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41
42 #include "qbuiltintypes_p.h"
43 #include "qcommonsequencetypes_p.h"
44 #include "qcommonvalues_p.h"
45 #include "qgenericsequencetype_p.h"
46 #include "qinteger_p.h"
47 #include "qliteral_p.h"
48 #include "qrangeiterator_p.h"
49
50 #include "qrangeexpression_p.h"
51
52 QT_BEGIN_NAMESPACE
53
54 using namespace QPatternist;
55
RangeExpression(const Expression::Ptr & operand1,const Expression::Ptr & operand2)56 RangeExpression::RangeExpression(const Expression::Ptr &operand1,
57 const Expression::Ptr &operand2) : PairContainer(operand1, operand2)
58 {
59 }
60
evaluateSequence(const DynamicContext::Ptr & context) const61 Item::Iterator::Ptr RangeExpression::evaluateSequence(const DynamicContext::Ptr &context) const
62 {
63 const Item s(m_operand1->evaluateSingleton(context));
64
65 if(!s)
66 return CommonValues::emptyIterator;
67
68 const Item e(m_operand2->evaluateSingleton(context));
69 if(!e)
70 return CommonValues::emptyIterator;
71
72 const xsInteger start = s.as<Numeric>()->toInteger();
73 const xsInteger end = e.as<Numeric>()->toInteger();
74
75 if(start > end)
76 return CommonValues::emptyIterator;
77 else if(start == end)
78 return makeSingletonIterator(s);
79 else
80 return Item::Iterator::Ptr(new RangeIterator(start, RangeIterator::Forward, end));
81 }
82
evaluateSingleton(const DynamicContext::Ptr & context) const83 Item RangeExpression::evaluateSingleton(const DynamicContext::Ptr &context) const
84 {
85 return m_operand1->evaluateSingleton(context);
86 }
87
expectedOperandTypes() const88 SequenceType::List RangeExpression::expectedOperandTypes() const
89 {
90 SequenceType::List result;
91 result.append(CommonSequenceTypes::ZeroOrOneInteger);
92 result.append(CommonSequenceTypes::ZeroOrOneInteger);
93 return result;
94 }
95
staticType() const96 SequenceType::Ptr RangeExpression::staticType() const
97 {
98 /* This logic makes the Cardinality more specific. */
99 Cardinality::Count from;
100 bool hasFrom;
101
102 if(m_operand1->is(IDIntegerValue))
103 {
104 from = m_operand1->as<Literal>()->item().as<Integer>()->toInteger();
105 hasFrom = true;
106 }
107 else
108 {
109 hasFrom = false;
110 from = 0;
111 }
112
113 /* We can't check whether to is -1 since maybe the user wrote -1. Hence
114 * hasTo is required. */
115 bool hasTo;
116 Cardinality::Count to;
117
118 if(m_operand2->is(IDIntegerValue))
119 {
120 const xsInteger asInt = m_operand2->as<Literal>()->item().as<Integer>()->toInteger();
121 to = asInt;
122
123 if(to == asInt)
124 hasTo = true;
125 else
126 {
127 /* Cardinality::Count is not the same as type xsInteger. We had overflow. */
128 to = -1;
129 hasTo = false;
130 }
131 }
132 else
133 {
134 to = -1;
135 hasTo = false;
136 }
137
138 if(hasTo && hasFrom)
139 {
140 if(from > to)
141 {
142 /* The query is incorrectly written, we'll evaluate to the empty sequence.
143 * Just return what's correct. */
144 return CommonSequenceTypes::ZeroOrMoreIntegers;
145 }
146 else
147 {
148 Cardinality::Count count = (to - from) + 1; /* + 1, since it's inclusive. */
149 return makeGenericSequenceType(BuiltinTypes::xsInteger, Cardinality::fromExact(count));
150 }
151 }
152 else
153 {
154 /* We can't do fromExact(from, -1) since the latter can evaluate to a value that actually is
155 * lower than from, although that unfortunately is very unlikely. */
156 return CommonSequenceTypes::ZeroOrMoreIntegers;
157 }
158 }
159
properties() const160 Expression::Properties RangeExpression::properties() const
161 {
162 return Expression::DisableElimination;
163 }
164
accept(const ExpressionVisitor::Ptr & visitor) const165 ExpressionVisitorResult::Ptr RangeExpression::accept(const ExpressionVisitor::Ptr &visitor) const
166 {
167 return visitor->visit(this);
168 }
169
170 QT_END_NAMESPACE
171