//***************************************
// Implements a list of message header objects which can manipulated by position
// Items can be added to a position (moving items to make space - if necessary)
// Items can be deleted from a specified position (moving items to fill the emptied
// space.
// Also you can retrieve any item by its position.
// Based on object described in Carrano Walls and Mirrors book.
// AUTHOR: Chris Wild
// DATE: July 25, 1997
//****************************************
#ifndef LIST_MESSAGE_H
#define LIST_MESSAGE_H

#include "message.h"

typedef struct {
	char topic[SIZE_TOPIC+1];	// topic of this message
	char fileName[10];	// file name where message is kept
} Item ;

struct ListNode;
typedef ListNode* ListPtr;
struct ListNode {
	Item item;
	ListPtr next;
};

class CListMsgs {
public:
	// Default constructor builds an empty message
	CListMsgs();
	// This constructor reads message list from file
	CListMsgs(HANDLE listHandle);
	~CListMsgs();
	// Adds topic to list in "position"
	// moves other messages down to make room
	bool AddItem(int position, Item thisItem);
	bool DeleteItem(int position);
	bool GetItem(int position, Item& thisItem) const;
	bool ReadListMsgs(HANDLE listHandle);
	bool WriteListMsgs(HANDLE listHandle) const;
	int length() const;
private:
	ListPtr PtrTo(int position) const; 
	int size;
	ListPtr head;
};
	
#endif