libcamera: v4l2_pixelformat: Move V4L2PixelFormat to a new file

Move the V4L2PixelFormat class to a new file to prepare for additional
changes that will make it grow. No functional modification is included.

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

1 files changed, 106 insertions, 0 deletions

diff --git a/src/libcamera/v4l2_pixelformat.cpp b/src/libcamera/v4l2_pixelformat.cpp
new file mode 100644
index 00000000..57d65c38
--- /dev/null
+++ b/src/libcamera/v4l2_pixelformat.cpp
@@ -0,0 +1,106 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2019, Google Inc.
+ * Copyright (C) 2020, Raspberry Pi (Trading) Ltd.
+ *
+ * v4l2_pixelformat.cpp - V4L2 Pixel Format
+ */
+
+#include "v4l2_pixelformat.h"
+
+#include <ctype.h>
+#include <map>
+#include <string.h>
+
+#include <linux/drm_fourcc.h>
+
+#include <libcamera/pixelformats.h>
+
+#include "log.h"
+
+/**
+ * \file v4l2_pixelformat.h
+ * \brief V4L2 Pixel Format
+ */
+namespace libcamera {
+
+LOG_DECLARE_CATEGORY(V4L2)
+
+/**
+ * \class V4L2PixelFormat
+ * \brief V4L2 pixel format FourCC wrapper
+ *
+ * The V4L2PixelFormat class describes the pixel format of a V4L2 buffer. It
+ * wraps the V4L2 numerical FourCC, and shall be used in all APIs that deal with
+ * V4L2 pixel formats. Its purpose is to prevent unintentional confusion of
+ * V4L2 and DRM FourCCs in code by catching implicit conversion attempts at
+ * compile time.
+ *
+ * To achieve this goal, construction of a V4L2PixelFormat from an integer value
+ * is explicit. To retrieve the integer value of a V4L2PixelFormat, both the
+ * explicit value() and implicit uint32_t conversion operators may be used.
+ */
+
+/**
+ * \fn V4L2PixelFormat::V4L2PixelFormat()
+ * \brief Construct a V4L2PixelFormat with an invalid format
+ *
+ * V4L2PixelFormat instances constructed with the default constructor are
+ * invalid, calling the isValid() function returns false.
+ */
+
+/**
+ * \fn V4L2PixelFormat::V4L2PixelFormat(uint32_t fourcc)
+ * \brief Construct a V4L2PixelFormat from a FourCC value
+ * \param[in] fourcc The pixel format FourCC numerical value
+ */
+
+/**
+ * \fn bool V4L2PixelFormat::isValid() const
+ * \brief Check if the pixel format is valid
+ *
+ * V4L2PixelFormat instances constructed with the default constructor are
+ * invalid. Instances constructed with a FourCC defined in the V4L2 API are
+ * valid. The behaviour is undefined otherwise.
+ *
+ * \return True if the pixel format is valid, false otherwise
+ */
+
+/**
+ * \fn uint32_t V4L2PixelFormat::fourcc() const
+ * \brief Retrieve the pixel format FourCC numerical value
+ * \return The pixel format FourCC numerical value
+ */
+
+/**
+ * \fn V4L2PixelFormat::operator uint32_t() const
+ * \brief Convert to the pixel format FourCC numerical value
+ * \return The pixel format FourCC numerical value
+ */
+
+/**
+ * \brief Assemble and return a string describing the pixel format
+ * \return A string describing the pixel format
+ */
+std::string V4L2PixelFormat::toString() const
+{
+	if (fourcc_ == 0)
+		return "<INVALID>";
+
+	char ss[8] = { 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(ss[i]))
+			ss[i] = '.';
+	}
+
+	if (fourcc_ & (1 << 31))
+		strcat(ss, "-BE");
+
+	return ss;
+}
+
+} /* namespace libcamera */