deflateroutputstream.cs

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// DeflaterOutputStream.cs
//
// Copyright (C) 2001 Mike Krueger
//
// This file was translated from java, it was part of the GNU Classpath
// Copyright (C) 2001 Free Software Foundation, Inc.
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// 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.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
//
// Linking this library statically or dynamically with other modules is
// making a combined work based on this library.  Thus, the terms and
// conditions of the GNU General Public License cover the whole
// combination.
// 
// As a special exception, the copyright holders of this library give you
// permission to link this library with independent modules to produce an
// executable, regardless of the license terms of these independent
// modules, and to copy and distribute the resulting executable under
// terms of your choice, provided that you also meet, for each linked
// independent module, the terms and conditions of the license of that
// module.  An independent module is a module which is not derived from
// or based on this library.  If you modify this library, you may extend
// this exception to your version of the library, but you are not
// obligated to do so.  If you do not wish to do so, delete this
// exception statement from your version.

using System;
using System.IO;
using ICSharpCode.SharpZipLib.Checksums;
using ICSharpCode.SharpZipLib.Zip.Compression;

#if !NETCF_1_0
using System.Security.Cryptography;
using ICSharpCode.SharpZipLib.Encryption;
#endif

namespace ICSharpCode.SharpZipLib.Zip.Compression.Streams 
{
	/// <summary>
	/// A special stream deflating or compressing the bytes that are
	/// written to it.  It uses a Deflater to perform actual deflating.<br/>
	/// Authors of the original java version : Tom Tromey, Jochen Hoenicke 
	/// </summary>
	public class DeflaterOutputStream : Stream
	{
		#region Constructors
		/// <summary>
		/// Creates a new DeflaterOutputStream with a default Deflater and default buffer size.
		/// </summary>
		/// <param name="baseOutputStream">
		/// the output stream where deflated output should be written.
		/// </param>
		public DeflaterOutputStream(Stream baseOutputStream)
			: this(baseOutputStream, new Deflater(), 512)
		{
		}
		
		/// <summary>
		/// Creates a new DeflaterOutputStream with the given Deflater and
		/// default buffer size.
		/// </summary>
		/// <param name="baseOutputStream">
		/// the output stream where deflated output should be written.
		/// </param>
		/// <param name="deflater">
		/// the underlying deflater.
		/// </param>
		public DeflaterOutputStream(Stream baseOutputStream, Deflater deflater)
			: this(baseOutputStream, deflater, 512)
		{
		}
		
		/// <summary>
		/// Creates a new DeflaterOutputStream with the given Deflater and
		/// buffer size.
		/// </summary>
		/// <param name="baseOutputStream">
		/// The output stream where deflated output is written.
		/// </param>
		/// <param name="deflater">
		/// The underlying deflater to use
		/// </param>
		/// <param name="bufferSize">
		/// The buffer size to use when deflating
		/// </param>
		/// <exception cref="ArgumentOutOfRangeException">
		/// bufsize is less than or equal to zero.
		/// </exception>
		/// <exception cref="ArgumentException">
		/// baseOutputStream does not support writing
		/// </exception>
		/// <exception cref="ArgumentNullException">
		/// deflater instance is null
		/// </exception>
		public DeflaterOutputStream(Stream baseOutputStream, Deflater deflater, int bufferSize)
		{
			if ( baseOutputStream == null ) {
				throw new ArgumentNullException("baseOutputStream");
			}

			if (baseOutputStream.CanWrite == false) {
				throw new ArgumentException("Must support writing", "baseOutputStream");
			}

			if (deflater == null) {
				throw new ArgumentNullException("deflater");
			}
			
			if (bufferSize <= 0) {
				throw new ArgumentOutOfRangeException("bufferSize");
			}
			
			baseOutputStream_ = baseOutputStream;
			buffer_ = new byte[bufferSize];
			deflater_ = deflater;
		}
		#endregion
		
