added list for holding messages

list.h

@@ -0,0 +1,168 @@
+/* 
+ Dane MacFadden
+ dgm288
+ 11283087
+
+ James Hom
+ jhh318
+ 11287431
+*/
+
+#ifndef __LIST_H__
+#define __LIST_H__
+
+
+typedef struct node {
+	void *data;
+	struct node *next;
+	struct node *previous;
+} NODE;
+
+typedef struct list {
+	
+	int size;
+	NODE *current;
+	NODE *head;
+	NODE *tail;
+	
+} LIST;
+
+/* 
+ Create empty list
+ Returns: Pointer to new empty list if successful, NULL pointer otherwise
+ */
+LIST *ListCreate();
+
+
+/* Returns the number of items contained by the list */
+int ListCount(LIST *list);
+
+
+/* 
+ Returns pointer to first item in the list and makes it the current item
+ list: Pointer to a list
+ Returns: Pointer to first item in the list
+*/
+void *ListFirst(LIST *list);
+
+
+/*
+ Return pointer to last item in list
+ list: Pointer to a list
+ Returns: Pointer to last item in list
+*/
+void *ListLast(LIST *list);
+
+
+/*
+ Return next item in the list
+ list: Pointer to a list
+ Returns: Pointer to next item in list
+*/
+
+void *ListNext(LIST *list);
+
+
+/*
+ Return previous item in list
+ list: Pointer to a list
+ Returns: Pointer to last item
+*/
+void *ListPrev(LIST *list);
+
+
+/* Get current item in list
+ list: Pointer to list
+ Returns: Pointer to last item
+*/
+void *ListCurr(LIST *list);
+
+
+/*
+ Add item to list after current item, 
+ switch current item to the item we just added.
+ If current item is at the end, item is added at the end.
+ list: List pointer
+ item: Pointer to an item to add to the list
+ Returns: 0 if successful, -1 otherwise
+*/
+int ListAdd(LIST *list, void *item);
+
+
+/*
+ Insert an item right before the current item.
+ If current is the start of the list, add to the start.
+ list: Pointer to list
+ item: Pointer to item to add
+ Returns: 0 if successful, -1 otherwise
+ */
+int ListInsert(LIST *list, void *item);
+
+
+/*
+ Add an item to the end of the list
+ list: Pointer to list
+ item: Pointer to item to add
+ Returns: 0 if successful, -1 otherwise
+*/
+int ListAppend(LIST *list, void *item);
+
+
+/* 
+ Add item to the front of the list
+ list: Pointer to list
+ item: Pointer to item to add
+ Returns: 0 if successful, -1 otherwise
+*/
+int ListPrepend(LIST *list, void *item);
+
+/* 
+ Delete current item from list and make next item current
+ list: Pointer to list
+ Returns: Deleted item
+*/
+void *ListRemove(LIST *list);
+
+
+/*
+ Adds list2 to the end of list1
+ Current pointer set to current pointer of list1
+ List2 ceases to exist
+ list1: Pointer to list1
+ list2: Pointer to list2
+*/
+void ListConcat(LIST *list1, LIST *list2);
+
+/*
+ Deletes list
+ list: Pointer to list
+ itemFree: routine that frees an item
+*/
+void ListFree(LIST *list, void (*itemFree)(void *));
+
+
+/* 
+ Returns last item and takes it out of the list
+ list: Pointer to list
+ Returns: Pointer to last item that was just deleted from list
+*/
+void *ListTrim(LIST *list);
+
+
+/*
+ Search list starting at current item. 
+ Finishes at end of list or when a match is found
+ list: Pointer to list
+ comparator: Routine that returns 0 
+ if the item and comparisonArg don't match,
+ or 1 if they do. If a match is found the current pointer 
+ is left at the matched item
+ If no match is found,
+ current pointer is left at the end
+ Returns: Pointer to matching item if found, otherwise NULL pointer
+*/
+void *ListSearch(LIST *list, int (*comparator)(void *, void *), void *comparisonArg);
+
+#endif
+
+