Implement processor for track tree instance binary

src/010 Templates/trees.bt

@@ -56,7 +56,7 @@ struct InstanceRef {
     if (isDirt3 || isGridAutosport) {
         int32 distant;
         int32 maxInstances;
-        local int32 numInstances = 0;
+        local int32 numInstances <hidden=true> = 0;
     }
     else {
         int32 maxInstances;

src/EgoEngineLibrary/IO/EndianBinaryReaderExtensions.cs

@@ -0,0 +1,23 @@
+using System.Runtime.InteropServices;
+
+namespace EgoEngineLibrary.IO;
+
+public static class EndianBinaryReaderExtensions
+{
+    extension(EndianBinaryReader reader)
+    {
+        public string ReadNullTerminatedString()
+        {
+            List<byte> bytes = [];
+            byte b = reader.ReadByte();
+
+            while (b != 0x00)
+            {
+                bytes.Add(b);
+                b = reader.ReadByte();
+            }
+
+            return reader.Encoding.GetString(CollectionsMarshal.AsSpan(bytes));
+        }
+    }
+}

src/EgoEngineLibrary/Text/EncodingExtensions.cs

@@ -0,0 +1,57 @@
+using System.Text;
+using EgoEngineLibrary.IO;
+
+namespace EgoEngineLibrary.Text;
+
+public static class EncodingExtensions
+{
+    extension(Encoding encoding)
+    {
+        public StringByteBuffer BuildStringByteBuffer(IEnumerable<string> strings)
+        {
+            return encoding.BuildStringByteBuffer([.. strings]);
+        }
+
+        public StringByteBuffer BuildStringByteBuffer(IReadOnlyCollection<string> strings)
+        {
+            int totalCharacters = 0;
+            int largestStringLength = 0;
+            foreach (var s in strings)
+            {
+                totalCharacters += s.Length;
+                largestStringLength = Math.Max(largestStringLength, s.Length);
+            }
+
+            int bufferSize = encoding.GetMaxByteCount(totalCharacters);
+            int singleBufferSize = encoding.GetMaxByteCount(largestStringLength);
+            int bufferIndex = 0;
+            byte[] buffer = new byte[bufferSize + strings.Count];
+            byte[] singleBuffer = new byte[singleBufferSize + 1];
+            var stringOffsetMap = new Dictionary<string, int>(strings.Count);
+            foreach (var s in strings)
+            {
+                if (stringOffsetMap.ContainsKey(s))
+                {
+                    continue;
+                }
+
+                var bytesWritten = encoding.GetBytes(s, singleBuffer);
+                singleBuffer[bytesWritten] = 0;
+                var filenameSpan = singleBuffer.AsSpan(0, bytesWritten + 1);
+                var index = buffer.IndexOf(filenameSpan);
+                if (index >= 0)
+                {
+                    stringOffsetMap.Add(s, index);
+                }
+                else
+                {
+                    stringOffsetMap.Add(s, bufferIndex);
+                    filenameSpan.CopyTo(buffer.AsSpan(bufferIndex));
+                    bufferIndex += filenameSpan.Length;
+                }
+            }
+
+            return new StringByteBuffer(buffer, bufferIndex, stringOffsetMap); 
+        }
+    }
+}

src/EgoEngineLibrary/Text/StringByteBuffer.cs

@@ -0,0 +1,3 @@
+namespace EgoEngineLibrary.Text;
+
+public record StringByteBuffer(byte[] Buffer, int BufferSize, Dictionary<string, int> StringOffsetMap);