1 files changed, 189 insertions, 0 deletions
diff --git a/src/dlist.c b/src/dlist.c
new file mode 100644
index 0000000..3ae571b
--- /dev/null
+++ b/src/dlist.c
@@ -0,0 +1,189 @@
+/*
+ * Copyright 2013  Samsung Electronics Co., Ltd
+ *
+ * Licensed under the Flora License, Version 1.1 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://floralicense.org/license/
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+
+#include "dlist.h"
+
+/*!
+ * \brief
+ * This dlist is called Modified Doubly Linked List.
+ *
+ * Noramlly, The dobule linked list contains address of previous and next element.
+ * This dlist also contains them, but the tail element only contains prev address.
+ *
+ * The head element's prev pointer indicates the last element.
+ * But the last element's next pointer indicates NIL.
+ *
+ * So we can find the last element while crawling this DList
+ * But we have to remember the address of the head element.
+ */
+
+struct dlist {
+	struct dlist *next;
+	struct dlist *prev;
+	void *data;
+};
+
+struct dlist *dlist_append(struct dlist *list, void *data)
+{
+	struct dlist *item;
+
+	item = malloc(sizeof(*item));
+	if (!item) {
+		return NULL;
+	}
+
+	item->next = NULL;
+	item->data = data;
+
+	if (!list) {
+		item->prev = item;
+
+		list = item;
+	} else {
+		item->prev = list->prev;
+		item->prev->next = item;
+		list->prev = item;
+	}
+
+	assert(!list->prev->next && "item NEXT");
+
+	return list;
+}
+
+struct dlist *dlist_prepend(struct dlist *list, void *data)
+{
+	struct dlist *item;
+
+	item = malloc(sizeof(*item));
+	if (!item) {
+		return NULL;
+	}
+
+	item->data = data;
+
+	if (!list) {
+		item->prev = item;
+		item->next = NULL;
+	} else {
+		if (list->prev->next) {
+			list->prev->next = item;
+		}
+
+		item->prev = list->prev;
+		item->next = list;
+
+		list->prev = item;
+
+	}
+
+	return item;
+}
+
+struct dlist *dlist_remove(struct dlist *list, struct dlist *l)
+{
+	if (!list || !l) {
+		return NULL;
+	}
+
+	if (l == list) {
+		list = l->next;
+	} else {
+		l->prev->next = l->next;
+	}
+
+	if (l->next) {
+		l->next->prev = l->prev;
+	}
+	/*!
+	 * \note
+	 * If the removed entry 'l' has no next element, it is the last element.
+	 * In this case, check the existence of the list first,
+	 * and if the list is not empty, update the 'prev' of the list (which is a head element of the list) 
+	 *
+	 * If we didn't care about this, the head element(list) can indicates the invalid element.
+	 */
+	else if (list) {
+		list->prev = l->prev;
+	}
+
+	free(l);
+	return list;
+}
+
+struct dlist *dlist_find_data(struct dlist *list, void *data)
+{
+	struct dlist *l;
+	void *_data;
+
+	dlist_foreach(list, l, _data) {
+		if (data == _data) {
+			return l;
+		}
+	}
+
+	return NULL;
+}
+
+void *dlist_data(struct dlist *l)
+{
+	return l ? l->data : NULL;
+}
+
+struct dlist *dlist_next(struct dlist *l)
+{
+	return l ? l->next : NULL;
+}
+
+struct dlist *dlist_prev(struct dlist *l)
+{
+	return l ? l->prev : NULL;
+}
+
+int dlist_count(struct dlist *l)
+{
+	register int i;
+	struct dlist *n;
+	void *data;
+
+	i = 0;
+	dlist_foreach(l, n, data) {
+		i++;
+	}
+
+	return i;
+}
+
+struct dlist *dlist_nth(struct dlist *l, int nth)
+{
+	register int i;
+	struct dlist *n;
+
+	i = 0;
+	for (n = l; n; n = n->next) {
+		if (i == nth) {
+			return n;
+		}
+		i++;
+	}
+
+	return NULL;
+}
+
+/* End of a file */