// ZlibStream.cs
// ------------------------------------------------------------------
//
// Copyright (c) 2009 Dino Chiesa and Microsoft Corporation.
// All rights reserved.
//
// This code module is part of DotNetZip, a zipfile class library.
//
// ------------------------------------------------------------------
//
// This code is licensed under the Microsoft Public License.
// See the file License.txt for the license details.
// More info on: http://dotnetzip.codeplex.com
//
// ------------------------------------------------------------------
//
// last saved (in emacs):
// Time-stamp: <2010-January-29 16:35:23>
//
// ------------------------------------------------------------------
//
// This module defines the ZlibStream class, which is similar in idea to
// the System.IO.Compression.DeflateStream and
// System.IO.Compression.GZipStream classes in the .NET BCL.
//
// ------------------------------------------------------------------
using System;
using System.IO;
namespace Ionic.Zlib
{
/// <summary>
/// Represents a Zlib stream for compression or decompression.
/// </summary>
/// <remarks>
///
/// <para>
/// The ZlibStream is a <see
/// href="http://en.wikipedia.org/wiki/Decorator_pattern">Decorator</see> on a <see
/// cref="System.IO.Stream"/>. It adds ZLIB compression or decompression to any
/// stream.
/// </para>
///
/// <para> Using this stream, applications can compress or decompress data via
/// stream <c>Read()</c> and <c>Write()</c> operations. Either compresssion or
/// decompression can occur through either reading or writing. The compression
/// format used is ZLIB, which is documented in <see
/// href="http://www.ietf.org/rfc/rfc1950.txt">IETF RFC 1950</see>, "ZLIB Compressed
/// Data Format Specification version 3.3". This implementation of ZLIB always uses
/// DEFLATE as the compression method. (see <see
/// href="http://www.ietf.org/rfc/rfc1951.txt">IETF RFC 1951</see>, "DEFLATE
/// Compressed Data Format Specification version 1.3.") </para>
///
/// <para>
/// The ZLIB format allows for varying compression methods, window sizes, and dictionaries.
/// This implementation always uses the DEFLATE compression method, a preset dictionary,
/// and 15 window bits by default.
/// </para>
///
/// <para>
/// This class is similar to <see cref="DeflateStream"/>, except that it adds the
/// RFC1950 header and trailer bytes to a compressed stream when compressing, or expects
/// the RFC1950 header and trailer bytes when decompressing. It is also similar to the
/// <see cref="GZipStream"/>.
/// </para>
/// </remarks>
/// <seealso cref="DeflateStream" />
/// <seealso cref="GZipStream" />
public class ZlibStream : System.IO.Stream
{
internal ZlibBaseStream _baseStream;
bool _disposed;
/// <summary>
/// Create a <c>ZlibStream</c> using the specified <c>CompressionMode</c>.
/// </summary>
/// <remarks>
///
/// <para>
/// When mode is <c>CompressionMode.Compress</c>, the <c>ZlibStream</c> will use the
/// default compression level. The "captive" stream will be closed when the
/// <c>ZlibStream</c> is closed.
/// </para>
///
/// </remarks>
///
/// <example>
/// This example uses a <c>ZlibStream</c> to compress a file, and writes the compressed
/// data to another file.
/// <code>
/// using (System.IO.Stream input = System.IO.File.OpenRead(fileToCompress))
/// {
/// using (var raw = System.IO.File.Create(fileToCompress + ".zlib"))
/// {
/// using (Stream compressor = new ZlibStream(raw, CompressionMode.Compress))
/// {
/// 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">
/// Using input As Stream = File.OpenRead(fileToCompress)
/// Using raw As FileStream = File.Create(fileToCompress & ".zlib")
/// Using compressor As Stream = New ZlibStream(raw, CompressionMode.Compress)
/// 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 ZlibStream will compress or decompress.</param>
public ZlibStream(System.IO.Stream stream, CompressionMode mode)
: this(stream, mode, CompressionLevel.Default, false)
{
}
/// <summary>
/// Create a <c>ZlibStream</c> using the specified <c>CompressionMode</c> and
/// the specified <c>CompressionLevel</c>.
/// </summary>
///
/// <remarks>
///
/// <para>
/// When mode is <c>CompressionMode.Decompress</c>, the level parameter is ignored.
/// The "captive" stream will be closed when the <c>ZlibStream</c> is closed.
/// </para>
///
/// </remarks>
///
/// <example>
/// This example uses a <c>ZlibStream</c> to compress data from a file, and writes the
/// compressed data to another file.
