much more on data resources loading and bugfixes

Source/Data/ImageDataFormat.cs

@@ -0,0 +1,114 @@
+
+#region ================== Copyright (c) 2007 Pascal vd Heiden
+
+/*
+ * Copyright (c) 2007 Pascal vd Heiden, www.codeimp.com
+ * This program is released under GNU General Public License
+ * 
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ */
+
+#endregion
+
+#region ================== Namespaces
+
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Text;
+using System.IO;
+using System.Drawing.Imaging;
+using CodeImp.DoomBuilder.IO;
+
+#endregion
+
+namespace CodeImp.DoomBuilder.Data
+{
+	public static class ImageDataFormat
+	{
+		// Input guess formats
+		public const int UNKNOWN = 0;			// No clue.
+		public const int DOOMPICTURE = 1;		// Could be Doom Picture format	(column list rendered data)
+		public const int DOOMFLAT = 2;			// Could be Doom Flat format	(raw 8-bit pixel data)
+		
+		// File format signatures
+		private static readonly int[] PNG_SIGNATURE = new int[] { 137, 80, 78, 71, 13, 10, 26, 10 };
+		private static readonly int[] GIF_SIGNATURE = new int[] { 71, 73, 70 };
+		private static readonly int[] BMP_SIGNATURE = new int[] { 66, 77 };
+
+		// This check image data and returns the appropriate image reader
+		public static IImageReader GetImageReader(Stream data, int guessformat, Playpal palette)
+		{
+			BinaryReader bindata = new BinaryReader(data);
+			DoomPictureReader picreader;
+			DoomFlatReader flatreader;
+			
+			// First check the formats that provide the means to 'ensure' that
+			// it actually is that format. Then guess the Doom image format.
+
+			// Data long enough to check for signatures?
+			if(data.Length > 10)
+			{
+				// Check for PNG signature
+				data.Seek(0, SeekOrigin.Begin);
+				if(CheckSignature(data, PNG_SIGNATURE)) return new FileImageReader();
+				
+				// Check for GIF signature
+				data.Seek(0, SeekOrigin.Begin);
+				if(CheckSignature(data, GIF_SIGNATURE)) return new FileImageReader();
+
+				// Check for BMP signature
+				data.Seek(0, SeekOrigin.Begin);
+				if(CheckSignature(data, BMP_SIGNATURE))
+				{
+					// Check if data size matches the size specified in the data
+					if(bindata.ReadUInt32() <= data.Length) return new FileImageReader();
+				}
+			}
+			
+			// Could it be a doom picture?
+			if(guessformat == DOOMPICTURE)
+			{
+				// Check if data is valid for a doom picture
+				data.Seek(0, SeekOrigin.Begin);
+				picreader = new DoomPictureReader(palette);
+				if(picreader.Validate(data)) return picreader;
+			}
+			// Could it be a doom flat?
+			else if(guessformat == DOOMFLAT)
+			{
+				// Check if data is valid for a doom flat
+				data.Seek(0, SeekOrigin.Begin);
+				flatreader = new DoomFlatReader(palette);
+				if(flatreader.Validate(data)) return flatreader;
+			}
+			
+			// Format not supported
+			return new UnknownImageReader();
+		}
+
+		// This checks a signature as byte array
+		// NOTE: Expects the stream position to be at the start of the
+		// signature, and expects the stream to be long enough.
+		private static bool CheckSignature(Stream data, int[] sig)
+		{
+			int b;
+			
+			// Go for all bytes
+			for(int i = 0; i < sig.Length; i++)
+			{
+				// When byte doesnt match the signature, leave
+				b = data.ReadByte();
+				if(b != sig[i]) return false;
+			}
+
+			// Signature matches
+			return true;
+		}
+	}
+}