Fix decoding invalid Exif dates. Closes #163

CHANGELOG.md

@@ -1,5 +1,23 @@
 # Changelog
 
+## Image 0.54.3
+
+This is the changelog for Image version 0.54.3 released on September 6th, 2024.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-image/image/tags)
+
+### Bug Fixes
+
+* Fix parsing invalid date time in Exif data. When invalid, the raw underlying string is returned.
+
+* Trim strings in Exif data. As a result, empty strings will be returned now as `nil` rather than `""`.
+
+* Replace a ``<<0, ....>>` sequence in an Exif string value with `nil`.
+
+* Decode additional tags:
+
+  * Exif tag `0xA005`, Interop Offset. The value is in internal file pointer so has no meaningful interpretation in `image`.
+
+  * TIFF tag `0xC4A5`, Print Image Matching. According to [this source](https://www.loc.gov/preservation/digital/formats/content/tiff_tags.shtml) the field has no standardised values so the raw value is returned.
+
 ## Image 0.54.2
 
 This is the changelog for Image version 0.54.2 released on September 1st, 2024.  For older changelogs please consult the release tag on [GitHub](https://github.com/elixir-image/image/tags)

lib/image/exif/decode.ex

@@ -14,20 +14,22 @@ defmodule Image.Exif.Decode do
   def tag(:tiff, 0x0100, value), do: {:image_width, value}
   def tag(:tiff, 0x0101, value), do: {:image_height, value}
   def tag(:tiff, 0x010D, value), do: {:document_name, value}
-  def tag(:tiff, 0x010E, value), do: {:image_description, value}
-  def tag(:tiff, 0x010F, value), do: {:make, value}
-  def tag(:tiff, 0x0110, value), do: {:model, value}
+  def tag(:tiff, 0x010E, value), do: {:image_description, trim(value)}
+  def tag(:tiff, 0x010F, value), do: {:make, trim(value)}
+  def tag(:tiff, 0x0110, value), do: {:model, trim(value)}
   def tag(:tiff, 0x0112, value), do: {:orientation, orientation(value)}
   def tag(:tiff, 0x011A, value), do: {:x_resolution, value}
   def tag(:tiff, 0x011B, value), do: {:y_resolution, value}
   def tag(:tiff, 0x0128, value), do: {:resolution_units, resolution(value)}
-  def tag(:tiff, 0x0131, value), do: {:software, value}
+  def tag(:tiff, 0x0131, value), do: {:software, trim(value)}
   def tag(:tiff, 0x0132, value), do: {:modify_date, date_time(value)}
   def tag(:tiff, 0x0213, value), do: {:YCbCr_positioning, ycbcr_positioning(value)}
 
   def tag(:tiff, 0x8769, value), do: {:exif, value}
   def tag(:tiff, 0x8825, value), do: {:gps, value}
 
+  def tag(:tiff, 0xC4A5, value), do: {:print_image_matching, value}
+
   def tag(:exif, 0x0201, value), do: {:thumbnail_offset, value}
   def tag(:exif, 0x0202, value), do: {:thumbnail_size, value}
 
@@ -66,6 +68,7 @@ defmodule Image.Exif.Decode do
   def tag(_, 0xA002, value), do: {:exif_image_width, value}
   def tag(_, 0xA003, value), do: {:exif_image_height, value}
   def tag(_, 0xA004, value), do: {:related_sound_file, value}
+  def tag(_, 0xA005, value), do: {:interopt_offset, value}
   def tag(_, 0xA20B, value), do: {:flash_energy, value}
   def tag(_, 0xA20C, value), do: {:spatial_frequency_response, value}
   def tag(_, 0xA20E, value), do: {:focal_plane_x_resolution, value}
@@ -98,8 +101,8 @@ defmodule Image.Exif.Decode do
   def tag(_, 0xA434, value), do: {:lens_model, value}
   def tag(_, 0xA435, value), do: {:lens_serial_number, value}
 
-  def tag(_, 0x8298, value), do: {:copyright, value}
-  def tag(_, 0x13B, value), do: {:artist, value}
+  def tag(_, 0x8298, value), do: {:copyright, trim(value)}
+  def tag(_, 0x13B, value), do: {:artist, trim(value)}
   def tag(_, 0x9010, value), do: {:time_offset, value}
   def tag(_, 0xA431, value), do: {:body_serial_number, value}
 
@@ -120,13 +123,26 @@ defmodule Image.Exif.Decode do
   defp date_time(date_time) do
     case String.split(date_time, [":", "-", "T", " "]) do
       [y, m, d, h, mm, s] ->
-        NaiveDateTime.new!(int(y), int(m), int(d), int(h), int(mm), int(s))
+        case NaiveDateTime.new(int(y), int(m), int(d), int(h), int(mm), int(s)) do
+          {:ok, naive_datetime} -> naive_datetime
+          {:error, _} -> date_time
+        end
 
       _other ->
         date_time
     end
   end
 
+  def trim(value) do
+    cond do
+      <<0::size(byte_size(value) * 8)>> == value ->
+        nil
+
+      true ->
+        String.trim(value)
+    end
+  end
+
   @compile {:inline, int: 1}
   defp int(string), do: String.to_integer(string)
 

mix.exs

@@ -1,7 +1,7 @@
 defmodule Image.MixProject do
   use Mix.Project
 
-  @version "0.54.2"
+  @version "0.54.3"
 
   @app_name "image"
 

test/exif_test.exs

@@ -21,6 +21,6 @@ defmodule Image.ExitTest do
     image = image_path("kodak-dc210.jpg")
     {:ok, image} = Image.open(image, access: :random)
 
-    assert {:ok, %{copyright: "", image_description: ""}} = Image.exif(image)
+    assert {:ok, %{copyright: nil, image_description: nil}} = Image.exif(image)
   end
 end