Move LCWCompression support to Mods.Cnc

OpenRA.Mods.Cnc/FileFormats/LCWCompression.cs

@@ -0,0 +1,167 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2020 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, either version 3 of
+ * the License, or (at your option) any later version. For more
+ * information, see COPYING.
+ */
+#endregion
+
+using System;
+using System.IO;
+using OpenRA.Mods.Common.FileFormats;
+
+namespace OpenRA.Mods.Cnc.FileFormats
+{
+	// Lempel - Castle - Welch algorithm (aka Format80)
+	public static class LCWCompression
+	{
+		static void ReplicatePrevious(byte[] dest, int destIndex, int srcIndex, int count)
+		{
+			if (srcIndex > destIndex)
+				throw new NotImplementedException("srcIndex > destIndex {0} {1}".F(srcIndex, destIndex));
+
+			for (var i = 0; i < count; i++)
+			{
+				if (destIndex - srcIndex == 1)
+					dest[destIndex + i] = dest[destIndex - 1];
+				else
+					dest[destIndex + i] = dest[srcIndex + i];
+			}
+		}
+
+		public static int DecodeInto(byte[] src, byte[] dest, int srcOffset = 0, bool reverse = false)
+		{
+			var ctx = new FastByteReader(src, srcOffset);
+			var destIndex = 0;
+			while (true)
+			{
+				var i = ctx.ReadByte();
+				if ((i & 0x80) == 0)
+				{
+					// case 2
+					var secondByte = ctx.ReadByte();
+					var count = ((i & 0x70) >> 4) + 3;
+					var rpos = ((i & 0xf) << 8) + secondByte;
+
+					if (destIndex + count > dest.Length)
+						return destIndex;
+
+					ReplicatePrevious(dest, destIndex, destIndex - rpos, count);
+					destIndex += count;
+				}
+				else if ((i & 0x40) == 0)
+				{
+					// case 1
+					var count = i & 0x3F;
+					if (count == 0)
+						return destIndex;
+
+					ctx.CopyTo(dest, destIndex, count);
+					destIndex += count;
+				}
+				else
+				{
+					var count3 = i & 0x3F;
+					if (count3 == 0x3E)
+					{
+						// case 4
+						var count = ctx.ReadWord();
+						var color = ctx.ReadByte();
+
+						for (var end = destIndex + count; destIndex < end; destIndex++)
+							dest[destIndex] = color;
+					}
+					else
+					{
+						// If count3 == 0x3F it's case 5, else case 3
+						var count = count3 == 0x3F ? ctx.ReadWord() : count3 + 3;
+						var srcIndex = reverse ? destIndex - ctx.ReadWord() : ctx.ReadWord();
+						if (srcIndex >= destIndex)
+							throw new NotImplementedException("srcIndex >= destIndex {0} {1}".F(srcIndex, destIndex));
+
+						for (var end = destIndex + count; destIndex < end; destIndex++)
+							dest[destIndex] = dest[srcIndex++];
+					}
+				}
+			}
+		}
+
+		static int CountSame(byte[] src, int offset, int maxCount)
+		{
+			maxCount = Math.Min(src.Length - offset, maxCount);
+			if (maxCount <= 0)
+				return 0;
+
+			var first = src[offset++];
+			var count = 1;
+
+			while (count < maxCount && src[offset++] == first)
+				count++;
+
+			return count;
+		}
+
+		static void WriteCopyBlocks(byte[] src, int offset, int count, MemoryStream output)
+		{
+			while (count > 0)
+			{
+				var writeNow = Math.Min(count, 0x3F);
+				output.WriteByte((byte)(0x80 | writeNow));
+				output.Write(src, offset, writeNow);
+
+				count -= writeNow;
+				offset += writeNow;
+			}
+		}
+
+		// Quick and dirty LCW encoder version 2
+		// Uses raw copy and RLE compression
+		public static byte[] Encode(byte[] src)
+		{
+			using (var ms = new MemoryStream())
+			{
+				var offset = 0;
+				var left = src.Length;
+				var blockStart = 0;
+
+				while (offset < left)
+				{
+					var repeatCount = CountSame(src, offset, 0xFFFF);
+					if (repeatCount >= 4)
+					{
+						// Write what we haven't written up to now
+						WriteCopyBlocks(src, blockStart, offset - blockStart, ms);
+
+						// Command 4: Repeat byte n times
+						ms.WriteByte(0xFE);
+
+						// Low byte
+						ms.WriteByte((byte)(repeatCount & 0xFF));
+
+						// High byte
+						ms.WriteByte((byte)(repeatCount >> 8));
+
+						// Value to repeat
+						ms.WriteByte(src[offset]);
+
+						offset += repeatCount;
+						blockStart = offset;
+					}
+					else
+						offset++;
+				}
+
+				// Write what we haven't written up to now
+				WriteCopyBlocks(src, blockStart, offset - blockStart, ms);
+
+				// Write terminator
+				ms.WriteByte(0x80);
+
+				return ms.ToArray();
+			}
+		}
+	}
+}

OpenRA.Mods.Cnc/SpriteLoaders/ShpD2Loader.cs

@@ -12,6 +12,7 @@
 using System;
 using System.IO;
 using OpenRA.Graphics;
+using OpenRA.Mods.Cnc.FileFormats;
 using OpenRA.Mods.Common.FileFormats;
 using OpenRA.Primitives;
 

OpenRA.Mods.Cnc/UtilityCommands/ImportRedAlertLegacyMapCommand.cs

@@ -14,6 +14,7 @@ using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Text;
+using OpenRA.Mods.Cnc.FileFormats;
 using OpenRA.Mods.Common.FileFormats;
 using OpenRA.Mods.Common.UtilityCommands;
 using OpenRA.Primitives;