///
/// <code>
/// using (System.IO.Stream input = System.IO.File.OpenRead(fileToCompress))
/// {
/// using (var raw = System.IO.File.Create(fileToCompress + ".zlib"))
/// {
/// using (Stream compressor = new ZlibStream(raw,
/// CompressionMode.Compress,
/// CompressionLevel.BestCompression))
/// {
/// 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">
/// Using input As Stream = File.OpenRead(fileToCompress)
/// Using raw As FileStream = File.Create(fileToCompress & ".zlib")
/// Using compressor As Stream = New ZlibStream(raw, CompressionMode.Compress, CompressionLevel.BestCompression)
/// 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 to be read or written while deflating or inflating.</param>
/// <param name="mode">Indicates whether the ZlibStream will compress or decompress.</param>
/// <param name="level">A tuning knob to trade speed for effectiveness.</param>
public ZlibStream(System.IO.Stream stream, CompressionMode mode, CompressionLevel level)
: this(stream, mode, level, false)
{
}
/// <summary>
/// Create a <c>ZlibStream</c> using the specified <c>CompressionMode</c>, and
/// explicitly specify whether the captive stream should be left open after
/// Deflation or Inflation.
/// </summary>
///
/// <remarks>
///
/// <para>
/// When mode is <c>CompressionMode.Compress</c>, the <c>ZlibStream</c> will use
/// the default compression level.
/// </para>
///
/// <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
/// <see cref="System.IO.MemoryStream"/> that will be re-read after
/// compression. Specify true for the <paramref name="leaveOpen"/> parameter to leave the stream
/// open.
/// </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 ZlibStream will compress or decompress.</param>
/// <param name="leaveOpen">true if the application would like the stream to remain
/// open after inflation/deflation.</param>
public ZlibStream(System.IO.Stream stream, CompressionMode mode, bool leaveOpen)
: this(stream, mode, CompressionLevel.Default, leaveOpen)
{
}
/// <summary>
/// Create a <c>ZlibStream</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 <see
/// cref="System.IO.MemoryStream"/> that will be re-read after compression.
/// Specify true for the <paramref name="leaveOpen"/> parameter to leave the stream open.
/// </para>
///
/// <para>
/// When mode is <c>CompressionMode.Decompress</c>, the level parameter is ignored.
/// </para>
///
/// </remarks>
///
/// <example>
/// This example shows how to use a ZlibStream to compress the data from a file,
/// and store the result into another file. The filestream remains open to allow
/// additional data to be written to it.
/// <code>
/// using (var output = System.IO.File.Create(fileToCompress + ".zlib"))
/// {
/// using (System.IO.Stream input = System.IO.File.OpenRead(fileToCompress))
/// {
/// using (Stream compressor = new ZlibStream(output, 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);
/// }
/// }
/// }
/// // can write additional data to the output stream here
/// }
/// </code>
/// <code lang="VB">
/// Using output As FileStream = File.Create(fileToCompress & ".zlib")
/// Using input As Stream = File.OpenRead(fileToCompress)
/// Using compressor As Stream = New ZlibStream(output, 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
/// ' can write additional data to the output stream here.
/// End Using
/// </code>
/// </example>
///
/// <param name="stream">The stream which will be read or written.</param>
///
/// <param name="mode">Indicates whether the ZlibStream 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. This parameter is effective only when
/// mode is <c>CompressionMode.Compress</c>.
/// </param>
public ZlibStream(System.IO.Stream stream, CompressionMode mode, CompressionLevel level, bool leaveOpen)
{
_baseStream = new ZlibBaseStream(stream, mode, level, ZlibStreamFlavor.ZLIB, leaveOpen);
}
#region Zlib properties
/// <summary>
/// This property sets the flush behavior on the stream.
/// Sorry, though, not sure exactly how to describe all the various settings.
/// </summary>
virtual public FlushType FlushMode
{
get { return (this._baseStream._flushMode); }
set
{
if (_disposed) throw new ObjectDisposedException("ZlibStream");
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("ZlibStream");
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 System.IO.Stream methods
/// <summary>
/// Dispose the stream.
/// </summary>
/// <remarks>
/// 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.
/// </remarks>
protected override void Dispose(bool disposing)
{
try
{
if (!_disposed)
{
if (disposing && (this._baseStream != null))
this._baseStream.Close();
_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("ZlibStream");
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("ZlibStream");
return _baseStream._stream.CanWrite;
}
}
/// <summary>
/// Flush the stream.
/// </summary>
public override void Flush()
{
if (_disposed) throw new ObjectDisposedException("ZlibStream");
_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 == Ionic.Zlib.ZlibBaseStream.StreamMode.Writer)
return this._baseStream._z.TotalBytesOut;
if (this._baseStream._streamMode == Ionic.Zlib.ZlibBaseStream.StreamMode.Reader)
return this._baseStream._z.TotalBytesIn;
return 0;
}
set { throw new NotImplementedException(); }
}
/// <summary>
/// Read data from the stream.
