/*
    * 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 long numbers.
   */
  @Immutable
  public class LongOperations implements MathOperations<Long>, Comparator<Long> {
  
      public Class<Long> getOperandClass() {
          return Long.class;
      }
  
      public Long add( Long value1,
                       Long value2 ) {
          if (value1 == null) return value2 != null ? value2 : createZeroValue();
          if (value2 == null) return value1;
          return (value1 + value2);
      }
  
      public Long subtract( Long value1,
                            Long value2 ) {
          if (value1 == null) return negate(value2);
          if (value2 == null) return value1;
          return (value1 - value2);
      }
  
      public Long multiply( Long value1,
                            Long value2 ) {
          if (value1 == null || value2 == null) return createZeroValue();
          return (value1 * value2);
      }
  
      public double divide( Long value1,
                            Long value2 ) {
          if (value1 == null || value2 == null) throw new IllegalArgumentException();
          return value1 / value2;
      }
  
      public Long negate( Long value ) {
          if (value == null) return createZeroValue();
          return (value * -1);
      }
  
      public Long increment( Long value ) {
          if (value == null) return createZeroValue();
          return (value + 1);
      }
  
      public Long maximum( Long value1,
                           Long value2 ) {
          if (value1 == null) return value2;
          if (value2 == null) return value1;
          return Math.max(value1, value2);
      }
  
      public Long minimum( Long value1,
                           Long value2 ) {
          if (value1 == null) return value2;
          if (value2 == null) return value1;
          return Math.min(value1, value2);
      }
  
      public int compare( Long value1,
                          Long value2 ) {
          if (value1 == null) return value2 != null ? -1 : 0;
          if (value2 == null) return 1;
          return value1.compareTo(value2);
      }
  
      public BigDecimal asBigDecimal( Long value ) {
          return value != null ? new BigDecimal(value) : null;
     }
 
     public Long fromBigDecimal( BigDecimal value ) {
         return value != null ? value.longValue() : null;
     }
 
     public Long createZeroValue() {
         return 0l;
     }
 
     public Long create( int value ) {
         return (long)value;
     }
 
     public Long create( long value ) {
         return value;
     }
 
     public Long create( double value ) {
         return (long)value;
     }
 
     public double sqrt( Long value ) {
         return Math.sqrt(value);
     }
 
     public Comparator<Long> getComparator() {
         return this;
     }
 
     public Long random( Long minimum,
                         Long maximum,
                         Random rng ) {
         Long difference = subtract(maximum, minimum);
         return minimum + rng.nextInt(difference.intValue());
     }
 
     public double doubleValue( Long value ) {
         return value.doubleValue();
     }
 
     public float floatValue( Long value ) {
         return value.floatValue();
     }
 
     public int intValue( Long value ) {
         return value.intValue();
     }
 
     public long longValue( Long value ) {
         return value.longValue();
     }
 
     public short shortValue( Long value ) {
         return value.shortValue();
     }
 
     public int getExponentInScientificNotation( Long value ) {
         long v = Math.abs(value);
         int exp = 0;
         if (v > 1l) {
             while (v >= 10l) {
                 v /= 10l;
                 ++exp;
             }
         } else if (v == 0l) {
         } else if (v < 1l) {
             while (v < 1l) {
                 v *= 10l;
                 --exp;
             }
         }
         return exp;
     }
 
     public Long roundUp( Long value,
                          int decimalShift ) {
         if (value == 0) return 0l;
         if (decimalShift >= 0) return value;
         long shiftedValueP5 = Math.abs(value);
         for (int i = 0; i != (-decimalShift - 1); ++i)
             shiftedValueP5 /= 10l;
         shiftedValueP5 += 5l;
         long shiftedValue = shiftedValueP5 / 10l;
         if (shiftedValue * 10l - shiftedValueP5 >= 5) ++shiftedValue;
         shiftedValue *= Long.signum(value);
         for (int i = 0; i != -decimalShift; ++i)
             shiftedValue *= 10l;
         return shiftedValue;
     }
 
     public Long roundDown( Long value,
                            int decimalShift ) {
         if (value == 0) return 0l;
         if (decimalShift >= 0) return value;
         long shiftedValue = Math.abs(value);
         for (int i = 0; i != -decimalShift; ++i)
             shiftedValue /= 10l;
         shiftedValue *= Long.signum(value);
         for (int i = 0; i != -decimalShift; ++i)
             shiftedValue *= 10l;
         return shiftedValue;
     }
 
     public Long keepSignificantFigures( Long value,
                                         int numSigFigs ) {
         if (value == 0l) return value;
         if (numSigFigs < 0) return value;
         if (numSigFigs == 0) return 0l;
         int currentExp = getExponentInScientificNotation(value);
         int decimalShift = -currentExp + numSigFigs - 1;
         return roundUp(value, decimalShift);
     }
 }