list.h

xgrafix 是PTSG模拟程序中的图形截面库 改版本是最新版本

#ifndef __List_h
#define __List_h

/*
====================================================================

LIST.H

0.9	(PeterM, 08-93) Original List and Stack classes in G++.
0.961	(PeterM, JohnV, 08-24-93) Replace Borland list containers with
		vanilla C++ template lists in list.h
0.964	(JohnV, 09-28-93) Add ListIter::delete() and supporting data.

0.97	(JamesA 12-30-93) Add restart() to ListIter
0.971	(JamesA 02-05-94) Add putAt(), getAt(), find() to List, itemName to ListItem.
0.975	(JamesA 03-12-94) Add removeItem() to List.
		(HadonN 06-16-94) Add removeAll(), fix(?) removeItem()
		(HadonN 09-19-94) fix(!) removeItem()
0.976	(Hadon 10-20-94) removed putAt(), getAt(), find() from List
0.977	(Hadon 10-28-94) fix operator=(), (call removeAll())
0.978	(JohnV 06-30-95) add deleteAll() to delete all data and remove all items.
0.979 (JohnV 01-11-96) incorporate undocumented additions (from Acquah?)
1.001 (JohnV 02-29-96) renamed N_items() -> nItems().

====================================================================
*/

#include <string.h>

#include <stdlib.h>

template <class Type> class List;
template <class Type> class ListItem;
template <class Type> class ListIter;

template <class Type> class ListItem
{
public:
  ListItem(Type *newitem, ListItem<Type> *nxt, const char* key = "")  // jbha
		{data=newitem; next=nxt; itemName = strdup(key);}
  ~ListItem() {free(itemName); itemName = NULL; next = NULL; data = NULL;}
/*	~ListItem() { free(itemName); }
	deleteData() {delete data; data = NULL; free(itemName); itemName = NULL;}
	(commented out 01-11-96 JohnV)
*/
  char* itemName; 					// jbha
  ListItem<Type> *next;
  Type *data;
};


template <class Type> class List
{
public:
	int nitems;
	ListItem<Type> *head;
	List() {head=0; nitems=0;}
	List(List<Type> &other) {
	  head=0;nitems=0;
	  *this=other;
	}
	~List() {removeAll();}

	void removeItem( Type *anItem);
	void removeAll();
	void deleteAll();
	void add(Type *newitem);

	List<Type>& operator=(List<Type> &other)
	{
			//Not a terribly efficient routine.
			//first copy of list is reversed.
			//reversed_list goes out of scope and is deleted.
		ListIter<Type> walk(other);

		removeAll();
		while(!walk.Done())
		{
			add(walk.current());
			walk++;
		}
		return *this;
	};

	Type * pop(void) {
		if(head)
		{
			Type* retval=head->data;
			ListItem<Type> *to_delete=head;
			head = head->next;
			delete to_delete;
			nitems--;
			return retval;
		}
		else return 0;
	}

	int isEmpty() {return (head==0);}
	void push(Type *newitem) { add(newitem); };
	int nItems() {return nitems;};
};

template <class Type> void List<Type>::add(Type *newitem)
{
   ListItem<Type> *New = new ListItem<Type>(newitem, head);

	nitems++;
	head = New;
}

template <class Type>
void List<Type>::removeItem( Type *anItem )
// use when you need to find the item first, else use version in ListIter
{
	ListItem<Type>	*prevPtr, *currentPtr;

	if (head == NULL) {
		return;
	} else if (head->data == anItem) {
		currentPtr = head->next;
		delete head;
		head = currentPtr;
		nitems--;
	} else {
		prevPtr = head;
		currentPtr = prevPtr->next;
		while( !(currentPtr == NULL) ) {
			if ( currentPtr->data == anItem ) {
				prevPtr->next = currentPtr->next;
				delete currentPtr;
				currentPtr = prevPtr->next;
				nitems--;
			} else {
				prevPtr = currentPtr;
				currentPtr = currentPtr->next;
			}
		}
	}
}

// removeAll: removes all list elements, but NOT the data!

template <class Type>
void List<Type>::removeAll()
{
	ListItem<Type> *next;
	while (head)
	{
		next = head->next;
		delete head;
		head = next;
	}
	nitems = 0;
}

// deleteAll: removes all list elements AND data

template <class Type>
void List<Type>::deleteAll()
{
	ListItem<Type> *next;
	while ( head )
	{
		next = head->next;
		delete head->data;
		delete head;
		head = next;
	}
	nitems = 0;
}

/*
	Acquah's version:

  template <class Type>
  void List<Type>::deleteAllData()
  {
	ListItem<Type> *next, *current;
	current = head; 					// necc because deleteData() sometimes
	head = NULL;          				// ... (eventually) calls removeItem()
	while ( current )
	{
		next = (*current).next;
		current->deleteData();
		delete current;
		current = next;
	}
	nitems = 0;
  }

*/

////////////////////////////////////////////////////////////////////////////////

template <class Type> class ListIter
{
public:
	ListItem<Type>*	currentPtr;
	ListItem<Type>*	previousPtr;
	List<Type>*	theList;
	ListIter(){}						// empty constructor, must be used with restart
	ListIter(List<Type>& aList) {theList=&aList; restart();};
	void	restart() {previousPtr = currentPtr = theList->head;};
	void	restart(List<Type>& aList) {theList=&aList; restart();};
	void	restart(Type& aGroup);
	Type*	data() {if (currentPtr) return currentPtr->data; else return NULL;};
	Type* current() {return data();};
	Type* operator () () {return data();};
	void	operator++(int) {if (currentPtr) {previousPtr = currentPtr;
		currentPtr = currentPtr->next;} else restart();};
	int	Done() {return currentPtr==NULL;};
	int	isEmpty() {return !(theList->head==0);};
	void	deleteCurrent();
};


//	This function removes an item from the list.  Might be cleaner
//	if it is inside List<Type>, but do not want order n search
//	for element.
template <class Type>
void ListIter<Type>::deleteCurrent()
{
	if (currentPtr == NULL) return;		//	bail out if empty or at end
	//	if at head of list, point head to next item
	if (currentPtr == theList->head)
	{
		theList->head = currentPtr->next;
		previousPtr = NULL;
	}
	else previousPtr->next = currentPtr->next;
	delete	current();						//	delete the data
	delete	currentPtr;						//	delete the list item
	currentPtr = previousPtr;
	theList->nitems--;
}

//  Some useful macros
#define ApplyToList(function,theList,listType) { ListIter<listType> titer(theList); for(titer.restart();!titer.Done();titer++) titer.current()->function;}
#endif