From 6e03faa3d6b4481424d9ed8bb00314a26ecc3652 Mon Sep 17 00:00:00 2001
From: Kaspar Schleiser <kaspar@schleiser.de>
Date: Thu, 11 Sep 2014 13:39:37 +0200
Subject: [PATCH] sys: lib: ringbuffer: introduce ringbuffer_get_free

This function returns the number of bytes available in the ringbuffer.
---
 sys/include/ringbuffer.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/sys/include/ringbuffer.h b/sys/include/ringbuffer.h
index 58ba3cd836..af8c20e419 100644
--- a/sys/include/ringbuffer.h
+++ b/sys/include/ringbuffer.h
@@ -106,6 +106,16 @@ static inline int ringbuffer_full(const ringbuffer_t *restrict rb)
     return rb->avail == rb->size;
 }
 
+/**
+ * @brief           Return available space in ringbuffer
+ * @param[in,out]   rb Ringbuffer to query.
+ * @returns         number of available bytes
+ */
+static inline unsigned int ringbuffer_get_free(const ringbuffer_t *restrict rb)
+{
+    return rb->size - rb->avail;
+}
+
 /**
  * @brief           Read, but don't remove, the oldest element in the buffer.
  * @param[in]       rb    Ringbuffer to operate on.