Detailed Description

A class for compressing and decompressing streams using the Deflate algorithm.

on a System.IO.Stream. It adds DEFLATE compression or decompression to any stream.

Using this stream, applications can compress or decompress data via stream Read and Write operations. Either compresssion or decompression can occur through either reading or writing. The compression format used is DEFLATE, which is documented in IETF RFC 1951

, "DEFLATE Compressed Data Format Specification version 1.3.".

This class is similar to ZlibStream, except that ZlibStream adds the RFC 1950 - ZLIB

framing bytes to a compressed stream when compressing, or expects the RFC1950 framing bytes when decompressing. The DeflateStream does not.

See Also: ZlibStream, GZipStream

Inheritance diagram for Zlib.DeflateStream:

Public Member Functions
	DeflateStream (System.IO.Stream stream, CompressionMode mode)
	Create a DeflateStream using the specified CompressionMode. More...

	DeflateStream (System.IO.Stream stream, CompressionMode mode, CompressionLevel level)
	Create a DeflateStream using the specified CompressionMode and the specified CompressionLevel. More...

	DeflateStream (System.IO.Stream stream, CompressionMode mode, bool leaveOpen)
	Create a `DeflateStream` using the specified `CompressionMode`, and explicitly specify whether the stream should be left open after Deflation or Inflation. More...

	DeflateStream (System.IO.Stream stream, CompressionMode mode, CompressionLevel level, bool leaveOpen)
	Create a `DeflateStream` using the specified `CompressionMode` and the specified `CompressionLevel`, and explicitly specify whether the stream should be left open after Deflation or Inflation. More...

void	SetDataToRead (int size)

void	ChangeStream (System.IO.Stream stream)

void	DoneRead ()

override void	Flush ()
	Flush the stream. More...

override int	Read (byte[] buffer, int offset, int count)
	Read data from the stream. More...

override long	Seek (long offset, System.IO.SeekOrigin origin)
	Calling this method always throws a NotImplementedException. More...

override void	SetLength (long value)
	Calling this method always throws a NotImplementedException. More...

override void	Write (byte[] buffer, int offset, int count)
	Write data to the stream. More...

Static Public Member Functions
static byte[]	CompressString (String s)
	Compress a string into a byte array using DEFLATE (RFC 1951). More...

static byte[]	CompressBuffer (byte[] b)
	Compress a byte array into a new byte array using DEFLATE. More...

static String	UncompressString (byte[] compressed)
	Uncompress a DEFLATE'd byte array into a single string. More...

static byte[]	UncompressBuffer (byte[] compressed)
	Uncompress a DEFLATE'd byte array into a byte array. More...

Protected Member Functions
override void	Dispose (bool disposing)
	Dispose the stream. More...

Package Attributes
ZlibBaseStream	_baseStream

System.IO.Stream	_innerStream

Properties
virtual FlushType	FlushMode `[get, set]`
	This property sets the flush behavior on the stream. More...

int	BufferSize `[get, set]`
	The size of the working buffer for the compression codec. More...

CompressionStrategy	Strategy `[get, set]`
	The ZLIB strategy to be used during compression. More...

virtual long	TotalIn `[get]`
	Returns the total number of bytes input so far. More...

virtual long	TotalOut `[get]`
	Returns the total number of bytes output so far. More...

override bool	CanRead `[get]`
	Indicates whether the stream can be read. More...

override bool	CanSeek `[get]`
	Indicates whether the stream supports Seek operations. More...

override bool	CanWrite `[get]`
	Indicates whether the stream can be written. More...

override long	Length `[get]`
	Reading this property always throws a NotImplementedException. More...

override long	Position `[get, set]`
	The position of the stream pointer. More...

Private Attributes
bool	_disposed

Constructor & Destructor Documentation

Zlib.DeflateStream.DeflateStream	(	System.IO.Stream	stream,
		CompressionMode	mode
	)

inline

Create a DeflateStream using the specified CompressionMode.

When mode is CompressionMode.Compress, the DeflateStream will use the default compression level. The "captive" stream will be closed when the DeflateStream is closed.

