zipfile.cs

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// ZipFile.cs
//
// Copyright (C) 2001 Mike Krueger
// Copyright (C) 2004 John Reilly
//
// 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.Security.Cryptography;
using System.Collections;
using System.IO;
using System.Text;

using ICSharpCode.SharpZipLib.Checksums;
using ICSharpCode.SharpZipLib.Zip.Compression.Streams;
using ICSharpCode.SharpZipLib.Zip.Compression;
using ICSharpCode.SharpZipLib.Encryption;

namespace ICSharpCode.SharpZipLib.Zip 
{

	/// <summary>
	/// Arguments used with KeysRequiredEvent
	/// </summary>
	public class KeysRequiredEventArgs : EventArgs
	{
		string fileName;
	
		/// <summary>
		/// Get the name of the file for which keys are required.
		/// </summary>
		public string FileName
		{
			get { return fileName; }
		}
	
		byte[] key;
		
		/// <summary>
		/// Get/set the key value
		/// </summary>
		public byte[] Key
		{
			get { return key; }
			set { key = value; }
		}
	
		/// <summary>
		/// Initialise a new instance of <see cref="KeysRequiredEventArgs"></see>
		/// </summary>
		/// <param name="name">The name of the file for which keys are required.</param>
		public KeysRequiredEventArgs(string name)
		{
			fileName = name;
		}
	
		/// <summary>
		/// Initialise a new instance of <see cref="KeysRequiredEventArgs"></see>
		/// </summary>
		/// <param name="name">The name of the file for which keys are required.</param>
		/// <param name="keyValue">The current key value.</param>
		public KeysRequiredEventArgs(string name, byte[] keyValue)
		{
			fileName = name;
			key = keyValue;
		}
	}
	
	/// <summary>
	/// This class represents a Zip archive.  You can ask for the contained
	/// entries, or get an input stream for a file entry.  The entry is
	/// automatically decompressed.
	/// 
	/// This class is thread safe:  You can open input streams for arbitrary
	/// entries in different threads.
	/// <br/>
	/// <br/>Author of the original java version : Jochen Hoenicke
	/// </summary>
	/// <example>
	/// <code>
	/// using System;
	/// using System.Text;
	/// using System.Collections;
	/// using System.IO;
	/// 
	/// using ICSharpCode.SharpZipLib.Zip;
	/// 
	/// class MainClass
	/// {
	/// 	static public void Main(string[] args)
	/// 	{
	/// 		ZipFile zFile = new ZipFile(args[0]);
	/// 		Console.WriteLine("Listing of : " + zFile.Name);
	/// 		Console.WriteLine("");
	/// 		Console.WriteLine("Raw Size    Size      Date     Time     Name");
	/// 		Console.WriteLine("--------  --------  --------  ------  ---------");
	/// 		foreach (ZipEntry e in zFile) {
	/// 			DateTime d = e.DateTime;
	/// 			Console.WriteLine("{0, -10}{1, -10}{2}  {3}   {4}", e.Size, e.CompressedSize,
	/// 			                                                    d.ToString("dd-MM-yy"), d.ToString("t"),
	/// 			                                                    e.Name);
	/// 		}
	/// 	}
	/// }
	/// </code>
	/// </example>
	public class ZipFile : IEnumerable
	{
		string     name;
		string     comment;
		Stream     baseStream;
		bool       isStreamOwner = true;
		long       offsetOfFirstEntry = 0;
		ZipEntry[] entries;
		
		#region KeyHandling
		
		/// <summary>
		/// Delegate for handling keys/password setting during compresion/decompression.
		/// </summary>
		public delegate void KeysRequiredEventHandler(
			object sender,
			KeysRequiredEventArgs e
		);

		/// <summary>
		/// Event handler for handling encryption keys.
		/// </summary>
		public KeysRequiredEventHandler KeysRequired;

		/// <summary>
		/// Handles getting of encryption keys when required.
		/// </summary>
		/// <param name="fileName">The file for which encryptino keys are required.</param>
		void OnKeysRequired(string fileName)
		{
			if (KeysRequired != null) {
				KeysRequiredEventArgs krea = new KeysRequiredEventArgs(fileName, key);
				KeysRequired(this, krea);
				key = krea.Key;
			}
		}
		
		byte[] key = null;
		
