1 files changed, 93 insertions, 0 deletions
diff --git a/xpp/xtalk/xlist.c b/xpp/xtalk/xlist.c
new file mode 100644
index 0000000..d28debd
--- /dev/null
+++ b/xpp/xtalk/xlist.c
@@ -0,0 +1,93 @@
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+#include <xlist.h>
+
+struct xlist_node *xlist_new(void *data)
+{
+	struct xlist_node	*list;
+
+	if((list = malloc(sizeof(*list))) == NULL)
+		return NULL;
+	list->next = list;
+	list->prev = list;
+	list->data = data;
+	return list;
+}
+
+void xlist_destroy(struct xlist_node *list, xlist_destructor_t destructor)
+{
+	struct xlist_node	*curr;
+	struct xlist_node	*next;
+
+	if (! list)
+		return;
+	curr = list->next;
+	while(curr != list) {
+		next = curr->next;
+		if(destructor)
+			destructor(curr->data);
+		memset(curr, 0, sizeof(*curr));
+		free(curr);
+		curr = next;
+	}
+	memset(list, 0, sizeof(*list));
+	free(list);
+}
+
+void xlist_append_item(struct xlist_node *list, struct xlist_node *item)
+{
+	assert(list);
+	assert(xlist_empty(item));
+	item->next = list;
+	item->prev = list->prev;
+	list->prev->next = item;
+	list->prev = item;
+}
+
+void xlist_prepend_item(struct xlist_node *list, struct xlist_node *item)
+{
+	assert(list);
+	assert(xlist_empty(item));
+	item->prev = list;
+	item->next = list->next;
+	list->next->prev = item;
+	list->next = item;
+}
+
+void xlist_remove_item(struct xlist_node *item)
+{
+	assert(item);
+	item->prev->next = item->next;
+	item->next->prev = item->prev;
+	item->next = item->prev = item;
+}
+
+struct xlist_node *xlist_shift(struct xlist_node *list)
+{
+	struct xlist_node	*item;
+
+	if(!list)
+		return NULL;
+	if(xlist_empty(list))
+		return NULL;
+	item = list->next;
+	xlist_remove_item(item);
+	return item;
+}
+
+int xlist_empty(const struct xlist_node *list)
+{
+	assert(list);
+	return list->next == list && list->prev == list;
+}
+
+size_t xlist_length(const struct xlist_node *list)
+{
+	struct xlist_node	*curr;
+	size_t			count = 0;
+
+	for(curr = list->next; curr != list; curr = curr->next)
+		count++;
+	return count;
+}