Add support for reading IPTC metadata

src/ImageSharp/Formats/Jpeg/Components/Decoder/ProfileResolver.cs

@@ -28,6 +28,30 @@ namespace SixLabors.ImageSharp.Formats.Jpeg.Components.Decoder
             (byte)'I', (byte)'L', (byte)'E', (byte)'\0'
         };
 
+        /// <summary>
+        /// Gets the adobe photoshop APP13 marker which can contain IPTC meta data.
+        /// </summary>
+        public static ReadOnlySpan<byte> AdobePhotoshopApp13Marker => new[]
+        {
+            (byte)'P', (byte)'h', (byte)'o', (byte)'t', (byte)'o', (byte)'s', (byte)'h', (byte)'o', (byte)'p', (byte)' ', (byte)'3', (byte)'.', (byte)'0', (byte)'\0'
+        };
+
+        /// <summary>
+        /// Gets the 8BIM marker, which signals the start of a adobe specific image resource block.
+        /// </summary>
+        public static ReadOnlySpan<byte> AdobeImageResourceBlockMarker => new[]
+        {
+            (byte)'8', (byte)'B', (byte)'I', (byte)'M'
+        };
+
+        /// <summary>
+        /// Gets a IPTC Image resource ID.
+        /// </summary>
+        public static ReadOnlySpan<byte> AdobeIptcMarker => new[]
+        {
+            (byte)4, (byte)4
+        };
+
         /// <summary>
         /// Gets the EXIF specific markers.
         /// </summary>

src/ImageSharp/Formats/Jpeg/JpegDecoderCore.cs

@@ -14,6 +14,7 @@ using SixLabors.ImageSharp.Memory;
 using SixLabors.ImageSharp.Metadata;
 using SixLabors.ImageSharp.Metadata.Profiles.Exif;
 using SixLabors.ImageSharp.Metadata.Profiles.Icc;
+using SixLabors.ImageSharp.Metadata.Profiles.Iptc;
 using SixLabors.ImageSharp.PixelFormats;
 
 namespace SixLabors.ImageSharp.Formats.Jpeg
@@ -46,7 +47,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
         private readonly byte[] markerBuffer = new byte[2];
 
         /// <summary>
-        /// The DC Huffman tables
+        /// The DC Huffman tables.
         /// </summary>
         private HuffmanTable[] dcHuffmanTables;
 
@@ -56,37 +57,47 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
         private HuffmanTable[] acHuffmanTables;
 
         /// <summary>
-        /// The reset interval determined by RST markers
+        /// The reset interval determined by RST markers.
         /// </summary>
         private ushort resetInterval;
 
         /// <summary>
-        /// Whether the image has an EXIF marker
+        /// Whether the image has an EXIF marker.
         /// </summary>
         private bool isExif;
 
         /// <summary>
-        /// Contains exif data
+        /// Contains exif data.
         /// </summary>
         private byte[] exifData;
 
         /// <summary>
-        /// Whether the image has an ICC marker
+        /// Whether the image has an ICC marker.
         /// </summary>
         private bool isIcc;
 
         /// <summary>
-        /// Contains ICC data
+        /// Contains ICC data.
         /// </summary>
         private byte[] iccData;
 
         /// <summary>
-        /// Contains information about the JFIF marker
+        /// Whether the image has a IPTC data.
+        /// </summary>
+        private bool isIptc;
+
+        /// <summary>
+        /// Contains IPTC data.
+        /// </summary>
+        private byte[] iptcData;
+
+        /// <summary>
+        /// Contains information about the JFIF marker.
         /// </summary>
         private JFifMarker jFif;
 
         /// <summary>
-        /// Contains information about the Adobe marker
+        /// Contains information about the Adobe marker.
         /// </summary>
         private AdobeMarker adobe;
 
