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| 1 | /* | ||
| 2 | * Copyright (c) 1999, 2007, Oracle and/or its affiliates. All rights reserved. | ||
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | ||
| 4 | * | ||
| 5 | * This code is free software; you can redistribute it and/or modify it | ||
| 6 | * under the terms of the GNU General Public License version 2 only, as | ||
| 7 | * published by the Free Software Foundation. Oracle designates this | ||
| 8 | * particular file as subject to the "Classpath" exception as provided | ||
| 9 | * by Oracle in the LICENSE file that accompanied this code. | ||
| 10 | * | ||
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT | ||
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | ||
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | ||
| 14 | * version 2 for more details (a copy is included in the LICENSE file that | ||
| 15 | * accompanied this code). | ||
| 16 | * | ||
| 17 | * You should have received a copy of the GNU General Public License version | ||
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, | ||
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | ||
| 20 | * | ||
| 21 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | ||
| 22 | * or visit www.oracle.com if you need additional information or have any | ||
| 23 | * questions. | ||
| 24 | */ | ||
| 25 | |||
| 26 | package java.math; | ||
| 27 | |||
| 28 | /** | ||
| 29 | * A class used to represent multiprecision integers that makes efficient | ||
| 30 | * use of allocated space by allowing a number to occupy only part of | ||
| 31 | * an array so that the arrays do not have to be reallocated as often. | ||
| 32 | * When performing an operation with many iterations the array used to | ||
| 33 | * hold a number is only increased when necessary and does not have to | ||
| 34 | * be the same size as the number it represents. A mutable number allows | ||
| 35 | * calculations to occur on the same number without having to create | ||
| 36 | * a new number for every step of the calculation as occurs with | ||
| 37 | * BigIntegers. | ||
| 38 | * | ||
| 39 | * Note that SignedMutableBigIntegers only support signed addition and | ||
| 40 | * subtraction. All other operations occur as with MutableBigIntegers. | ||
| 41 | * | ||
| 42 | * @see BigInteger | ||
| 43 | * @author Michael McCloskey | ||
| 44 | * @since 1.3 | ||
| 45 | */ | ||
| 46 | |||
| 47 | class SignedMutableBigInteger extends MutableBigInteger { | ||
| 48 | |||
| 49 | /** | ||
| 50 | * The sign of this MutableBigInteger. | ||
| 51 | */ | ||
| 52 | int sign = 1; | ||
| 53 | |||
| 54 | // Constructors | ||
| 55 | |||
| 56 | /** | ||
| 57 | * The default constructor. An empty MutableBigInteger is created with | ||
| 58 | * a one word capacity. | ||
| 59 | */ | ||
| 60 | SignedMutableBigInteger() { | ||
| 61 | super(); | ||
| 62 | } | ||
| 63 | |||
| 64 | /** | ||
| 65 | * Construct a new MutableBigInteger with a magnitude specified by | ||
| 66 | * the int val. | ||
| 67 | */ | ||
| 68 | SignedMutableBigInteger(int val) { | ||
| 69 | super(val); | ||
| 70 | } | ||
| 71 | |||
| 72 | /** | ||
| 73 | * Construct a new MutableBigInteger with a magnitude equal to the | ||
| 74 | * specified MutableBigInteger. | ||
| 75 | */ | ||
| 76 | SignedMutableBigInteger(MutableBigInteger val) { | ||
| 77 | super(val); | ||
| 78 | } | ||
| 79 | |||
| 80 | // Arithmetic Operations | ||
| 81 | |||
| 82 | /** | ||
| 83 | * Signed addition built upon unsigned add and subtract. | ||
| 84 | */ | ||
| 85 | void signedAdd(SignedMutableBigInteger addend) { | ||
| 86 | if (sign == addend.sign) | ||
| 87 | add(addend); | ||
| 88 | else | ||
| 89 | sign = sign * subtract(addend); | ||
| 90 | |||
| 91 | } | ||
| 92 | |||
| 93 | /** | ||
| 94 | * Signed addition built upon unsigned add and subtract. | ||
| 95 | */ | ||
| 96 | void signedAdd(MutableBigInteger addend) { | ||
| 97 | if (sign == 1) | ||
| 98 | add(addend); | ||
| 99 | else | ||
| 100 | sign = sign * subtract(addend); | ||
| 101 | |||
| 102 | } | ||
| 103 | |||
| 104 | /** | ||
| 105 | * Signed subtraction built upon unsigned add and subtract. | ||
| 106 | */ | ||
| 107 | void signedSubtract(SignedMutableBigInteger addend) { | ||
| 108 | if (sign == addend.sign) | ||
| 109 | sign = sign * subtract(addend); | ||
| 110 | else | ||
| 111 | add(addend); | ||
| 112 | |||
| 113 | } | ||
| 114 | |||
| 115 | /** | ||
| 116 | * Signed subtraction built upon unsigned add and subtract. | ||
| 117 | */ | ||
| 118 | void signedSubtract(MutableBigInteger addend) { | ||
| 119 | if (sign == 1) | ||
| 120 | sign = sign * subtract(addend); | ||
| 121 | else | ||
| 122 | add(addend); | ||
| 123 | if (intLen == 0) | ||
| 124 | sign = 1; | ||
| 125 | } | ||
| 126 | |||
| 127 | /** | ||
| 128 | * Print out the first intLen ints of this MutableBigInteger's value | ||
| 129 | * array starting at offset. | ||
| 130 | */ | ||
| 131 | public String toString() { | ||
| 132 | return this.toBigInteger(sign).toString(); | ||
| 133 | } | ||
| 134 | |||
| 135 | } | ||