interval( 1, 0 ); /** A singleton located at −&infty;. */ public final static Interval MINUS_INFINITY = new Interval( Integer.MIN_VALUE, Integer.MIN_VALUE ); /** A comparator between intervals defined as follows: * [<var>a</var>..<var>b</var>] is less than [<var>a</var>'..<var>b</var>'] iff * the first interval starts before or prolongs the second one, that is, * iff <var>a</var> < <var>a</var>' or <var>a</var>=<var>a</var>' and <var>b</var>' < <var>b</var>. */ public final static Comparator<Interval> STARTS_BEFORE_OR_PROLONGS = new Comparator<Interval>() { public int compare( final Interval i1, final Interval i2 ) { if ( i1.left != i2.left ) return i1.left < i2.left ? -1 : 1; if ( i1.right != i2.right ) return i2.right < i1.right ? -1 : 1; return 0; } }; /** A comparator between intervals defined as follows: * [<var>a</var>..<var>b</var>] is less than [<var>a</var>'..<var>b</var>'] iff * the first interval ends before or is a suffix of the second one, that is, * iff <var>b</var> < <var>b</var>' or <var>b</var>=<var>b</var>' and <var>a</var>' < <var>a</var>. */ public final static Comparator<Interval> ENDS_BEFORE_OR_IS_SUFFIX = new Comparator<Interval>() { public int compare( final Interval i1, final Interval i2 ) { if ( i1.right != i2.right ) return i1.right < i2.right ? -1 : 1; if ( i1.left != i2.left ) return i2.left < i1.left ? -1 : 1; return 0; } }; /** A comparator between intervals defined as follows: * [<var>a</var>..<var>b</var>] is less than [<var>a</var>'..<var>b</var>'] * iff the first interval starts <em>after</em> the second one, that is, * iff <var>a</var>' < <var>a</var>. */ public final static Comparator<Interval> STARTS_AFTER = new Comparator<Interval>() { public int compare( final Interval i1, final Interval i2 ) { if ( i1.left != i2.left ) return i2.left < i1.left ? -1 : 1; return 0; } }; /** A comparator between intervals defined as follows: * [<var>a</var>..<var>b</var>] is less than [<var>a</var>'..<var>b</var>'] * iff the first interval starts <em>before</em> the second one, that is, * iff <var>a</var>' > <var>a</var>. */ public final static Comparator<Interval> STARTS_BEFORE = new Comparator<Interval>() { public int compare( final Interval i1, final Interval i2 ) { if ( i1.left != i2.left ) return i2.left < i1.left ? 1 : -1; return 0; } }; /** A comparator between intervals defined as follows: * [<var>a</var>..<var>b</var>] is less than [<var>a</var>'..<var>b</var>'] * iff the first interval ends <em>after</em> the second one, that is, * iff <var>b</var>' < <var>b</var>. */ public final static Comparator<Interval> ENDS_AFTER = new Comparator<Interval>() { public int compare( final Interval i1, final Interval i2 ) { if ( i1.right != i2.right ) return i2.right < i1.right ? -1 : 1; return 0; } }; /** A comparator between intervals defined as follows: * [<var>a</var>..<var>b</var>] is less than [<var>a</var>'..<var>b</var>'] * iff the first interval ends <em>before</em> the second one, that is, * iff <var>b</var>' > <var>b</var>. */ public final static Comparator<Interval> ENDS_BEFORE = new Comparator<Interval>() { public int compare( final Interval i1, final Interval i2 ) { if ( i1.right != i2.right ) return i2.right < i1.right ? 1 : -1; return 0; } }; /** A comparator between intervals based on their length. */ public final static Comparator<Interval> LENGTH_COMPARATOR = new Comparator<Interval>() { public int compare( final Interval i1, final Interval i2 ) { return i1.length() - i2.length(); } }; }