@@ -213,6 +224,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
             this.ParseStream(stream);
             this.InitExifProfile();
             this.InitIccProfile();
+            this.InitIptcProfile();
             this.InitDerivedMetadataProperties();
             return this.PostProcessIntoImage<TPixel>();
         }
@@ -226,6 +238,7 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
             this.ParseStream(stream, true);
             this.InitExifProfile();
             this.InitIccProfile();
+            this.InitIptcProfile();
             this.InitDerivedMetadataProperties();
 
             return new ImageInfo(new PixelTypeInfo(this.BitsPerPixel), this.ImageWidth, this.ImageHeight, this.Metadata);
@@ -344,10 +357,13 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
                         case JpegConstants.Markers.APP10:
                         case JpegConstants.Markers.APP11:
                         case JpegConstants.Markers.APP12:
-                        case JpegConstants.Markers.APP13:
                             this.InputStream.Skip(remaining);
                             break;
 
+                        case JpegConstants.Markers.APP13:
+                            this.ProcessApp13Marker(remaining);
+                            break;
+
                         case JpegConstants.Markers.APP14:
                             this.ProcessApp14Marker(remaining);
                             break;
@@ -437,6 +453,18 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
             }
         }
 
+        /// <summary>
+        /// Initializes the IPTC profile.
+        /// </summary>
+        private void InitIptcProfile()
+        {
+            if (this.isIptc)
+            {
+                var profile = new IptcProfile(this.iptcData);
+                this.Metadata.IptcProfile = profile;
+            }
+        }
+
         /// <summary>
         /// Assigns derived metadata properties to <see cref="Metadata"/>, eg. horizontal and vertical resolution if it has a JFIF header.
         /// </summary>
@@ -582,6 +610,80 @@ namespace SixLabors.ImageSharp.Formats.Jpeg
             }
         }
 
+        /// <summary>
+        /// Processes a App13 marker, which contains IPTC data stored with Adobe Photoshop.
+        /// The content of an APP13 segment is formed by an identifier string followed by a sequence of resource data blocks.
+        /// </summary>
+        /// <param name="remaining">The remaining bytes in the segment block.</param>
+        private void ProcessApp13Marker(int remaining)
+        {
+            if (remaining < ProfileResolver.AdobePhotoshopApp13Marker.Length || this.IgnoreMetadata)
+            {
+                this.InputStream.Skip(remaining);
+                return;
+            }
+
+            var identifier = new byte[ProfileResolver.AdobePhotoshopApp13Marker.Length];
+            this.InputStream.Read(identifier, 0, identifier.Length);
+            remaining -= identifier.Length;
+            if (ProfileResolver.IsProfile(identifier, ProfileResolver.AdobePhotoshopApp13Marker))
+            {
+                var resourceBlockData = new byte[remaining];
+                this.InputStream.Read(resourceBlockData, 0, remaining);
+                Span<byte> blockDataSpan = resourceBlockData.AsSpan();
+
+                while (blockDataSpan.Length > 10)
+                 {
+                    if (!ProfileResolver.IsProfile(blockDataSpan.Slice(0, 4), ProfileResolver.AdobeImageResourceBlockMarker))
+                    {
+                        return;
+                    }
+
+                    blockDataSpan = blockDataSpan.Slice(4);
+                    Span<byte> imageResourceBlockId = blockDataSpan.Slice(0, 2);
+                    if (ProfileResolver.IsProfile(imageResourceBlockId, ProfileResolver.AdobeIptcMarker))
+                    {
+                        var resourceBlockNameLength = ReadImageResourceNameLength(blockDataSpan);
+                        var resourceDataSize = ReadResourceDataLength(blockDataSpan, resourceBlockNameLength);
+                        this.isIptc = true;
+                        this.iptcData = blockDataSpan.Slice(2 + resourceBlockNameLength + 4, resourceDataSize).ToArray();
+                        break;
+                    }
+                    else
+                    {
+                        var resourceBlockNameLength = ReadImageResourceNameLength(blockDataSpan);
+                        var resourceDataSize = ReadResourceDataLength(blockDataSpan, resourceBlockNameLength);
+                        blockDataSpan = blockDataSpan.Slice(2 + resourceBlockNameLength + 4 + resourceDataSize);
+                    }
+                }
+            }
+        }
+
+        /// <summary>
+        /// Reads the adobe image resource block name: a Pascal string (padded to make size even).
+        /// </summary>
+        /// <param name="blockDataSpan">The span holding the block resource data.</param>
+        /// <returns>The length of the name.</returns>
+        [MethodImpl(InliningOptions.ShortMethod)]
+        private static int ReadImageResourceNameLength(Span<byte> blockDataSpan)
+        {
+            byte nameLength = blockDataSpan[2];
+            var nameDataSize = nameLength == 0 ? 2 : nameLength;
+            return nameDataSize;
+        }
+
+        /// <summary>
+        /// Reads the length of a adobe image resource data block.
+        /// </summary>
+        /// <param name="blockDataSpan">The span holding the block resource data.</param>
+        /// <param name="resourceBlockNameLength">The length of the block name.</param>
+        /// <returns>The block length.</returns>
+        [MethodImpl(InliningOptions.ShortMethod)]
+        private static int ReadResourceDataLength(Span<byte> blockDataSpan, int resourceBlockNameLength)
+        {
+            return BinaryPrimitives.ReadInt32BigEndian(blockDataSpan.Slice(2 + resourceBlockNameLength, 4));
+        }
+
         /// <summary>
         /// Processes the application header containing the Adobe identifier
         /// which stores image encoding information for DCT filters.

