Added audio.bag/audio.idx support used in RA2

OpenRA.Game/Primitives/MergedStream.cs

@@ -0,0 +1,116 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2015 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.IO;
+
+namespace OpenRA.Primitives
+{
+	public class MergedStream : Stream
+	{
+		public Stream Stream1 { get; set; }
+		public Stream Stream2 { get; set; }
+
+		long VirtualLength { get; set; }
+
+		public MergedStream(Stream stream1, Stream stream2)
+		{
+			Stream1 = stream1;
+			Stream2 = stream2;
+
+			VirtualLength = Stream1.Length + Stream2.Length;
+		}
+
+		public override void Flush()
+		{
+			Stream1.Flush();
+			Stream2.Flush();
+		}
+
+		public override long Seek(long offset, SeekOrigin origin)
+		{
+			var position = Position;
+
+			switch (origin)
+			{
+				case SeekOrigin.Begin:
+					position = offset;
+					break;
+				case SeekOrigin.Current:
+					position += offset;
+					break;
+				case SeekOrigin.End:
+					position = Length;
+					position += offset;
+					break;
+			}
+
+			if (position >= Stream1.Length)
+				Position = Stream1.Length + Stream2.Seek(offset - Stream1.Length, SeekOrigin.Begin);
+			else
+				Position = Stream1.Seek(offset, SeekOrigin.Begin);
+
+			return position;
+		}
+
+		public override void SetLength(long value)
+		{
+			VirtualLength = value;
+		}
+
+		public override int Read(byte[] buffer, int offset, int count)
+		{
+			int bytesRead;
+
+			if (Position >= Stream1.Length)
+				bytesRead = Stream2.Read(buffer, offset, count);
+			else if (count > Stream1.Length)
+			{
+				bytesRead = Stream1.Read(buffer, offset, (int)Stream1.Length);
+				bytesRead += Stream2.Read(buffer, (int)Stream1.Length, count - (int)Stream1.Length);
+			}
+			else
+				bytesRead = Stream1.Read(buffer, offset, count);
+
+			Position += bytesRead;
+
+			return bytesRead;
+		}
+
+		public override void Write(byte[] buffer, int offset, int count)
+		{
+			if (Position >= Stream1.Length)
+				Stream2.Write(buffer, offset - (int)Stream1.Length, count);
+			else
+				Stream1.Write(buffer, offset, count);
+		}
+
+		public override bool CanRead
+		{
+			get { return Stream1.CanRead && Stream2.CanRead; }
+		}
+
+		public override bool CanSeek
+		{
+			get { return Stream1.CanSeek && Stream2.CanSeek; }
+		}
+
+		public override bool CanWrite
+		{
+			get { return Stream1.CanWrite && Stream2.CanWrite; }
+		}
+
+		public override long Length
+		{
+			get { return VirtualLength; }
+		}
+
+		public override long Position { get; set; }
+	}
+}