Move WW compression formats into Mods.Common.

2016-01-04 20:10:28 +00:00
parent 83477ec19e
commit 9f4b7097b2
9 changed files with 10 additions and 9 deletions
--- a/OpenRA.Mods.Common/FileFormats/XORDeltaCompression.cs
+++ b/OpenRA.Mods.Common/FileFormats/XORDeltaCompression.cs
@@ -0,0 +1,79 @@
+#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
+
+namespace OpenRA.Mods.Common.FileFormats
+{
+	// Data that is to be XORed against another set of data (aka Format40)
+	public static class XORDeltaCompression
+	{
+		public static int DecodeInto(byte[] src, byte[] dest, int srcOffset)
+		{
+			var ctx = new FastByteReader(src, srcOffset);
+			var destIndex = 0;
+
+			while (true)
+			{
+				var i = ctx.ReadByte();
+				if ((i & 0x80) == 0)
+				{
+					var count = i & 0x7F;
+					if (count == 0)
+					{
+						// case 6
+						count = ctx.ReadByte();
+						var value = ctx.ReadByte();
+						for (var end = destIndex + count; destIndex < end; destIndex++)
+							dest[destIndex] ^= value;
+					}
+					else
+					{
+						// case 5
+						for (var end = destIndex + count; destIndex < end; destIndex++)
+							dest[destIndex] ^= ctx.ReadByte();
+					}
+				}
+				else
+				{
+					var count = i & 0x7F;
+					if (count == 0)
+					{
+						count = ctx.ReadWord();
+						if (count == 0)
+							return destIndex;
+
+						if ((count & 0x8000) == 0)
+						{
+							// case 2
+							destIndex += count & 0x7FFF;
+						}
+						else if ((count & 0x4000) == 0)
+						{
+							// case 3
+							for (var end = destIndex + (count & 0x3FFF); destIndex < end; destIndex++)
+								dest[destIndex] ^= ctx.ReadByte();
+						}
+						else
+						{
+							// case 4
+							var value = ctx.ReadByte();
+							for (var end = destIndex + (count & 0x3FFF); destIndex < end; destIndex++)
+								dest[destIndex] ^= value;
+						}
+					}
+					else
+					{
+						// case 1
+						destIndex += count;
+					}
+				}
+			}
+		}
+	}
+}