// GZipStream.cs
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// ------------------------------------------------------------------
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//
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// Copyright (c) 2009 Dino Chiesa and Microsoft Corporation.
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// All rights reserved.
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//
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// This code module is part of DotNetZip, a zipfile class library.
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//
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// ------------------------------------------------------------------
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//
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// This code is licensed under the Microsoft Public License.
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// See the file License.txt for the license details.
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// More info on: http://dotnetzip.codeplex.com
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//
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// ------------------------------------------------------------------
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//
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// last saved (in emacs):
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// Time-stamp: <2011-July-11 21:42:34>
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//
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// ------------------------------------------------------------------
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//
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// This module defines the GZipStream class, which can be used as a replacement for
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// the System.IO.Compression.GZipStream class in the .NET BCL. NB: The design is not
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// completely OO clean: there is some intelligence in the ZlibBaseStream that reads the
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// GZip header.
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//
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// ------------------------------------------------------------------
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using System;
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using System.IO;
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namespace HH.WMS.Utils.Ionic.Zlib
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{
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/// <summary>
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/// A class for compressing and decompressing GZIP streams.
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/// </summary>
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/// <remarks>
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///
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/// <para>
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/// The <c>GZipStream</c> is a <see
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/// href="http://en.wikipedia.org/wiki/Decorator_pattern">Decorator</see> on a
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/// <see cref="Stream"/>. It adds GZIP compression or decompression to any
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/// stream.
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/// </para>
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///
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/// <para>
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/// Like the <c>System.IO.Compression.GZipStream</c> in the .NET Base Class Library, the
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/// <c>HH.WMS.Utils.Ionic.Zlib.GZipStream</c> can compress while writing, or decompress while
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/// reading, but not vice versa. The compression method used is GZIP, which is
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/// documented in <see href="http://www.ietf.org/rfc/rfc1952.txt">IETF RFC
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/// 1952</see>, "GZIP file format specification version 4.3".</para>
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///
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/// <para>
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/// A <c>GZipStream</c> can be used to decompress data (through <c>Read()</c>) or
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/// to compress data (through <c>Write()</c>), but not both.
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/// </para>
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///
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/// <para>
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/// If you wish to use the <c>GZipStream</c> to compress data, you must wrap it
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/// around a write-able stream. As you call <c>Write()</c> on the <c>GZipStream</c>, the
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/// data will be compressed into the GZIP format. If you want to decompress data,
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/// you must wrap the <c>GZipStream</c> around a readable stream that contains an
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/// IETF RFC 1952-compliant stream. The data will be decompressed as you call
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/// <c>Read()</c> on the <c>GZipStream</c>.
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/// </para>
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///
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/// <para>
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/// Though the GZIP format allows data from multiple files to be concatenated
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/// together, this stream handles only a single segment of GZIP format, typically
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/// representing a single file.
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/// </para>
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///
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/// <para>
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/// This class is similar to <see cref="ZlibStream"/> and <see cref="DeflateStream"/>.
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/// <c>ZlibStream</c> handles RFC1950-compliant streams. <see cref="DeflateStream"/>
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/// handles RFC1951-compliant streams. This class handles RFC1952-compliant streams.
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/// </para>
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///
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/// </remarks>
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///
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/// <seealso cref="DeflateStream" />
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/// <seealso cref="ZlibStream" />
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public class GZipStream : System.IO.Stream
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{
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// GZip format
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// source: http://tools.ietf.org/html/rfc1952
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//
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// header id: 2 bytes 1F 8B
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// compress method 1 byte 8= DEFLATE (none other supported)
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// flag 1 byte bitfield (See below)
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// mtime 4 bytes time_t (seconds since jan 1, 1970 UTC of the file.
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// xflg 1 byte 2 = max compress used , 4 = max speed (can be ignored)
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// OS 1 byte OS for originating archive. set to 0xFF in compression.
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// extra field length 2 bytes optional - only if FEXTRA is set.
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// extra field varies
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// filename varies optional - if FNAME is set. zero terminated. ISO-8859-1.
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// file comment varies optional - if FCOMMENT is set. zero terminated. ISO-8859-1.
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// crc16 1 byte optional - present only if FHCRC bit is set
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// compressed data varies
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// CRC32 4 bytes
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// isize 4 bytes data size modulo 2^32
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//
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// FLG (FLaGs)
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// bit 0 FTEXT - indicates file is ASCII text (can be safely ignored)
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// bit 1 FHCRC - there is a CRC16 for the header immediately following the header
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// bit 2 FEXTRA - extra fields are present
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// bit 3 FNAME - the zero-terminated filename is present. encoding; ISO-8859-1.
