RFC1950-compatible wrapper around DeflateStream class.

ArcFormats/ZLibStream.cs

@@ -0,0 +1,230 @@
+//! \file       ZLibStream.cs
+//! \date       Tue Jul 28 04:34:13 2015
+//! \brief      RFC 1950 compatible wrapper around .Net DeflateStream class.
+//
+// Copyright (C) 2015 by morkt
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to
+// deal in the Software without restriction, including without limitation the
+// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+// sell copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+// IN THE SOFTWARE.
+//
+
+using System;
+using System.IO;
+using System.IO.Compression;
+using GameRes.Utility;
+
+namespace GameRes.Compression
+{
+    public enum CompressionMode
+    {
+        Compress,
+        Decompress
+    }
+
+    /// <summary>
+    /// Enum for backwards compatibility with ZLibNet
+    /// </summary>
+    public enum CompressionLevel
+	{
+		NoCompression = 0,
+		BestSpeed = 1,
+		BestCompression = 9,
+		Default = 6,
+		Level0 = 0,
+		Level1 = 1,
+		Level2 = 2,
+		Level3 = 3,
+		Level4 = 4,
+		Level5 = 5,
+		Level6 = 6,
+		Level7 = 7,
+		Level8 = 8,
+		Level9 = 9
+	}
+
+    public class ZLibStream : Stream
+    {
+        DeflateStream   m_stream;
+        CheckedStream   m_adler;
+        bool            m_writing;
+        int             m_total_in = 0;
+
+        public Stream BaseStream { get { return m_stream.BaseStream; } }
+
+        /// <summary>
+        /// When compressing: returns total number of uncompressed bytes. Undefined for decompression streams.
+        /// </summary>
+        public int       TotalIn { get { return m_total_in; } }
+
+        public ZLibStream (Stream stream, CompressionMode mode, bool leave_open = false)
+            : this (stream, mode, CompressionLevel.Default, leave_open)
+        {
+        }
+
+        public ZLibStream (Stream stream, CompressionMode mode, CompressionLevel level, bool leave_open = false)
+		{
+            if (CompressionMode.Decompress == mode)
+                InitDecompress (stream, leave_open);
+            else
+                InitCompress (stream, level, leave_open);
+		}
+
+        private void InitDecompress (Stream stream, bool leave_open)
+        {
+            int b1 = stream.ReadByte();
+            int b2 = stream.ReadByte();
+            if (0x78 != b1 || 0 != (b1 << 8 | b2) % 31)
+                throw new InvalidDataException ("Data not recoginzed as zlib-compressed stream");
+            m_stream = new DeflateStream (stream, System.IO.Compression.CompressionMode.Decompress, leave_open);
+            m_writing = false;
+        }
+
+        private void InitCompress (Stream stream, CompressionLevel level, bool leave_open)
+        {
+            int flevel = (int)level;
+            System.IO.Compression.CompressionLevel sys_level;
+            if (0 == flevel)
+            {
+                sys_level = System.IO.Compression.CompressionLevel.NoCompression;
+            }
+            else if (flevel > 5)
+            {
+                sys_level = System.IO.Compression.CompressionLevel.Optimal;
+                flevel = 3;
+            }
+            else
+            {
+                sys_level = System.IO.Compression.CompressionLevel.Fastest;
+                flevel = 1;
+            }
+            int cmf = 0x7800 | flevel << 6;
+            cmf = ((cmf + 30) / 31) * 31;
+            stream.WriteByte ((byte)(cmf >> 8));
+            stream.WriteByte ((byte)cmf);
+            m_stream = new DeflateStream (stream, sys_level, leave_open);
+            m_adler  = new CheckedStream (m_stream, new Adler32());
+            m_writing = true;
+        }
+
+        #region IO.Stream Members
+        public override bool CanRead  { get { return !m_writing; } }
+        public override bool CanSeek  { get { return false; } }
+        public override bool CanWrite { get { return m_writing; } }
+        public override long Length   { get { return m_stream.Length; } }
+        public override long Position
+        {
+            get { return m_stream.Position; }
+            set { m_stream.Position = value; }
+        }
+
+        public override int Read (byte[] buffer, int offset, int count)
+        {
+            return m_stream.Read (buffer, offset, count);
+        }
+
+        public override int ReadByte ()
+        {
+            return m_stream.ReadByte();
+        }
+
+        public override void Flush()
+        {
+            m_stream.Flush();
+        }
+
+        public override long Seek (long offset, SeekOrigin origin)
+        {
+            throw new NotSupportedException ("ZLibStream.Seek method not supported");
+        }
+
+        public override void SetLength (long length)
+        {
+            throw new NotSupportedException ("ZLibStream.SetLength method not supported");
+        }
+
+        public override void Write (byte[] buffer, int offset, int count)
+        {
+            m_adler.Write (buffer, offset, count);
+            m_total_in += count;
+        }
+
+        public override void WriteByte (byte value)
+        {
+            m_adler.WriteByte (value);
+            m_total_in++;
+        }
+        #endregion
+
+        #region IDisposable Members
+        bool m_disposed = false;
+        protected override void Dispose (bool disposing)
+        {
+            if (!m_disposed)
+            {
+                try
+                {
+                    if (disposing)
+                    {
+                        if (m_writing)
+                        {
+                            uint checksum = m_adler.CheckSumValue;
+                            m_stream.Flush();
+                            m_stream.BaseStream.WriteByte ((byte)(checksum >> 24));
+                            m_stream.BaseStream.WriteByte ((byte)(checksum >> 16));
+                            m_stream.BaseStream.WriteByte ((byte)(checksum >> 8));
+                            m_stream.BaseStream.WriteByte ((byte)(checksum));
+                            m_adler.Dispose();
+                        }
+                        m_stream.Dispose();
+                    }
+                    m_disposed = true;
+                }
+                finally
+                {
+                    base.Dispose (disposing);
+                }
+            }
+        }
+        #endregion
+    }
+
+    public class ZLibCompressor
+	{
+		public static MemoryStream Compress (Stream source)
+		{
+			var dest = new MemoryStream();
+			using (var zs = new ZLibStream (dest, CompressionMode.Compress, true))
+			{
+				source.CopyTo (zs);
+			}
+			dest.Position = 0;
+			return dest;
+		}
+
+		public static MemoryStream DeCompress (Stream source)
+		{
+			var dest = new MemoryStream();
+			using (var zs = new ZLibStream (source, CompressionMode.Decompress, true))
+			{
+				zs.CopyTo (dest);
+			}
+			dest.Position = 0;
+			return dest;
+		}
+	}
+}