This example uses a DeflateStream to compress data from a file, and writes the compressed data to another file.

using (System.IO.Stream input = System.IO.File.OpenRead(fileToCompress))
{
    using (var raw = System.IO.File.Create(fileToCompress + ".deflated"))
    {
        using (Stream compressor = new DeflateStream(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);
            }
        }
    }
}

Using input As Stream = File.OpenRead(fileToCompress)
    Using raw As FileStream = File.Create(fileToCompress &amp; ".deflated")
        Using compressor As Stream = New DeflateStream(raw, CompressionMode.Compress)
            Dim buffer As Byte() = New Byte(4096) {}
            Dim n As Integer = -1
            Do While (n &lt;&gt; 0)
                If (n &gt; 0) Then
                    compressor.Write(buffer, 0, n)
                End If
                n = input.Read(buffer, 0, buffer.Length)
            Loop
        End Using
    End Using
End Using

Parameters

stream	The stream which will be read or written.
mode	Indicates whether the DeflateStream will compress or decompress.

Zlib.DeflateStream.DeflateStream	(	System.IO.Stream	stream,
		CompressionMode	mode,
		CompressionLevel	level
	)

inline

Create a DeflateStream using the specified CompressionMode and the specified CompressionLevel.

When mode is CompressionMode.Decompress, the level parameter is ignored. The "captive" stream will be closed when the DeflateStream is closed.

This example uses a DeflateStream to compress data from a file, and writes the compressed data to another file.

using (System.IO.Stream input = System.IO.File.OpenRead(fileToCompress))
{
    using (var raw = System.IO.File.Create(fileToCompress + ".deflated"))
    {
        using (Stream compressor = new DeflateStream(raw,
                                                     CompressionMode.Compress,
                                                     CompressionLevel.BestCompression))
        {
            byte[] buffer = new byte[WORKING_BUFFER_SIZE];
            int n= -1;
            while (n != 0)
            {
                if (n &gt; 0)
                    compressor.Write(buffer, 0, n);
                n= input.Read(buffer, 0, buffer.Length);
            }
        }
    }
}

Using input As Stream = File.OpenRead(fileToCompress)
    Using raw As FileStream = File.Create(fileToCompress &amp; ".deflated")
        Using compressor As Stream = New DeflateStream(raw, CompressionMode.Compress, CompressionLevel.BestCompression)
            Dim buffer As Byte() = New Byte(4096) {}
            Dim n As Integer = -1
            Do While (n &lt;&gt; 0)
                If (n &gt; 0) Then
                    compressor.Write(buffer, 0, n)
                End If
                n = input.Read(buffer, 0, buffer.Length)
            Loop
        End Using
    End Using
End Using

Parameters

stream	The stream to be read or written while deflating or inflating.
mode	Indicates whether the `DeflateStream` will compress or decompress.
level	A tuning knob to trade speed for effectiveness.

Zlib.DeflateStream.DeflateStream	(	System.IO.Stream	stream,
		CompressionMode	mode,
		bool	leaveOpen
	)

inline

Create a DeflateStream using the specified CompressionMode, and explicitly specify whether the stream should be left open after Deflation or Inflation.

This constructor allows the application to request that the captive stream remain open after the deflation or inflation occurs. By default, after Close() 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 compression. Specify true for the leaveOpen parameter to leave the stream open.

The DeflateStream will use the default compression level.

See the other overloads of this constructor for example code.

Parameters

stream The stream which will be read or written. This is called the "captive" stream in other places in this documentation.

Parameters

mode	Indicates whether the `DeflateStream` will compress or decompress.

Parameters

leaveOpen true if the application would like the stream to remain open after inflation/deflation.

Zlib.DeflateStream.DeflateStream	(	System.IO.Stream	stream,
		CompressionMode	mode,
		CompressionLevel	level,
		bool	leaveOpen
	)

inline

Create a DeflateStream using the specified CompressionMode and the specified CompressionLevel, and explicitly specify whether the stream should be left open after Deflation or Inflation.

When mode is CompressionMode.Decompress, the level parameter is ignored.

This constructor allows the application to request that the captive stream remain open after the deflation or inflation occurs. By default, after Close() 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 System.IO.MemoryStream that will be re-read after compression. Specify true for the leaveOpen parameter to leave the stream open.