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// bit 4 FCOMMENT - a zero-terminated file comment is present. encoding: ISO-8859-1
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// bit 5 reserved
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// bit 6 reserved
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// bit 7 reserved
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//
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// On consumption:
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// Extra field is a bunch of nonsense and can be safely ignored.
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// Header CRC and OS, likewise.
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//
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// on generation:
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// all optional fields get 0, except for the OS, which gets 255.
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//
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/// <summary>
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/// The comment on the GZIP stream.
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/// </summary>
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///
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/// <remarks>
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/// <para>
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/// The GZIP format allows for each file to optionally have an associated
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/// comment stored with the file. The comment is encoded with the ISO-8859-1
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/// code page. To include a comment in a GZIP stream you create, set this
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/// property before calling <c>Write()</c> for the first time on the
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/// <c>GZipStream</c>.
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/// </para>
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///
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/// <para>
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/// When using <c>GZipStream</c> to decompress, you can retrieve this property
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/// after the first call to <c>Read()</c>. If no comment has been set in the
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/// GZIP bytestream, the Comment property will return <c>null</c>
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/// (<c>Nothing</c> in VB).
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/// </para>
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/// </remarks>
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public String Comment
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{
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get
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{
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return _Comment;
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}
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set
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{
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if (_disposed) throw new ObjectDisposedException("GZipStream");
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_Comment = value;
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}
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}
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/// <summary>
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/// The FileName for the GZIP stream.
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/// </summary>
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///
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/// <remarks>
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///
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/// <para>
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/// The GZIP format optionally allows each file to have an associated
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/// filename. When compressing data (through <c>Write()</c>), set this
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/// FileName before calling <c>Write()</c> the first time on the <c>GZipStream</c>.
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/// The actual filename is encoded into the GZIP bytestream with the
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/// ISO-8859-1 code page, according to RFC 1952. It is the application's
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/// responsibility to insure that the FileName can be encoded and decoded
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/// correctly with this code page.
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/// </para>
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///
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/// <para>
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/// When decompressing (through <c>Read()</c>), you can retrieve this value
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/// any time after the first <c>Read()</c>. In the case where there was no filename
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/// encoded into the GZIP bytestream, the property will return <c>null</c> (<c>Nothing</c>
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/// in VB).
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/// </para>
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/// </remarks>
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public String FileName
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{
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get { return _FileName; }
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set
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{
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if (_disposed) throw new ObjectDisposedException("GZipStream");
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_FileName = value;
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if (_FileName == null) return;
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if (_FileName.IndexOf("/") != -1)
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{
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_FileName = _FileName.Replace("/", "\\");
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}
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if (_FileName.EndsWith("\\"))
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throw new Exception("Illegal filename");
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if (_FileName.IndexOf("\\") != -1)
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{
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// trim any leading path
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_FileName = Path.GetFileName(_FileName);
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}
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}
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}
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/// <summary>
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/// The last modified time for the GZIP stream.
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/// </summary>
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///
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/// <remarks>
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/// GZIP allows the storage of a last modified time with each GZIP entry.
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/// When compressing data, you can set this before the first call to
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/// <c>Write()</c>. When decompressing, you can retrieve this value any time
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/// after the first call to <c>Read()</c>.
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/// </remarks>
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public DateTime? LastModified;
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/// <summary>
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/// The CRC on the GZIP stream.
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/// </summary>
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/// <remarks>
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/// This is used for internal error checking. You probably don't need to look at this property.
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/// </remarks>
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public int Crc32 { get { return _Crc32; } }
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private int _headerByteCount;
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internal ZlibBaseStream _baseStream;
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bool _disposed;
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bool _firstReadDone;
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string _FileName;
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string _Comment;
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int _Crc32;
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/// <summary>
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/// Create a <c>GZipStream</c> using the specified <c>CompressionMode</c>.
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/// </summary>
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/// <remarks>
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///
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/// <para>
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/// When mode is <c>CompressionMode.Compress</c>, the <c>GZipStream</c> will use the
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/// default compression level.
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/// </para>
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///
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/// <para>
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/// As noted in the class documentation, the <c>CompressionMode</c> (Compress
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/// or Decompress) also establishes the "direction" of the stream. A
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/// <c>GZipStream</c> with <c>CompressionMode.Compress</c> works only through
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/// <c>Write()</c>. A <c>GZipStream</c> with
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/// <c>CompressionMode.Decompress</c> works only through <c>Read()</c>.
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/// </para>
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///
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/// </remarks>
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///
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/// <example>
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/// This example shows how to use a GZipStream to compress data.
