Update PIEX

4 files changed, 50 insertions, 56 deletions

diff --git a/src/piex.cc b/src/piex.cc
index 83906f7..9fd028c 100644
--- a/src/piex.cc
+++ b/src/piex.cc
@@ -309,6 +309,7 @@ Error DngGetPreviewData(StreamInterface* stream,
 
   // Find the largest jpeg compressed preview image.
   std::uint32_t jpeg_length = 0;
+  std::uint32_t jpeg_offset = 0;
   for (const auto& ifd : tiff_content.tiff_directory[0].GetSubDirectories()) {
     std::uint32_t compression;
     std::uint32_t photometric_interpretation;
@@ -325,16 +326,12 @@ Error DngGetPreviewData(StreamInterface* stream,
           strip_offsets.size() == 1 && byte_counts.size() == 1 &&
           byte_counts[0] > jpeg_length) {
         jpeg_length = byte_counts[0];
-        preview_image_data->jpeg_length = jpeg_length;
-        preview_image_data->jpeg_offset = strip_offsets[0];
+        jpeg_offset = strip_offsets[0];
       }
     }
   }
-
-  // A 'jpeg_length' of 0 indicates that we could not find any jpeg preview.
-  if (jpeg_length == 0) {
-    return kUnsupported;
-  }
+  preview_image_data->jpeg_length = jpeg_length;
+  preview_image_data->jpeg_offset = jpeg_offset;
 
   // This format doesn't necessarily embed a full jpeg.
   preview_image_data->full_preview = false;
@@ -362,25 +359,27 @@ Error NefGetPreviewData(StreamInterface* stream,
   // size needs to be taken into account. Based on experiments the preview image
   // dimensions must be at least 90% of the sensor image dimensions to let it be
   // a full size preview image.
-  const float kEpsilon = 0.9f;
-
-  std::uint16_t width;
-  std::uint16_t height;
-  if (!GetPreviewDimensions(preview_image_data->jpeg_offset, stream, &width,
-                            &height) ||
-      preview_image_data->full_width == 0 ||
-      preview_image_data->full_height == 0) {
-    return kUnsupported;
-  }
+  if (preview_image_data->jpeg_length > 0) {  // when preview image exists
+    const float kEpsilon = 0.9f;
+
+    std::uint16_t width;
+    std::uint16_t height;
+    if (!GetPreviewDimensions(preview_image_data->jpeg_offset, stream, &width,
+                              &height) ||
+        preview_image_data->full_width == 0 ||
+        preview_image_data->full_height == 0) {
+      return kUnsupported;
+    }
 
-  if (static_cast<float>(width) /
-              static_cast<float>(preview_image_data->full_width) >
-          kEpsilon ||
-      static_cast<float>(height) /
-              static_cast<float>(preview_image_data->full_height) >
-          kEpsilon) {
-    preview_image_data->full_width = width;
-    preview_image_data->full_height = height;
+    if (static_cast<float>(width) /
+                static_cast<float>(preview_image_data->full_width) >
+            kEpsilon ||
+        static_cast<float>(height) /
+                static_cast<float>(preview_image_data->full_height) >
+            kEpsilon) {
+      preview_image_data->full_width = width;
+      preview_image_data->full_height = height;
+    }
   }
   return kOk;
 }
@@ -416,11 +415,13 @@ Error RafGetPreviewData(StreamInterface* stream,
     return kFail;
   }
 
-  // Parse the Exif information from the preview image. Omit kUnsupported,
-  // because the exif data does not contain any preview image.
-  const std::uint32_t exif_offset = jpeg_offset + 12;
-  if (GetExifData(exif_offset, stream, preview_image_data) == kFail) {
-    return kFail;
+  if (jpeg_length > 0) {  // when preview image exists
+    // Parse the Exif information from the preview image. Omit kUnsupported,
+    // because the exif data does not contain any preview image.
+    const std::uint32_t exif_offset = jpeg_offset + 12;
+    if (GetExifData(exif_offset, stream, preview_image_data) == kFail) {
+      return kFail;
+    }
   }
 
   // Merge the Exif data with the RAW data to form the preview_image_data.
@@ -453,11 +454,13 @@ Error Rw2GetPreviewData(StreamInterface* stream,
     return error;
   }
 
-  // Parse the Exif information from the preview image. Omit kUnsupported,
-  // because the exif data does not contain any preview image.
-  const std::uint32_t exif_offset = preview_data.jpeg_offset + 12;
-  if (GetExifData(exif_offset, stream, preview_image_data) == kFail) {
-    return kFail;
+  if (preview_data.jpeg_length > 0) {  // when preview image exists
+    // Parse the Exif information from the preview image. Omit kUnsupported,
+    // because the exif data does not contain any preview image.
+    const std::uint32_t exif_offset = preview_data.jpeg_offset + 12;
+    if (GetExifData(exif_offset, stream, preview_image_data) == kFail) {
+      return kFail;
+    }
   }
 
