RTM Project

DLL/dll.c

@@ -0,0 +1,71 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include "dll.h"
+
+/*
+* Initialize an empty list in which the head 
+* and the tail are the same, i.e. they both 
+* point to dummy node.
+*/
+
+dll_t* init_dll() {
+	
+	dll_t* dll = calloc(1, sizeof(dll_t));
+	dll_node_t* node = calloc(1, sizeof(dll_node_t));
+	node->next = node;
+	node->prev = node;
+	dll->head = node;
+	dll->tail = node;
+	return dll;
+
+}
+
+/*
+* Add new node with data to back of list.
+*/
+
+void append(dll_t* dll, void* data) {
+
+	dll_node_t* head = dll->head;
+	dll_node_t* node = calloc(1, sizeof(dll_node_t));
+	node->data = data;
+	node->next = dll->head;
+	node->prev = dll->tail;
+	dll->head->prev = node;
+	dll->tail->next = node;
+	dll->tail = node;
+	if (dll->head != head) {
+		printf("Head of the list is compromised.\n");
+	}
+}
+
+/*
+* Delete a node from the lists.
+*/
+
+void del(dll_t* dll, dll_node_t* node) {
+	node->prev->next = node->next;
+	node->next->prev = node->prev;
+	if (node == dll->tail) {
+		// need to update the tail node if we're deleting it.
+		dll->tail = node->prev;
+	}
+
+	free(node);
+}
+
+/*
+* Delete all nodes from the list.
+*/
+
+void deinit_dll(dll_t* dll) {
+
+	dll_node_t* node = dll->head->next;
+	while (node != dll->head) {
+		dll_node_t* next = node->next;
+		del(dll, node);
+		node = next;
+	}
+	free(dll);
+
+}