1 files changed, 35 insertions, 0 deletions
diff --git a/dlist.c b/dlist.c
new file mode 100644
index 0000000..766f940
--- /dev/null
+++ b/dlist.c
@@ -0,0 +1,35 @@
+struct LIST *
+LIST_UNLINK(struct LIST **root, struct LIST *p)
+{
+	if (p->prev)
+		p->prev->next = p->next;
+	else
+		*root = p->next;
+	if (p->next)
+		p->next->prev = p->prev;
+	p->next = p->prev = NULL;
+	return p;
+}
+
+struct LIST *
+LIST_POP(struct LIST **pp)
+{
+	if (*pp)
+		return LIST_UNLINK(pp, *pp);
+	return NULL;
+}
+
+void
+LIST_PUSH(struct LIST **pp, struct LIST *p)
+{
+	p->prev = NULL;
+	p->next = *pp;
+	if (*pp)
+		(*pp)->prev = p;
+	*pp = p;
+}
+
+#undef LIST
+#undef LIST_PUSH
+#undef LIST_POP
+#undef LIST_UNLINK