mirror of
https://github.com/jezhiggins/arabica
synced 2025-01-04 23:01:54 +01:00
75 lines
2 KiB
C++
75 lines
2 KiB
C++
#ifndef ARABICA_XPATHIC_XPATH_UNION_HPP
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#define ARABICA_XPATHIC_XPATH_UNION_HPP
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#include "xpath_value.hpp"
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#include <algorithm>
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namespace Arabica
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{
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namespace XPath
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{
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class UnionExpression : private BinaryExpression, public XPathExpression
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{
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public:
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UnionExpression(XPathExpression* lhs, XPathExpression* rhs) :
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BinaryExpression(lhs, rhs) { }
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virtual XPathValuePtr evaluate(const DOM::Node<std::string>& context,
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const ExecutionContext& executionContext) const
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{
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XPathValuePtr p1 = lhs()->evaluate(context, executionContext);
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if(p1->type() != NODE_SET)
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throw RuntimeException("Union operator joins node-sets. First argument is not a node-set.");
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XPathValuePtr p2 = rhs()->evaluate(context, executionContext);
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if(p2->type() != NODE_SET)
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throw RuntimeException("Union operator joins node-sets. First argument is not a node-set.");
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NodeSet ns1(p1->asNodeSet());
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NodeSet ns2(p2->asNodeSet());
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// do the obvious optimizations
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if(ns1.empty())
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return wrap(ns2);
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if(ns2.empty())
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return wrap(ns1);
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ns1.to_document_order();
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ns2.to_document_order();
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NodeSet::const_iterator n1 = ns1.begin(), n1e = ns1.end();
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NodeSet::const_iterator n2 = ns2.begin(), n2e = ns2.end();
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NodeSet result(true);
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while((n1 != n1e) && (n2 != n2e))
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{
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int c = compareNodes(*n1, *n2);
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if(c < 0)
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result.push_back(*n1++);
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else if(c > 0)
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result.push_back(*n2++);
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else
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{ // same node, so bin out duplicate
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result.push_back(*n1++);
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++n2;
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} // if ...
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} // while ...
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// pop on any left overs, leftovers
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std::copy(n1, n1e, std::back_inserter(result));
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std::copy(n2, n2e, std::back_inserter(result));
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return wrap(result);
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} // evaluate
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private:
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XPathValuePtr wrap(const NodeSet& ns) const
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{
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return XPathValuePtr(new NodeSetValue(ns));
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} // wrap
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}; // UnionExpression
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} // namespace XPath
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} // namespace Arabica
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#endif
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