extend deletion functions in LL.c, use them to make "bye" client command work

shared/LL.c

@@ -242,7 +242,7 @@ LL_Prev(LinkedList *list)
  * Return pointer to list's \c current node's data.
  * \param list   List object.
  * \return       Pointer to \c current node's payload data;
- *               \c NULL may be empty payload or an error.
+ *               \c NULL may be empty payload or an error.  
  */
 void *
 LL_Get(LinkedList *list)
@@ -469,12 +469,13 @@ LL_InsertNode(LinkedList *list, void *add)
 
 
 /** Remove current node from the list.
- * Set the list's \c current pointer to the node after the deleted one.
- * \param list   List object.
- * \return       Pointer to data of deleted node; \c NULL on error.
+ * Set the list's \c current pointer to the one denoted by \c whereto.
+ * \param list     List object.
+ * \param whereto  Direction where to set the list's \c current pointer
+ * \return         Pointer to data of deleted node; \c NULL on error.
  */ 
 void *
-LL_DeleteNode(LinkedList *list)
+LL_DeleteNode(LinkedList *list, Direction whereto)
 {
 	LL_node *next, *prev;
 	void *data;
@@ -506,7 +507,16 @@ LL_DeleteNode(LinkedList *list)
 
 	free(list->current);
 
-	list->current = next;
+	switch (whereto) {
+		case FIRST:	list->current = list->head.next;
+				break;
+		case LAST:	list->current = list->tail.prev;
+				break;
+		case PREV:	list->current = prev;
+				break;
+		default:
+		case NEXT:	list->current = next;
+	}
 
 	return data;
 }
@@ -514,13 +524,14 @@ LL_DeleteNode(LinkedList *list)
 
 /** Remove a specific node from the list.
  * Find a node by a pointer to its data and remove it.
- * After the deletion the \c current pointer is on the node after the deleted one.
+ * Set the list's \c current pointer to the one denoted by \c whereto.
  * \param list   List object.
  * \param data   Pointer to data of node to delete.
+ * \param whereto  Direction where to set the list's \c current pointer
  * \return       Pointer to data of deleted node; \c NULL on error.
  */ 
 void *
-LL_Remove(LinkedList *list, void *data)
+LL_Remove(LinkedList *list, void *data, Direction whereto)
 {
 	if (!list)
 		return NULL;
@@ -530,7 +541,7 @@ LL_Remove(LinkedList *list, void *data)
 		void *find = LL_Get(list);
 
 		if (find == data)
-			return LL_DeleteNode(list);
+			return LL_DeleteNode(list, whereto);
 	} while (LL_Next(list) == 0);
 
 	return NULL;
@@ -574,7 +585,7 @@ LL_Pop(LinkedList *list)				  // Remove node from end of list
 	if (0 > LL_End(list))
 		return NULL;
 
-	return LL_DeleteNode(list);
+	return LL_DeleteNode(list, PREV);
 }
 
 
@@ -604,7 +615,7 @@ LL_Shift(LinkedList *list)				  // Remove node from start of list
 	if (0 > LL_Rewind(list))
 		return NULL;
 
-	return LL_DeleteNode(list);
+	return LL_DeleteNode(list, NEXT);
 }
 
 

shared/LL.h

@@ -57,7 +57,7 @@
 
     my_data * thingie;
 
-    thingie = (my_data *)LL_DeleteNode(list);
+    thingie = (my_data *)LL_DeleteNode(list, NEXT);
     free(thingie);
 
     thingie->number = 666;
@@ -116,6 +116,16 @@
 // See LL.c for more detailed descriptions of these functions.
 
 
+/** Symbolic values for directions */
+typedef enum _direction {
+	FIRST    = -2,
+	PREV     = -1,
+	CURRENT	 = 0,
+	NEXT     = +1,
+	LAST     = +2
+} Direction;
+
+
 /** Structure for a node in a linked list */
 typedef struct LL_node {
 	struct LL_node *prev;	/**< Pointer to previous node */
@@ -164,9 +174,9 @@ void *LL_GetLast(LinkedList *list);	  //            ... last node
 int LL_AddNode(LinkedList *list, void *add);	// Adds node AFTER current one
 int LL_InsertNode(LinkedList *list, void *add);	// Adds node BEFORE current one
 // Removes a node from the link; returns the data from the node
-void *LL_DeleteNode(LinkedList *list);
+void *LL_DeleteNode(LinkedList *list, Direction whereto);
 // Removes a specific node...
-void *LL_Remove(LinkedList *list, void *data);
+void *LL_Remove(LinkedList *list, void *data, Direction whereto);
 
 // Stack operations
 int LL_Push(LinkedList *list, void *add);	// Add node to end of list