src/ImageSharp/Metadata/ImageMetadata.cs

@@ -5,6 +5,7 @@ using System.Collections.Generic;
 using SixLabors.ImageSharp.Formats;
 using SixLabors.ImageSharp.Metadata.Profiles.Exif;
 using SixLabors.ImageSharp.Metadata.Profiles.Icc;
+using SixLabors.ImageSharp.Metadata.Profiles.Iptc;
 
 namespace SixLabors.ImageSharp.Metadata
 {
@@ -122,6 +123,11 @@ namespace SixLabors.ImageSharp.Metadata
         /// </summary>
         public IccProfile IccProfile { get; set; }
 
+        /// <summary>
+        /// Gets or sets the iptc profile.
+        /// </summary>
+        public IptcProfile IptcProfile { get; set; }
+
         /// <summary>
         /// Gets the metadata value associated with the specified key.
         /// </summary>

src/ImageSharp/Metadata/Profiles/IPTC/IptcProfile.cs

@@ -0,0 +1,204 @@
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+using System.Buffers.Binary;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Text;
+
+namespace SixLabors.ImageSharp.Metadata.Profiles.Iptc
+{
+    /// <summary>
+    /// Class that can be used to access an Iptc profile.
+    /// </summary>
+    /// <remarks>This source code is from the Magick.Net project:
+    /// https://github.com/dlemstra/Magick.NET/tree/master/src/Magick.NET/Shared/Profiles/Iptc/IptcProfile.cs
+    /// </remarks>
+    public sealed class IptcProfile
+    {
+        private Collection<IptcValue> values;
+
+        private byte[] data;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="IptcProfile"/> class.
+        /// </summary>
+        public IptcProfile()
+        {
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="IptcProfile"/> class.
+        /// </summary>
+        /// <param name="data">The byte array to read the iptc profile from.</param>
+        public IptcProfile(byte[] data)
+        {
+            this.data = data;
+        }
+
+        /// <summary>
+        /// Gets the values of this iptc profile.
+        /// </summary>
+        public IEnumerable<IptcValue> Values
+        {
+            get
+            {
+                this.Initialize();
+                return this.values;
+            }
+        }
+
+        /// <summary>
+        /// Returns the value with the specified tag.
+        /// </summary>
+        /// <param name="tag">The tag of the iptc value.</param>
+        /// <returns>The value with the specified tag.</returns>
+        public IptcValue GetValue(IptcTag tag)
+        {
+            foreach (IptcValue iptcValue in this.Values)
+            {
+                if (iptcValue.Tag == tag)
+                {
+                    return iptcValue;
+                }
+            }
+
+            return null;
+        }
+
+        /// <summary>
+        /// Removes the value with the specified tag.
+        /// </summary>
+        /// <param name="tag">The tag of the iptc value.</param>
+        /// <returns>True when the value was fount and removed.</returns>
+        public bool RemoveValue(IptcTag tag)
+        {
+            this.Initialize();
+
+            for (int i = 0; i < this.values.Count; i++)
+            {
+                if (this.values[i].Tag == tag)
+                {
+                    this.values.RemoveAt(i);
+                    return true;
+                }
+            }
+
+            return false;
+        }
+
+        /// <summary>
+        /// Changes the encoding for all the values.
+        /// </summary>
