68 lines
1.1 KiB
C++
68 lines
1.1 KiB
C++
#ifndef CURSOR_H_
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#define CURSOR_H_
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#include <boost/make_shared.hpp>
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#include <boost/shared_ptr.hpp>
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template<typename Obj>
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class Cursor
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{
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public:
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typedef Obj ElementType;
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private:
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class SourceBase
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{
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public:
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virtual ~SourceBase() {}
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virtual bool step() = 0;
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virtual ElementType* get() = 0;
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};
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template<typename Inner>
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class Source : public SourceBase
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{
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public:
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Source(Inner inner)
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: inner(inner)
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{
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}
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bool step()
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{
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return inner.step();
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}
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ElementType* get()
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{
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return inner.get();
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}
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private:
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Inner inner;
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};
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public:
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template<typename Inner>
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explicit Cursor(Inner inner)
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: source(boost::make_shared<Source<Inner> >(inner) )
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{
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}
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bool step()
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{
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return source->step();
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}
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ElementType* get()
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{
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return source->get();
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}
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private:
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boost::shared_ptr<SourceBase> source;
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};
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#endif
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