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/// <code>
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/// using (System.IO.Stream input = System.IO.File.OpenRead(fileToCompress))
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/// {
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/// using (var raw = System.IO.File.Create(outputFile))
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/// {
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/// using (Stream compressor = new GZipStream(raw, CompressionMode.Compress))
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/// {
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/// byte[] buffer = new byte[WORKING_BUFFER_SIZE];
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/// int n;
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/// while ((n= input.Read(buffer, 0, buffer.Length)) != 0)
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/// {
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/// compressor.Write(buffer, 0, n);
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/// }
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/// }
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/// }
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/// }
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/// </code>
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/// <code lang="VB">
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/// Dim outputFile As String = (fileToCompress & ".compressed")
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/// Using input As Stream = File.OpenRead(fileToCompress)
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/// Using raw As FileStream = File.Create(outputFile)
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/// Using compressor As Stream = New GZipStream(raw, CompressionMode.Compress)
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/// Dim buffer As Byte() = New Byte(4096) {}
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/// Dim n As Integer = -1
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/// Do While (n <> 0)
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/// If (n > 0) Then
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/// compressor.Write(buffer, 0, n)
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/// End If
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/// n = input.Read(buffer, 0, buffer.Length)
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/// Loop
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/// End Using
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/// End Using
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/// End Using
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/// </code>
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/// </example>
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///
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/// <example>
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/// This example shows how to use a GZipStream to uncompress a file.
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/// <code>
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/// private void GunZipFile(string filename)
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/// {
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/// if (!filename.EndsWith(".gz))
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/// throw new ArgumentException("filename");
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/// var DecompressedFile = filename.Substring(0,filename.Length-3);
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/// byte[] working = new byte[WORKING_BUFFER_SIZE];
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/// int n= 1;
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/// using (System.IO.Stream input = System.IO.File.OpenRead(filename))
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/// {
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/// using (Stream decompressor= new HH.WMS.Utils.Ionic.Zlib.GZipStream(input, CompressionMode.Decompress, true))
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/// {
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/// using (var output = System.IO.File.Create(DecompressedFile))
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/// {
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/// while (n !=0)
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/// {
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/// n= decompressor.Read(working, 0, working.Length);
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/// if (n > 0)
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/// {
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/// output.Write(working, 0, n);
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/// }
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/// }
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/// }
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/// }
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/// }
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/// }
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/// </code>
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///
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/// <code lang="VB">
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/// Private Sub GunZipFile(ByVal filename as String)
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/// If Not (filename.EndsWith(".gz)) Then
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/// Throw New ArgumentException("filename")
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/// End If
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/// Dim DecompressedFile as String = filename.Substring(0,filename.Length-3)
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/// Dim working(WORKING_BUFFER_SIZE) as Byte
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/// Dim n As Integer = 1
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/// Using input As Stream = File.OpenRead(filename)
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/// Using decompressor As Stream = new HH.WMS.Utils.Ionic.Zlib.GZipStream(input, CompressionMode.Decompress, True)
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/// Using output As Stream = File.Create(UncompressedFile)
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/// Do
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/// n= decompressor.Read(working, 0, working.Length)
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/// If n > 0 Then
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/// output.Write(working, 0, n)
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/// End IF
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/// Loop While (n > 0)
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/// End Using
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/// End Using
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/// End Using
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/// End Sub
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/// </code>
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/// </example>
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///
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/// <param name="stream">The stream which will be read or written.</param>
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/// <param name="mode">Indicates whether the GZipStream will compress or decompress.</param>
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public GZipStream(Stream stream, CompressionMode mode)
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: this(stream, mode, CompressionLevel.Default, false)
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{
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}
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/// <summary>
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/// Create a <c>GZipStream</c> using the specified <c>CompressionMode</c> and
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/// the specified <c>CompressionLevel</c>.
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/// </summary>
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/// <remarks>
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///
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/// <para>
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/// The <c>CompressionMode</c> (Compress or Decompress) also establishes the
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/// "direction" of the stream. A <c>GZipStream</c> with
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/// <c>CompressionMode.Compress</c> works only through <c>Write()</c>. A
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/// <c>GZipStream</c> with <c>CompressionMode.Decompress</c> works only
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/// through <c>Read()</c>.
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/// </para>
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///
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/// </remarks>
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///
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/// <example>
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///
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/// This example shows how to use a <c>GZipStream</c> to compress a file into a .gz file.
