From b6655d54d0765862acdd06a75e17e76039a135b6 Mon Sep 17 00:00:00 2001
From: UnknownShadow200 <unknownshadow200@gmail.com>
Date: Sat, 12 Sep 2015 07:37:34 +1000
Subject: [PATCH] Add simple .zip reader (For reading texture packs), partially
 addresses #44.

---
 ClassicalSharp/ClassicalSharp.csproj          |  6 +-
 .../{Utils => TexturePack}/TerrainAtlas1D.cs  |  0
 .../{Utils => TexturePack}/TerrainAtlas2D.cs  |  0
 ClassicalSharp/TexturePack/ZipExtractor.cs    | 70 +++++++++++++++++++
 4 files changed, 74 insertions(+), 2 deletions(-)
 rename ClassicalSharp/{Utils => TexturePack}/TerrainAtlas1D.cs (100%)
 rename ClassicalSharp/{Utils => TexturePack}/TerrainAtlas2D.cs (100%)
 create mode 100644 ClassicalSharp/TexturePack/ZipExtractor.cs

diff --git a/ClassicalSharp/ClassicalSharp.csproj b/ClassicalSharp/ClassicalSharp.csproj
index aa01ed9d1..d87dbf9f3 100644
--- a/ClassicalSharp/ClassicalSharp.csproj
+++ b/ClassicalSharp/ClassicalSharp.csproj
@@ -159,11 +159,12 @@
     <Compile Include="Selections\SelectionManager.cs" />
     <Compile Include="Singleplayer\Commands.cs" />
     <Compile Include="Singleplayer\Server.cs" />
+    <Compile Include="TexturePack\TerrainAtlas1D.cs" />
+    <Compile Include="TexturePack\TerrainAtlas2D.cs" />
+    <Compile Include="TexturePack\ZipExtractor.cs" />
     <Compile Include="Utils\Camera.cs" />
     <Compile Include="Utils\FastBitmap.cs" />
     <Compile Include="Utils\FastColour.cs" />
-    <Compile Include="Utils\TerrainAtlas1D.cs" />
-    <Compile Include="Utils\TerrainAtlas2D.cs" />
     <Compile Include="Utils\TextureRectangle.cs" />
     <Compile Include="Utils\StringBuffer.cs" />
     <Compile Include="Utils\Utils.cs" />
@@ -190,6 +191,7 @@
     <Folder Include="Game" />
     <Folder Include="Model" />
     <Folder Include="Network\Utils" />
+    <Folder Include="TexturePack" />
     <Folder Include="Singleplayer" />
     <Folder Include="Utils" />
     <Folder Include="Physics" />
diff --git a/ClassicalSharp/Utils/TerrainAtlas1D.cs b/ClassicalSharp/TexturePack/TerrainAtlas1D.cs
similarity index 100%
rename from ClassicalSharp/Utils/TerrainAtlas1D.cs
rename to ClassicalSharp/TexturePack/TerrainAtlas1D.cs
diff --git a/ClassicalSharp/Utils/TerrainAtlas2D.cs b/ClassicalSharp/TexturePack/TerrainAtlas2D.cs
similarity index 100%
rename from ClassicalSharp/Utils/TerrainAtlas2D.cs
rename to ClassicalSharp/TexturePack/TerrainAtlas2D.cs
diff --git a/ClassicalSharp/TexturePack/ZipExtractor.cs b/ClassicalSharp/TexturePack/ZipExtractor.cs
new file mode 100644
index 000000000..ce2b1e20f
--- /dev/null
+++ b/ClassicalSharp/TexturePack/ZipExtractor.cs
@@ -0,0 +1,70 @@
+using System;
+using System.IO;
+using System.IO.Compression;
+using System.Text;
+
+namespace ClassicalSharp.TexturePack {
+
+	public sealed class ZipExtractor {
+		
+		static Encoding enc = Encoding.ASCII;
+		public void Extract( Stream stream ) {
+			
+			BinaryReader reader = new BinaryReader( stream );
+			while( true ) {
+				uint sig = reader.ReadUInt32();
+				if( sig == 0x04034b50 ) { // local file header
+					ReadLocalFileHeader( reader );
+				} else if( sig == 0x02014b50 ) { // central directory header
+					break;
+				} else {
+					throw new NotSupportedException( "Unsupported signature: " + sig.ToString( "X8" ) );
+				}
+			}
+		}
+		
+		void ReadLocalFileHeader( BinaryReader reader ) {
+			ushort versionNeeded = reader.ReadUInt16();
+			ushort flags = reader.ReadUInt16();
+			ushort compressionMethod = reader.ReadUInt16();
+			reader.ReadUInt32(); // last modified
+			reader.ReadUInt32(); // CRC 32
+			int compressedSize = reader.ReadInt32();
+			int uncompressedSize = reader.ReadInt32();
+			ushort fileNameLen = reader.ReadUInt16();
+			ushort extraFieldLen = reader.ReadUInt16();
+			string fileName = enc.GetString( reader.ReadBytes( fileNameLen ) );
+			reader.ReadBytes( extraFieldLen );
+			
+			if( versionNeeded > 20 )
+				Utils.LogWarning( "May not be able to properly extract a .zip enty with a version later than 2.0" );
+			
+			byte[] data = DecompressEntry( reader, compressionMethod, compressedSize, uncompressedSize );
+			if( data != null ) 
+				HandleZipEntry( fileName, data );
+		}
+		
+		byte[] DecompressEntry( BinaryReader reader, ushort compressionMethod, int compressedSize, int uncompressedSize ) {
+			if( compressionMethod == 0 ) { // Store/Raw
+				return reader.ReadBytes( uncompressedSize );
+			} else if( compressionMethod == 8 ) { // Deflate
+				byte[] data = new byte[uncompressedSize];
+				int index = 0, read = 0;
+				DeflateStream deflater = new DeflateStream( reader.BaseStream, CompressionMode.Decompress );
+				while( index < uncompressedSize &&
+				      ( read = deflater.Read( data, index, data.Length - index ) ) > 0 ) {
+					index += read;
+				}
+				return data;
+			} else {
+				Utils.LogWarning( "Unsupported .zip entry compression method: " + compressionMethod );
+				reader.ReadBytes( compressedSize );
+				return null;
+			}
+		}
+		
+		void HandleZipEntry( string filename, byte[] data ) {
+			Console.WriteLine( filename );
+		}
+	}
+}