core: ringbuffer: reset read and write pointers to 0 when a read buffer consumes all available data

core/ringbuffer.c

@@ -289,6 +289,14 @@ enum b_status b_ringbuffer_close_read_buffer(
 		buf->r_read_ptr = 0;
 	}
 
+	if (buf->r_read_ptr == buf->r_write_ptr) {
+		/* the ringbuffer is now empty. set both pointers to 0.
+		 * this ensures that the whole buffer will be available
+		 * contiguously to the next call to open_write_buffer */
+		buf->r_read_ptr = 0;
+		buf->r_write_ptr = 0;
+	}
+
 	buf->r_opened_buf = NULL;
 	buf->r_opened_capacity = 0;
 	buf->r_flags &= ~B_RINGBUFFER_READ_LOCKED;