QPatternist::AtomicComparator Class Reference

Base class for classes responsible of comparing two atomic values. More...

#include <qatomiccomparator_p.h>

Inheritance diagram for QPatternist::AtomicComparator:

Public Types
enum	ComparisonResult { LessThan = 1, Equal = 2, GreaterThan = 4, Incomparable = 8 }
enum	ComparisonType { AsGeneralComparison = 1, AsValueComparison }
enum	Operator {   OperatorEqual = 1, OperatorNotEqual = 1 << 1, OperatorGreaterThan = 1 << 2, OperatorLessThan = 1 << 3,   OperatorLessThanNaNLeast = 1 << 4, OperatorLessThanNaNGreatest = 1 << 5, OperatorGreaterOrEqual = OperatorEqual | OperatorGreaterThan, OperatorLessOrEqual = OperatorEqual | OperatorLessThan }
typedef QFlags< Operator >	Operators
typedef QExplicitlySharedDataPointer< AtomicComparator >	Ptr
Public Types inherited from QPatternist::AtomicTypeVisitorResult
typedef QExplicitlySharedDataPointer< AtomicTypeVisitorResult >	Ptr

Public Functions
	AtomicComparator ()
virtual ComparisonResult	compare (const Item &op1, const AtomicComparator::Operator op, const Item &op2) const
virtual bool	equals (const Item &op1, const Item &op2) const =0
virtual	~AtomicComparator ()
Public Functions inherited from QPatternist::AtomicTypeVisitorResult
	AtomicTypeVisitorResult ()
virtual	~AtomicTypeVisitorResult ()
Public Functions inherited from QSharedData
	QSharedData ()
	Constructs a QSharedData object with a reference count of 0. More...
	QSharedData (const QSharedData &)
	Constructs a QSharedData object with reference count 0. More...

Static Public Functions
static QString	displayName (const AtomicComparator::Operator op, const ComparisonType type)

Additional Inherited Members
Public Variables inherited from QSharedData
QAtomicInt	ref

Detailed Description

Base class for classes responsible of comparing two atomic values.

This class is also known as the AtomicParrot.

Author

Frans Englich frans.nosp@m..eng.nosp@m.lich@.nosp@m.noki.nosp@m.a.com

Definition at line 77 of file qatomiccomparator_p.h.

Typedefs

Operators

typedef QFlags<Operator> QPatternist::AtomicComparator::Operators

Definition at line 140 of file qatomiccomparator_p.h.

Ptr

typedef QExplicitlySharedDataPointer<AtomicComparator> QPatternist::AtomicComparator::Ptr

Definition at line 83 of file qatomiccomparator_p.h.

Enumerations

ComparisonResult

enum QPatternist::AtomicComparator::ComparisonResult

Signifies the result of a value comparison. This is used for value comparisons, and in the future likely also for sorting.

See also

W3C XML Path Language (XPath) 2.0, 3.5.1 Value Comparisons

Enumerator
LessThan
Equal
GreaterThan
Incomparable

Definition at line 149 of file qatomiccomparator_p.h.

        {
            LessThan     = 1,
            Equal        = 2,
            GreaterThan  = 4,
            Incomparable = 8
        };

ComparisonType

enum QPatternist::AtomicComparator::ComparisonType

Identifies the kind of comparison.

Enumerator
AsGeneralComparison	Identifies a general comparison; operator =, >, <=, and so on.
AsValueComparison	Identifies a value comparison; operator eq, lt, le, and so on.

Definition at line 188 of file qatomiccomparator_p.h.

        {
            AsGeneralComparison = 1,

            AsValueComparison
        };

Operator

enum QPatternist::AtomicComparator::Operator

Identifies operators used in value comparisons.

The enum values are bit-significant.

See also

W3C XML Path Language (XPath) 2.0, 3.5.1 Value Comparisons

Enumerator
OperatorEqual	Operator eq and =.
OperatorNotEqual	Operator ne and !=.
OperatorGreaterThan	Operator gt and >.
OperatorLessThan	Operator lt and <.
OperatorLessThanNaNLeast	One of the operators we use for sorting. The only difference from OperatorLessThan is that it sees NaN as ordered and smaller than other numbers.
OperatorLessThanNaNGreatest	One of the operators we use for sorting. The only difference from OperatorLessThanLeast is that it sees NaN as ordered and larger than other numbers.
OperatorGreaterOrEqual	Operator ge and >=.
OperatorLessOrEqual	Operator le and <=.

Definition at line 93 of file qatomiccomparator_p.h.

