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39
40#include "qbuiltintypes_p.h"
41#include "qcommonsequencetypes_p.h"
42#include "qcommonvalues_p.h"
43#include "qgenericsequencetype_p.h"
44#include "qinteger_p.h"
45#include "qliteral_p.h"
46#include "qrangeiterator_p.h"
47
48#include "qrangeexpression_p.h"
49
50QT_BEGIN_NAMESPACE
51
52using namespace QPatternist;
53
54RangeExpression::RangeExpression(const Expression::Ptr &operand1,
55 const Expression::Ptr &operand2) : PairContainer(operand1, operand2)
56{
57}
58
59Item::Iterator::Ptr RangeExpression::evaluateSequence(const DynamicContext::Ptr &context) const
60{
61 const Item s(m_operand1->evaluateSingleton(context));
62
63 if(!s)
64 return CommonValues::emptyIterator;
65
66 const Item e(m_operand2->evaluateSingleton(context));
67 if(!e)
68 return CommonValues::emptyIterator;
69
70 const xsInteger start = s.as<Numeric>()->toInteger();
71 const xsInteger end = e.as<Numeric>()->toInteger();
72
73 if(start > end)
74 return CommonValues::emptyIterator;
75 else if(start == end)
76 return makeSingletonIterator(item: s);
77 else
78 return Item::Iterator::Ptr(new RangeIterator(start, RangeIterator::Forward, end));
79}
80
81Item RangeExpression::evaluateSingleton(const DynamicContext::Ptr &context) const
82{
83 return m_operand1->evaluateSingleton(context);
84}
85
86SequenceType::List RangeExpression::expectedOperandTypes() const
87{
88 SequenceType::List result;
89 result.append(t: CommonSequenceTypes::ZeroOrOneInteger);
90 result.append(t: CommonSequenceTypes::ZeroOrOneInteger);
91 return result;
92}
93
94SequenceType::Ptr RangeExpression::staticType() const
95{
96 /* This logic makes the Cardinality more specific. */
97 Cardinality::Count from;
98 bool hasFrom;
99
100 if(m_operand1->is(i: IDIntegerValue))
101 {
102 from = m_operand1->as<Literal>()->item().as<Integer>()->toInteger();
103 hasFrom = true;
104 }
105 else
106 {
107 hasFrom = false;
108 from = 0;
109 }
110
111 /* We can't check whether to is -1 since maybe the user wrote -1. Hence
112 * hasTo is required. */
113 bool hasTo;
114 Cardinality::Count to;
115
116 if(m_operand2->is(i: IDIntegerValue))
117 {
118 const xsInteger asInt = m_operand2->as<Literal>()->item().as<Integer>()->toInteger();
119 to = asInt;
120
121 if(to == asInt)
122 hasTo = true;
123 else
124 {
125 /* Cardinality::Count is not the same as type xsInteger. We had overflow. */
126 to = -1;
127 hasTo = false;
128 }
129 }
130 else
131 {
132 to = -1;
133 hasTo = false;
134 }
135
136 if(hasTo && hasFrom)
137 {
138 if(from > to)
139 {
140 /* The query is incorrectly written, we'll evaluate to the empty sequence.
141 * Just return what's correct. */
142 return CommonSequenceTypes::ZeroOrMoreIntegers;
143 }
144 else
145 {
146 Cardinality::Count count = (to - from) + 1; /* + 1, since it's inclusive. */
147 return makeGenericSequenceType(itemType: BuiltinTypes::xsInteger, cardinality: Cardinality::fromExact(count));
148 }
149 }
150 else
151 {
152 /* We can't do fromExact(from, -1) since the latter can evaluate to a value that actually is
153 * lower than from, although that unfortunately is very unlikely. */
154 return CommonSequenceTypes::ZeroOrMoreIntegers;
155 }
156}
157
158Expression::Properties RangeExpression::properties() const
159{
160 return Expression::DisableElimination;
161}
162
163ExpressionVisitorResult::Ptr RangeExpression::accept(const ExpressionVisitor::Ptr &visitor) const
164{
165 return visitor->visit(this);
166}
167
168QT_END_NAMESPACE
169

source code of qtxmlpatterns/src/xmlpatterns/expr/qrangeexpression.cpp