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// $Id: baseq.h,v 1.3 2005/04/10 18:30:25 tom Exp $
#ifndef _QUEUE_LIST_HEADER
#define _QUEUE_LIST_HEADER
// Code written by Steven De Toni ACBC 11
// this header definition contains a container class that stores data
// in a queued linked list.
#include "anyobj.h" // include base class
struct LinkItem
{
LinkItem* pLinkedItem; // linker (pointer to the next item in the list)
ANYOBJECT* pStoredItem; // data that is store within a list item
};
class QueueList
{
protected:
int itemCount;
LinkItem* pEndPos;
int spaceAvailable; // set to 0 for space available,
// -1 if no space available;
// Create new list item and place programmer's data within it,
// make new links with previous item if wished.
// returns a pointer to the new item, NULL if operation failed.
//
// Parameters:
// pItem : Pointer to the object to be stored.
// LinkItem : Pointer to end of list where item to be added.
//
// Return Values:
// LinkItem : returns pointer to newly added item in list,
// NULL if operation failed. However items within list
// before hand still exist.
LinkItem* newItem (ANYOBJECT* pItem, LinkItem* pEndList);
public:
// constructors
QueueList (void);
// Parameters:
// pItem : Pointer to a object to be stored, must be descendant of
// base class ANYOBJECT.
QueueList (ANYOBJECT* pItem);
// use the defaults here
QueueList(const QueueList&);
QueueList& operator=(const QueueList&);
// Place programmers object into list
//
// Parameters:
// pItem : Pointer to a object to be stored, must be descendant of
// base class ANYOBJECT.
//
// Return Values:
// int : Returns a error code indicating whether operation was
// successful.
// Values:
// 0 = No Worries
// -1 = Arrgh ... No memory
//
int putLast (ANYOBJECT* pItem);
// Take first item placed in Queue, out and return it.
// Type casting is required to return object back to it's original
// state.
//
// Return Values:
// ANYOBJECT* : Pointer to the object that was stored within queue.
//
ANYOBJECT* takeNext (void);
// Returns the number of items contained within the queue.
//
// Returns Values:
// int : Num of items within queue.
//
int status (void);
// Method returns whether last operation failed due to memory allocation
// failure.
//
// Return Values:
// int : Returns 1 of two values ...
// Values:
// 0 = memory available
// -1 = Last memory allocation failed.
//
int space (void); // return Queue space left
// Methods is used to peek within the queue at objects, and return there
// pointer without taking them out of the queue.
//
// Parameters:
// NumFromNext : The object number to look at from the start of the
// queue. The start of the queue is 1, not 0.
//
// Return Values:
// ANYOBJECT* : Pointer to the object that is stored within queue,
// at said position. Returns NULL if operation failed.
//
ANYOBJECT* peek (int numFromNext);
// Method will remove all list items from memory if they still exist,
// no garbage collection provided, or used.
//
~QueueList (void);
};
#endif
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