Add swap to double ended queue

2 files changed, 23 insertions, 1 deletions

diff --git a/collections/double_ended_queue.c b/collections/double_ended_queue.c
index ee93196..6a3a810 100644
--- a/collections/double_ended_queue.c
+++ b/collections/double_ended_queue.c
@@ -159,3 +159,25 @@ deq *root;
 	copy->beg = copy->base;
 	copy->end = copy->base + deq_size(root);
 }
+
+void deq_swap(root, i, j)
+deq *root;
+int i, j;
+{
+	int len;
+	void *tmp;
+
+	if (!root) {
+		return;
+	}
+
+	len = deq_size(root);
+
+	if (i >= len || j >= len) {
+		return;
+	}
+
+	tmp = root->end[i];
+	root->end[j] = root->end[i];
+	root->end[i] = tmp;
+}
diff --git a/collections/double_ended_queue.h b/collections/double_ended_queue.h
index a5645e2..d1d687a 100644
--- a/collections/double_ended_queue.h
+++ b/collections/double_ended_queue.h
@@ -19,10 +19,10 @@ void* deq_pop_front(deq*);
 void* deq_index(deq*, int);
 void* deq_pop_back(deq*);
 
+void deq_swap(deq*, int, int);
 
 
 /*
- * swap
  * resevee
  * truncate
  * front