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39
40//
41// W A R N I N G
42// -------------
43//
44// This file is not part of the Qt API. It exists purely as an
45// implementation detail. This header file may change from version to
46// version without notice, or even be removed.
47//
48// We mean it.
49
50#ifndef Patternist_UnlimitedContainer_H
51#define Patternist_UnlimitedContainer_H
52
53#include <QList>
54#include <private/qexpression_p.h>
55#include <private/qgenericsequencetype_p.h>
56
57QT_BEGIN_NAMESPACE
58
59namespace QPatternist
60{
61 /**
62 * @short Base class for expressions that has any amount of operands.
63 *
64 * @author Frans Englich <frans.englich@nokia.com>
65 * @ingroup Patternist_expressions
66 */
67 class UnlimitedContainer : public Expression
68 {
69 public:
70 /**
71 * Creates an UnlimitedContainer containing the operands @p operands. @p operands
72 * may be empty.
73 */
74 UnlimitedContainer(const Expression::List &operands = Expression::List());
75
76 virtual void setOperands(const Expression::List &list);
77
78 virtual Expression::List operands() const;
79
80 /**
81 * @note This function cannot be called before setOperands is called.
82 */
83 virtual bool compressOperands(const StaticContext::Ptr &);
84
85 /**
86 * Tells how operandsUnionType() should compute the cardinality of
87 * its children.
88 *
89 * This type is public because of a bug in the HP-UX aCC compiler.
90 */
91 enum CardinalityComputation
92 {
93 ProductOfCardinality,
94 UnionOfCardinality
95 };
96
97 protected:
98 /**
99 * Computes and returns the union type of all the Expression instances
100 * in this Expression's operands.
101 *
102 * This implementation is placed inside because CardinalityComputation
103 * can't be referenced from the outside(in conforming compilers).
104 */
105 template<CardinalityComputation suppliedCard>
106 inline
107 SequenceType::Ptr operandsUnionType() const
108 {
109 Q_ASSERT(suppliedCard == ProductOfCardinality || suppliedCard == UnionOfCardinality);
110 const Expression::List::const_iterator end(m_operands.constEnd());
111 Expression::List::const_iterator it(m_operands.constBegin());
112
113 /* Load the first one, and jump over it in the loop. */
114 SequenceType::Ptr t(m_operands.first()->staticType());
115 ItemType::Ptr type(t->itemType());
116 Cardinality card(t->cardinality());
117 ++it;
118
119 for(; it != end; ++it)
120 {
121 t = (*it)->staticType();
122 type |= t->itemType();
123
124 /* Since this function is a template function, it doesn't
125 * hurt performance that this test is inside the loop. */
126 if(suppliedCard == ProductOfCardinality)
127 card += t->cardinality();
128 else
129 card |= t->cardinality();
130 }
131
132 return makeGenericSequenceType(itemType: type, cardinality: card);
133 }
134
135 Expression::List m_operands;
136 };
137
138
139}
140
141QT_END_NAMESPACE
142
143#endif
144

source code of qtxmlpatterns/src/xmlpatterns/expr/qunlimitedcontainer_p.h