From 0ff054e9b4dff4e254ebfa4d718c4183c32d5bee Mon Sep 17 00:00:00 2001
From: Martin Piatka <piatka@cesnet.cz>
Date: Tue, 24 Aug 2021 16:01:53 +0200
Subject: [PATCH] ring_buffer: add ring_get_available_write_size()

---
 src/utils/ring_buffer.c | 6 ++++++
 src/utils/ring_buffer.h | 6 ++++++
 2 files changed, 12 insertions(+)

diff --git a/src/utils/ring_buffer.c b/src/utils/ring_buffer.c
index a85392fe1..8afbdb4d1 100644
--- a/src/utils/ring_buffer.c
+++ b/src/utils/ring_buffer.c
@@ -130,6 +130,12 @@ int ring_get_current_size(struct ring_buffer * ring)
         return (ring->end - ring->start + ring->len) % ring->len;
 }
 
+int ring_get_available_write_size(struct ring_buffer * ring){
+        /* Ring buffer needs at least one free byte, otherwise start == end
+         * and the ring would appear empty */
+        return ring_get_size(ring) - ring_get_current_size(ring) - 1;
+}
+
 struct audio_buffer_api ring_buffer_fns = {
         (void (*)(void *)) ring_buffer_destroy,
         (int (*)(void *, char *, int)) ring_buffer_read,
diff --git a/src/utils/ring_buffer.h b/src/utils/ring_buffer.h
index ede79d1e0..ace179d83 100644
--- a/src/utils/ring_buffer.h
+++ b/src/utils/ring_buffer.h
@@ -1,6 +1,7 @@
 /**
  * @file   utils/ring_buffer.h
  * @author Martin Pulec     <martin.pulec@cesnet.cz>
+ * @author Martin Piatka    <piatka@cesnet.cz>
  */
 /*
  * Copyright (c) 2011-2019 CESNET, z. s. p. o.
@@ -76,6 +77,11 @@ void ring_buffer_flush(struct ring_buffer *ring);
  */
 int ring_get_current_size(struct ring_buffer * ring);
 
+/**
+ * Returns size available for writing
+ */
+int ring_get_available_write_size(struct ring_buffer * ring);
+
 extern struct audio_buffer_api ring_buffer_fns;
 
 #ifdef __cplusplus