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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.
Author:
 Michael McCloskey
See Also:
BigInteger
Since:
  1.3/**
 * 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.
/**
     * The sign of this MutableBigInteger.
     */
    int sign = 1;

    // Constructors

    
The default constructor. An empty MutableBigInteger is created with
a one word capacity.
/**
     * 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.
/**
     * 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.
/**
     * 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.
/**
     * 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.
/**
     * 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.
/**
     * 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.
/**
     * 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.
/**
     * Print out the first intLen ints of this MutableBigInteger's value
     * array starting at offset.
     */
    public String toString() {
        return this.toBigInteger(sign).toString();
    }

}