libcamera: pixel_format: Replace hex with format names

Print format names defined in formats namespace instead of the hex
values in toString() as they are easier to comprehend. For this add
a property of 'name' in PixelFormatInfo' so as to map the formats
with their names. Print fourcc for formats which are not used in
libcamera.

Signed-off-by: Kaaira Gupta <kgupta@es.iitr.ac.in>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

test/pixel-format.cpp

@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2020, Kaaira Gupta
+ * libcamera pixel format handling test
+ */
+
+#include <iostream>
+#include <vector>
+
+#include <libcamera/formats.h>
+#include <libcamera/pixel_format.h>
+
+#include "libcamera/internal/utils.h"
+
+#include "test.h"
+
+using namespace std;
+using namespace libcamera;
+
+class PixelFormatTest : public Test
+{
+protected:
+	int run()
+	{
+		std::vector<std::pair<PixelFormat, const char *>> formatsMap{
+			{ formats::R8, "R8" },
+			{ formats::SRGGB10_CSI2P, "SRGGB10_CSI2P" },
+			{ PixelFormat(0, 0), "<INVALID>" },
+			{ PixelFormat(0x20203843), "<C8  >" }
+		};
+
+		for (const auto &format : formatsMap) {
+			if ((format.first).toString() != format.second) {
+				cerr << "Failed to convert PixelFormat "
+				     << utils::hex(format.first.fourcc()) << " to string"
+				     << endl;
+				return TestFail;
+			}
+		}
+
+		if (PixelFormat().toString() != "<INVALID>") {
+			cerr << "Failed to convert default PixelFormat to string"
+			     << endl;
+			return TestFail;
+		}
+
+		return TestPass;
+	}
+};
+
+TEST_REGISTER(PixelFormatTest)