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/BigFile.cs

@@ -0,0 +1,124 @@
+#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.IO;
+using OpenRA.FileSystem;
+using OpenRA.Primitives;
+using FS = OpenRA.FileSystem.FileSystem;
+
+namespace OpenRA.Mods.Cnc.FileSystem
+{
+	public class BigLoader : IPackageLoader
+	{
+		sealed class BigFile : IReadOnlyPackage
+		{
+			public string Name { get; }
+			public IEnumerable<string> Contents => index.Keys;
+
+			readonly Dictionary<string, Entry> index;
+			readonly Stream s;
+
+			public BigFile(Stream s, string filename)
+			{
+				Name = filename;
+				this.s = s;
+
+				try
+				{
+					s.ReadASCII(4); // signature
+
+					// 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();
+
+					index = new Dictionary<string, Entry>((int)entryCount);
+					for (var i = 0; i < entryCount; i++)
+					{
+						var entry = new Entry(s);
+						index.Add(entry.Path, entry);
+					}
+				}
+				catch
+				{
+					Dispose();
+					throw;
+				}
+			}
+
+			sealed class Entry
+			{
+				public readonly uint Offset;
+				public readonly uint Size;
+				public readonly string Path;
+
+				public Entry(Stream s)
+				{
+					Offset = s.ReadUInt32();
+					Size = s.ReadUInt32();
+					if (BitConverter.IsLittleEndian)
+					{
+						Offset = int2.Swap(Offset);
+						Size = int2.Swap(Size);
+					}
+
+					Path = s.ReadASCIIZ();
+				}
+			}
+
+			public Stream GetStream(string filename)
+			{
+				var entry = index[filename];
+				return SegmentStream.CreateWithoutOwningStream(s, entry.Offset, (int)entry.Size);
+			}
+
+			public bool Contains(string filename)
+			{
+				return index.ContainsKey(filename);
+			}
+
+			public IReadOnlyPackage OpenPackage(string filename, FS context)
+			{
+				// Not implemented
+				return null;
+			}
+
+			public void Dispose()
+			{
+				s.Dispose();
+			}
+		}
+
+		bool IPackageLoader.TryParsePackage(Stream s, string filename, FS context, out IReadOnlyPackage package)
+		{
+			// Take a peek at the file signature
+			var signature = s.ReadASCII(4);
+			s.Position -= 4;
+
+			if (signature != "BIGF")
+			{
+				package = null;
+				return false;
+			}
+
+			package = new BigFile(s, filename);
+			return true;
+		}
+	}
+}