[libcamera-devel] [PATCH] src: android: exif: Set the class byte ordering

[Kieran Bingham]

The exif object sets the byte ordering on construction, and then
during later calls re-states the byte ordering when setting values.

It could be argued that this ordering should already be known to the exif
library and is redudant, but even so we must provide it.

Ensure we are consistent in always using the same byte ordering by setting
a private class member to re-use a single value.

Signed-off-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
---

This patch itself feels like it might be a bit redundant, but I saw the
repetition, and whilst we're not likely to change the byte order, I
thought it might make sense to ensure it's always set from the same
state variable.

If this is helpful we can add it, but if this is overkill I don't mind
dropping it. It's just an idea.

 src/android/jpeg/exif.cpp | 11 ++++++-----
 src/android/jpeg/exif.h   |  1 +
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/src/android/jpeg/exif.cpp b/src/android/jpeg/exif.cpp
index 1ced55343ee9..f29a7c71d1ec 100644
--- a/src/android/jpeg/exif.cpp
+++ b/src/android/jpeg/exif.cpp
@@ -25,7 +25,8 @@ LOG_DEFINE_CATEGORY(EXIF)
  * data can be obtained using the data() method.
  */
 Exif::Exif()
-	: valid_(false), data_(nullptr), exifData_(0), size_(0)
+	: valid_(false), data_(nullptr), order_(EXIF_BYTE_ORDER_INTEL),
+	  exifData_(0), size_(0)
 {
 	/* Create an ExifMem allocator to construct entries. */
 	mem_ = exif_mem_new_default();
@@ -49,7 +50,7 @@ Exif::Exif()
 	 * Big-Endian: EXIF_BYTE_ORDER_MOTOROLA
 	 * Little Endian: EXIF_BYTE_ORDER_INTEL
 	 */
-	exif_data_set_byte_order(data_, EXIF_BYTE_ORDER_INTEL);
+	exif_data_set_byte_order(data_, order_);
 
 	/* Create the mandatory EXIF fields with default data. */
 	exif_data_fix(data_);
@@ -131,7 +132,7 @@ void Exif::setShort(ExifIfd ifd, ExifTag tag, uint16_t item)
 	if (!entry)
 		return;
 
-	exif_set_short(entry->data, EXIF_BYTE_ORDER_INTEL, item);
+	exif_set_short(entry->data, order_, item);
 	exif_entry_unref(entry);
 }
 
@@ -141,7 +142,7 @@ void Exif::setLong(ExifIfd ifd, ExifTag tag, uint32_t item)
 	if (!entry)
 		return;
 
-	exif_set_long(entry->data, EXIF_BYTE_ORDER_INTEL, item);
+	exif_set_long(entry->data, order_, item);
 	exif_entry_unref(entry);
 }
 
@@ -151,7 +152,7 @@ void Exif::setRational(ExifIfd ifd, ExifTag tag, ExifRational item)
 	if (!entry)
 		return;
 
-	exif_set_rational(entry->data, EXIF_BYTE_ORDER_INTEL, item);
+	exif_set_rational(entry->data, order_, item);
 	exif_entry_unref(entry);
 }
 
diff --git a/src/android/jpeg/exif.h b/src/android/jpeg/exif.h
index 622de4cfd593..6e8ce04a2e67 100644
--- a/src/android/jpeg/exif.h
+++ b/src/android/jpeg/exif.h
@@ -46,6 +46,7 @@ private:
 
 	ExifData *data_;
 	ExifMem *mem_;
+	ExifByteOrder order_;
 
 	unsigned char *exifData_;
 	unsigned int size_;
-- 
2.25.1