+        /// <param name="encoding">The encoding to use when storing the bytes.</param>
+        public void SetEncoding(Encoding encoding)
+        {
+            Guard.NotNull(encoding, nameof(encoding));
+
+            foreach (IptcValue value in this.Values)
+            {
+                value.Encoding = encoding;
+            }
+        }
+
+        /// <summary>
+        /// Sets the value of the specified tag.
+        /// </summary>
+        /// <param name="tag">The tag of the iptc value.</param>
+        /// <param name="encoding">The encoding to use when storing the bytes.</param>
+        /// <param name="value">The value.</param>
+        public void SetValue(IptcTag tag, Encoding encoding, string value)
+        {
+            Guard.NotNull(encoding, nameof(encoding));
+
+            foreach (IptcValue iptcValue in this.Values)
+            {
+                if (iptcValue.Tag == tag)
+                {
+                    iptcValue.Encoding = encoding;
+                    iptcValue.Value = value;
+                    return;
+                }
+            }
+
+            this.values.Add(new IptcValue(tag, encoding, value));
+        }
+
+        /// <summary>
+        /// Sets the value of the specified tag.
+        /// </summary>
+        /// <param name="tag">The tag of the iptc value.</param>
+        /// <param name="value">The value.</param>
+        public void SetValue(IptcTag tag, string value) => this.SetValue(tag, Encoding.UTF8, value);
+
+        /// <summary>
+        /// Updates the data of the profile.
+        /// </summary>
+        public void UpdateData()
+        {
+            var length = 0;
+            foreach (IptcValue value in this.Values)
+            {
+                length += value.Length + 5;
+            }
+
+            this.data = new byte[length];
+
+            int i = 0;
+            foreach (IptcValue value in this.Values)
+            {
+                this.data[i++] = 28;
+                this.data[i++] = 2;
+                this.data[i++] = (byte)value.Tag;
+                this.data[i++] = (byte)(value.Length >> 8);
+                this.data[i++] = (byte)value.Length;
+                if (value.Length > 0)
+                {
+                    Buffer.BlockCopy(value.ToByteArray(), 0, this.data, i, value.Length);
+                    i += value.Length;
+                }
+            }
+        }
+
+        private void Initialize()
+        {
+            if (this.values != null)
+            {
+                return;
+            }
+
+            this.values = new Collection<IptcValue>();
+
+            if (this.data == null || this.data[0] != 0x1c)
+            {
+                return;
+            }
+
+            int i = 0;
+            while (i + 4 < this.data.Length)
+            {
+                if (this.data[i++] != 28)
+                {
+                    continue;
+                }
+
+                i++;
+
+                var tag = (IptcTag)this.data[i++];
+
+                int count = BinaryPrimitives.ReadInt16BigEndian(this.data.AsSpan(i, 2));
+                i += 2;
+
+                var iptcData = new byte[count];
+                if ((count > 0) && (i + count <= this.data.Length))
+                {
+                    Buffer.BlockCopy(this.data, i, iptcData, 0, count);
+                    this.values.Add(new IptcValue(tag, iptcData));
+                }
+
+                i += count;
+            }
+        }
+    }
+}