This example shows how to use a DeflateStream to compress data from a file, and store the compressed data into another file.

using (var output = System.IO.File.Create(fileToCompress + ".deflated"))
{
    using (System.IO.Stream input = System.IO.File.OpenRead(fileToCompress))
    {
        using (Stream compressor = new DeflateStream(output, CompressionMode.Compress, CompressionLevel.BestCompression, true))
        {
            byte[] buffer = new byte[WORKING_BUFFER_SIZE];
            int n= -1;
            while (n != 0)
            {
                if (n &gt; 0)
                    compressor.Write(buffer, 0, n);
                n= input.Read(buffer, 0, buffer.Length);
            }
        }
    }
    // can write additional data to the output stream here
}

Using output As FileStream = File.Create(fileToCompress &amp; ".deflated")
    Using input As Stream = File.OpenRead(fileToCompress)
        Using compressor As Stream = New DeflateStream(output, CompressionMode.Compress, CompressionLevel.BestCompression, True)
            Dim buffer As Byte() = New Byte(4096) {}
            Dim n As Integer = -1
            Do While (n &lt;&gt; 0)
                If (n &gt; 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

Parameters

stream	The stream which will be read or written.
mode	Indicates whether the DeflateStream will compress or decompress.
leaveOpen	true if the application would like the stream to remain open after inflation/deflation.
level	A tuning knob to trade speed for effectiveness.

Member Function Documentation

void Zlib.DeflateStream.ChangeStream ( System.IO.Stream stream)

inline

static byte [] Zlib.DeflateStream.CompressBuffer ( byte[] b)

inlinestatic

Compress a byte array into a new byte array using DEFLATE.

Uncompress it with DeflateStream.UncompressBuffer(byte[]).

See Also: DeflateStream.CompressString(string)

DeflateStream.CompressString(string)

See Also: DeflateStream.UncompressBuffer(byte[])

DeflateStream.UncompressBuffer(byte[])

See Also: GZipStream.CompressBuffer(byte[])

GZipStream.CompressBuffer(byte[])

See Also: ZlibStream.CompressBuffer(byte[])

ZlibStream.CompressBuffer(byte[])

Parameters

b	A buffer to compress.

Returns: The data in compressed form

static byte [] Zlib.DeflateStream.CompressString ( String s)

inlinestatic

Compress a string into a byte array using DEFLATE (RFC 1951).

Uncompress it with DeflateStream.UncompressString(byte[]).

See Also: DeflateStream.UncompressString(byte[])

DeflateStream.UncompressString(byte[])

See Also: DeflateStream.CompressBuffer(byte[])

DeflateStream.CompressBuffer(byte[])

See Also: GZipStream.CompressString(string)

GZipStream.CompressString(string)

See Also: ZlibStream.CompressString(string)

ZlibStream.CompressString(string)

Parameters

s	A string to compress. The string will first be encoded using UTF8, then compressed.

Returns: The string in compressed form

override void Zlib.DeflateStream.Dispose ( bool disposing)

inlineprotected

Dispose the stream.

This may or may not result in a Close() call on the captive stream. See the constructors that have a leaveOpen parameter for more information.

Application code won't call this code directly. 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.

Parameters

disposing true if the Dispose method was invoked by user code.

void Zlib.DeflateStream.DoneRead ( )

inline

override void Zlib.DeflateStream.Flush ( )

inline

Flush the stream.

override int Zlib.DeflateStream.Read	(	byte[]	buffer,
		int	offset,
		int	count
	)

inline

Read data from the stream.

If you wish to use the DeflateStream to compress data while reading, you can create a DeflateStream with CompressionMode.Compress, providing an uncompressed data stream. Then call Read() on that DeflateStream, and the data read will be compressed as you read. If you wish to use the DeflateStream to decompress data while reading, you can create a DeflateStream with CompressionMode.Decompress, providing a readable compressed data stream. Then call Read() on that DeflateStream, and the data read will be decompressed as you read.

A DeflateStream can be used for Read() or Write(), but not both.

Parameters

buffer	The buffer into which the read data should be placed.
offset	the offset within that data array to put the first byte read.
count	the number of bytes to read.

Returns: the number of bytes actually read

override long Zlib.DeflateStream.Seek	(	long	offset,
		System.IO.SeekOrigin	origin
	)

inline

Calling this method always throws a NotImplementedException.

