Add support for C&C Generals .big archive files

OpenRA.Game/FileSystem/BigFile.cs

@@ -0,0 +1,111 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2014 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation. For more information,
+ * see COPYING.
+ */
+#endregion
+
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+
+namespace OpenRA.FileSystem
+{
+	public class BigFile : IFolder
+	{
+		public string Name { get; private set; }
+		public int Priority { get; private set; }
+		readonly Dictionary<string, Entry> entries = new Dictionary<string, Entry>();
+
+		public BigFile(string filename, int priority)
+		{
+			Name = filename;
+			Priority = priority;
+
+			var s = GlobalFileSystem.Open(filename);
+
+			if (s.ReadASCII(4) != "BIGF")
+				throw new InvalidDataException("Header is not BIGF");
+
+			// Total archive size.
+			s.ReadUInt32();
+
+			var entryCount = s.ReadUInt32();
+			if (BitConverter.IsLittleEndian)
+				entryCount = int2.Swap(entryCount);
+
+			// First entry offset? This is apparently bogus for EA's .big files
+			// and we don't have to try seeking there since the entries typically start next in EA's .big files.
+			s.ReadUInt32();
+
+			for (var i = 0; i < entryCount; i++)
+			{
+				var entry = new Entry(s);
+				entries.Add(entry.Path, entry);
+			}
+		}
+
+		class Entry
+		{
+			readonly Stream s;
+			readonly uint offset;
+			readonly uint size;
+			public readonly string Path;
+
+			public Entry(Stream s)
+			{
+				this.s = s;
+
+				offset = s.ReadUInt32();
+				size = s.ReadUInt32();
+				if (BitConverter.IsLittleEndian)
+				{
+					offset = int2.Swap(offset);
+					size = int2.Swap(size);
+				}
+
+				Path = s.ReadASCIIZ();
+			}
+
+			public Stream GetData()
+			{
+				s.Position = offset;
+				return new MemoryStream(s.ReadBytes((int)size));
+			}
+		}
+
+		public Stream GetContent(string filename)
+		{
+			return entries[filename].GetData();
+		}
+
+		public bool Exists(string filename)
+		{
+			return entries.ContainsKey(filename);
+		}
+
+		public IEnumerable<uint> ClassicHashes()
+		{
+			return entries.Keys.Select(filename => PackageEntry.HashFilename(filename, PackageHashType.Classic));
+		}
+
+		public IEnumerable<uint> CrcHashes()
+		{
+			return Enumerable.Empty<uint>();
+		}
+
+		public IEnumerable<string> AllFileNames()
+		{
+			return entries.Keys;
+		}
+
+		public void Write(Dictionary<string, byte[]> contents)
+		{
+			throw new NotImplementedException();
+		}
+	}
+}