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373 lines
9.9 KiB
Java
373 lines
9.9 KiB
Java
/* java.math.BigDecimal -- Arbitrary precision decimals.
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Copyright (C) 1999, 2000, 2001 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA.
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As a special exception, if you link this library with other files to
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produce an executable, this library does not by itself cause the
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resulting executable to be covered by the GNU General Public License.
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This exception does not however invalidate any other reasons why the
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executable file might be covered by the GNU General Public License. */
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package java.math;
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import java.math.BigInteger;
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public class BigDecimal extends Number implements Comparable {
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private BigInteger intVal;
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private int scale;
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private static final long serialVersionUID = 6108874887143696463L;
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private final static BigDecimal ZERO =
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new BigDecimal (BigInteger.valueOf (0), 0);
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private final static BigDecimal ONE =
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new BigDecimal (BigInteger.valueOf (1), 0);
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public final static int ROUND_UP = 0;
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public final static int ROUND_DOWN = 1;
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public final static int ROUND_CEILING = 2;
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public final static int ROUND_FLOOR = 3;
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public final static int ROUND_HALF_UP = 4;
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public final static int ROUND_HALF_DOWN = 5;
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public final static int ROUND_HALF_EVEN = 6;
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public final static int ROUND_UNNECESSARY = 7;
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public BigDecimal (BigInteger num)
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{
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this (num, 0);
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}
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public BigDecimal (BigInteger num, int scale) throws NumberFormatException
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{
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if (scale < 0)
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throw new NumberFormatException ("scale of " + scale + " is < 0");
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this.intVal = num;
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this.scale = scale;
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}
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public BigDecimal (double num) throws NumberFormatException
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{
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this (Double.toString (num));
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}
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public BigDecimal (String num) throws NumberFormatException
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{
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int point = num.indexOf('.');
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this.intVal = new BigInteger (point == -1 ? num :
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num.substring (0, point) +
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num.substring (point + 1));
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scale = num.length() - (point == -1 ? num.length () : point + 1);
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}
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public static BigDecimal valueOf (long val)
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{
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return valueOf (val, 0);
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}
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public static BigDecimal valueOf (long val, int scale)
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throws NumberFormatException
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{
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if (scale == 0)
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switch ((int) val)
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{
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case 0:
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return ZERO;
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case 1:
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return ONE;
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}
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return new BigDecimal (BigInteger.valueOf (val), scale);
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}
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public BigDecimal add (BigDecimal val)
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{
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// For addition, need to line up decimals. Note that the movePointRight
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// method cannot be used for this as it might return a BigDecimal with
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// scale == 0 instead of the scale we need.
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BigInteger op1 = intVal;
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BigInteger op2 = val.intVal;
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if (scale < val.scale)
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op1 = op1.multiply (BigInteger.valueOf (10).pow (val.scale - scale));
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else if (scale > val.scale)
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op2 = op2.multiply (BigInteger.valueOf (10).pow (scale - val.scale));
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return new BigDecimal (op1.add (op2), Math.max (scale, val.scale));
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}
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public BigDecimal subtract (BigDecimal val)
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{
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return this.add(val.negate());
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}
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public BigDecimal multiply (BigDecimal val)
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{
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return new BigDecimal (intVal.multiply (val.intVal), scale + val.scale);
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}
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public BigDecimal divide (BigDecimal val, int roundingMode)
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throws ArithmeticException, IllegalArgumentException
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{
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return divide (val, scale, roundingMode);
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}
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public BigDecimal divide(BigDecimal val, int newScale, int roundingMode)
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throws ArithmeticException, IllegalArgumentException
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{
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if (roundingMode < 0 || roundingMode > 7)
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throw
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new IllegalArgumentException("illegal rounding mode: " + roundingMode);
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if (newScale < 0)
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throw new ArithmeticException ("scale is negative: " + newScale);
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if (intVal.signum () == 0) // handle special case of 0.0/0.0
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return ZERO;
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// Ensure that pow gets a non-negative value.
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int valScale = val.scale;
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BigInteger valIntVal = val.intVal;
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int power = newScale + 1 - (scale - val.scale);
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if (power < 0)
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{
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// Effectively increase the scale of val to avoid an
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// ArithmeticException for a negative power.