Parameters

offset	this is irrelevant, since it will always throw!
origin	this is irrelevant, since it will always throw!

Returns: irrelevant!

void Zlib.DeflateStream.SetDataToRead ( int size)

inline

override void Zlib.DeflateStream.SetLength ( long value)

inline

Calling this method always throws a NotImplementedException.

Parameters

value this is irrelevant, since it will always throw!

static byte [] Zlib.DeflateStream.UncompressBuffer ( byte[] compressed)

inlinestatic

Uncompress a DEFLATE'd byte array into a byte array.

See Also: DeflateStream.CompressBuffer(byte[])

DeflateStream.CompressBuffer(byte[])

See Also: DeflateStream.UncompressString(byte[])

DeflateStream.UncompressString(byte[])

See Also: GZipStream.UncompressBuffer(byte[])

GZipStream.UncompressBuffer(byte[])

See Also: ZlibStream.UncompressBuffer(byte[])

ZlibStream.UncompressBuffer(byte[])

Parameters

compressed A buffer containing data that has been compressed with DEFLATE.

Returns: The data in uncompressed form

static String Zlib.DeflateStream.UncompressString ( byte[] compressed)

inlinestatic

Uncompress a DEFLATE'd byte array into a single string.

See Also: DeflateStream.CompressString(String)

DeflateStream.CompressString(String)

See Also: DeflateStream.UncompressBuffer(byte[])

DeflateStream.UncompressBuffer(byte[])

See Also: GZipStream.UncompressString(byte[])

GZipStream.UncompressString(byte[])

See Also: ZlibStream.UncompressString(byte[])

ZlibStream.UncompressString(byte[])

Parameters

compressed A buffer containing DEFLATE-compressed data.

Returns: The uncompressed string

override void Zlib.DeflateStream.Write	(	byte[]	buffer,
		int	offset,
		int	count
	)

inline

Write data to the stream.

If you wish to use the DeflateStream to compress data while writing, you can create a DeflateStream with CompressionMode.Compress, and a writable output stream. Then call Write() on that DeflateStream, 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 DeflateStream to decompress data while writing, you can create a DeflateStream with CompressionMode.Decompress, and a writable output stream. Then call Write() on that stream, providing previously compressed data. The data sent to the output stream will be the decompressed form of the data written.

A DeflateStream can be used for Read() or Write(), but not both.

Parameters

buffer	The buffer holding data to write to the stream.
offset	the offset within that data array to find the first byte to write.
count	the number of bytes to write.

Member Data Documentation

ZlibBaseStream Zlib.DeflateStream._baseStream

package

bool Zlib.DeflateStream._disposed

private

System.IO.Stream Zlib.DeflateStream._innerStream

package

Property Documentation

int Zlib.DeflateStream.BufferSize

getset

The size of the working buffer for the compression codec.

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.

Set this before the first call to Read() or Write() on the stream. If you try to set it afterwards, it will throw.

override bool Zlib.DeflateStream.CanRead

get

Indicates whether the stream can be read.

The return value depends on whether the captive stream supports reading.

override bool Zlib.DeflateStream.CanSeek

get

Indicates whether the stream supports Seek operations.

Always returns false.

override bool Zlib.DeflateStream.CanWrite

get

Indicates whether the stream can be written.

The return value depends on whether the captive stream supports writing.

virtual FlushType Zlib.DeflateStream.FlushMode

getsetpackage

This property sets the flush behavior on the stream.

See the ZLIB documentation for the meaning of the flush behavior.

override long Zlib.DeflateStream.Length

get

Reading this property always throws a NotImplementedException.

override long Zlib.DeflateStream.Position

getset

The position of the stream pointer.

Setting this property always throws a 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.

CompressionStrategy Zlib.DeflateStream.Strategy

getsetpackage

The ZLIB strategy to be used during compression.

By tweaking this parameter, you may be able to optimize the compression for data with particular characteristics.

virtual long Zlib.DeflateStream.TotalIn

get

Returns the total number of bytes input so far.

virtual long Zlib.DeflateStream.TotalOut

get

Returns the total number of bytes output so far.

Detailed Description

Public Member Functions

Static Public Member Functions

Protected Member Functions

Package Attributes

Properties

Private Attributes

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation

Property Documentation