package rsa;/** * <p>Title: </p> * <p>Description: </p> * <p>Copyright: Copyright (c) 2003</p> * <p>Company: </p> * @author not attributable * @version 1.0 */import java.io.PrintStream;/** * A class implementing arbitrary length integers. * <p>Copyright (C) 1995, 1996 Systemics Ltd (http://www.systemics.com/) * All rights reserved. */public class BigInteger extends BigNum{        public static final BigInteger zero = new BigInteger();        public static final BigInteger one = new BigInteger( 1 );        static        {                zero.zero();        }        public BigInteger()        {                super();        }        public BigInteger( int from )        {                super();                assign( from );        }        public BigInteger( BigInteger from )        {                super();                copy( this, from );        }        public BigInteger( String hexString )        {                super();                fromString( hexString );        }        public BigInteger( byte buffer[] )        {                super();                fromByteArray( buffer );        }        public int bitLength() { return bitLength(this); }        public Object        clone()        {                return new BigInteger( this );        }        public void        copy( Object src )        {                copy( this, (BigInteger)src );        }        public BigInteger        assign( BigInteger n )        {                copy( this, n );                return this;        }        public BigInteger        assign( int n )        {                assign( this, n );                return this;        }        public void        fromString(String inHex)        {                int len=inHex.length();                if ( len == 0 )                {                        zero( this );                        return;                }                int pos =0;                byte buffer[] = new byte [( ( len + 1 ) / 2 )];                if ( ( len % 2 ) == 1 )                {                        buffer[0]=(byte)asciiToHex(inHex.charAt(0));                        pos=1;                        len--;                }                for(int ptr = pos; len > 0; len -= 2 )                        buffer[pos++] = (byte)(                                        ( asciiToHex( inHex.charAt( ptr++ ) ) << 4 ) |                                        ( asciiToHex( inHex.charAt( ptr++ ) ) )                                        );                fromBinary( buffer );        }        public String        toString()        {                byte buffer[] = toByteArray();                StringBuffer returnBuffer = new StringBuffer();                int pos = 0, len = buffer.length;                // remove leading 0's.                while ( ( pos < len ) && ( buffer[pos] == 0 ) )                        pos++;                if ( ( pos < len ) && ( ( ( buffer[pos] >>> 4 ) & 0x0F ) == 0 ) )                {                        returnBuffer.append(  hexToAscii( buffer[0] & 0x0F ) );                        pos++;                }                for (; pos<len; pos++)                        returnBuffer.append( hexToAscii( ( buffer[pos] >>> 4 ) & 0x0F ) )                                                .append( hexToAscii( buffer[pos] & 0x0F ) );                if ( returnBuffer.length() > 0 )                        return returnBuffer.toString();                return "0";        } //       protected void //       finalize() //       {   //             super.finalize(); //       }        public BigInteger        modExp(BigInteger power, BigInteger modulo)        {                modExp( this, this, power, modulo );                return this;        }        public BigInteger        inverseModN( BigInteger a, BigInteger n )        {                inverseModN( this, a, n );                return this;        }        public BigInteger        mod( BigInteger a, BigInteger b )        {                mod( this, a, b );                return this;        }        public BigInteger        mul( BigInteger a, BigInteger b )        {                mul( this, a, b );                return this;        }        public BigInteger        div( BigInteger a, BigInteger b )        {                div( this, a, b );                return this;        }        public BigInteger        add( BigInteger a, BigInteger b )        {                add( this, a, b );                return this;        }        public BigInteger        add( int a )        {                add( this, a );                return this;        }        public BigInteger        sub( BigInteger a, BigInteger b )        {                sub( this, a, b );                return this;        }        public BigInteger        gcd( BigNum a, BigNum b )        {                gcd( this, a, b );                return this;        }        public int        cmp( BigInteger a )        {                return cmp( this, a );        }    public boolean    equals( Object o )    {        if (!(o instanceof BigInteger)) return false;        return (cmp( (BigInteger) o ) == 0);    }    public BigInteger        inc()        {                inc(this);                return this;        }        public BigInteger        dec()        {                dec(this);                return this;        }        public BigInteger        shiftLeft(int n)        {                shiftLeft(this, this, (short)n);                return this;        }        public BigInteger        shiftRight(int n)        {                shiftRight(this, this, (short)n);                return this;        }        public static BigInteger        zero()        {                BigInteger r = new BigInteger();                zero( r );                return r;        }        /**         * An internal function to create a buffer big enough in which         * to store a number.         * @param bitLen The number of <b>bits</b> in the number.         * @return a buffer in which to store a number.         */        protected static final byte[]        newBuffer( int bitLen )        {                return new byte[( bitLen + 7 ) / 8];        }        /**         * Convert a number into a byte array         * @return a byte array         */        public byte[]        toByteArray()        {                byte buffer[] = newBuffer( bitLength() );                intoBinary( buffer );                return buffer;        }        public void        fromByteArray( byte buf[] )        {                fromBinary( buf );        }        private static final int        asciiToHex(char c)        {                if ( ( c >= 'a' ) && ( c <= 'f' ) )                        return ( c - 'a' + 10 );                if ( ( c >= 'A' ) && ( c <= 'F' ) )                        return ( c - 'A' + 10 );                if ( ( c >= '0' ) && ( c <= '9' ) )                        return ( c - '0' );                throw new MathError("ascii to hex failed");        }        private static char        hexToAscii(int h)        {                if ( ( h >= 10 ) && ( h <= 15 ) )                        return (char)( 'A' + ( h - 10 ) );                if ( ( h >= 0 ) && ( h <= 9 ) )                        return (char)( '0' + h );                throw new MathError("hex to ascii failed");        }        //        //	Test code        //        public static void        main(String argv[])        {                try {                        self_test(System.out, argv);                }                catch(Throwable t)                {                        t.printStackTrace();