		#region Public API
		/// <summary>
		/// Finishes the stream by calling finish() on the deflater. 
		/// </summary>
		/// <exception cref="SharpZipBaseException">
		/// Not all input is deflated
		/// </exception>
		public virtual void Finish()
		{
			deflater_.Finish();
			while (!deflater_.IsFinished)  {
				int len = deflater_.Deflate(buffer_, 0, buffer_.Length);
				if (len <= 0) {
					break;
				}
				
#if NETCF_1_0
				if ( keys != null ) {
#else
				if (cryptoTransform_ != null) {
#endif	
					EncryptBlock(buffer_, 0, len);
				}
				
				baseOutputStream_.Write(buffer_, 0, len);
			}

			if (!deflater_.IsFinished) {
				throw new SharpZipBaseException("Can't deflate all input?");
			}

			baseOutputStream_.Flush();
			
#if NETCF_1_0
			if ( keys != null ) {
				keys = null;
			}
#else
			if (cryptoTransform_ != null) {
				cryptoTransform_.Dispose();
				cryptoTransform_ = null;
			}
#endif			
		}
		
		/// <summary>
		/// Get/set flag indicating ownership of the underlying stream.
		/// When the flag is true <see cref="Close"></see> will close the underlying stream also.
		/// </summary>
		public bool IsStreamOwner
		{
			get { return isStreamOwner_; }
			set { isStreamOwner_ = value; }
		}
		
		///	<summary>
		/// Allows client to determine if an entry can be patched after its added
		/// </summary>
		public bool CanPatchEntries {
			get { 
				return baseOutputStream_.CanSeek; 
			}
		}
		
		#endregion
		
		#region Encryption
		
		string password;
		
#if NETCF_1_0
		uint[] keys;
#else
		ICryptoTransform cryptoTransform_;
#endif
		
		/// <summary>
		/// Get/set the password used for encryption.
		/// </summary>
		/// <remarks>When set to null or if the password is empty no encryption is performed</remarks>
		public string Password {
			get { 
				return password; 
			}
			set {
				if ( (value != null) && (value.Length == 0) ) {
					password = null;
				} else {
					password = value; 
				}
			}
		}

		/// <summary>
		/// Encrypt a block of data
		/// </summary>
		/// <param name="buffer">
		/// Data to encrypt.  NOTE the original contents of the buffer are lost
		/// </param>
		/// <param name="offset">
		/// Offset of first byte in buffer to encrypt
		/// </param>
		/// <param name="length">
		/// Number of bytes in buffer to encrypt
		/// </param>
		protected void EncryptBlock(byte[] buffer, int offset, int length)
		{
#if NETCF_1_0
			for (int i = offset; i < offset + length; ++i) {
				byte oldbyte = buffer[i];
				buffer[i] ^= EncryptByte();
				UpdateKeys(oldbyte);
			}
#else
			cryptoTransform_.TransformBlock(buffer, 0, length, buffer, 0);
#endif
		}

		/// <summary>
		/// Initializes encryption keys based on given password
		/// </summary>
		/// <param name="password">The password.</param>
		protected void InitializePassword(string password)
		{
#if NETCF_1_0
			keys = new uint[] {
				0x12345678,
				0x23456789,
				0x34567890
			};
			
			byte[] rawPassword = ZipConstants.ConvertToArray(password);
			
			for (int i = 0; i < rawPassword.Length; ++i) {
				UpdateKeys((byte)rawPassword[i]);
			}
			
#else			
			PkzipClassicManaged pkManaged = new PkzipClassicManaged();
			byte[] key = PkzipClassic.GenerateKeys(ZipConstants.ConvertToArray(password));
			cryptoTransform_ = pkManaged.CreateEncryptor(key, null);
#endif
		}

#if NETCF_1_0
		
		/// <summary>
		/// Encrypt a single byte 
		/// </summary>
		/// <returns>
		/// The encrypted value