linkedstack.h

用于词法分析的词法分析器

/*
  $Id: LinkedStack.h,v 1.2 1997/02/02 01:31:04 matt Exp $

  Linked list stack.
  
  (c) Apr 17 1994 Matt Phillips.
  */

#ifndef _LSTACK_H
#define _LSTACK_H

#include "Stack.h"
#include "LinkedList.h"

template <class T, class E>
class LinkedStackImp : public Stack<T>, protected LinkedListImp<T, E>
{
public:

  typedef LinkedStackImpIter<T, E> Iterator;

  const char *name () const {return Stack<T>::name ();}
  int nItems () const {return LinkedListImp<T, E>::nItems ();}
  int isFull () const {return LinkedListImp<T, E>::isFull ();}
  int isEmpty () const {return LinkedListImp<T, E>::isEmpty ();}
  void clear () {LinkedListImp<T, E>::clear ();}

  virtual void push (T &i)
  {STACK_OVERFLOW (!isFull ()); add (i);}

  virtual void pop ()
  {
    STACK_UNDERFLOW (!isEmpty ());
    E *next = head->next;
    delete head;
    head = next;
    _nItems--;
  }

  virtual T &top () const
  {
    STACK_UNDERFLOW (!isEmpty ());
    return head->ref ();
  }

  Iterator *makeIter () const {return new Iterator (*this);}

  friend class Iterator;
};

template <class T, class E>
class LinkedStackImpIter : public LinkedListImpIter<T, E>
{
public:
  LinkedStackImpIter (const LinkedStackImp<T, E> &s) :
    LinkedListImpIter<T, E> (s) {}
};

#define TypeDLinkedStack(T)  LinkedStackImp<T, DLinkedItem<T> >
#define TypeILinkedStack(T)  LinkedStackImp<T, ILinkedItem<T, 0> >
#define TypeIOLinkedStack(T) LinkedStackImp<T, ILinkedItem<T, 1> >

#endif