Merge pull request #843 from ClassiCube/PNGDecoder

WIP Png decoder

Author: UnknownShadow200

MCGalaxy/MCGalaxy_.csproj

@@ -672,7 +672,9 @@
     <Compile Include="util\Formatting\Wildcard.cs" />
     <Compile Include="util\DotnetBackend.cs" />
     <Compile Include="util\Imaging\Bitmap2D.cs" />
+    <Compile Include="util\Imaging\ImageDecoder.cs" />
     <Compile Include="util\Imaging\ImageUtils.cs" />
+    <Compile Include="util\Imaging\PngDecoder.cs" />
     <Compile Include="util\NumberUtils.cs" />
     <Compile Include="util\OperatingSystem.cs" />
     <Compile Include="Server\Server.cs" />

MCGalaxy/util/Imaging/Bitmap2D.cs

@@ -32,7 +32,16 @@ namespace MCGalaxy.Util
 {
     public delegate Pixel PixelGet(int x, int y);
     public delegate void  PixelSet(int x, int y, Pixel pixel);
-    public struct Pixel { public byte A, R, G, B; }
+    
+    public struct Pixel 
+    { 
+        public byte A, R, G, B;
+        
+        public Pixel(byte r, byte g, byte b, byte a)
+        {
+            R = r; G = g; B = b; A = a;
+        }
+    }
 
     /// <summary> Represents a 2D image </summary>
     /// <remarks> Backing implementation depends on whether running on dotnet or .NET </remarks>

MCGalaxy/util/Imaging/ImageDecoder.cs

@@ -0,0 +1,50 @@
+using System;
+using System.IO;
+using System.IO.Compression;
+using MCGalaxy.Util;
+
+namespace MCGalaxy
+{
+    public sealed class SimpleBitmap //: IBitmap2D
+    {
+        public int Width, Height;
+        public Pixel[] pixels;
+    }
+    
+    public abstract class ImageDecoder
+    {
+        protected byte[] buf_data;
+        protected int buf_offset, buf_length;       
+        
+        protected int AdvanceOffset(int amount) {
+            int offset = buf_offset;
+            
+            buf_offset += amount;
+            if (buf_offset > buf_length)
+                throw new EndOfStreamException("End of stream reading data");
+            return offset;
+        }
+        
+        protected static void Fail(string reason) {
+            throw new InvalidDataException(reason);
+        }
+        
+        protected static bool MatchesSignature(byte[] data, byte[] sig) {
+            if (data.Length < sig.Length) return false;
+            
+            for (int i = 0; i < sig.Length; i++)
+            {
+                if (data[i] != sig[i]) return false;
+            }
+            return true;
+        }
+        
+        
+        public static SimpleBitmap DecodeFrom(byte[] src) {
+            if (PngDecoder.DetectHeader(src))
+                return new PngDecoder().Decode(src);
+            
+            throw new InvalidDataException("Unsupported or invalid image format");
+        }
+    }
+}