src/ImageSharp/Metadata/Profiles/IPTC/IptcTag.cs

@@ -0,0 +1,351 @@
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
+
+namespace SixLabors.ImageSharp.Metadata.Profiles.Iptc
+{
+    /// <summary>
+    /// All iptc tags.
+    /// </summary>
+    public enum IptcTag
+    {
+        /// <summary>
+        /// Unknown
+        /// </summary>
+        Unknown = -1,
+
+        /// <summary>
+        /// Record version
+        /// </summary>
+        RecordVersion = 0,
+
+        /// <summary>
+        /// Object type
+        /// </summary>
+        ObjectType = 3,
+
+        /// <summary>
+        /// Object attribute
+        /// </summary>
+        ObjectAttribute = 4,
+
+        /// <summary>
+        /// Title
+        /// </summary>
+        Title = 5,
+
+        /// <summary>
+        /// Edit status
+        /// </summary>
+        EditStatus = 7,
+
+        /// <summary>
+        /// Editorial update
+        /// </summary>
+        EditorialUpdate = 8,
+
+        /// <summary>
+        /// Priority
+        /// </summary>
+        Priority = 10,
+
+        /// <summary>
+        /// Category
+        /// </summary>
+        Category = 15,
+
+        /// <summary>
+        /// Supplemental categories
+        /// </summary>
+        SupplementalCategories = 20,
+
+        /// <summary>
+        /// Fixture identifier
+        /// </summary>
+        FixtureIdentifier = 22,
+
+        /// <summary>
+        /// Keyword
+        /// </summary>
+        Keyword = 25,
+
+        /// <summary>
+        /// Location code
+        /// </summary>
+        LocationCode = 26,
+
+        /// <summary>
+        /// Location name
+        /// </summary>
+        LocationName = 27,
+
+        /// <summary>
+        /// Release date
+        /// </summary>
+        ReleaseDate = 30,
+
+        /// <summary>
+        /// Release time
+        /// </summary>
+        ReleaseTime = 35,
+
+        /// <summary>
+        /// Expiration date
+        /// </summary>
+        ExpirationDate = 37,
+
+        /// <summary>
+        /// Expiration time
+        /// </summary>
+        ExpirationTime = 38,
+
+        /// <summary>
+        /// Special instructions
+        /// </summary>
+        SpecialInstructions = 40,
+
+        /// <summary>
+        /// Action advised
+        /// </summary>
+        ActionAdvised = 42,
+
+        /// <summary>
+        /// Reference service
+        /// </summary>
+        ReferenceService = 45,
+
+        /// <summary>
+        /// Reference date
+        /// </summary>
+        ReferenceDate = 47,
+
+        /// <summary>
+        /// ReferenceNumber
+        /// </summary>
+        ReferenceNumber = 50,
+
+        /// <summary>
+        /// Created date
+        /// </summary>
+        CreatedDate = 55,
+
+        /// <summary>
+        /// Created time
+        /// </summary>
+        CreatedTime = 60,
+
+        /// <summary>
+        /// Digital creation date
+        /// </summary>
+        DigitalCreationDate = 62,
+
+        /// <summary>
+        /// Digital creation time
+        /// </summary>
+        DigitalCreationTime = 63,
+
+        /// <summary>
+        /// Originating program
+        /// </summary>
+        OriginatingProgram = 65,
+
+        /// <summary>
+        /// Program version
+        /// </summary>
+        ProgramVersion = 70,
+
+        /// <summary>
+        /// Object cycle
+        /// </summary>
+        ObjectCycle = 75,
+
+        /// <summary>
+        /// Byline
+        /// </summary>
+        Byline = 80,
+
+        /// <summary>
+        /// Byline title
+        /// </summary>
+        BylineTitle = 85,
+
+        /// <summary>
+        /// City
+        /// </summary>
