001/*
002 * Copyright 2006 - 2013
003 *     Stefan Balev     <stefan.balev@graphstream-project.org>
004 *     Julien Baudry    <julien.baudry@graphstream-project.org>
005 *     Antoine Dutot    <antoine.dutot@graphstream-project.org>
006 *     Yoann Pigné      <yoann.pigne@graphstream-project.org>
007 *     Guilhelm Savin   <guilhelm.savin@graphstream-project.org>
008 * 
009 * This file is part of GraphStream <http://graphstream-project.org>.
010 * 
011 * GraphStream is a library whose purpose is to handle static or dynamic
012 * graph, create them from scratch, file or any source and display them.
013 * 
014 * This program is free software distributed under the terms of two licenses, the
015 * CeCILL-C license that fits European law, and the GNU Lesser General Public
016 * License. You can  use, modify and/ or redistribute the software under the terms
017 * of the CeCILL-C license as circulated by CEA, CNRS and INRIA at the following
018 * URL <http://www.cecill.info> or under the terms of the GNU LGPL as published by
019 * the Free Software Foundation, either version 3 of the License, or (at your
020 * option) any later version.
021 * 
022 * This program is distributed in the hope that it will be useful, but WITHOUT ANY
023 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
024 * PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.
025 * 
026 * You should have received a copy of the GNU Lesser General Public License
027 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
028 * 
029 * The fact that you are presently reading this means that you have had
030 * knowledge of the CeCILL-C and LGPL licenses and that you accept their terms.
031 */
032package org.graphstream.algorithm.networksimplex;
033
034/**
035 * This class is used to present numbers of the form a + bM, where M is
036 * "big enough". A helper class for the network simplex method
037 * 
038 * @author Stefan Balev
039 * 
040 */
041class BigMNumber {
042        protected long small;
043        protected long big;
044
045        public BigMNumber() {
046                set(0, 0);
047        }
048        
049        public BigMNumber(long small) {
050                set(small, 0);
051        }
052
053        public void set(long small, long big) {
054                this.small = small;
055                this.big = big;
056        }
057
058        public void set(BigMNumber b) {
059                set(b.small, b.big);
060        }
061        
062        public void set(long small) {
063                set(small, 0);
064        }
065
066        public void plus(BigMNumber b) {
067                small += b.small;
068                big += b.big;
069        }
070
071        public void minus(BigMNumber b) {
072                small -= b.small;
073                big -= b.big;
074        }
075
076        public void minus() {
077                small = -small;
078                big = -big;
079        }
080        
081        public void plusTimes(int multiplier, BigMNumber b) {
082                small += multiplier * b.small;
083                big += multiplier * b.big;
084        }
085        
086        public boolean isNegative() {
087                return big < 0 || (big == 0 && small < 0);
088        }
089        
090        public boolean isInfinite() {
091                return big != 0;
092        }
093        
094        public int compareTo(BigMNumber b) {
095                if (big < b.big)
096                        return -1;
097                if (big > b.big)
098                        return 1;
099                if (small < b.small)
100                        return -1;
101                if (small > b.small)
102                        return 1;
103                return 0;
104        }
105        
106        public long getSmall() {
107                return small;
108        }
109        
110        @Override
111        public String toString() {
112                if (big == 0)
113                        return small + "";
114                String r = "";
115                if (small != 0) {
116                        r += small;
117                        if (big > 0)
118                                r += "+";
119                }
120                if (big == -1)
121                        r += "-";
122                else if (big != 1)
123                        r+= big;
124                r += "M";
125                return r;
126        }
127
128}