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valIntVal = valIntVal.multiply (BigInteger.valueOf (10).pow (-power));
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power = 0;
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}
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BigInteger dividend = intVal.multiply (BigInteger.valueOf (10).pow (power));
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BigInteger parts[] = dividend.divideAndRemainder (valIntVal);
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// System.out.println("int: " + parts[0]);
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// System.out.println("rem: " + parts[1]);
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int roundDigit = parts[0].mod (BigInteger.valueOf (10)).intValue ();
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BigInteger unrounded = parts[0].divide (BigInteger.valueOf (10));
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if (roundDigit == 0 && parts[1].signum () == 0) // no rounding necessary
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return new BigDecimal (unrounded, newScale);
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int sign = unrounded.signum ();
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switch (roundingMode)
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{
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case ROUND_UNNECESSARY:
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throw new ArithmeticException ("newScale is not large enough");
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case ROUND_CEILING:
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roundingMode = (sign == 1) ? ROUND_UP : ROUND_DOWN;
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break;
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case ROUND_FLOOR:
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roundingMode = (sign == 1) ? ROUND_DOWN : ROUND_UP;
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break;
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case ROUND_HALF_UP:
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roundingMode = (roundDigit >= 5) ? ROUND_UP : ROUND_DOWN;
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break;
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case ROUND_HALF_DOWN:
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roundingMode = (roundDigit > 5) ? ROUND_UP : ROUND_DOWN;
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break;
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case ROUND_HALF_EVEN:
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if (roundDigit < 5)
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roundingMode = ROUND_DOWN;
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else
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{
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int rightmost =
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unrounded.mod (BigInteger.valueOf (10)).intValue ();
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if (rightmost % 2 == 1) // odd, then ROUND_HALF_UP
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roundingMode = ROUND_UP;
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else // even, then ROUND_HALF_DOWN
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roundingMode = (roundDigit > 5) ? ROUND_UP : ROUND_DOWN;
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}
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break;
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}
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if (roundingMode == ROUND_UP)
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return new BigDecimal (unrounded.add (BigInteger.valueOf (1)), newScale);
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// roundingMode == ROUND_DOWN
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return new BigDecimal (unrounded, newScale);
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}
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public int compareTo (BigDecimal val)
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{
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if (scale == val.scale)
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return intVal.compareTo (val.intVal);
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BigInteger thisParts[] =
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intVal.divideAndRemainder (BigInteger.valueOf (10).pow (scale));
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BigInteger valParts[] =
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val.intVal.divideAndRemainder (BigInteger.valueOf (10).pow (val.scale));
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int compare;
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if ((compare = thisParts[0].compareTo (valParts[0])) != 0)
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return compare;
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// quotients are the same, so compare remainders
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// remove trailing zeros
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if (thisParts[1].equals (BigInteger.valueOf (0)) == false)
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while (thisParts[1].mod (BigInteger.valueOf (10)).equals
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(BigInteger.valueOf (0)))
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thisParts[1] = thisParts[1].divide (BigInteger.valueOf (10));
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// again...
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if (valParts[1].equals(BigInteger.valueOf (0)) == false)
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while (valParts[1].mod (BigInteger.valueOf (10)).equals
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(BigInteger.valueOf (0)))
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valParts[1] = valParts[1].divide (BigInteger.valueOf (10));
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// and compare them
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return thisParts[1].compareTo (valParts[1]);
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}
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public int compareTo (Object val)
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{
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return(compareTo((BigDecimal)val));
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}
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public boolean equals (Object o)
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{
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return (o instanceof BigDecimal
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&& scale == ((BigDecimal) o).scale
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&& compareTo ((BigDecimal) o) == 0);
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}
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public int hashCode()
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{
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return intValue() ^ scale;
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}
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public BigDecimal max (BigDecimal val)
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{
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switch (compareTo (val))
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{
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case 1:
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return this;
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default:
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return val;
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}
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}
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public BigDecimal min (BigDecimal val)
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{
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switch (compareTo (val))
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{
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case -1:
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return this;
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default:
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return val;
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}
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}
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public BigDecimal movePointLeft (int n)
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{
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return (n < 0) ? movePointRight (-n) : new BigDecimal (intVal, scale + n);
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}
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public BigDecimal movePointRight (int n)
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{
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if (n < 0)
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return movePointLeft (-n);
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if (scale >= n)
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return new BigDecimal (intVal, scale - n);
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return new BigDecimal (intVal.multiply
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(BigInteger.valueOf (10).pow (n - scale)), 0);
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}
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public int signum ()
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{
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return intVal.signum ();
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}
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public int scale ()
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{
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return scale;
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}
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public BigDecimal abs ()
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{
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return new BigDecimal (intVal.abs (), scale);
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}
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public BigDecimal negate ()
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{
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return new BigDecimal (intVal.negate (), scale);
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}
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public String toString ()
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{
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String bigStr = intVal.toString();
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if (scale == 0)
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return bigStr;
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int point = bigStr.length() - scale;
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boolean negative = (bigStr.charAt(0) == '-');
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StringBuffer sb = new StringBuffer(bigStr.length() + 1 +
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(point <= 0 ? -point+1 : 0));
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if (negative)
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sb.append('-');
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while (point <= 0)
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{
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sb.append('0');
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point++;
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}
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sb.append(bigStr.substring(negative ? 1 : 0));
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sb.insert(point, '.');
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return sb.toString();
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}
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public BigInteger toBigInteger ()
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{
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return scale == 0 ? intVal :
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intVal.divide (BigInteger.valueOf (10).pow (scale));
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}
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public int intValue ()
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{
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return toBigInteger ().intValue ();
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}
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public long longValue ()
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{
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return toBigInteger().longValue();
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}
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public float floatValue()
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{
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return Float.valueOf(toString()).floatValue();
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}
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public double doubleValue()
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{
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return Double.valueOf(toString()).doubleValue();
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}
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public BigDecimal setScale (int scale) throws ArithmeticException
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{
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return setScale (scale, ROUND_UNNECESSARY);
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}
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public BigDecimal setScale (int scale, int roundingMode)
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throws ArithmeticException, IllegalArgumentException
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{
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return divide (ONE, scale, roundingMode);
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}
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}
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