src/xmlpatterns/functions/qaggregatefns_p.h
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     1 /****************************************************************************
       
     2 **
       
     3 ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
       
     4 ** All rights reserved.
       
     5 ** Contact: Nokia Corporation (qt-info@nokia.com)
       
     6 **
       
     7 ** This file is part of the QtXmlPatterns module of the Qt Toolkit.
       
     8 **
       
     9 ** $QT_BEGIN_LICENSE:LGPL$
       
    10 ** No Commercial Usage
       
    11 ** This file contains pre-release code and may not be distributed.
       
    12 ** You may use this file in accordance with the terms and conditions
       
    13 ** contained in the Technology Preview License Agreement accompanying
       
    14 ** this package.
       
    15 **
       
    16 ** GNU Lesser General Public License Usage
       
    17 ** Alternatively, this file may be used under the terms of the GNU Lesser
       
    18 ** General Public License version 2.1 as published by the Free Software
       
    19 ** Foundation and appearing in the file LICENSE.LGPL included in the
       
    20 ** packaging of this file.  Please review the following information to
       
    21 ** ensure the GNU Lesser General Public License version 2.1 requirements
       
    22 ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
       
    23 **
       
    24 ** In addition, as a special exception, Nokia gives you certain additional
       
    25 ** rights.  These rights are described in the Nokia Qt LGPL Exception
       
    26 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
       
    27 **
       
    28 ** If you have questions regarding the use of this file, please contact
       
    29 ** Nokia at qt-info@nokia.com.
       
    30 **
       
    31 **
       
    32 **
       
    33 **
       
    34 **
       
    35 **
       
    36 **
       
    37 **
       
    38 ** $QT_END_LICENSE$
       
    39 **
       
    40 ****************************************************************************/
       
    41 
       
    42 //
       
    43 //  W A R N I N G
       
    44 //  -------------
       
    45 //
       
    46 // This file is not part of the Qt API.  It exists purely as an
       
    47 // implementation detail.  This header file may change from version to
       
    48 // version without notice, or even be removed.
       
    49 //
       
    50 // We mean it.
       
    51 
       
    52 #ifndef Patternist_AggregateFNs_H
       
    53 #define Patternist_AggregateFNs_H
       
    54 
       
    55 #include "qaggregator_p.h"
       
    56 #include "qatomiccomparator_p.h"
       
    57 #include "qatomicmathematician_p.h"
       
    58 #include "qcomparisonplatform_p.h"
       
    59 
       
    60 /**
       
    61  * @file
       
    62  * @short Contains classes implementing the functions found in
       
    63  * <a href="http://www.w3.org/TR/xpath-functions/#aggregate-functions">XQuery 1.0 and
       
    64  * XPath 2.0 Functions and Operators, 15.4 Aggregate Functions</a>.
       
    65  *
       
    66  * @todo document that some functions have both eval funcs implented.
       
    67  *
       
    68  * @ingroup Patternist_functions
       
    69  */
       
    70 
       
    71 QT_BEGIN_HEADER
       
    72 
       
    73 QT_BEGIN_NAMESPACE
       
    74 
       
    75 namespace QPatternist
       
    76 {
       
    77     /**
       
    78      * @short Implements the function <tt>fn:count()</tt>.
       
    79      *
       
    80      * @ingroup Patternist_functions
       
    81      * @author Frans Englich <frans.englich@nokia.com>
       
    82      */
       
    83     class CountFN : public FunctionCall
       
    84     {
       
    85     public:
       
    86         virtual Item evaluateSingleton(const DynamicContext::Ptr &context) const;
       
    87 
       
    88         /**
       
    89          * If @p reqType is CommonSequenceTypes::EBV, this function call is rewritten
       
    90          * into a call to <tt>fn:exists()</tt>. Hence, <tt>if(count(X)) then ...</tt> is
       
    91          * rewritten into <tt>if(exists(X)) then ...</tt>.
       
    92          */
       
    93         virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,
       
    94                                           const SequenceType::Ptr &reqType);
       
    95         /**
       
    96          * If CountFN's operand has a Cardinality that is exact, as per Cardinality::isExact(),
       
    97          * it is rewritten to the Cardinality's count.
       
    98          */
       
    99         virtual Expression::Ptr compress(const StaticContext::Ptr &context);
       
   100     };
       
   101 
       
   102     /**
       
   103      * @short Base class for the implementations of the <tt>fn:avg()</tt> and <tt>fn:sum()</tt> function.
       
   104      *
       
   105      * @ingroup Patternist_functions
       
   106      * @author Frans Englich <frans.englich@nokia.com>
       
   107      */
       
   108     class AddingAggregate : public FunctionCall
       
   109     {
       
   110     public:
       
   111         virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,
       
   112                                           const SequenceType::Ptr &reqType);
       
   113     protected:
       
   114         AtomicMathematician::Ptr m_mather;
       
   115     };
       
   116 
       
   117     /**
       
   118      * @short Implements the function <tt>fn:avg()</tt>.
       
   119      *
       
   120      * @ingroup Patternist_functions
       
   121      * @author Frans Englich <frans.englich@nokia.com>
       
   122      */
       
   123     class AvgFN : public AddingAggregate
       
   124     {
       
   125     public:
       
   126         virtual Item evaluateSingleton(const DynamicContext::Ptr &context) const;
       
   127         virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,
       
   128                                           const SequenceType::Ptr &reqType);
       
   129 
       
   130         virtual SequenceType::Ptr staticType() const;
       
   131     private:
       
   132         AtomicMathematician::Ptr m_adder;
       
   133         AtomicMathematician::Ptr m_divider;
       
   134     };
       
   135 
       
   136     /**
       
   137      * @short Implements the function <tt>fn:sum()</tt>.
       
   138      *
       
   139      * @ingroup Patternist_functions
       
   140      * @author Frans Englich <frans.englich@nokia.com>
       
   141      */
       
   142     class SumFN : public AddingAggregate
       
   143     {
       
   144     public:
       
   145         virtual Item evaluateSingleton(const DynamicContext::Ptr &context) const;
       
   146         virtual Expression::Ptr typeCheck(const StaticContext::Ptr &context,
       
   147                                           const SequenceType::Ptr &reqType);
       
   148         virtual SequenceType::Ptr staticType() const;
       
   149     };
       
   150 }
       
   151 
       
   152 QT_END_NAMESPACE
       
   153 
       
   154 QT_END_HEADER
       
   155 
       
   156 #endif