        {
            OperatorEqual           = 1,

            OperatorNotEqual        = 1 << 1,

            OperatorGreaterThan     = 1 << 2,

            OperatorLessThan        = 1 << 3,

            OperatorLessThanNaNLeast    = 1 << 4,

            OperatorLessThanNaNGreatest    = 1 << 5,

            OperatorGreaterOrEqual  = OperatorEqual | OperatorGreaterThan,

            OperatorLessOrEqual     = OperatorEqual | OperatorLessThan
        };

Constructors and Destructors

AtomicComparator()

AtomicComparator::AtomicComparator

(

)

Definition at line 50 of file qatomiccomparator.cpp.

{
}

~AtomicComparator()

AtomicComparator::~AtomicComparator ( )

virtual

Definition at line 54 of file qatomiccomparator.cpp.

{
}

Functions

compare()

AtomicComparator::ComparisonResult AtomicComparator::compare ( const Item &  op1, const AtomicComparator::Operator  op, const Item &  op2  ) const

virtual

Compares op1 and op2 and determines the relationship between the two. This is used for sorting and comparisons. The implementation performs an assert crash, and must therefore be re-implemented if comparing the relevant values should be possible.

Parameters

op1	the first operand
op	the operator. How a comparison is carried out shouldn't depend on what the operator is, but in some cases it is of interest.
op2	the second operand

Reimplemented in QPatternist::AbstractDurationComparator, QPatternist::AbstractDateTimeComparator, QPatternist::IntegerComparator, QPatternist::DecimalComparator, QPatternist::AbstractFloatSortComparator< t_op >, QPatternist::AbstractFloatComparator, QPatternist::BooleanComparator, QPatternist::CaseInsensitiveStringComparator, and QPatternist::StringComparator.

Definition at line 59 of file qatomiccomparator.cpp.

{
    Q_ASSERT_X(false, Q_FUNC_INFO, "This function should never be called.");
    return LessThan;
}

displayName()

QString AtomicComparator::displayName ( const AtomicComparator::Operator  op, const ComparisonType  type  )

static

Utility function for getting the lexical representation for the comparison operator op. Depending on the type argument, the string returned is either a general comparison or a value comparison operator.

Parameters

op	the operator which the display name should be determined for.
type	signifies whether the returned display name should be for a value comparison or a general comparison. For example, if op is OperatorEqual and type is AsValueComparision, "eq" is returned.

Definition at line 67 of file qatomiccomparator.cpp.

{
    Q_ASSERT(type == AsGeneralComparison || type == AsValueComparison);
    if(type == AsGeneralComparison)
    {
        switch(op)
        {
            case OperatorEqual:
                return QLatin1String("=");
            case OperatorGreaterOrEqual:
                return QLatin1String("<=");
            case OperatorGreaterThan:
                return QLatin1String("<");
            case OperatorLessOrEqual:
                return QLatin1String(">=");
            case OperatorLessThanNaNLeast:
            /* Fallthrough. */
            case OperatorLessThanNaNGreatest:
            /* Fallthrough. */
            case OperatorLessThan:
                return QLatin1String(">");
            case OperatorNotEqual:
                return QLatin1String("!=");
        }
    }

    switch(op)
    {
        case OperatorEqual:
            return QLatin1String("eq");
        case OperatorGreaterOrEqual:
            return QLatin1String("ge");
        case OperatorGreaterThan:
            return QLatin1String("gt");
        case OperatorLessOrEqual:
            return QLatin1String("le");
        case OperatorLessThanNaNLeast:
        /* Fallthrough. */
        case OperatorLessThanNaNGreatest:
        /* Fallthrough. */
        case OperatorLessThan:
            return QLatin1String("lt");
        case OperatorNotEqual:
            return QLatin1String("ne");
    }

    Q_ASSERT(false);
    return QString(); /* GCC unbarfer. */
}

equals()

virtual bool QPatternist::AtomicComparator::equals ( const Item &  op1, const Item &  op2  ) const

pure virtual

Determines whether op1 and op2 are equal. It is the same as calling compare() and checking whether the return value is Equal, but since comparison testing is such a common operation, this specialized function exists.

Returns

true if op1 and op2 are equal.

Parameters

op1	the first operand
op2	the second operand

Implemented in QPatternist::AbstractDurationComparator, QPatternist::AbstractDateTimeComparator, QPatternist::QNameComparator, QPatternist::IntegerComparator, QPatternist::DecimalComparator, QPatternist::AbstractFloatComparator, QPatternist::BooleanComparator, QPatternist::BinaryDataComparator, QPatternist::CaseInsensitiveStringComparator, and QPatternist::StringComparator.

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The documentation for this class was generated from the following files:

• /src/xmlpatterns/data/qatomiccomparator_p.h
• /src/xmlpatterns/data/qatomiccomparator.cpp