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///
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/// <code>
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/// using (System.IO.Stream input = System.IO.File.OpenRead(fileToCompress))
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/// {
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/// using (var raw = System.IO.File.Create(fileToCompress + ".gz"))
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/// {
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/// using (Stream compressor = new GZipStream(raw,
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/// CompressionMode.Compress,
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/// CompressionLevel.BestCompression))
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/// {
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/// byte[] buffer = new byte[WORKING_BUFFER_SIZE];
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/// int n;
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/// while ((n= input.Read(buffer, 0, buffer.Length)) != 0)
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/// {
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/// compressor.Write(buffer, 0, n);
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/// }
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/// }
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/// }
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/// }
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/// </code>
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///
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/// <code lang="VB">
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/// Using input As Stream = File.OpenRead(fileToCompress)
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/// Using raw As FileStream = File.Create(fileToCompress & ".gz")
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/// Using compressor As Stream = New GZipStream(raw, CompressionMode.Compress, CompressionLevel.BestCompression)
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/// Dim buffer As Byte() = New Byte(4096) {}
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/// Dim n As Integer = -1
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/// Do While (n <> 0)
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/// If (n > 0) Then
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/// compressor.Write(buffer, 0, n)
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/// End If
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/// n = input.Read(buffer, 0, buffer.Length)
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/// Loop
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/// End Using
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/// End Using
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/// End Using
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/// </code>
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/// </example>
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/// <param name="stream">The stream to be read or written while deflating or inflating.</param>
|
/// <param name="mode">Indicates whether the <c>GZipStream</c> will compress or decompress.</param>
|
/// <param name="level">A tuning knob to trade speed for effectiveness.</param>
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public GZipStream(Stream stream, CompressionMode mode, CompressionLevel level)
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: this(stream, mode, level, false)
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{
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}
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/// <summary>
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/// Create a <c>GZipStream</c> using the specified <c>CompressionMode</c>, and
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/// explicitly specify whether the stream should be left open after Deflation
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/// or Inflation.
|
/// </summary>
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///
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/// <remarks>
|
/// <para>
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/// This constructor allows the application to request that the captive stream
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/// remain open after the deflation or inflation occurs. By default, after
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/// <c>Close()</c> is called on the stream, the captive stream is also
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/// closed. In some cases this is not desired, for example if the stream is a
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/// memory stream that will be re-read after compressed data has been written
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/// to it. Specify true for the <paramref name="leaveOpen"/> parameter to leave
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/// the stream open.
|
/// </para>
|
///
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/// <para>
|
/// The <see cref="CompressionMode"/> (Compress or Decompress) also
|
/// establishes the "direction" of the stream. A <c>GZipStream</c> with
|
/// <c>CompressionMode.Compress</c> works only through <c>Write()</c>. A <c>GZipStream</c>
|
/// with <c>CompressionMode.Decompress</c> works only through <c>Read()</c>.
|
/// </para>
|
///
|
/// <para>
|
/// The <c>GZipStream</c> will use the default compression level. If you want
|
/// to specify the compression level, see <see cref="GZipStream(Stream,
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/// CompressionMode, CompressionLevel, bool)"/>.
|
/// </para>
|
///
|
/// <para>
|
/// See the other overloads of this constructor for example code.
|
/// </para>
|
///
|
/// </remarks>
|
///
|
/// <param name="stream">
|
/// The stream which will be read or written. This is called the "captive"
|
/// stream in other places in this documentation.
|
/// </param>
|
///
|
/// <param name="mode">Indicates whether the GZipStream will compress or decompress.
|
/// </param>
|
///
|
/// <param name="leaveOpen">
|
/// true if the application would like the base stream to remain open after
|
/// inflation/deflation.
|
/// </param>
|
public GZipStream(Stream stream, CompressionMode mode, bool leaveOpen)
|
: this(stream, mode, CompressionLevel.Default, leaveOpen)
|
{
|
}
|
|
/// <summary>
|
/// Create a <c>GZipStream</c> using the specified <c>CompressionMode</c> and the
|
/// specified <c>CompressionLevel</c>, and explicitly specify whether the
|
/// stream should be left open after Deflation or Inflation.
|
/// </summary>
|
///
|
/// <remarks>
|
///
|
/// <para>
|
/// This constructor allows the application to request that the captive stream
|
/// remain open after the deflation or inflation occurs. By default, after
|
/// <c>Close()</c> is called on the stream, the captive stream is also
|
/// closed. In some cases this is not desired, for example if the stream is a
|
/// memory stream that will be re-read after compressed data has been written
|
/// to it. Specify true for the <paramref name="leaveOpen"/> parameter to
|
/// leave the stream open.
|
/// </para>
|
///
|
/// <para>
|
/// As noted in the class documentation, the <c>CompressionMode</c> (Compress
|
/// or Decompress) also establishes the "direction" of the stream. A
|
/// <c>GZipStream</c> with <c>CompressionMode.Compress</c> works only through
|
/// <c>Write()</c>. A <c>GZipStream</c> with <c>CompressionMode.Decompress</c> works only
|
/// through <c>Read()</c>.
