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    1   /*
    2    * Copyright (c) 2003 The Visigoth Software Society. All rights
    3    * reserved.
    4    *
    5    * Redistribution and use in source and binary forms, with or without
    6    * modification, are permitted provided that the following conditions
    7    * are met:
    8    *
    9    * 1. Redistributions of source code must retain the above copyright
   10    *    notice, this list of conditions and the following disclaimer.
   11    *
   12    * 2. Redistributions in binary form must reproduce the above copyright
   13    *    notice, this list of conditions and the following disclaimer in
   14    *    the documentation and/or other materials provided with the
   15    *    distribution.
   16    *
   17    * 3. The end-user documentation included with the redistribution, if
   18    *    any, must include the following acknowledgement:
   19    *       "This product includes software developed by the
   20    *        Visigoth Software Society (http://www.visigoths.org/)."
   21    *    Alternately, this acknowledgement may appear in the software itself,
   22    *    if and wherever such third-party acknowledgements normally appear.
   23    *
   24    * 4. Neither the name "FreeMarker", "Visigoth", nor any of the names of the 
   25    *    project contributors may be used to endorse or promote products derived
   26    *    from this software without prior written permission. For written
   27    *    permission, please contact visigoths@visigoths.org.
   28    *
   29    * 5. Products derived from this software may not be called "FreeMarker" or "Visigoth"
   30    *    nor may "FreeMarker" or "Visigoth" appear in their names
   31    *    without prior written permission of the Visigoth Software Society.
   32    *
   33    * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
   34    * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   35    * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
   36    * DISCLAIMED.  IN NO EVENT SHALL THE VISIGOTH SOFTWARE SOCIETY OR
   37    * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   38    * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   39    * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
   40    * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   41    * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   42    * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
   43    * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   44    * SUCH DAMAGE.
   45    * ====================================================================
   46    *
   47    * This software consists of voluntary contributions made by many
   48    * individuals on behalf of the Visigoth Software Society. For more
   49    * information on the Visigoth Software Society, please see
   50    * http://www.visigoths.org/
   51    */
   52   
   53   package freemarker.template.utility;
   54   
   55   import java.math.BigDecimal;
   56   import java.math.BigInteger;
   57   import java.util.ArrayList;
   58   import java.util.Collections;
   59   import java.util.List;
   60   
   61   /**
   62    * @version $Id: OptimizerUtil.java,v 1.9 2003/02/25 11:52:58 szegedia Exp $
   63    * @author Attila Szegedi
   64    */
   65   public class OptimizerUtil
   66   {
   67       private static final BigInteger INTEGER_MIN = new BigInteger(Integer.toString(Integer.MIN_VALUE));
   68       private static final BigInteger INTEGER_MAX = new BigInteger(Integer.toString(Integer.MAX_VALUE));
   69       private static final BigInteger LONG_MIN = new BigInteger(Long.toString(Long.MIN_VALUE));
   70       private static final BigInteger LONG_MAX = new BigInteger(Long.toString(Long.MAX_VALUE));
   71   
   72       private OptimizerUtil()
   73       {
   74       }
   75       
   76       public static List optimizeListStorage(List list)
   77       {
   78           switch(list.size())
   79           {
   80               case 0:
   81               {
   82                   return Collections.EMPTY_LIST;
   83               }
   84               case 1:
   85               {
   86                   return Collections12.singletonList(list.get(0));
   87               }
   88               default:
   89               {
   90                   if(list instanceof ArrayList)
   91                   {
   92                       ((ArrayList)list).trimToSize();
   93                   }
   94                   return list;
   95               }
   96           }
   97       }
   98       
   99       /**
  100        * This is needed to reverse the extreme conversions in arithmetic 
  101        * operations so that numbers can be meaningfully used with models that
  102        * don't know what to do with a BigDecimal. Of course, this will make
  103        * impossible for these models (i.e. Jython) to receive a BigDecimal even if 
  104        * it was originally placed as such in the data model. However, since 
  105        * arithmetic operations aggressively erase the information regarding the 
  106        * original number type, we have no other choice to ensure expected operation
  107        * in majority of cases.
  108        */
  109       public static Number optimizeNumberRepresentation(Number number)
  110       {
  111           if(number instanceof BigDecimal)
  112           {
  113               BigDecimal bd = (BigDecimal) number;
  114               if(bd.scale() == 0)
  115               {
  116                   // BigDecimal -> BigInteger
  117                   number = bd.unscaledValue();
  118               }
  119               else
  120               {
  121                   double d = bd.doubleValue();
  122                   if(d != Double.POSITIVE_INFINITY && d != Double.NEGATIVE_INFINITY)
  123                   {
  124                       // BigDecimal -> Double
  125                       return new Double(d);
  126                   }
  127               }
  128           }
  129           if(number instanceof BigInteger)
  130           {
  131               BigInteger bi = (BigInteger)number;
  132               if(bi.compareTo(INTEGER_MAX) <= 0 && bi.compareTo(INTEGER_MIN) >= 0)
  133               {
  134                   // BigInteger -> Integer
  135                   return new Integer(bi.intValue());
  136               }
  137               if(bi.compareTo(LONG_MAX) <= 0 && bi.compareTo(LONG_MIN) >= 0)
  138               {
  139                   // BigInteger -> Long
  140                   return new Long(bi.longValue());
  141               }
  142           }
  143           return number;
  144       }
  145   }

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