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// Null Node |
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// |
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// Douglas Thrift |
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// |
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// $Id$ |
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|
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#ifndef _NullNode_hpp_ |
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#define _NullNode_hpp_ |
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|
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#include "Visitor.hpp" |
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|
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template<typename Type> |
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class NullNode |
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{ |
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private: |
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Type value; |
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NullNode<Type>* next; |
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NullNode<Type>* previous; |
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bool null; |
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public: |
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NullNode() : null(true) {} |
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NullNode(const Type& value) : value(value), null(false) {} |
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void setValue(const Type& value) { this->value = value; } |
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const Type& getValue(void) const { return value; } |
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void addNext(const Type& value); |
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void addPrevious(const Type& value); |
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void removeNext(void); |
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void removePrevious(void); |
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void setNext(NullNode<Type>* next) { this->next = next; } |
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void setPrevious(NullNode<Type>* previous) { this->previous = previous; } |
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NullNode<Type>* getNext(void) const { return next; } |
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NullNode<Type>* getPrevious(void) const { return next; } |
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bool contains(const Type& value, NullNode<Type>* end, bool forward = true); |
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void remove(const Type& value, NullNode<Type>* end, bool forward = true); |
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void accept(Visitor<Type>* visitor, NullNode<Type>* end, bool forward = true); |
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}; |
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|
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template<typename Type> |
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void NullNode<Type>::addNext(const Type& value) |
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{ |
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NullNode<Type>* behind = next; |
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|
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next = new NullNode<Type>(value); |
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next->previous = this; |
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next->next = behind; |
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behind->previous = next; |
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} |
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|
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template<typename Type> |
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void NullNode<Type>::addPrevious(const Type& value) |
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{ |
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NullNode<Type>* ahead = previous; |
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|
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previous = new NullNode<Type>(value); |
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previous->next = this; |
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previous->previous = ahead; |
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ahead->next = previous; |
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} |
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|
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template<typename Type> |
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void NullNode<Type>::removeNext(void) |
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{ |
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NullNode<Type>* behind = next->next; |
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|
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delete next; |
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|
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next = behind; |
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next->previous = this; |
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} |
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|
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template<typename Type> |
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void NullNode<Type>::removePrevious(void) |
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{ |
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NullNode<Type>* ahead = previous->previous; |
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|
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delete previous; |
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|
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previous = ahead; |
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previous->next = this; |
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} |
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|
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template<typename Type> |
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bool NullNode<Type>::contains(const Type& value, NullNode<Type>* end, bool forward) |
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{ |
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NullNode<Type>* another = forward ? next : previous; |
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|
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if (null && end == this) |
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{ |
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return false; |
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} |
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else if (!null && value == this->value) |
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{ |
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return true; |
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} |
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else return another->contains(value, end); |
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} |
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|
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template<typename Type> |
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void NullNode<Type>::remove(const Type& value, NullNode<Type>* end, bool forward) |
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{ |
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NullNode<Type>* another = forward ? next : previous; |
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|
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if (!null && value == this->value) |
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{ |
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next->previous = previous; |
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previous->next = next; |
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|
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delete this; |
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} |
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else if (end != this) another->remove(value, end, forward); |
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} |
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|
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template<typename Type> |
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void NullNode<Type>::accept(Visitor<Type>* visitor, NullNode<Type>* end, bool forward) |
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{ |
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NullNode<Type>* another = forward ? next : previous; |
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|
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if (!null) visitor->visit(value); |
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|
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if (end != this) another->accept(visitor, end, forward); |
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} |
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|
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#endif // _NullNode_hpp_ |
