Initial commit: OpenRA game engine

Fork from OpenRA/OpenRA with one-click launch script (start-ra.cmd)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

OpenRA.Mods.Cnc/FileSystem/MixFile.cs

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+#region Copyright & License Information
+/*
+ * Copyright (c) The OpenRA Developers and Contributors
+ * 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, either version 3 of
+ * the License, or (at your option) any later version. For more
+ * information, see COPYING.
+ */
+#endregion
+
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.IO;
+using System.Linq;
+using OpenRA.FileSystem;
+using OpenRA.Mods.Cnc.FileFormats;
+using OpenRA.Primitives;
+using FS = OpenRA.FileSystem.FileSystem;
+
+namespace OpenRA.Mods.Cnc.FileSystem
+{
+	public class MixLoader : IPackageLoader
+	{
+		public sealed class MixFile : IReadOnlyPackage
+		{
+			public string Name { get; }
+			public IEnumerable<string> Contents => index.Keys;
+
+			readonly Dictionary<string, PackageEntry> index;
+			readonly long dataStart;
+			readonly Stream s;
+
+			public MixFile(Stream s, string filename, string[] globalFilenames)
+			{
+				Name = filename;
+				this.s = s;
+
+				try
+				{
+					// Detect format type
+					var isCncMix = s.ReadUInt16() != 0;
+
+					// The C&C mix format doesn't contain any flags or encryption
+					var isEncrypted = false;
+					if (!isCncMix)
+						isEncrypted = (s.ReadUInt16() & 0x2) != 0;
+
+					List<PackageEntry> entries;
+					if (isEncrypted)
+						entries = ParseHeader(DecryptHeader(s, 4, out dataStart), 0, out _);
+					else
+						entries = ParseHeader(s, isCncMix ? 0 : 4, out dataStart);
+
+					index = ParseIndex(entries.ToDictionaryWithConflictLog(x => x.Hash,
+						$"{filename} ({(isCncMix ? "C&C" : "RA/TS/RA2")} format, Encrypted: {isEncrypted}, DataStart: {dataStart})",
+						null, x => $"(offs={x.Offset}, len={x.Length})"), globalFilenames);
+				}
+				catch (Exception)
+				{
+					Dispose();
+					throw;
+				}
+			}
+
+			Dictionary<string, PackageEntry> ParseIndex(Dictionary<uint, PackageEntry> entries, string[] globalFilenames)
+			{
+				var allPossibleFilenames = new HashSet<string>(globalFilenames);
+
+				// Try and find a local mix database
+				var dbNameClassic = PackageEntry.HashFilename("local mix database.dat", PackageHashType.Classic);
+				var dbNameCRC = PackageEntry.HashFilename("local mix database.dat", PackageHashType.CRC32);
+				foreach (var kv in entries)
+				{
+					if (kv.Key == dbNameClassic || kv.Key == dbNameCRC)
+					{
+						using (var content = GetContent(kv.Value))
+						{
+							var db = new XccLocalDatabase(content);
+							allPossibleFilenames.EnsureCapacity(allPossibleFilenames.Count + db.Entries.Length);
+							allPossibleFilenames.UnionWith(db.Entries);
+						}
+
+						break;
+					}
+				}
+
+				var classicIndex = new Dictionary<string, PackageEntry>(entries.Count);
+				var crcIndex = new Dictionary<string, PackageEntry>(entries.Count);
+
+				foreach (var filename in allPossibleFilenames)
+				{
+					var classicHash = PackageEntry.HashFilename(filename, PackageHashType.Classic);
+					var crcHash = PackageEntry.HashFilename(filename, PackageHashType.CRC32);
+
+					if (entries.TryGetValue(classicHash, out var e))
+						classicIndex.Add(filename, e);
+
+					if (entries.TryGetValue(crcHash, out e))
+						crcIndex.Add(filename, e);
+				}
+
+				var bestIndex = crcIndex.Count > classicIndex.Count ? crcIndex : classicIndex;
+
+				var unknown = entries.Count - bestIndex.Count;
+				if (unknown > 0)
+					Log.Write("debug", $"{Name}: failed to resolve filenames for {unknown} unknown hashes");
+
+				bestIndex.TrimExcess();
+				return bestIndex;
+			}
+
+			static List<PackageEntry> ParseHeader(Stream s, long offset, out long headerEnd)
+			{
