/*

  * Copyright (c) 1999, 2007, Oracle and/or its affiliates. All rights reserved.

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

  *

  * This code is free software; you can redistribute it and/or modify it

  * under the terms of the GNU General Public License version 2 only, as

  * published by the Free Software Foundation.  Oracle designates this

  * particular file as subject to the "Classpath" exception as provided

  * by Oracle in the LICENSE file that accompanied this code.

  *

  * This code 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 General Public License

  * version 2 for more details (a copy is included in the LICENSE file that

  * accompanied this code).

  *

  * You should have received a copy of the GNU General Public License version

  * 2 along with this work; if not, write to the Free Software Foundation,

  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

  *

  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

  * or visit www.oracle.com if you need additional information or have any

  * questions.

  */

 package java.math;

 /**

  * A class used to represent multiprecision integers that makes efficient

  * use of allocated space by allowing a number to occupy only part of

  * an array so that the arrays do not have to be reallocated as often.

  * When performing an operation with many iterations the array used to

  * hold a number is only increased when necessary and does not have to

  * be the same size as the number it represents. A mutable number allows

  * calculations to occur on the same number without having to create

  * a new number for every step of the calculation as occurs with

  * BigIntegers.

  *

  * Note that SignedMutableBigIntegers only support signed addition and

  * subtraction. All other operations occur as with MutableBigIntegers.

  *

  * @see     BigInteger

  * @author  Michael McCloskey

  * @since   1.3

  */

 class SignedMutableBigInteger extends MutableBigInteger {

    /**

      * The sign of this MutableBigInteger.

      */

     int sign = 1;

     // Constructors

     /**

      * The default constructor. An empty MutableBigInteger is created with

      * a one word capacity.

      */

     SignedMutableBigInteger() {

         super();

     }

     /**

      * Construct a new MutableBigInteger with a magnitude specified by

      * the int val.

      */

     SignedMutableBigInteger(int val) {

         super(val);

     }

     /**

      * Construct a new MutableBigInteger with a magnitude equal to the

      * specified MutableBigInteger.

      */

     SignedMutableBigInteger(MutableBigInteger val) {

         super(val);

     }

    // Arithmetic Operations

    /**

      * Signed addition built upon unsigned add and subtract.

      */

     void signedAdd(SignedMutableBigInteger addend) {

         if (sign == addend.sign)

             add(addend);

         else

             sign = sign * subtract(addend);

     }

    /**

      * Signed addition built upon unsigned add and subtract.

      */

     void signedAdd(MutableBigInteger addend) {

         if (sign == 1)

             add(addend);

         else

             sign = sign * subtract(addend);

     }

    /**

      * Signed subtraction built upon unsigned add and subtract.

      */

     void signedSubtract(SignedMutableBigInteger addend) {

         if (sign == addend.sign)

             sign = sign * subtract(addend);

         else

             add(addend);

     }

    /**

      * Signed subtraction built upon unsigned add and subtract.

      */

     void signedSubtract(MutableBigInteger addend) {

         if (sign == 1)

             sign = sign * subtract(addend);

         else

             add(addend);

         if (intLen == 0)

              sign = 1;

     }

     /**

      * Print out the first intLen ints of this MutableBigInteger's value

      * array starting at offset.

      */

     public String toString() {

         return this.toBigInteger(sign).toString();

     }

 }