/// </summary>
///
/// <remarks>
///
/// <para>
/// If you wish to use the <c>ZlibStream</c> to compress data while reading,
/// you can create a <c>ZlibStream</c> with <c>CompressionMode.Compress</c>,
/// providing an uncompressed data stream. Then call <c>Read()</c> on that
/// <c>ZlibStream</c>, and the data read will be compressed. If you wish to
/// use the <c>ZlibStream</c> to decompress data while reading, you can create
/// a <c>ZlibStream</c> with <c>CompressionMode.Decompress</c>, providing a
/// readable compressed data stream. Then call <c>Read()</c> on that
/// <c>ZlibStream</c>, and the data will be decompressed as it is read.
/// </para>
///
/// <para>
/// A <c>ZlibStream</c> can be used for <c>Read()</c> or <c>Write()</c>, but
/// not both.
/// </para>
///
/// </remarks>
/// <param name="buffer">The buffer into which the read 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>
public override int Read(byte[] buffer, int offset, int count)
{
if (_disposed) throw new ObjectDisposedException("ZlibStream");
return _baseStream.Read(buffer, offset, count);
}
/// <summary>
/// Calling this method always throws a <see cref="NotImplementedException"/>.
/// </summary>
public override long Seek(long offset, System.IO.SeekOrigin origin)
{
throw new NotImplementedException();
}
/// <summary>
/// Calling this method always throws a <see cref="NotImplementedException"/>.
/// </summary>
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>ZlibStream</c> to compress data while writing,
/// you can create a <c>ZlibStream</c> with <c>CompressionMode.Compress</c>,
/// and a writable output stream. Then call <c>Write()</c> on that
/// <c>ZlibStream</c>, providing uncompressed data as input. The data sent to
/// the output stream will be the compressed form of the data written. If you
/// wish to use the <c>ZlibStream</c> to decompress data while writing, you
/// can create a <c>ZlibStream</c> with <c>CompressionMode.Decompress</c>, and a
/// writable output stream. Then call <c>Write()</c> on that stream,
/// providing previously compressed data. The data sent to the output stream
/// will be the decompressed form of the data written.
/// </para>
///
/// <para>
/// A <c>ZlibStream</c> can be used for <c>Read()</c> or <c>Write()</c>, but not both.
/// </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("ZlibStream");
_baseStream.Write(buffer, offset, count);
}
#endregion
/// <summary>
/// Compress a string into a byte array using ZLIB.
/// </summary>
///
/// <remarks>
/// Uncompress it with <see cref="ZlibStream.UncompressString(byte[])"/>.
/// </remarks>
///
/// <seealso cref="ZlibStream.UncompressString(byte[])"/>
/// <seealso cref="ZlibStream.CompressBuffer(byte[])"/>
/// <seealso cref="GZipStream.CompressString(string)"/>
///
/// <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())
{
Stream compressor =
new ZlibStream(ms, CompressionMode.Compress, CompressionLevel.BestCompression);
ZlibBaseStream.CompressString(s, compressor);
return ms.ToArray();
}
}
/// <summary>
/// Compress a byte array into a new byte array using ZLIB.
/// </summary>
///
/// <remarks>
/// Uncompress it with <see cref="ZlibStream.UncompressBuffer(byte[])"/>.
/// </remarks>
///
/// <seealso cref="ZlibStream.CompressString(string)"/>
/// <seealso cref="ZlibStream.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())
{
Stream compressor =
new ZlibStream( ms, CompressionMode.Compress, CompressionLevel.BestCompression );
ZlibBaseStream.CompressBuffer(b, compressor);
return ms.ToArray();
}
}
/// <summary>
/// Uncompress a ZLIB-compressed byte array into a single string.
/// </summary>
///
/// <seealso cref="ZlibStream.CompressString(String)"/>
/// <seealso cref="ZlibStream.UncompressBuffer(byte[])"/>
///
/// <param name="compressed">
/// A buffer containing ZLIB-compressed data.
/// </param>
///
/// <returns>The uncompressed string</returns>
public static String UncompressString(byte[] compressed)
{
using (var input = new MemoryStream(compressed))
{
Stream decompressor =
new ZlibStream(input, CompressionMode.Decompress);
return ZlibBaseStream.UncompressString(compressed, decompressor);
}
}
/// <summary>
/// Uncompress a ZLIB-compressed byte array into a byte array.
/// </summary>
///
/// <seealso cref="ZlibStream.CompressBuffer(byte[])"/>
/// <seealso cref="ZlibStream.UncompressString(byte[])"/>
///
/// <param name="compressed">
/// A buffer containing ZLIB-compressed data.
/// </param>
///
/// <returns>The data in uncompressed form</returns>
public static byte[] UncompressBuffer(byte[] compressed)
{
using (var input = new MemoryStream(compressed))
{
Stream decompressor =
new ZlibStream( input, CompressionMode.Decompress );
return ZlibBaseStream.UncompressBuffer(compressed, decompressor);
}
}
}
}
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