|
/// </para>
|
///
|
/// </remarks>
|
///
|
/// <example>
|
/// This example shows how to use a <c>GZipStream</c> to compress data.
|
/// <code>
|
/// using (System.IO.Stream input = System.IO.File.OpenRead(fileToCompress))
|
/// {
|
/// using (var raw = System.IO.File.Create(outputFile))
|
/// {
|
/// using (Stream compressor = new GZipStream(raw, CompressionMode.Compress, CompressionLevel.BestCompression, true))
|
/// {
|
/// byte[] buffer = new byte[WORKING_BUFFER_SIZE];
|
/// int n;
|
/// while ((n= input.Read(buffer, 0, buffer.Length)) != 0)
|
/// {
|
/// compressor.Write(buffer, 0, n);
|
/// }
|
/// }
|
/// }
|
/// }
|
/// </code>
|
/// <code lang="VB">
|
/// Dim outputFile As String = (fileToCompress & ".compressed")
|
/// Using input As Stream = File.OpenRead(fileToCompress)
|
/// Using raw As FileStream = File.Create(outputFile)
|
/// Using compressor As Stream = New GZipStream(raw, CompressionMode.Compress, CompressionLevel.BestCompression, True)
|
/// Dim buffer As Byte() = New Byte(4096) {}
|
/// Dim n As Integer = -1
|
/// Do While (n <> 0)
|
/// If (n > 0) Then
|
/// compressor.Write(buffer, 0, n)
|
/// End If
|
/// n = input.Read(buffer, 0, buffer.Length)
|
/// Loop
|
/// End Using
|
/// End Using
|
/// End Using
|
/// </code>
|
/// </example>
|
/// <param name="stream">The stream which will be read or written.</param>
|
/// <param name="mode">Indicates whether the GZipStream will compress or decompress.</param>
|
/// <param name="leaveOpen">true if the application would like the stream to remain open after inflation/deflation.</param>
|
/// <param name="level">A tuning knob to trade speed for effectiveness.</param>
|
public GZipStream(Stream stream, CompressionMode mode, CompressionLevel level, bool leaveOpen)
|
{
|
_baseStream = new ZlibBaseStream(stream, mode, level, ZlibStreamFlavor.GZIP, leaveOpen);
|
}
|
|
#region Zlib properties
|
|
/// <summary>
|
/// This property sets the flush behavior on the stream.
|
/// </summary>
|
virtual public FlushType FlushMode
|
{
|
get { return (this._baseStream._flushMode); }
|
set {
|
if (_disposed) throw new ObjectDisposedException("GZipStream");
|
this._baseStream._flushMode = value;
|
}
|
}
|
|
/// <summary>
|
/// The size of the working buffer for the compression codec.
|
/// </summary>
|
///
|
/// <remarks>
|
/// <para>
|
/// The working buffer is used for all stream operations. The default size is
|
/// 1024 bytes. The minimum size is 128 bytes. You may get better performance
|
/// with a larger buffer. Then again, you might not. You would have to test
|
/// it.
|
/// </para>
|
///
|
/// <para>
|
/// Set this before the first call to <c>Read()</c> or <c>Write()</c> on the
|
/// stream. If you try to set it afterwards, it will throw.
|
/// </para>
|
/// </remarks>
|
public int BufferSize
|
{
|
get
|
{
|
return this._baseStream._bufferSize;
|
}
|
set
|
{
|
if (_disposed) throw new ObjectDisposedException("GZipStream");
|
if (this._baseStream._workingBuffer != null)
|
throw new ZlibException("The working buffer is already set.");
|
if (value < ZlibConstants.WorkingBufferSizeMin)
|
throw new ZlibException(String.Format("Don't be silly. {0} bytes?? Use a bigger buffer, at least {1}.", value, ZlibConstants.WorkingBufferSizeMin));
|
this._baseStream._bufferSize = value;
|
}
|
}
|
|
|
/// <summary> Returns the total number of bytes input so far.</summary>
|
virtual public long TotalIn
|
{
|
get
|
{
|
return this._baseStream._z.TotalBytesIn;
|
}
|
}
|
|
/// <summary> Returns the total number of bytes output so far.</summary>
|
virtual public long TotalOut
|
{
|
get
|
{
|
return this._baseStream._z.TotalBytesOut;
|
}
|
}
|
|
#endregion
|
|
#region Stream methods
|
|
/// <summary>
|
/// Dispose the stream.
