From de4b32ef543191ea5f598de4300372f2af0e0514 Mon Sep 17 00:00:00 2001
From: Hendrik van Essen <hendrik.ve@fu-berlin.de>
Date: Mon, 29 Nov 2021 13:37:19 +0100
Subject: [PATCH] sys/tsrb: add tsrb_clear

---
 sys/include/tsrb.h                      | 11 +++++++++++
 tests/unittests/tests-tsrb/tests-tsrb.c | 15 +++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/sys/include/tsrb.h b/sys/include/tsrb.h
index 04d8b26345..4d9c610dcb 100644
--- a/sys/include/tsrb.h
+++ b/sys/include/tsrb.h
@@ -67,6 +67,17 @@ static inline void tsrb_init(tsrb_t *rb, uint8_t *buffer, unsigned bufsize)
     rb->writes = 0;
 }
 
+/**
+ * @brief        Clear a tsrb.
+ * @param[out]   rb Ringbuffer to operate on
+ */
+static inline void tsrb_clear(tsrb_t *rb)
+{
+    unsigned irq_state = irq_disable();
+    rb->reads = rb->writes;
+    irq_restore(irq_state);
+}
+
 /**
  * @brief       Test if the tsrb is empty.
  * @param[in]   rb  Ringbuffer to operate on
diff --git a/tests/unittests/tests-tsrb/tests-tsrb.c b/tests/unittests/tests-tsrb/tests-tsrb.c
index 94d7a8745b..028d75c7f7 100644
--- a/tests/unittests/tests-tsrb/tests-tsrb.c
+++ b/tests/unittests/tests-tsrb/tests-tsrb.c
@@ -37,6 +37,20 @@ static void tear_down(void)
     tsrb_init(&_tsrb, _tsrb_buffer, BUFFER_SIZE);
 }
 
+static void test_clear(void)
+{
+    TEST_ASSERT_EQUAL_INT(0, tsrb_avail(&_tsrb));
+
+    for (int i = 0; i < BUFFER_SIZE; i++) {
+        TEST_ASSERT_EQUAL_INT(0, tsrb_add_one(&_tsrb, TEST_INPUT));
+        TEST_ASSERT_EQUAL_INT(i + 1, tsrb_avail(&_tsrb));
+    }
+
+    tsrb_clear(&_tsrb);
+
+    TEST_ASSERT_EQUAL_INT(0, tsrb_avail(&_tsrb));
+}
+
 static void test_empty(void)
 {
     TEST_ASSERT_EQUAL_INT(1, tsrb_empty(&_tsrb));
@@ -202,6 +216,7 @@ static void test_add(void)
 static Test *tests_tsrb_tests(void)
 {
     EMB_UNIT_TESTFIXTURES(fixtures) {
+        new_TestFixture(test_clear),
         new_TestFixture(test_empty),
         new_TestFixture(test_avail),
         new_TestFixture(test_full),