Fixes issue #2216 InstallShield .Z package decompression

AUTHORS

@@ -12,6 +12,7 @@ The OpenRA developers are:
 Also thanks to:
 	* Akseli Virtanen       (RAGEQUIT)
 	* Andrew Riedi
+	* Andreas Beck		(baxtor)
 	* Barnaby Smith		(mvi)
 	* Bellator
 	* Bugra Cuhadaroglu (BugraC)

OpenRA.FileFormats/Filesystem/InstallShieldPackage.cs

@@ -49,11 +49,20 @@ namespace OpenRA.FileFormats
 			// Parse the directory list
 			s.Seek(TOCAddress, SeekOrigin.Begin);
 			BinaryReader TOCreader = new BinaryReader(s);
+
+			var fileCountInDirs = new List<uint>();
+			// Parse directories
 			for (var i = 0; i < DirCount; i++)
-				ParseDirectory(TOCreader);
+				fileCountInDirs.Add(ParseDirectory(TOCreader));
+
+			// Parse files
+			foreach (var fileCount in fileCountInDirs)
+				for (var i = 0; i < fileCount; i++)
+					ParseFile(reader);
+
 		}
 
-		void ParseDirectory(BinaryReader reader)
+		uint ParseDirectory(BinaryReader reader)
 		{
 			// Parse directory header
 			var FileCount = reader.ReadUInt16();
@@ -63,10 +72,7 @@ namespace OpenRA.FileFormats
 
 			// Skip to the end of the chunk
 			reader.ReadBytes(ChunkSize - NameLength - 6);
-
+			return FileCount;
-			// Parse files
-			for (var i = 0; i < FileCount; i++)
-				ParseFile(reader);
 		}
 
 		uint AccumulatedData = 0;
@@ -81,7 +87,8 @@ namespace OpenRA.FileFormats
 			var FileName = new String(reader.ReadChars(NameLength));
 
 			var hash = PackageEntry.HashFilename(FileName, PackageHashType.Classic);
-			index.Add(hash, new PackageEntry(hash, AccumulatedData, CompressedSize));
+			if(!index.ContainsKey(hash))
+				index.Add(hash, new PackageEntry(hash,AccumulatedData, CompressedSize));
 			filenames.Add(FileName);
 			AccumulatedData += CompressedSize;