/*
    * ModeShape (http://www.modeshape.org)
    * See the COPYRIGHT.txt file distributed with this work for information
    * regarding copyright ownership.  Some portions may be licensed
    * to Red Hat, Inc. under one or more contributor license agreements.
    * See the AUTHORS.txt file in the distribution for a full listing of 
    * individual contributors. 
    *
    * ModeShape is free software. Unless otherwise indicated, all code in ModeShape
   * is licensed to you under the terms of the GNU Lesser General Public License as
   * published by the Free Software Foundation; either version 2.1 of
   * the License, or (at your option) any later version.
   *
   * ModeShape 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
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with this software; if not, write to the Free
   * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
   * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
   */
  package org.modeshape.common.math;
  
  import java.math.BigDecimal;
  import java.util.Comparator;
  import java.util.Random;
  import net.jcip.annotations.Immutable;
  
  /**
   * The {@link MathOperations math operations} for double numbers.
   */
  @Immutable
  public class DoubleOperations implements MathOperations<Double>, Comparator<Double> {
  
      public Class<Double> getOperandClass() {
          return Double.class;
      }
  
      public Double add( Double value1,
                         Double value2 ) {
          if (value1 == null) return value2 != null ? value2 : createZeroValue();
          if (value2 == null) return value1;
          return (value1 + value2);
      }
  
      public Double subtract( Double value1,
                              Double value2 ) {
          if (value1 == null) return negate(value2);
          if (value2 == null) return value1;
          return (value1 - value2);
      }
  
      public Double multiply( Double value1,
                              Double value2 ) {
          if (value1 == null || value2 == null) return createZeroValue();
          return (value1 * value2);
      }
  
      public double divide( Double value1,
                            Double value2 ) {
          if (value1 == null || value2 == null) throw new IllegalArgumentException();
          return value1 / value2;
      }
  
      public Double negate( Double value ) {
          if (value == null) return createZeroValue();
          return (value * -1);
      }
  
      public Double increment( Double value ) {
          if (value == null) return createZeroValue();
          return (value + 1);
      }
  
      public Double maximum( Double value1,
                             Double value2 ) {
          if (value1 == null) return value2;
          if (value2 == null) return value1;
          return Math.max(value1, value2);
      }
  
      public Double minimum( Double value1,
                             Double value2 ) {
          if (value1 == null) return value2;
          if (value2 == null) return value1;
          return Math.min(value1, value2);
      }
  
      public int compare( Double value1,
                          Double value2 ) {
          if (value1 == null) return value2 != null ? -1 : 0;
          if (value2 == null) return 1;
          return value1.compareTo(value2);
      }
  
      public BigDecimal asBigDecimal( Double value ) {
          return value != null ? new BigDecimal(value) : null;
     }
 
     public Double fromBigDecimal( BigDecimal value ) {
         return value != null ? value.doubleValue() : null;
     }
 
     public Double createZeroValue() {
         return 0.0d;
     }
 
     public Double create( int value ) {
         return (double)value;
     }
 
     public Double create( long value ) {
         return (double)value;
     }
 
     public Double create( double value ) {
         return value;
     }
 
     public double sqrt( Double value ) {
         return Math.sqrt(value);
     }
 
     public Comparator<Double> getComparator() {
         return this;
     }
 
     public Double random( Double minimum,
                           Double maximum,
                           Random rng ) {
         Double difference = subtract(maximum, minimum);
         return minimum + difference.doubleValue() * rng.nextDouble();
     }
 
     public double doubleValue( Double value ) {
         return value.doubleValue();
     }
 
     public float floatValue( Double value ) {
         return value.floatValue();
     }
 
     public int intValue( Double value ) {
         return value.intValue();
     }
 
     public long longValue( Double value ) {
         return value.longValue();
     }
 
     public short shortValue( Double value ) {
         return value.shortValue();
     }
 
     public int getExponentInScientificNotation( Double value ) {
         double v = Math.abs(value);
         int exp = 0;
         if (v > 1.0d) {
             while (v >= 10.0d) {
                 v /= 10.0d;
                 ++exp;
             }
         } else if (v == 0.0d) {
         } else if (v < 1.0d) {
             while (v < 1.0d) {
                 v *= 10.0d;
                 --exp;
             }
         }
         return exp;
     }
 
     public Double roundUp( Double value,
                            int decimalShift ) {
         if (value == 0) return 0.0d;
         double shiftedValue = (Math.abs(value) * Math.pow(10.0d, decimalShift) + 0.5d) * Math.signum(value);
         double roundedValue = (int)shiftedValue;
         return roundedValue * Math.pow(10.0d, -decimalShift);
     }
 
     public Double roundDown( Double value,
                              int decimalShift ) {
         if (value == 0) return 0.0d;
         double shiftedValue = (Math.abs(value) * Math.pow(10.0d, decimalShift)) * Math.signum(value);
         double roundedValue = (int)shiftedValue;
         return roundedValue * Math.pow(10.0d, -decimalShift);
     }
 
     public Double keepSignificantFigures( Double value,
                                           int numSigFigs ) {
         if (numSigFigs < 0) return value;
         if (numSigFigs == 0) return 0.0d;
         int currentExp = getExponentInScientificNotation(value);
         int decimalShift = -currentExp + numSigFigs - 1;
         return roundUp(value, decimalShift);
     }
 }