android: jpeg: Add EXIF infrastructure

Provide helper classes to utilise the libexif interfaces and link
against libexif to support tag additions when creating JPEG images.

Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Signed-off-by: Umang Jain <email@uajain.com>
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>

1 files changed, 46 insertions, 0 deletions

diff --git a/src/android/jpeg/exif.h b/src/android/jpeg/exif.h
new file mode 100644
index 00000000..8dfc3245
--- /dev/null
+++ b/src/android/jpeg/exif.h
@@ -0,0 +1,46 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2020, Google Inc.
+ *
+ * exif.h - EXIF tag creator using libexif
+ */
+#ifndef __ANDROID_JPEG_EXIF_H__
+#define __ANDROID_JPEG_EXIF_H__
+
+#include <ctime>
+#include <string>
+
+#include <libexif/exif-data.h>
+
+#include <libcamera/span.h>
+
+class Exif
+{
+public:
+	Exif();
+	~Exif();
+
+	libcamera::Span<const uint8_t> data() const { return { exifData_, size_ }; }
+	[[nodiscard]] int generate();
+
+private:
+	ExifEntry *createEntry(ExifIfd ifd, ExifTag tag);
+	ExifEntry *createEntry(ExifIfd ifd, ExifTag tag, ExifFormat format,
+			       unsigned long components, unsigned int size);
+
+	void setShort(ExifIfd ifd, ExifTag tag, uint16_t item);
+	void setLong(ExifIfd ifd, ExifTag tag, uint32_t item);
+	void setString(ExifIfd ifd, ExifTag tag, ExifFormat format,
+		       const std::string &item);
+	void setRational(ExifIfd ifd, ExifTag tag, ExifRational item);
+
+	bool valid_;
+
+	ExifData *data_;
+	ExifMem *mem_;
+
+	unsigned char *exifData_;
+	unsigned int size_;
+};
+
+#endif /* __ANDROID_JPEG_EXIF_H__ */