libcamera: formats: Define FormatEnum type

Add an internal format.h and format.cpp files to collect libcamera image
format related types, helpers and structures. Define and document the
FormatEnum type, used to enumerate pixel image formats and associated
image resolutions.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo@jmondi.org>

src/libcamera/include/formats.h

@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2019, Google Inc.
+ *
+ * formats.h - Libcamera image formats
+ */
+
+#ifndef __LIBCAMERA_FORMATS_H__
+#define __LIBCAMERA_FORMATS_H__
+
+#include <map>
+#include <vector>
+
+#include "geometry.h"
+
+namespace libcamera {
+
+typedef std::map<unsigned int, std::vector<SizeRange>> FormatEnum;
+
+} /* namespace libcamera */
+
+#endif /* __LIBCAMERA_FORMATS_H__ */