|
/// </summary>
|
/// <remarks>
|
/// <para>
|
/// This may or may not result in a <c>Close()</c> call on the captive
|
/// stream. See the constructors that have a <c>leaveOpen</c> parameter
|
/// for more information.
|
/// </para>
|
/// <para>
|
/// This method may be invoked in two distinct scenarios. If disposing
|
/// == true, the method has been called directly or indirectly by a
|
/// user's code, for example via the public Dispose() method. In this
|
/// case, both managed and unmanaged resources can be referenced and
|
/// disposed. If disposing == false, the method has been called by the
|
/// runtime from inside the object finalizer and this method should not
|
/// reference other objects; in that case only unmanaged resources must
|
/// be referenced or disposed.
|
/// </para>
|
/// </remarks>
|
/// <param name="disposing">
|
/// indicates whether the Dispose method was invoked by user code.
|
/// </param>
|
protected override void Dispose(bool disposing)
|
{
|
try
|
{
|
if (!_disposed)
|
{
|
if (disposing && (this._baseStream != null))
|
{
|
this._baseStream.Close();
|
this._Crc32 = _baseStream.Crc32;
|
}
|
_disposed = true;
|
}
|
}
|
finally
|
{
|
base.Dispose(disposing);
|
}
|
}
|
|
|
/// <summary>
|
/// Indicates whether the stream can be read.
|
/// </summary>
|
/// <remarks>
|
/// The return value depends on whether the captive stream supports reading.
|
/// </remarks>
|
public override bool CanRead
|
{
|
get
|
{
|
if (_disposed) throw new ObjectDisposedException("GZipStream");
|
return _baseStream._stream.CanRead;
|
}
|
}
|
|
/// <summary>
|
/// Indicates whether the stream supports Seek operations.
|
/// </summary>
|
/// <remarks>
|
/// Always returns false.
|
/// </remarks>
|
public override bool CanSeek
|
{
|
get { return false; }
|
}
|
|
|
/// <summary>
|
/// Indicates whether the stream can be written.
|
/// </summary>
|
/// <remarks>
|
/// The return value depends on whether the captive stream supports writing.
|
/// </remarks>
|
public override bool CanWrite
|
{
|
get
|
{
|
if (_disposed) throw new ObjectDisposedException("GZipStream");
|
return _baseStream._stream.CanWrite;
|
}
|
}
|
|
/// <summary>
|
/// Flush the stream.
|
/// </summary>
|
public override void Flush()
|
{
|
if (_disposed) throw new ObjectDisposedException("GZipStream");
|
_baseStream.Flush();
|
}
|
|
/// <summary>
|
/// Reading this property always throws a <see cref="NotImplementedException"/>.
|
/// </summary>
|
public override long Length
|
{
|
get { throw new NotImplementedException(); }
|
}
|
|
/// <summary>
|
/// The position of the stream pointer.
|
/// </summary>
|
///
|
/// <remarks>
|
/// Setting this property always throws a <see
|
/// cref="NotImplementedException"/>. Reading will return the total bytes
|
/// written out, if used in writing, or the total bytes read in, if used in
|
/// reading. The count may refer to compressed bytes or uncompressed bytes,
|
/// depending on how you've used the stream.
|
/// </remarks>
|
public override long Position
|
{
|
get
|
{
|
if (this._baseStream._streamMode == HH.WMS.Utils.Ionic.Zlib.ZlibBaseStream.StreamMode.Writer)
|
return this._baseStream._z.TotalBytesOut + _headerByteCount;
|
if (this._baseStream._streamMode == HH.WMS.Utils.Ionic.Zlib.ZlibBaseStream.StreamMode.Reader)
|
return this._baseStream._z.TotalBytesIn + this._baseStream._gzipHeaderByteCount;
|
return 0;
|
}
|
|
set { throw new NotImplementedException(); }
|
}
|
|
/// <summary>
|
/// Read and decompress data from the source stream.
|
/// </summary>
|
///
|
/// <remarks>
|
/// With a <c>GZipStream</c>, decompression is done through reading.
