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FunctionRound.hpp

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00001 /*
00002  * The Apache Software License, Version 1.1
00003  *
00004  *
00005  * Copyright (c) 1999 The Apache Software Foundation.  All rights 
00006  * reserved.
00007  *
00008  * Redistribution and use in source and binary forms, with or without
00009  * modification, are permitted provided that the following conditions
00010  * are met:
00011  *
00012  * 1. Redistributions of source code must retain the above copyright
00013  *    notice, this list of conditions and the following disclaimer. 
00014  *
00015  * 2. Redistributions in binary form must reproduce the above copyright
00016  *    notice, this list of conditions and the following disclaimer in
00017  *    the documentation and/or other materials provided with the
00018  *    distribution.
00019  *
00020  * 3. The end-user documentation included with the redistribution,
00021  *    if any, must include the following acknowledgment:  
00022  *       "This product includes software developed by the
00023  *        Apache Software Foundation (http://www.apache.org/)."
00024  *    Alternately, this acknowledgment may appear in the software itself,
00025  *    if and wherever such third-party acknowledgments normally appear.
00026  *
00027  * 4. The names "Xalan" and "Apache Software Foundation" must
00028  *    not be used to endorse or promote products derived from this
00029  *    software without prior written permission. For written 
00030  *    permission, please contact apache@apache.org.
00031  *
00032  * 5. Products derived from this software may not be called "Apache",
00033  *    nor may "Apache" appear in their name, without prior written
00034  *    permission of the Apache Software Foundation.
00035  *
00036  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
00037  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
00038  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
00039  * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
00040  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
00041  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
00042  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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00046  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
00047  * SUCH DAMAGE.
00048  * ====================================================================
00049  *
00050  * This software consists of voluntary contributions made by many
00051  * individuals on behalf of the Apache Software Foundation and was
00052  * originally based on software copyright (c) 1999, International
00053  * Business Machines, Inc., http://www.ibm.com.  For more
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00055  * <http://www.apache.org/>.
00056  */
00057 #if !defined(FUNCTIONROUND_HEADER_GUARD_1357924680)
00058 #define FUNCTIONROUND_HEADER_GUARD_1357924680
00059 
00060 
00061 
00062 // Base header file.  Must be first.
00063 #include <XPath/XPathDefinitions.hpp>
00064 
00065 
00066 
00067 #include <cmath>
00068 #include <vector>
00069 
00070 
00071 
00072 // Base class header file...
00073 #include <XPath/Function.hpp>
00074 
00075 
00076 
00077 #include <PlatformSupport/DoubleSupport.hpp>
00078 
00079 
00080 
00081 #include <XPath/XObject.hpp>
00082 #include <XPath/XObjectFactory.hpp>
00083 #include <XPath/XPathExecutionContext.hpp>
00084 
00085 
00086 
00090 //
00091 // These are all inline, even though
00092 // there are virtual functions, because we expect that they will only be
00093 // needed by the XPath class.
00094 class XALAN_XPATH_EXPORT FunctionRound : public Function
00095 {
00096 public:
00097 
00098     // These methods are inherited from Function ...
00099 
00100     virtual XObject*
00101     execute(
00102             XPathExecutionContext&          executionContext,
00103             XalanNode*                      context,
00104             int                             /* opPos */,
00105             const XObjectArgVectorType&     args)
00106     {
00107         if (args.size() != 1)
00108         {
00109             executionContext.error("The round() function takes one argument!",
00110                                    context);
00111         }
00112 
00113         const double    theValue = args[0]->num();
00114 
00115         return executionContext.getXObjectFactory().createNumber(getRoundedValue(theValue));
00116     }
00117 
00118 #if defined(XALAN_NO_COVARIANT_RETURN_TYPE)
00119     virtual Function*
00120 #else
00121     virtual FunctionRound*
00122 #endif
00123     clone() const
00124     {
00125         return new FunctionRound(*this);
00126     }
00127 
00128     static double
00129     getRoundedValue(double  theValue)
00130     {
00131         if (DoubleSupport::isNaN(theValue))
00132         {
00133             return DoubleSupport::getNaN();
00134         }
00135         else if (DoubleSupport::isPositiveInfinity(theValue))
00136         {
00137             return DoubleSupport::getPositiveInfinity();
00138         }
00139         if (DoubleSupport::isNegativeInfinity(theValue))
00140         {
00141             return DoubleSupport::getNegativeInfinity();
00142         }
00143         else if (theValue == 0)
00144         {
00145             return 0.0;
00146         }
00147         else if (theValue > 0)
00148         {
00149             return long(theValue + 0.5);
00150         }
00151         else
00152         {
00153             // Negative numbers are a special case.  Any time we
00154             // have -0.5 as the fractional part, we have to
00155             // round up (toward 0), rather than down.
00156             double          intPart = 0;
00157 
00158             const double    fracPart = modf(theValue, &intPart);
00159 
00160             if (fracPart == -0.5)
00161             {
00162                 // special case -- we have have to round toward 0...
00163                 return long(theValue + 0.5);
00164             }
00165             else
00166             {
00167                 return long(theValue - 0.5);
00168             }
00169         }
00170     }
00171 
00172 private:
00173 
00174     // Not implemented...
00175     FunctionRound&
00176     operator=(const FunctionRound&);
00177 
00178     bool
00179     operator==(const FunctionRound&) const;
00180 };
00181 
00182 
00183 
00184 #endif  // FUNCTIONROUND_HEADER_GUARD_1357924680

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