Add enum for RecordNumber

Author: brianpopow

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

@@ -6,6 +6,7 @@
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Text;
+using SixLabors.ImageSharp.Metadata.Profiles.IPTC;
 
 namespace SixLabors.ImageSharp.Metadata.Profiles.Iptc
 {
@@ -265,7 +266,7 @@ public void UpdateData()
             {
                 // Envelope Record.
                 this.Data[i++] = IptcTagMarkerByte;
-                this.Data[i++] = 1; // Envelope
+                this.Data[i++] = (byte)IptcRecordNumber.Envelope;
                 this.Data[i++] = IptcEnvelopeCodedCharacterSet;
                 this.Data[i++] = (byte)(CodedCharacterSetUtf8Value.Length >> 8);
                 this.Data[i++] = (byte)CodedCharacterSetUtf8Value.Length;
@@ -293,7 +294,7 @@ public void UpdateData()
                 // |           |                | octet 4(most significant bit) always will be 0.                                 |
                 // +-----------+----------------+---------------------------------------------------------------------------------+
                 this.Data[i++] = IptcTagMarkerByte;
-                this.Data[i++] = 2; // Application
+                this.Data[i++] = (byte)IptcRecordNumber.Application;
                 this.Data[i++] = (byte)value.Tag;
                 this.Data[i++] = (byte)(value.Length >> 8);
                 this.Data[i++] = (byte)value.Length;
@@ -327,7 +328,7 @@ private void Initialize()
                 bool isValidRecordNumber = recordNumber is >= 1 and <= 9;
                 var tag = (IptcTag)this.Data[offset++];
                 bool isValidEntry = isValidTagMarker && isValidRecordNumber;
-                bool isApplicationRecord = recordNumber == 0x02;
+                bool isApplicationRecord = recordNumber == (byte)IptcRecordNumber.Application;
 
                 uint byteCount = BinaryPrimitives.ReadUInt16BigEndian(this.Data.AsSpan(offset, 2));
                 offset += 2;

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

@@ -0,0 +1,21 @@
+// Copyright (c) Six Labors.
+// Licensed under the Six Labors Split License.
+
+namespace SixLabors.ImageSharp.Metadata.Profiles.IPTC
+{
+    /// <summary>
+    /// Enum for the different record types of a IPTC value.
+    /// </summary>
+    internal enum IptcRecordNumber : byte
+    {
+        /// <summary>
+        /// A Envelope Record.
+        /// </summary>
+        Envelope = 0x01,
+
+        /// <summary>
+        /// A Application Record.
+        /// </summary>
+        Application = 0x02
+    }
+}

tests/ImageSharp.Tests/Formats/Jpg/JpegEncoderTests.Metadata.cs

@@ -38,8 +38,10 @@ public void Encode_PreservesIptcProfile()
         {
             // arrange
             using var input = new Image<Rgba32>(1, 1);
-            input.Metadata.IptcProfile = new IptcProfile();
-            input.Metadata.IptcProfile.SetValue(IptcTag.Byline, "unit_test");
+            var expectedProfile = new IptcProfile();
+            expectedProfile.SetValue(IptcTag.Country, "ESPAÑA");
+            expectedProfile.SetValue(IptcTag.City, "unit-test-city");
+            input.Metadata.IptcProfile = expectedProfile;
 
             // act
             using var memStream = new MemoryStream();
@@ -50,7 +52,7 @@ public void Encode_PreservesIptcProfile()
             using var output = Image.Load<Rgba32>(memStream);
             IptcProfile actual = output.Metadata.IptcProfile;
             Assert.NotNull(actual);
-            IEnumerable<IptcValue> values = input.Metadata.IptcProfile.Values;
+            IEnumerable<IptcValue> values = expectedProfile.Values;
             Assert.Equal(values, actual.Values);
         }