   // Merge the Exif data with the RAW data to form the preview_image_data.
diff --git a/src/piex.h b/src/piex.h
index 39ad578..0426772 100644
--- a/src/piex.h
+++ b/src/piex.h
@@ -67,7 +67,10 @@ bool IsRaw(StreamInterface* data);
 // offset to a JPEG compressed image from the beginning of the file.
 //
 // Returns 'kFail' when something with the data is wrong.
-// Returns 'kUnsupported' if no preview image data was found.
+// Returns 'kUnsupported' if file format is not supported.
+//
+// One could check the "preview_image_data->jpeg_length != 0" for the existance
+// of a preview image.
 Error GetPreviewImageData(StreamInterface* data,
                           PreviewImageData* preview_image_data);
 
diff --git a/src/piex_types.h b/src/piex_types.h
index 36ae5b9..54dc5b6 100644
--- a/src/piex_types.h
+++ b/src/piex_types.h
@@ -56,7 +56,7 @@ struct PreviewImageData {
     std::string date_stamp;  // Giving as "YYYY:MM:DD" format.
   };
 
-  // Required data to find the preview image and to handle it correctly.
+  // Optional data to find the preview image and to handle it correctly.
   std::uint32_t jpeg_offset = 0;
   std::uint32_t jpeg_length = 0;
   std::uint32_t exif_orientation = 1;  // horizontal as default
diff --git a/src/tiff_parser.cc b/src/tiff_parser.cc
index ce98a9c..af25803 100644
--- a/src/tiff_parser.cc
+++ b/src/tiff_parser.cc
@@ -158,8 +158,7 @@ void FillGpsPreviewImageData(const TiffDirectory& gps_directory,
 }
 
 Error FillPreviewImageData(const TiffDirectory& tiff_directory,
-                           PreviewImageData* preview_image_data,
-                           bool* has_preview) {
+                           PreviewImageData* preview_image_data) {
   bool success = true;
   // Get jpeg_offset and jpeg_length
   if (tiff_directory.Has(kTiffTagStripOffsets) &&
@@ -170,19 +169,16 @@ Error FillPreviewImageData(const TiffDirectory& tiff_directory,
         !tiff_directory.Get(kTiffTagStripByteCounts, &strip_byte_counts)) {
       return kFail;
     }
-    if (strip_offsets.size() != 1 || strip_byte_counts.size() != 1) {
-      return kUnsupported;
+    if (strip_offsets.size() == 1 && strip_byte_counts.size() == 1) {
+      preview_image_data->jpeg_offset = strip_offsets[0];
+      preview_image_data->jpeg_length = strip_byte_counts[0];
     }
-    preview_image_data->jpeg_offset = strip_offsets[0];
-    preview_image_data->jpeg_length = strip_byte_counts[0];
-    *has_preview = true;
   } else if (tiff_directory.Has(kTiffTagJpegOffset) &&
              tiff_directory.Has(kTiffTagJpegByteCount)) {
     success &= tiff_directory.Get(kTiffTagJpegOffset,
                                   &preview_image_data->jpeg_offset);
     success &= tiff_directory.Get(kTiffTagJpegByteCount,
                                   &preview_image_data->jpeg_length);
-    *has_preview = true;
   } else if (tiff_directory.Has(kPanaTagJpegImage)) {
     if (!tiff_directory.GetOffsetAndLength(kPanaTagJpegImage,
                                            TIFF_TYPE_UNDEFINED,
@@ -190,7 +186,6 @@ Error FillPreviewImageData(const TiffDirectory& tiff_directory,
                                            &preview_image_data->jpeg_length)) {
       return kFail;
     }
-    *has_preview = true;
   }
 
   // Get exif_orientation
@@ -484,15 +479,13 @@ TiffParser::TiffParser(StreamInterface* stream, const std::uint32_t offset)
 
 Error TiffParser::GetPreviewImageData(const TiffContent& tiff_content,
                                       PreviewImageData* preview_image_data) {
-  bool has_preview = false;
   Error error = kOk;
   for (const auto& tiff_directory : tiff_content.tiff_directory) {
-    error =
-        FillPreviewImageData(tiff_directory, preview_image_data, &has_preview);
+    error = FillPreviewImageData(tiff_directory, preview_image_data);
     if (error == kOk && tiff_directory.Has(kTiffTagExifIfd) &&
         tiff_content.exif_directory) {
       error = FillPreviewImageData(*tiff_content.exif_directory,
-                                   preview_image_data, &has_preview);
+                                   preview_image_data);
     }
     if (error == kOk && tiff_directory.Has(kExifTagGps) &&
         tiff_content.gps_directory) {
@@ -500,15 +493,10 @@ Error TiffParser::GetPreviewImageData(const TiffContent& tiff_content,
     }
     for (const auto& sub_directory : tiff_directory.GetSubDirectories()) {
       if (error == kOk) {
-        error = FillPreviewImageData(sub_directory, preview_image_data,
-                                     &has_preview);
+        error = FillPreviewImageData(sub_directory, preview_image_data);
       }
     }
   }
-
-  if (error == kOk && !has_preview) {
-    return kUnsupported;
-  }
   return error;
 }