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Diffstat (limited to 'src/xmlpatterns/expr/qrangeexpression.cpp')
| -rw-r--r-- | src/xmlpatterns/expr/qrangeexpression.cpp | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/src/xmlpatterns/expr/qrangeexpression.cpp b/src/xmlpatterns/expr/qrangeexpression.cpp new file mode 100644 index 0000000..2313880 --- /dev/null +++ b/src/xmlpatterns/expr/qrangeexpression.cpp @@ -0,0 +1,170 @@ +/**************************************************************************** +** +** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). +** Contact: Qt Software Information (qt-info@nokia.com) +** +** This file is part of the QtXmlPatterns module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** No Commercial Usage +** This file contains pre-release code and may not be distributed. +** You may use this file in accordance with the terms and conditions +** contained in the either Technology Preview License Agreement or the +** Beta Release License Agreement. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 2.1 requirements +** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Nokia gives you certain +** additional rights. These rights are described in the Nokia Qt LGPL +** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this +** package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3.0 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU General Public License version 3.0 requirements will be +** met: http://www.gnu.org/copyleft/gpl.html. +** +** If you are unsure which license is appropriate for your use, please +** contact the sales department at qt-sales@nokia.com. +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "qbuiltintypes_p.h" +#include "qcommonsequencetypes_p.h" +#include "qcommonvalues_p.h" +#include "qgenericsequencetype_p.h" +#include "qinteger_p.h" +#include "qliteral_p.h" +#include "qrangeiterator_p.h" + +#include "qrangeexpression_p.h" + +QT_BEGIN_NAMESPACE + +using namespace QPatternist; + +RangeExpression::RangeExpression(const Expression::Ptr &operand1, + const Expression::Ptr &operand2) : PairContainer(operand1, operand2) +{ +} + +Item::Iterator::Ptr RangeExpression::evaluateSequence(const DynamicContext::Ptr &context) const +{ + const Item s(m_operand1->evaluateSingleton(context)); + + if(!s) + return CommonValues::emptyIterator; + + const Item e(m_operand2->evaluateSingleton(context)); + if(!e) + return CommonValues::emptyIterator; + + const xsInteger start = s.as<Numeric>()->toInteger(); + const xsInteger end = e.as<Numeric>()->toInteger(); + + if(start > end) + return CommonValues::emptyIterator; + else if(start == end) + return makeSingletonIterator(s); + else + return Item::Iterator::Ptr(new RangeIterator(start, RangeIterator::Forward, end)); +} + +Item RangeExpression::evaluateSingleton(const DynamicContext::Ptr &context) const +{ + return m_operand1->evaluateSingleton(context); +} + +SequenceType::List RangeExpression::expectedOperandTypes() const +{ + SequenceType::List result; + result.append(CommonSequenceTypes::ZeroOrOneInteger); + result.append(CommonSequenceTypes::ZeroOrOneInteger); + return result; +} + +SequenceType::Ptr RangeExpression::staticType() const +{ + /* This logic makes the Cardinality more specific. */ + Cardinality::Count from; + bool hasFrom; + + if(m_operand1->is(IDIntegerValue)) + { + from = m_operand1->as<Literal>()->item().as<Integer>()->toInteger(); + hasFrom = true; + } + else + { + hasFrom = false; + from = 0; + } + + /* We can't check whether to is -1 since maybe the user wrote -1. Hence + * hasTo is required. */ + bool hasTo; + Cardinality::Count to; + + if(m_operand2->is(IDIntegerValue)) + { + const xsInteger asInt = m_operand2->as<Literal>()->item().as<Integer>()->toInteger(); + to = asInt; + + if(to == asInt) + hasTo = true; + else + { + /* Cardinality::Count is not the same as type xsInteger. We had overflow. */ + to = -1; + hasTo = false; + } + } + else + { + to = -1; + hasTo = false; + } + + if(hasTo && hasFrom) + { + if(from > to) + { + /* The query is incorrectly written, we'll evaluate to the empty sequence. + * Just return what's correct. */ + return CommonSequenceTypes::ZeroOrMoreIntegers; + } + else + { + Cardinality::Count count = (to - from) + 1; /* + 1, since it's inclusive. */ + return makeGenericSequenceType(BuiltinTypes::xsInteger, Cardinality::fromExact(count)); + } + } + else + { + /* We can't do fromExact(from, -1) since the latter can evaluate to a value that actually is + * lower than from, although that unfortunately is very unlikely. */ + return CommonSequenceTypes::ZeroOrMoreIntegers; + } +} + +Expression::Properties RangeExpression::properties() const +{ + return Expression::DisableElimination; +} + +ExpressionVisitorResult::Ptr RangeExpression::accept(const ExpressionVisitor::Ptr &visitor) const +{ + return visitor->visit(this); +} + +QT_END_NAMESPACE |