[libcamera-devel] [PATCH v4] libcamera: PixelFormat: Replace hex with fourcc and modifiers

[Kaaira Gupta]

Print fourCC characters instead of the hex values in toString() as they
are easier to comprehend. Also, print the corresponding modifiers for
MIPI vendor as it is mostly used in libcamera.

Signed-off-by: Kaaira Gupta <kgupta at es.iitr.ac.in>
---

Changes since v3:
	-shortened the texts.
	-Removed default case as well.
	-changed commit message and tests to reflect the changes.

Changes since v2:
        - Remove description for all vendors except for MIPI
        - Change commit message to reflect this change.
        - Change tests accordingly.

Changes since v1:
        - Replaced magic numbers with expressive values.
        - Re-wrote ARM vendor's modifiers
        - Re-wrote the vendors' map with a macro.
        - Changed the copyrights in test file.
        - Changed the tests.

 src/libcamera/pixelformats.cpp | 28 +++++++++++++++++---
 test/meson.build               |  1 +
 test/pixel-format.cpp          | 47 ++++++++++++++++++++++++++++++++++
 3 files changed, 73 insertions(+), 3 deletions(-)
 create mode 100644 test/pixel-format.cpp

diff --git a/src/libcamera/pixelformats.cpp b/src/libcamera/pixelformats.cpp
index 1330dc5..16aa7e4 100644
--- a/src/libcamera/pixelformats.cpp
+++ b/src/libcamera/pixelformats.cpp
@@ -6,6 +6,7 @@
  */
 
 #include <libcamera/pixelformats.h>
+#include <string.h>
 
 /**
  * \file pixelformats.h
@@ -108,9 +109,30 @@ bool PixelFormat::operator<(const PixelFormat &other) const
  */
 std::string PixelFormat::toString() const
 {
-	char str[11];
-	snprintf(str, 11, "0x%08x", fourcc_);
-	return str;
+	if (fourcc_ == DRM_FORMAT_INVALID)
+		return "<INVALID>";
+
+	char fourcc[5] = { static_cast<char>(fourcc_ & 0x7f),
+			   static_cast<char>((fourcc_ >> 8) & 0x7f),
+			   static_cast<char>((fourcc_ >> 16) & 0x7f),
+			   static_cast<char>((fourcc_ >> 24) & 0x7f) };
+
+	for (unsigned int i = 0; i < 4; i++) {
+		if (!isprint(fourcc[i]))
+			fourcc[i] = '.';
+	}
+
+	std::string formatString(fourcc);
+
+	if (fourcc_ & (1 << 31))
+		formatString += "-BE";
+
+	if (modifier_ == DRM_FORMAT_MOD_INVALID)
+		formatString += ":<INVALID> modifier";
+	else if (modifier_ == MIPI_FORMAT_MOD_CSI2_PACKED)
+		formatString += ":packed";
+
+	return formatString;
 }
 
 } /* namespace libcamera */
diff --git a/test/meson.build b/test/meson.build
index bd7da14..591d848 100644
--- a/test/meson.build
+++ b/test/meson.build
@@ -33,6 +33,7 @@ internal_tests = [
     ['message',                         'message.cpp'],
     ['object',                          'object.cpp'],
     ['object-invoke',                   'object-invoke.cpp'],
+    ['pixel-format',                    'pixel-format.cpp'],
     ['signal-threads',                  'signal-threads.cpp'],
     ['threads',                         'threads.cpp'],
     ['timer',                           'timer.cpp'],
diff --git a/test/pixel-format.cpp b/test/pixel-format.cpp
new file mode 100644
index 0000000..84062b7
--- /dev/null
+++ b/test/pixel-format.cpp
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2020, Kaaira Gupta
+ * libcamera pixel format handling test
+ */
+
+#include <iostream>
+#include <vector>
+
+#include "libcamera/pixelformats.h"
+
+#include "test.h"
+
+using namespace std;
+using namespace libcamera;
+
+class PixelFormatTest : public Test
+{
+protected:
+	int run()
+	{
+		std::vector<std::pair<PixelFormat, const char *>> formats{
+			{ PixelFormat(DRM_FORMAT_SRGGB8, DRM_FORMAT_MOD_INVALID), "RGGB:<INVALID> modifier" },
+			{ PixelFormat(DRM_FORMAT_SRGGB8, DRM_FORMAT_MOD_LINEAR), "RGGB" },
+			{ PixelFormat(DRM_FORMAT_C8, DRM_FORMAT_MOD_SAMSUNG_64_32_TILE), "C8  " },
+			{ PixelFormat(DRM_FORMAT_BIG_ENDIAN, MIPI_FORMAT_MOD_CSI2_PACKED), "....-BE:packed" }
+		};
+		for (const auto &format : formats) {
+			if ((format.first).toString() != format.second) {
+				cerr << "Failed to convert PixelFormat "
+				     << 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)
-- 
2.17.1