GARbro-mirror/ArcFormats/ZLibStream.cs

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//! \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_should_dispose_base;
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)
{
try
{
if (CompressionMode.Decompress == mode)
InitDecompress (stream);
else
InitCompress (stream, level);
m_should_dispose_base = !leave_open;
}
catch
{
if (!leave_open)
stream.Dispose();
throw;
}
}
private void InitDecompress (Stream stream)
{
int b1 = stream.ReadByte();
int b2 = stream.ReadByte();
if ((0x78 != b1 && 0x58 != 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, true);
m_writing = false;
}
private void InitCompress (Stream stream, CompressionLevel level)
{
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, true);
m_adler = new CheckedStream (m_stream, new Adler32());
m_writing = true;
}
void WriteCheckSum (Stream output)
{
uint checksum = m_adler.CheckSumValue;
output.WriteByte ((byte)(checksum >> 24));
output.WriteByte ((byte)(checksum >> 16));
output.WriteByte ((byte)(checksum >> 8));
output.WriteByte ((byte)(checksum));
}
#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)
{
var output = m_stream.BaseStream;
m_stream.Dispose();
if (m_writing)
{
WriteCheckSum (output);
m_adler.Dispose();
}
if (m_should_dispose_base)
output.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;
}
}
}