		/// <summary>
		/// Get/set the encryption key value.
		/// </summary>
		byte[] Key
		{
			get { return key; }
			set { key = value; }
		}
		
		/// <summary>
		/// Password to be used for encrypting/decrypting files.
		/// </summary>
		/// <remarks>Set to null if no password is required.</remarks>
		public string Password
		{
			set 
			{
				if ( (value == null) || (value.Length == 0) ) {
					key = null;
				}
				else {
					key = PkzipClassic.GenerateKeys(Encoding.ASCII.GetBytes(value));
				}
			}
		}
		
		byte[] iv = null;
		
		bool HaveKeys
		{
		 get { return key != null; }
		}
		#endregion
	
		/// <summary>
		/// Opens a Zip file with the given name for reading.
		/// </summary>
		/// <exception cref="IOException">
		/// An i/o error occurs
		/// </exception>
		/// <exception cref="ZipException">
		/// The file doesn't contain a valid zip archive.
		/// </exception>
		public ZipFile(string name)
		{
			this.name = name;
			this.baseStream = File.OpenRead(name);
			try {
				ReadEntries();
			}
			catch {
				Close();
				throw;
			}
		}
		
		/// <summary>
		/// Opens a Zip file reading the given FileStream
		/// </summary>
		/// <exception cref="IOException">
		/// An i/o error occurs.
		/// </exception>
		/// <exception cref="ZipException">
		/// The file doesn't contain a valid zip archive.
		/// </exception>
		public ZipFile(FileStream file)
		{
			this.baseStream  = file;
			this.name = file.Name;
			try {
				ReadEntries();
			}
			catch {
				Close();
				throw;
			}
		}
		
		/// <summary>
		/// Opens a Zip file reading the given Stream
		/// </summary>
		/// <exception cref="IOException">
		/// An i/o error occurs
		/// </exception>
		/// <exception cref="ZipException">
		/// The file doesn't contain a valid zip archive.<br/>
		/// The stream provided cannot seek
		/// </exception>
		public ZipFile(Stream baseStream)
		{
			this.baseStream  = baseStream;
			this.name = null;
			try {
				ReadEntries();
			}
			catch {
				Close();
				throw;
			}
		}
		
		
		/// <summary>
		/// Get/set a flag indicating if the underlying stream is owned by the ZipFile instance.
		/// If the flag is true then the stream will be closed when <see cref="Close">Close</see> is called.
		/// </summary>
		/// <remarks>
		/// The default value is true in all cases.
		/// </remarks>
		bool IsStreamOwner
		{
			get { return isStreamOwner; }
			set { isStreamOwner = value; }
		}
		
		/// <summary>
		/// Read an unsigned short in little endian byte order.
		/// </summary>
		/// <returns>Returns the value read.</returns>
		/// <exception cref="IOException">
		/// An i/o error occurs.
		/// </exception>
		/// <exception cref="EndOfStreamException">
		/// The file ends prematurely
		/// </exception>
		int ReadLeShort()
		{
			return baseStream.ReadByte() | baseStream.ReadByte() << 8;
		}
		
		/// <summary>
		/// Read an int in little endian byte order.
		/// </summary>
		/// <returns>Returns the value read.</returns>
		/// <exception cref="IOException">
		/// An i/o error occurs.
		/// </exception>
		/// <exception cref="System.IO.EndOfStreamException">
		/// The file ends prematurely
		/// </exception>
		int ReadLeInt()
		{
			return ReadLeShort() | ReadLeShort() << 16;
		}
		
		// NOTE this returns the offset of the first byte after the signature.
		long LocateBlockWithSignature(int signature, long endLocation, int minimumBlockSize, int maximumVariableData)
		{
			long pos = endLocation - minimumBlockSize;
			if (pos < 0) {
				return -1;
			}
		
			long giveUpMarker = Math.Max(pos - maximumVariableData, 0);
		
			// TODO: this loop could be optimised for speed.
			do 
			{
				if (pos < giveUpMarker) {
					return -1;
				}