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  ** Copyright (C) 2016 The Qt Company Ltd.
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  ** This file is part of the QtXmlPatterns module of the Qt Toolkit.
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  //
  //  W A R N I N G
  //  -------------
  //
  // This file is not part of the Qt API.  It exists purely as an
  // implementation detail.  This header file may change from version to
  // version without notice, or even be removed.
  //
  // We mean it.
  
  #ifndef Patternist_Numeric_H
  #define Patternist_Numeric_H
  
  #include <private/qitem_p.h>
  #include <private/qprimitives_p.h>
  
  QT_BEGIN_NAMESPACE
  
  /**
   * @file
   * @short Contains class Numeric. This file was originally called qnumeric_p.h,
   * but various build systems cannot handle that that name happens to be
   * identical to another one, the one in QtCore.
   */
  
  namespace QPatternist
  {
      /**
       * @short Base class for all numeric values.
       *
       * @section creation Creating Instances
       *
       * @todo
       * - Depending on what type of val
       * - Numeric::createFromString
       * - Various classes has ::Zero(), ::PosINF(), ::NaN(), NegINF()
       * - Never use constructor, use createFromNative, or createFromString.
       *
       * @see <a href="http://www.w3.org/TR/xquery-operators/#numeric-functions">XQuery 1.0
       * and XPath 2.0 Functions and Operators, 6 Functions and Operators on Numerics</a>
       * @see <a href="http://www.w3.org/TR/xquery-operators/#func-overloading">XQuery 1.0
       * and XPath 2.0 Functions and Operators, 1.2 Function Overloading</a>
       * @author Frans Englich <frans.englich@nokia.com>
       * @ingroup Patternist_xdm
       * @todo discuss data hierarchy the non existatnt number data type
       */
      class Numeric : public AtomicValue
      {
      public:
  
          typedef QExplicitlySharedDataPointer<Numeric> Ptr;
  
          /**
           * Creates a Numeric sub-class that is appropriate for @p number.
           *
           * @note usages of e/E is not handled; Double::fromLexical should
           * be used in that case. There is no function similar to fromLexical that also
           * takes double values into account(because that distinction is done in the scanner).
           *
           * Currently used in the parser to create appropriate expressions.
           */
          static AtomicValue::Ptr fromLexical(const QString &number);
  
          /**
           * @returns the particular number's value as a native representation of
           * the type xs:double. This can be considered that the value is cast to
           * xs:double.
           */
          virtual xsDouble toDouble() const = 0;
  
          /**
           * @returns the particular number's value as a native representation of
           * the type xs:integer. This can be considered that the value is cast to
           * xs:integer.
           */
          virtual xsInteger toInteger() const = 0;
  
          /**
           * @returns the number as an unsigned integer. If the value is not
           * unsigned, the code asserts and behavior is undefined.
           */
          virtual qulonglong toUnsignedInteger() const = 0;
  
          /**
           * @returns the particular number's value as a native representation of
           * the type xs:float. This can be considered that the value is cast to
           * xs:float.
           */
          virtual xsFloat toFloat() const = 0;
  
          /**
           * @returns the particular number's value as a native representation of
           * the type xs:decimal. This can be considered that the value is cast to
           * xs:decimal.
           */
          virtual xsFloat toDecimal() const = 0;
  
          /**
           * Performs the algorithm specified for the function fn:round on this Numeric,
           * and whose result is returned.
           *
           * @see <a href="http://www.w3.org/TR/xpath-functions/#func-round">XQuery 1.0
           * and XPath 2.0 Functions and Operators, 6.4.4 fn:round</a>
           */
          virtual Numeric::Ptr round() const = 0;
  
          /**
           * Performs rounding as defined for the fn:round-half-to-even  on this Numeric,
           * and whose result is returned.
           *
           * @see <a href="http://www.w3.org/TR/xpath-functions/#func-round-half-to-even">XQuery 1.0
           * and XPath 2.0 Functions and Operators, 6.4.5 fn:round-half-to-even</a>
           */
          virtual Numeric::Ptr roundHalfToEven(const xsInteger scale) const = 0;
  
          /**
           * Performs the algorithm specified for the function fn:floor on this Numeric,
           * and whose result is returned.
           *
           * @see <a href="http://www.w3.org/TR/xpath-functions/#func-floor">XQuery 1.0
           * and XPath 2.0 Functions and Operators, 6.4.3 fn:floor</a>
           */
          virtual Numeric::Ptr floor() const = 0;
  
          /**
           * Performs the algorithm specified for the function fn:ceiling on this Numeric,
           * and whose result is returned.
           *
           * @see <a href="http://www.w3.org/TR/xpath-functions/#func-ceiling">XQuery 1.0
           * and XPath 2.0 Functions and Operators, 6.4.2 fn:ceiling</a>
           */
          virtual Numeric::Ptr ceiling() const = 0;
  
          /**
           * Performs the algorithm specified for the function fn:abs on this Numeric,
           * and whose result is returned.
           *
           * @see <a href="http://www.w3.org/TR/xpath-functions/#func-ceiling">XQuery 1.0
           * and XPath 2.0 Functions and Operators, 6.4.1 fn:abs</a>
           */
          virtual Numeric::Ptr abs() const = 0;
  
          /**
           * Determines whether this Numeric is not-a-number, @c NaN. For numeric types
           * that cannot represent @c NaN, this function should return @c false.
           *
           * @returns @c true if this Numeric is @c NaN
           */
          virtual bool isNaN() const = 0;
  
          /**
           * Determines whether this Numeric is an infinite number. Signedness
           * is irrelevant, -INF as well as INF is considered infinity.
           *
           * For numeric types that cannot represent infinity, such as xs:integer
           * , this function should return @c false.
           *
           * @returns @c true if this Numeric is an infinite number
           */
          virtual bool isInf() const = 0;
  
          /**
           * Unary minus.
           */
          virtual Item toNegated() const = 0;
  
          /**
           * @short Returns @c true if this value is signed. If @c false is
           * returned, the value is unsigned.
           *
           * For float and decimal values, @c xs:double, @c xs:float and @c
           * xs:decimal, the code asserts and behavior is undefined.
           */
          virtual bool isSigned() const = 0;
  
      protected:
          /**
           * @short Implements @c fn:round() for types implemented with floating
           * point.
           *
           * MS Windows and at least IRIX does not have C99's nearbyint() function(see the man
           * page), so we reinvent it.
           */
          static xsDouble roundFloat(const xsDouble val);
      };
  }
  
  QT_END_NAMESPACE
  
  #endif
  