cam: Add BufferWriter helper

Add a simpler helper to allow the cam application to write raw captured
frames to disk.

Signed-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>
Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

src/cam/buffer_writer.h

@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2019, Google Inc.
+ *
+ * buffer_writer.h - Buffer writer
+ */
+#ifndef __LIBCAMERA_BUFFER_WRITER_H__
+#define __LIBCAMERA_BUFFER_WRITER_H__
+
+#include <string>
+
+#include <libcamera/buffer.h>
+
+class BufferWriter
+{
+public:
+	BufferWriter(const std::string &pattern = "frame-#.bin");
+
+	int write(libcamera::Buffer *buffer);
+
+private:
+	std::string pattern_;
+};
+
+#endif /* __LIBCAMERA_BUFFER_WRITER_H__ */