|
/// </remarks>
|
///
|
/// <example>
|
/// <code>
|
/// byte[] working = new byte[WORKING_BUFFER_SIZE];
|
/// using (System.IO.Stream input = System.IO.File.OpenRead(_CompressedFile))
|
/// {
|
/// using (Stream decompressor= new HH.WMS.Utils.Ionic.Zlib.GZipStream(input, CompressionMode.Decompress, true))
|
/// {
|
/// using (var output = System.IO.File.Create(_DecompressedFile))
|
/// {
|
/// int n;
|
/// while ((n= decompressor.Read(working, 0, working.Length)) !=0)
|
/// {
|
/// output.Write(working, 0, n);
|
/// }
|
/// }
|
/// }
|
/// }
|
/// </code>
|
/// </example>
|
/// <param name="buffer">The buffer into which the decompressed data should be placed.</param>
|
/// <param name="offset">the offset within that data array to put the first byte read.</param>
|
/// <param name="count">the number of bytes to read.</param>
|
/// <returns>the number of bytes actually read</returns>
|
public override int Read(byte[] buffer, int offset, int count)
|
{
|
if (_disposed) throw new ObjectDisposedException("GZipStream");
|
int n = _baseStream.Read(buffer, offset, count);
|
|
// Console.WriteLine("GZipStream::Read(buffer, off({0}), c({1}) = {2}", offset, count, n);
|
// Console.WriteLine( Util.FormatByteArray(buffer, offset, n) );
|
|
if (!_firstReadDone)
|
{
|
_firstReadDone = true;
|
FileName = _baseStream._GzipFileName;
|
Comment = _baseStream._GzipComment;
|
}
|
return n;
|
}
|
|
|
|
/// <summary>
|
/// Calling this method always throws a <see cref="NotImplementedException"/>.
|
/// </summary>
|
/// <param name="offset">irrelevant; it will always throw!</param>
|
/// <param name="origin">irrelevant; it will always throw!</param>
|
/// <returns>irrelevant!</returns>
|
public override long Seek(long offset, SeekOrigin origin)
|
{
|
throw new NotImplementedException();
|
}
|
|
/// <summary>
|
/// Calling this method always throws a <see cref="NotImplementedException"/>.
|
/// </summary>
|
/// <param name="value">irrelevant; this method will always throw!</param>
|
public override void SetLength(long value)
|
{
|
throw new NotImplementedException();
|
}
|
|
/// <summary>
|
/// Write data to the stream.
|
/// </summary>
|
///
|
/// <remarks>
|
/// <para>
|
/// If you wish to use the <c>GZipStream</c> to compress data while writing,
|
/// you can create a <c>GZipStream</c> with <c>CompressionMode.Compress</c>, and a
|
/// writable output stream. Then call <c>Write()</c> on that <c>GZipStream</c>,
|
/// providing uncompressed data as input. The data sent to the output stream
|
/// will be the compressed form of the data written.
|
/// </para>
|
///
|
/// <para>
|
/// A <c>GZipStream</c> can be used for <c>Read()</c> or <c>Write()</c>, but not
|
/// both. Writing implies compression. Reading implies decompression.
|
/// </para>
|
///
|
/// </remarks>
|
/// <param name="buffer">The buffer holding data to write to the stream.</param>
|
/// <param name="offset">the offset within that data array to find the first byte to write.</param>
|
/// <param name="count">the number of bytes to write.</param>
|
public override void Write(byte[] buffer, int offset, int count)
|
{
|
if (_disposed) throw new ObjectDisposedException("GZipStream");
|
if (_baseStream._streamMode == HH.WMS.Utils.Ionic.Zlib.ZlibBaseStream.StreamMode.Undefined)
|
{
|
//Console.WriteLine("GZipStream: First write");
|
if (_baseStream._wantCompress)
|
{
|
// first write in compression, therefore, emit the GZIP header
|
_headerByteCount = EmitHeader();
|
}
|
else
|
{
|
throw new InvalidOperationException();
|
}
|
}
|
|
_baseStream.Write(buffer, offset, count);
|
}
|
#endregion
|
|
|
internal static readonly System.DateTime _unixEpoch = new System.DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
|
internal static readonly System.Text.Encoding iso8859dash1 = System.Text.Encoding.GetEncoding("iso-8859-1");
|
|
|
private int EmitHeader()
|
{
|
byte[] commentBytes = (Comment == null) ? null : iso8859dash1.GetBytes(Comment);
|
byte[] filenameBytes = (FileName == null) ? null : iso8859dash1.GetBytes(FileName);
|
|
int cbLength = (Comment == null) ? 0 : commentBytes.Length + 1;
|
int fnLength = (FileName == null) ? 0 : filenameBytes.Length + 1;
|
|
int bufferLength = 10 + cbLength + fnLength;
|
byte[] header = new byte[bufferLength];
|
int i = 0;
|
// ID
|
header[i++] = 0x1F;
|
header[i++] = 0x8B;
|
|
// compression method
|
header[i++] = 8;
|
byte flag = 0;
|
if (Comment != null)
|
flag ^= 0x10;
|
if (FileName != null)
|
flag ^= 0x8;
|
|
// flag
|
header[i++] = flag;
|
|
// mtime
|
if (!LastModified.HasValue) LastModified = DateTime.Now;
|
System.TimeSpan delta = LastModified.Value - _unixEpoch;
|
Int32 timet = (Int32)delta.TotalSeconds;
|
Array.Copy(BitConverter.GetBytes(timet), 0, header, i, 4);
|
i += 4;
|
|
// xflg
|
header[i++] = 0; // this field is totally useless
|
// OS
|
header[i++] = 0xFF; // 0xFF == unspecified
|
|
// extra field length - only if FEXTRA is set, which it is not.