+        City = 90,
+
+        /// <summary>
+        /// Sub location
+        /// </summary>
+        SubLocation = 92,
+
+        /// <summary>
+        /// Province/State
+        /// </summary>
+        ProvinceState = 95,
+
+        /// <summary>
+        /// Country code
+        /// </summary>
+        CountryCode = 100,
+
+        /// <summary>
+        /// Country
+        /// </summary>
+        Country = 101,
+
+        /// <summary>
+        /// Original transmission reference
+        /// </summary>
+        OriginalTransmissionReference = 103,
+
+        /// <summary>
+        /// Headline
+        /// </summary>
+        Headline = 105,
+
+        /// <summary>
+        /// Credit
+        /// </summary>
+        Credit = 110,
+
+        /// <summary>
+        /// Source
+        /// </summary>
+        Source = 115,
+
+        /// <summary>
+        /// Copyright notice
+        /// </summary>
+        CopyrightNotice = 116,
+
+        /// <summary>
+        /// Contact
+        /// </summary>
+        Contact = 118,
+
+        /// <summary>
+        /// Caption
+        /// </summary>
+        Caption = 120,
+
+        /// <summary>
+        /// Local caption
+        /// </summary>
+        LocalCaption = 121,
+
+        /// <summary>
+        /// Caption writer
+        /// </summary>
+        CaptionWriter = 122,
+
+        /// <summary>
+        /// Image type
+        /// </summary>
+        ImageType = 130,
+
+        /// <summary>
+        /// Image orientation
+        /// </summary>
+        ImageOrientation = 131,
+
+        /// <summary>
+        /// Custom field 1
+        /// </summary>
+        CustomField1 = 200,
+
+        /// <summary>
+        /// Custom field 2
+        /// </summary>
+        CustomField2 = 201,
+
+        /// <summary>
+        /// Custom field 3
+        /// </summary>
+        CustomField3 = 202,
+
+        /// <summary>
+        /// Custom field 4
+        /// </summary>
+        CustomField4 = 203,
+
+        /// <summary>
+        /// Custom field 5
+        /// </summary>
+        CustomField5 = 204,
+
+        /// <summary>
+        /// Custom field 6
+        /// </summary>
+        CustomField6 = 205,
+
+        /// <summary>
+        /// Custom field 7
+        /// </summary>
+        CustomField7 = 206,
+
+        /// <summary>
+        /// Custom field 8
+        /// </summary>
+        CustomField8 = 207,
+
+        /// <summary>
+        /// Custom field 9
+        /// </summary>
+        CustomField9 = 208,
+
+        /// <summary>
+        /// Custom field 10
+        /// </summary>
+        CustomField10 = 209,
+
+        /// <summary>
+        /// Custom field 11
+        /// </summary>
+        CustomField11 = 210,
+
+        /// <summary>
+        /// Custom field 12
+        /// </summary>
+        CustomField12 = 211,
+
+        /// <summary>
+        /// Custom field 13
+        /// </summary>
+        CustomField13 = 212,
+
+        /// <summary>
+        /// Custom field 14
+        /// </summary>
+        CustomField14 = 213,
+
+        /// <summary>
+        /// Custom field 15
+        /// </summary>
+        CustomField15 = 214,
+
+        /// <summary>
+        /// Custom field 16
+        /// </summary>
+        CustomField16 = 215,
+
+        /// <summary>
+        /// Custom field 17
+        /// </summary>
+        CustomField17 = 216,
+
+        /// <summary>
+        /// Custom field 18
+        /// </summary>
+        CustomField18 = 217,
+
+        /// <summary>
+        /// Custom field 19
+        /// </summary>
+        CustomField19 = 218,
+
+        /// <summary>
+        /// Custom field 20
+        /// </summary>
+        CustomField20 = 219,
+    }
+}