+				s.Seek(offset, SeekOrigin.Begin);
+				var numFiles = s.ReadUInt16();
+				s.ReadUInt32(); // dataSize
+
+				var items = new List<PackageEntry>();
+				for (var i = 0; i < numFiles; i++)
+					items.Add(new PackageEntry(s));
+
+				headerEnd = offset + 6 + numFiles * PackageEntry.Size;
+				return items;
+			}
+
+			static MemoryStream DecryptHeader(Stream s, long offset, out long headerEnd)
+			{
+				s.Seek(offset, SeekOrigin.Begin);
+
+				// Decrypt blowfish key
+				var keyblock = s.ReadBytes(80);
+				var blowfishKey = new BlowfishKeyProvider().DecryptKey(keyblock);
+				var fish = new Blowfish(blowfishKey);
+
+				// Decrypt first block to work out the header length
+				var ms = Decrypt(ReadBlocks(s, offset + 80, 1), fish);
+				var numFiles = ms.ReadUInt16();
+
+				// Decrypt the full header - round bytes up to a full block
+				var blockCount = (13 + numFiles * PackageEntry.Size) / 8;
+				headerEnd = offset + 80 + blockCount * 8;
+
+				return Decrypt(ReadBlocks(s, offset + 80, blockCount), fish);
+			}
+
+			static MemoryStream Decrypt(uint[] h, Blowfish fish)
+			{
+				var decrypted = fish.Decrypt(h);
+
+				var ms = new MemoryStream(decrypted.Length * 4);
+				var writer = new BinaryWriter(ms);
+				foreach (var t in decrypted)
+					writer.Write(t);
+				writer.Flush();
+
+				ms.Seek(0, SeekOrigin.Begin);
+				return ms;
+			}
+
+			static uint[] ReadBlocks(Stream s, long offset, int count)
+			{
+				if (offset < 0)
+					throw new ArgumentOutOfRangeException(nameof(offset), "Non-negative number required.");
+
+				if (count < 0)
+					throw new ArgumentOutOfRangeException(nameof(count), "Non-negative number required.");
+
+				if (offset + count * 2 > s.Length)
+					throw new ArgumentException($"Bytes to read {count * 2} and offset {offset} greater than stream length {s.Length}.");
+
+				s.Seek(offset, SeekOrigin.Begin);
+
+				// A block is a single encryption unit (represented as two 32-bit integers)
+				var ret = new uint[2 * count];
+				for (var i = 0; i < ret.Length; i++)
+					ret[i] = s.ReadUInt32();
+
+				return ret;
+			}
+
+			public Stream GetContent(PackageEntry entry)
+			{
+				return SegmentStream.CreateWithoutOwningStream(s, dataStart + entry.Offset, (int)entry.Length);
+			}
+
+			public Stream GetStream(string filename)
+			{
+				if (!index.TryGetValue(filename, out var e))
+					return null;
+
+				return GetContent(e);
+			}
+
+			public IReadOnlyDictionary<string, PackageEntry> Index
+			{
+				get
+				{
+					var absoluteIndex = index.ToDictionary(e => e.Key, e => new PackageEntry(e.Value.Hash, (uint)(e.Value.Offset + dataStart), e.Value.Length));
+					return new ReadOnlyDictionary<string, PackageEntry>(absoluteIndex);
+				}
+			}
+
+			public bool Contains(string filename)
+			{
+				return index.ContainsKey(filename);
+			}
+
+			public IReadOnlyPackage OpenPackage(string filename, FS context)
+			{
+				var childStream = GetStream(filename);
+				if (childStream == null)
+					return null;
+
+				if (context.TryParsePackage(childStream, filename, out var package))
+					return package;
+
+				childStream.Dispose();
+				return null;
+			}
+
+			public void Dispose()
+			{
+				s.Dispose();
+			}
+		}
+
+		string[] globalFilenames;
+
+		bool IPackageLoader.TryParsePackage(Stream s, string filename, FS context, out IReadOnlyPackage package)
+		{
+			if (!filename.EndsWith(".mix", StringComparison.InvariantCultureIgnoreCase))
+			{
+				package = null;
+				return false;
+			}
+
+			// Load the global mix database
+			if (globalFilenames == null && context.TryOpen("global mix database.dat", out var mixDatabase))
+				using (var db = new XccGlobalDatabase(mixDatabase))
+					globalFilenames = db.Entries.ToHashSet().ToArray();
+
+			package = new MixFile(s, filename, globalFilenames ?? []);
+			return true;
+		}
+	}
+}