From 3ea2978b7b939304e6473920db4a51026cc7dc43 Mon Sep 17 00:00:00 2001
From: popow <popow@gmx.de>
Date: Sat, 7 Jul 2018 13:30:19 +0200
Subject: [PATCH] if Exif data exceeds 64K and is split over multiple App1
 marker, it will be extended like the ICC profile does

---
 .../Jpeg/PdfJsPort/PdfJsJpegDecoderCore.cs       | 10 +++++++++-
 .../MetaData/Profiles/Exif/ExifProfile.cs        | 16 ++++++++++++++--
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/src/ImageSharp/Formats/Jpeg/PdfJsPort/PdfJsJpegDecoderCore.cs b/src/ImageSharp/Formats/Jpeg/PdfJsPort/PdfJsJpegDecoderCore.cs
index bd1d84ecc9..8b5b7b151b 100644
--- a/src/ImageSharp/Formats/Jpeg/PdfJsPort/PdfJsJpegDecoderCore.cs
+++ b/src/ImageSharp/Formats/Jpeg/PdfJsPort/PdfJsJpegDecoderCore.cs
@@ -472,7 +472,15 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.PdfJsPort
             if (ProfileResolver.IsProfile(profile, ProfileResolver.ExifMarker))
             {
                 this.isExif = true;
-                this.MetaData.ExifProfile = new ExifProfile(profile);
+                if (this.MetaData.ExifProfile == null)
+                {
+                    this.MetaData.ExifProfile = new ExifProfile(profile);
+                }
+                else
+                {
+                    // if the exif information exceeds 64K, it will be split over multiple APP1 marker
+                    this.MetaData.ExifProfile.Extend(profile);
+                }
             }
         }
 
diff --git a/src/ImageSharp/MetaData/Profiles/Exif/ExifProfile.cs b/src/ImageSharp/MetaData/Profiles/Exif/ExifProfile.cs
index b38097060e..1f2695c5e6 100644
--- a/src/ImageSharp/MetaData/Profiles/Exif/ExifProfile.cs
+++ b/src/ImageSharp/MetaData/Profiles/Exif/ExifProfile.cs
@@ -4,7 +4,6 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
-using System.Linq;
 using SixLabors.ImageSharp.PixelFormats;
 using SixLabors.ImageSharp.Primitives;
 
@@ -18,7 +17,7 @@ namespace SixLabors.ImageSharp.MetaData.Profiles.Exif
         /// <summary>
         /// The byte array to read the EXIF profile from.
         /// </summary>
-        private readonly byte[] data;
+        private byte[] data;
 
         /// <summary>
         /// The collection of EXIF values
@@ -230,6 +229,19 @@ namespace SixLabors.ImageSharp.MetaData.Profiles.Exif
             this.values.Add(newExifValue);
         }
 
+        /// <summary>
+        /// Extends the profile with additional data.
+        /// </summary>
+        /// <param name="bytes">The array containing addition profile data.</param>
+        public void Extend(byte[] bytes)
+        {
+            int currentLength = this.data.Length;
+
+            // the first 6 bytes are Exif00 and will be skipped
+            Array.Resize(ref this.data, currentLength + bytes.Length - 6);
+            Buffer.BlockCopy(bytes, 6, this.data, currentLength, bytes.Length - 6);
+        }
+
         /// <summary>
         /// Converts this instance to a byte array.
         /// </summary>