add basic italics payload

Dalamud/Game/Chat/SeStringHandling/Payload.cs

@@ -8,12 +8,12 @@ using Serilog;
 
 // TODOs:
 //   - refactor integer handling now that we have multiple packed types
-//   - common construction/property design for subclasses
 //   - wrapper class(es) for handling of composite links in chat (item, map etc) and formatting operations
-//   - add italics payload
 // Maybes:
 //   - convert parsing to custom structs for each payload?  would make some code prettier and easier to work with
 //     but also wouldn't work out as well for things that are dynamically-sized
+//   - [SeString] some way to add surrounding formatting information as flags/data to text (or other?) payloads?
+//     eg, if a text payload is surrounded by italics payloads, strip them out and mark the text payload as italicized
 
 namespace Dalamud.Game.Chat.SeStringHandling
 {
@@ -98,6 +98,10 @@ namespace Dalamud.Game.Chat.SeStringHandling
 
             switch (chunkType)
             {
+                case SeStringChunkType.EmphasisItalic:
+                    payload = new EmphasisItalicPayload();
+                    break;
+
                 case SeStringChunkType.Interactable:
                     {
                         var subType = (EmbeddedInfoType)reader.ReadByte();
@@ -176,6 +180,7 @@ namespace Dalamud.Game.Chat.SeStringHandling
 
         protected enum SeStringChunkType
         {
+            EmphasisItalic = 0x1A,
             Interactable = 0x27,
             AutoTranslateKey = 0x2E,
             UIForeground = 0x48,

Dalamud/Game/Chat/SeStringHandling/PayloadType.cs

@@ -39,6 +39,10 @@ namespace Dalamud.Game.Chat.SeStringHandling
         /// </summary>
         AutoTranslateText,
         /// <summary>
+        /// An SeString payload representing italic emphasis formatting on text.
+        /// </summary>
+        EmphasisItalic,
+        /// <summary>
         /// An SeString payload representing any data we don't handle.
         /// </summary>
         Unknown

Dalamud/Game/Chat/SeStringHandling/Payloads/EmphasisItalicPayload.cs

@@ -0,0 +1,47 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+
+namespace Dalamud.Game.Chat.SeStringHandling.Payloads
+{
+    class EmphasisItalicPayload : Payload
+    {
+        public override PayloadType Type => PayloadType.EmphasisItalic;
+
+        public bool IsEnabled { get; private set; }
+
+        internal EmphasisItalicPayload() { }
+
+        public EmphasisItalicPayload(bool enabled)
+        {
+            IsEnabled = enabled;
+        }
+
+        public override string ToString()
+        {
+            return $"{Type} - Enabled: {IsEnabled}";
+        }
+
+        protected override byte[] EncodeImpl()
+        {
+            // realistically this will always be a single byte of value 1 or 2
+            // but we'll treat it normally anyway
+            var enabledBytes = MakeInteger(IsEnabled ? (uint)1 : 0);
+
+            var chunkLen = enabledBytes.Length + 1;
+            var bytes = new List<byte>()
+            {
+                START_BYTE, (byte)SeStringChunkType.EmphasisItalic, (byte)chunkLen
+            };
+            bytes.AddRange(enabledBytes);
+            bytes.Add(END_BYTE);
+
+            return bytes.ToArray();
+        }
+
+        protected override void DecodeImpl(BinaryReader reader, long endOfStream)
+        {
+            IsEnabled = (GetInteger(reader) == 1);
+        }
+    }
+}