|
//header[i++]= 0;
|
//header[i++]= 0;
|
|
// filename
|
if (fnLength != 0)
|
{
|
Array.Copy(filenameBytes, 0, header, i, fnLength - 1);
|
i += fnLength - 1;
|
header[i++] = 0; // terminate
|
}
|
|
// comment
|
if (cbLength != 0)
|
{
|
Array.Copy(commentBytes, 0, header, i, cbLength - 1);
|
i += cbLength - 1;
|
header[i++] = 0; // terminate
|
}
|
|
_baseStream._stream.Write(header, 0, header.Length);
|
|
return header.Length; // bytes written
|
}
|
|
|
|
/// <summary>
|
/// Compress a string into a byte array using GZip.
|
/// </summary>
|
///
|
/// <remarks>
|
/// Uncompress it with <see cref="GZipStream.UncompressString(byte[])"/>.
|
/// </remarks>
|
///
|
/// <seealso cref="GZipStream.UncompressString(byte[])"/>
|
/// <seealso cref="GZipStream.CompressBuffer(byte[])"/>
|
///
|
/// <param name="s">
|
/// A string to compress. The string will first be encoded
|
/// using UTF8, then compressed.
|
/// </param>
|
///
|
/// <returns>The string in compressed form</returns>
|
public static byte[] CompressString(String s)
|
{
|
using (var ms = new MemoryStream())
|
{
|
System.IO.Stream compressor =
|
new GZipStream(ms, CompressionMode.Compress, CompressionLevel.BestCompression);
|
ZlibBaseStream.CompressString(s, compressor);
|
return ms.ToArray();
|
}
|
}
|
|
|
/// <summary>
|
/// Compress a byte array into a new byte array using GZip.
|
/// </summary>
|
///
|
/// <remarks>
|
/// Uncompress it with <see cref="GZipStream.UncompressBuffer(byte[])"/>.
|
/// </remarks>
|
///
|
/// <seealso cref="GZipStream.CompressString(string)"/>
|
/// <seealso cref="GZipStream.UncompressBuffer(byte[])"/>
|
///
|
/// <param name="b">
|
/// A buffer to compress.
|
/// </param>
|
///
|
/// <returns>The data in compressed form</returns>
|
public static byte[] CompressBuffer(byte[] b)
|
{
|
using (var ms = new MemoryStream())
|
{
|
System.IO.Stream compressor =
|
new GZipStream( ms, CompressionMode.Compress, CompressionLevel.BestCompression );
|
|
ZlibBaseStream.CompressBuffer(b, compressor);
|
return ms.ToArray();
|
}
|
}
|
|
|
/// <summary>
|
/// Uncompress a GZip'ed byte array into a single string.
|
/// </summary>
|
///
|
/// <seealso cref="GZipStream.CompressString(String)"/>
|
/// <seealso cref="GZipStream.UncompressBuffer(byte[])"/>
|
///
|
/// <param name="compressed">
|
/// A buffer containing GZIP-compressed data.
|
/// </param>
|
///
|
/// <returns>The uncompressed string</returns>
|
public static String UncompressString(byte[] compressed)
|
{
|
using (var input = new MemoryStream(compressed))
|
{
|
Stream decompressor = new GZipStream(input, CompressionMode.Decompress);
|
return ZlibBaseStream.UncompressString(compressed, decompressor);
|
}
|
}
|
|
|
/// <summary>
|
/// Uncompress a GZip'ed byte array into a byte array.
|
/// </summary>
|
///
|
/// <seealso cref="GZipStream.CompressBuffer(byte[])"/>
|
/// <seealso cref="GZipStream.UncompressString(byte[])"/>
|
///
|
/// <param name="compressed">
|
/// A buffer containing data that has been compressed with GZip.
|
/// </param>
|
///
|
/// <returns>The data in uncompressed form</returns>
|
public static byte[] UncompressBuffer(byte[] compressed)
|
{
|
using (var input = new System.IO.MemoryStream(compressed))
|
{
|
System.IO.Stream decompressor =
|
new GZipStream( input, CompressionMode.Decompress );
|
|
return ZlibBaseStream.UncompressBuffer(compressed, decompressor);
|
}
|
}
|
|
|
}
|
}
|
