Erste Version

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Shared/PacketReader.cs

@@ -0,0 +1,36 @@
+using System.IO;
+
+namespace BSO.Net
+{
+    /// <summary>
+    /// BinaryReader fuer Daten aus dem Netz (wie bei MSCO): jede Laengenangabe wird gegen die tatsaechlich vorhandenen
+    /// Bytes geprueft - eine gefaelschte Laenge darf nicht zu einer riesigen Speicheranforderung fuehren.
+    /// </summary>
+    public sealed class PacketReader : BinaryReader
+    {
+        public PacketReader(byte[] data) : base(new MemoryStream(data ?? new byte[0], false)) { }
+
+        long Remaining => BaseStream.Length - BaseStream.Position;
+
+        public override byte[] ReadBytes(int count)
+        {
+            if (count < 0 || count > Remaining) throw new EndOfStreamException("Invalid length " + count);
+            return base.ReadBytes(count);
+        }
+
+        public override char[] ReadChars(int count)
+        {
+            if (count < 0 || count > Remaining) throw new EndOfStreamException("Invalid length " + count);
+            return base.ReadChars(count);
+        }
+
+        public override string ReadString()
+        {
+            long start = BaseStream.Position;
+            int length = Read7BitEncodedInt();
+            if (length < 0 || length > Remaining) throw new EndOfStreamException("Invalid string length " + length);
+            BaseStream.Position = start;
+            return base.ReadString();
+        }
+    }
+}