www.pudn.com > MicroWindows-Source-200606.zip > list.cpp

// 
// Micro Windows Implementation 
// list.cpp: list implementation 
// 
// $Revision: 1.1 $ 
// $Source: P:/MWINDOWS/LIB/rcs/list.cpp $ 
// $Date: 1993/10/03 03:45:14 $ 
// 
#include "list.h" 
 
List::List () 
{ 
    head = new ListNode; 
    tail = new ListNode; 
 
    head->prev = head; 
    head->next = tail; 
 
    tail->prev = head; 
    tail->next = tail; 
 
    current = head; 
} 
 
List::~List () 
{ 
    purge(); 
    delete head; 
    delete tail; 
} 
 
BOOL List::put (Object *obj) 
{ 
    ListNode *newNode = new ListNode (obj, current, current->next); 
 
    current->next->prev = newNode; 
    current->next = newNode; 
    current = newNode; 
 
    return (TRUE); 
} 
 
BOOL List::hasElement (Object *obj) 
{ 
    ListNode *n = head; 
 
    while ((n = n->next) != tail) if (n == obj) return (TRUE); 
    return (FALSE); 
} 
 
void List::purge () 
{ 
    ListNode *n = head->next, *b; 
 
    while (1) 
    { 
        if (n == tail) break; 
        b = n->next; 
        delete n; 
        n = b; 
    } 
 
    head->next = tail; 
    tail->prev = head; 
} 
 
BOOL List::isEmpty () 
{ 
    if (head->next == tail) return (TRUE); 
    return (FALSE); 
} 
 
Object *List::first () 
{ 
    if ((current = head->next) == tail) current = head; 
    return (current->obj); 
} 
 
Object *List::next () 
{ 
    if (current->next == tail) return (NULL); 
    current = current->next; 
    return (current->obj); 
} 
 
Object *List::last () 
{ 
    current = tail->prev; 
    return (current->obj); 
} 
 
Object *List::previous () 
{ 
    if (current->prev == head) return (NULL); 
    current = current->prev; 
    return (current->obj); 
} 
 
BOOL List::remove () 
{ 
    if (current == head) return (FALSE); 
 
    current->prev->next = current->next; 
    current->next->prev = current->prev; 
 
    ListNode *cp = current->prev; 
 
    delete current; 
    current = cp; 
    if (current == head) first(); 
 
    return (TRUE); 
}