From 8d9cb25ed7a69017f45bc3673f45c83095fd6896 Mon Sep 17 00:00:00 2001
From: Koen Zandberg <koen@bergzand.net>
Date: Fri, 31 Aug 2018 10:35:02 +0200
Subject: [PATCH] tsrb: add drop function

The get function does not support passing NULL as an input buffer. to be
able to drop bytes from the buffer, a dedicated drop function is
required
---
 sys/include/tsrb.h |  8 ++++++++
 sys/tsrb/tsrb.c    | 10 ++++++++++
 2 files changed, 18 insertions(+)

diff --git a/sys/include/tsrb.h b/sys/include/tsrb.h
index f0d7f698aa..0dcc04730f 100644
--- a/sys/include/tsrb.h
+++ b/sys/include/tsrb.h
@@ -127,6 +127,14 @@ int tsrb_get_one(tsrb_t *rb);
  */
 int tsrb_get(tsrb_t *rb, char *dst, size_t n);
 
+/**
+ * @brief       Drop bytes from ringbuffer
+ * @param[in]   rb  Ringbuffer to operate on
+ * @param[in]   n   max number of bytes to drop
+ * @return      nr of bytes dropped
+ */
+int tsrb_drop(tsrb_t *rb, size_t n);
+
 /**
  * @brief       Add a byte to ringbuffer
  * @param[in]   rb  Ringbuffer to operate on
diff --git a/sys/tsrb/tsrb.c b/sys/tsrb/tsrb.c
index 334550fa4a..e85ea52664 100644
--- a/sys/tsrb/tsrb.c
+++ b/sys/tsrb/tsrb.c
@@ -49,6 +49,16 @@ int tsrb_get(tsrb_t *rb, char *dst, size_t n)
     return (n - tmp);
 }
 
+int tsrb_drop(tsrb_t *rb, size_t n)
+{
+    size_t tmp = n;
+    while (tmp && !tsrb_empty(rb)) {
+        _pop(rb);
+        tmp--;
+    }
+    return (n - tmp);
+}
+
 int tsrb_add_one(tsrb_t *rb, char c)
 {
     if (!tsrb_full(rb)) {