// Removes an element from the list l, decrements ref count on element
void removeElement(List_PNTR l, void *element) {
// case: error, l is null, i.e. no list defined
if(l==NULL){
DAL_error(NULL_POINTER_ERROR);
return;
}
if(isEmpty(l)){
#if DEBUG
DAL_error(EMPTY_CONTAINER_ERROR);
#endif
return;
}
if(element == NULL){
DAL_error(ELEMENT_NOT_FOUND_ERROR);
return;
}
// case: element we want to remove is right at the start of the list
if(l->first->payload == element){
ListNode_PNTR oldFirst = l->first;
l->first = oldFirst->tail;
// take action if we are removing the next iterator node
if(l->next == oldFirst) l->next = l->first;
listFreeNode(oldFirst); // explicitly free memory used by node
return;
}
// case: otherwise try to find element to remove
ListNode_PNTR previous = l->first, current = previous->tail;
while(current != NULL && current->payload!=element){
previous = current;
current = current->tail;
}
if(current!=NULL){ // we found the element to remove
// take action if we are removing the next iterator node
if(l->next == current) l->next = current->tail;
if(l->next == NULL) l->next = l->first;
// deal with removal
previous->tail = current->tail;
// explicitly free memory used by node
listFreeNode(current);
}
else
DAL_error(ELEMENT_NOT_FOUND_ERROR);
}
void removeAllElements(List_PNTR l){
if(l==NULL){
DAL_error(NULL_POINTER_ERROR);
return;
}
if(isEmpty(l)){
#if DEBUG
DAL_error(EMPTY_CONTAINER_ERROR);
#endif
return;
}
ListNode_PNTR previous, current = l->first;
while( current != NULL){
previous = current;
current = current->tail;
listFreeNode(previous); // free memory used by list node
}
l->first = l->next = NULL;
}