src/ImageSharp/Metadata/Profiles/IPTC/IptcValue.cs

@@ -0,0 +1,167 @@
+// Copyright (c) Six Labors and contributors.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+using System.Text;
+
+namespace SixLabors.ImageSharp.Metadata.Profiles.Iptc
+{
+    /// <summary>
+    /// A value of the iptc profile.
+    /// </summary>
+    public sealed class IptcValue
+    {
+        private byte[] data;
+        private Encoding encoding;
+
+        internal IptcValue(IptcTag tag, byte[] value)
+        {
+            Guard.NotNull(value, nameof(value));
+
+            this.Tag = tag;
+            this.data = value;
+            this.encoding = Encoding.UTF8;
+        }
+
+        internal IptcValue(IptcTag tag, Encoding encoding, string value)
+        {
+            this.Tag = tag;
+            this.encoding = encoding;
+            this.Value = value;
+        }
+
+        /// <summary>
+        /// Gets or sets the encoding to use for the Value.
+        /// </summary>
+        public Encoding Encoding
+        {
+            get => this.encoding;
+            set
+            {
+                if (value != null)
+                {
+                    this.encoding = value;
+                }
+            }
+        }
+
+        /// <summary>
+        /// Gets the tag of the iptc value.
+        /// </summary>
+        public IptcTag Tag { get; }
+
+        /// <summary>
+        /// Gets or sets the value.
+        /// </summary>
+        public string Value
+        {
+            get => this.encoding.GetString(this.data);
+            set
+            {
+                if (string.IsNullOrEmpty(value))
+                {
+                    this.data = new byte[0];
+                }
+                else
+                {
+                    this.data = this.encoding.GetBytes(value);
+                }
+            }
+        }
+
+        /// <summary>
+        /// Gets the length of the value.
+        /// </summary>
+        public int Length => this.data.Length;
+
+        /// <summary>
+        /// Determines whether the specified object is equal to the current <see cref="IptcValue"/>.
+        /// </summary>
+        /// <param name="obj">The object to compare this <see cref="IptcValue"/> with.</param>
+        /// <returns>True when the specified object is equal to the current <see cref="IptcValue"/>.</returns>
+        public override bool Equals(object obj)
+        {
+            if (ReferenceEquals(this, obj))
+            {
+                return true;
+            }
+
+            return this.Equals(obj as IptcValue);
+        }
+
+        /// <summary>
+        /// Determines whether the specified iptc value is equal to the current <see cref="IptcValue"/>.
+        /// </summary>
+        /// <param name="other">The iptc value to compare this <see cref="IptcValue"/> with.</param>
+        /// <returns>True when the specified iptc value is equal to the current <see cref="IptcValue"/>.</returns>
+        public bool Equals(IptcValue other)
+        {
+            if (other is null)
+            {
+                return false;
+            }
+
+            if (ReferenceEquals(this, other))
+            {
+                return true;
+            }
+
+            if (this.Tag != other.Tag)
+            {
+                return false;
+            }
+
+            byte[] data = other.ToByteArray();
+
+            if (this.data.Length != data.Length)
+            {
+                return false;
+            }
+
+            for (int i = 0; i < this.data.Length; i++)
+            {
+                if (this.data[i] != data[i])
+                {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+
+        /// <summary>
+        /// Serves as a hash of this type.
+        /// </summary>
+        /// <returns>A hash code for the current instance.</returns>
+        public override int GetHashCode() => HashCode.Combine(this.data, this.Tag);
+
+        /// <summary>
+        /// Converts this instance to a byte array.
+        /// </summary>
+        /// <returns>A <see cref="byte"/> array.</returns>
+        public byte[] ToByteArray()
+        {
+            var result = new byte[this.data.Length];
+            this.data.CopyTo(result, 0);
+            return result;
+        }
+
+        /// <summary>
+        /// Returns a string that represents the current value.
+        /// </summary>
+        /// <returns>A string that represents the current value.</returns>
+        public override string ToString() => this.Value;
+
+        /// <summary>
+        /// Returns a string that represents the current value with the specified encoding.
+        /// </summary>
+        /// <param name="enc">The encoding to use.</param>
+        /// <returns>A string that represents the current value with the specified encoding.</returns>
+        public string ToString(Encoding enc)
+        {
+            Guard.NotNull(enc, nameof(enc));
+
+            return enc.GetString(this.data);
+        }
+    }
+}

src/ImageSharp/Metadata/Profiles/IPTC/README.md

@@ -0,0 +1,9 @@
+IPTC source code is from [Magick.NET](https://github.com/dlemstra/Magick.NET)
+
+Information about IPTC can be found here in the folowing sources:
+
+- [metacpan.org, APP13-segment](https://metacpan.org/pod/Image::MetaData::JPEG::Structures#Structure-of-a-Photoshop-style-APP13-segment)
+
+- [iptc.org](https://www.iptc.org/std/photometadata/documentation/userguide/)
+
+- [Adobe File Formats Specification](http://oldschoolprg.x10.mx/downloads/ps6ffspecsv2.pdf)