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1 /**************************************************************************** |
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2 ** |
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3 ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). |
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4 ** All rights reserved. |
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5 ** Contact: Nokia Corporation (qt-info@nokia.com) |
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6 ** |
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7 ** This file is part of the QtXmlPatterns module of the Qt Toolkit. |
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8 ** |
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9 ** $QT_BEGIN_LICENSE:LGPL$ |
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10 ** No Commercial Usage |
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11 ** This file contains pre-release code and may not be distributed. |
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12 ** You may use this file in accordance with the terms and conditions |
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13 ** contained in the Technology Preview License Agreement accompanying |
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14 ** this package. |
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15 ** |
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16 ** GNU Lesser General Public License Usage |
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17 ** Alternatively, this file may be used under the terms of the GNU Lesser |
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18 ** General Public License version 2.1 as published by the Free Software |
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19 ** Foundation and appearing in the file LICENSE.LGPL included in the |
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20 ** packaging of this file. Please review the following information to |
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21 ** ensure the GNU Lesser General Public License version 2.1 requirements |
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22 ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. |
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23 ** |
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24 ** In addition, as a special exception, Nokia gives you certain additional |
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25 ** rights. These rights are described in the Nokia Qt LGPL Exception |
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26 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. |
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27 ** |
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28 ** If you have questions regarding the use of this file, please contact |
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29 ** Nokia at qt-info@nokia.com. |
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30 ** |
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31 ** |
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32 ** |
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33 ** |
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34 ** |
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35 ** |
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36 ** |
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37 ** |
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38 ** $QT_END_LICENSE$ |
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39 ** |
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40 ****************************************************************************/ |
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41 |
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42 #include "qbuiltintypes_p.h" |
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43 #include "qcommonsequencetypes_p.h" |
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44 #include "qcommonvalues_p.h" |
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45 #include "qgenericsequencetype_p.h" |
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46 #include "qinteger_p.h" |
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47 #include "qliteral_p.h" |
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48 #include "qrangeiterator_p.h" |
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49 |
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50 #include "qrangeexpression_p.h" |
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51 |
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52 QT_BEGIN_NAMESPACE |
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53 |
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54 using namespace QPatternist; |
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55 |
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56 RangeExpression::RangeExpression(const Expression::Ptr &operand1, |
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57 const Expression::Ptr &operand2) : PairContainer(operand1, operand2) |
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58 { |
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59 } |
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60 |
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61 Item::Iterator::Ptr RangeExpression::evaluateSequence(const DynamicContext::Ptr &context) const |
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62 { |
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63 const Item s(m_operand1->evaluateSingleton(context)); |
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64 |
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65 if(!s) |
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66 return CommonValues::emptyIterator; |
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67 |
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68 const Item e(m_operand2->evaluateSingleton(context)); |
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69 if(!e) |
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70 return CommonValues::emptyIterator; |
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71 |
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72 const xsInteger start = s.as<Numeric>()->toInteger(); |
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73 const xsInteger end = e.as<Numeric>()->toInteger(); |
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74 |
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75 if(start > end) |
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76 return CommonValues::emptyIterator; |
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77 else if(start == end) |
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78 return makeSingletonIterator(s); |
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79 else |
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80 return Item::Iterator::Ptr(new RangeIterator(start, RangeIterator::Forward, end)); |
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81 } |
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82 |
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83 Item RangeExpression::evaluateSingleton(const DynamicContext::Ptr &context) const |
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84 { |
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85 return m_operand1->evaluateSingleton(context); |
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86 } |
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87 |
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88 SequenceType::List RangeExpression::expectedOperandTypes() const |
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89 { |
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90 SequenceType::List result; |
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91 result.append(CommonSequenceTypes::ZeroOrOneInteger); |
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92 result.append(CommonSequenceTypes::ZeroOrOneInteger); |
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93 return result; |
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94 } |
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95 |
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96 SequenceType::Ptr RangeExpression::staticType() const |
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97 { |
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98 /* This logic makes the Cardinality more specific. */ |
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99 Cardinality::Count from; |
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100 bool hasFrom; |
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101 |
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102 if(m_operand1->is(IDIntegerValue)) |
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103 { |
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104 from = m_operand1->as<Literal>()->item().as<Integer>()->toInteger(); |
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105 hasFrom = true; |
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106 } |
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107 else |
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108 { |
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109 hasFrom = false; |
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110 from = 0; |
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111 } |
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112 |
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113 /* We can't check whether to is -1 since maybe the user wrote -1. Hence |
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114 * hasTo is required. */ |
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115 bool hasTo; |
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116 Cardinality::Count to; |
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117 |
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118 if(m_operand2->is(IDIntegerValue)) |
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119 { |
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120 const xsInteger asInt = m_operand2->as<Literal>()->item().as<Integer>()->toInteger(); |
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121 to = asInt; |
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122 |
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123 if(to == asInt) |
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124 hasTo = true; |
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125 else |
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126 { |
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127 /* Cardinality::Count is not the same as type xsInteger. We had overflow. */ |
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128 to = -1; |
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129 hasTo = false; |
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130 } |
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131 } |
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132 else |
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133 { |
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134 to = -1; |
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135 hasTo = false; |
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136 } |
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137 |
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138 if(hasTo && hasFrom) |
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139 { |
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140 if(from > to) |
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141 { |
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142 /* The query is incorrectly written, we'll evaluate to the empty sequence. |
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143 * Just return what's correct. */ |
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144 return CommonSequenceTypes::ZeroOrMoreIntegers; |
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145 } |
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146 else |
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147 { |
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148 Cardinality::Count count = (to - from) + 1; /* + 1, since it's inclusive. */ |
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149 return makeGenericSequenceType(BuiltinTypes::xsInteger, Cardinality::fromExact(count)); |
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150 } |
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151 } |
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152 else |
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153 { |
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154 /* We can't do fromExact(from, -1) since the latter can evaluate to a value that actually is |
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155 * lower than from, although that unfortunately is very unlikely. */ |
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156 return CommonSequenceTypes::ZeroOrMoreIntegers; |
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157 } |
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158 } |
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159 |
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160 Expression::Properties RangeExpression::properties() const |
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161 { |
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162 return Expression::DisableElimination; |
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163 } |
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164 |
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165 ExpressionVisitorResult::Ptr RangeExpression::accept(const ExpressionVisitor::Ptr &visitor) const |
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166 { |
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167 return visitor->visit(this); |
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168 } |
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169 |
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170 QT_END_NAMESPACE |