C# Class Cimbalino.Phone.Toolkit.Compression.ZlibCodec

Encoder and Decoder for ZLIB and DEFLATE (IETF RFC1950 and RFC1951).

This class compresses and decompresses data according to the Deflate algorithm and optionally, the ZLIB format, as documented in RFC 1950 - ZLIB and RFC 1951 - DEFLATE.

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Public Properties

Property	Type	Description
AvailableBytesIn	int
AvailableBytesOut	int
CompressLevel	CompressionLevel
InputBuffer	byte[]
Message	System.String
NextIn	int
NextOut	int
OutputBuffer	byte[]
Strategy	CompressionStrategy
TotalBytesIn	long
TotalBytesOut	long
WindowBits	int

Public Methods

Method	Description
Deflate ( FlushType flush ) : int	Deflate one batch of data. You must have set InputBuffer and OutputBuffer before calling this method.
EndDeflate ( ) : int	End a deflation session. Call this after making a series of one or more calls to Deflate(). All buffers are flushed.
EndInflate ( ) : int	Ends an inflation session. Call this after successively calling Inflate(). This will cause all buffers to be flushed. After calling this you cannot call Inflate() without a intervening call to one of the InitializeInflate() overloads.
Inflate ( FlushType flush ) : int	Inflate the data in the InputBuffer, placing the result in the OutputBuffer. You must have set InputBuffer and OutputBuffer, NextIn and NextOut, and AvailableBytesIn and AvailableBytesOut before calling this method.
InitializeDeflate ( ) : int	Initialize the ZlibCodec for deflation operation. The codec will use the MAX window bits and the default level of compression.
InitializeDeflate ( CompressionLevel level ) : int	Initialize the ZlibCodec for deflation operation, using the specified CompressionLevel. The codec will use the maximum window bits (15) and the specified CompressionLevel. It will emit a ZLIB stream as it compresses.
InitializeDeflate ( CompressionLevel level, bool wantRfc1950Header ) : int	Initialize the ZlibCodec for deflation operation, using the specified CompressionLevel, and the explicit flag governing whether to emit an RFC1950 header byte pair. The codec will use the maximum window bits (15) and the specified CompressionLevel. If you want to generate a zlib stream, you should specify true for wantRfc1950Header. In this case, the library will emit a ZLIB header, as defined in RFC 1950, in the compressed stream.
InitializeDeflate ( CompressionLevel level, int bits ) : int	Initialize the ZlibCodec for deflation operation, using the specified CompressionLevel, and the specified number of window bits. The codec will use the specified number of window bits and the specified CompressionLevel.
InitializeDeflate ( CompressionLevel level, int bits, bool wantRfc1950Header ) : int	Initialize the ZlibCodec for deflation operation, using the specified CompressionLevel, the specified number of window bits, and the explicit flag governing whether to emit an RFC1950 header byte pair.
InitializeInflate ( ) : int	Initialize the inflation state. It is not necessary to call this before using the ZlibCodec to inflate data; It is implicitly called when you call the constructor.
InitializeInflate ( bool expectRfc1950Header ) : int	Initialize the inflation state with an explicit flag to govern the handling of RFC1950 header bytes. By default, the ZLIB header defined in RFC 1950 is expected. If you want to read a zlib stream you should specify true for expectRfc1950Header. If you have a deflate stream, you will want to specify false. It is only necessary to invoke this initializer explicitly if you want to specify false.
InitializeInflate ( int windowBits ) : int	Initialize the ZlibCodec for inflation, with the specified number of window bits.
InitializeInflate ( int windowBits, bool expectRfc1950Header ) : int	Initialize the inflation state with an explicit flag to govern the handling of RFC1950 header bytes. If you want to read a zlib stream you should specify true for expectRfc1950Header. In this case, the library will expect to find a ZLIB header, as defined in RFC 1950, in the compressed stream. If you will be reading a DEFLATE or GZIP stream, which does not have such a header, you will want to specify false.
ResetDeflate ( ) : void	Reset a codec for another deflation session. Call this to reset the deflation state. For example if a thread is deflating non-consecutive blocks, you can call Reset() after the Deflate(Sync) of the first block and before the next Deflate(None) of the second block.
SetDeflateParams ( CompressionLevel level, CompressionStrategy strategy ) : int	Set the CompressionStrategy and CompressionLevel for a deflation session.
SetDictionary ( byte dictionary ) : int	Set the dictionary to be used for either Inflation or Deflation.
SyncInflate ( ) : int	I don't know what this does!
ZlibCodec ( ) : System	Create a ZlibCodec. If you use this default constructor, you will later have to explicitly call InitializeInflate() or InitializeDeflate() before using the ZlibCodec to compress or decompress.
ZlibCodec ( CompressionMode mode ) : System	Create a ZlibCodec that either compresses or decompresses.

Private Methods

Method	Description
_InternalInitializeDeflate ( bool wantRfc1950Header ) : int
flush_pending ( ) : void
read_buf ( byte buf, int start, int size ) : int

Method Details

Deflate() public method

Deflate one batch of data.

You must have set InputBuffer and OutputBuffer before calling this method.

public Deflate ( FlushType flush ) : int
flush	FlushType	whether to flush all data as you deflate. Generally you will want to /// use Z_NO_FLUSH here, in a series of calls to Deflate(), and then call EndDeflate() to /// flush everything. ///
return	int

EndDeflate() public method

End a deflation session.

Call this after making a series of one or more calls to Deflate(). All buffers are flushed.

public EndDeflate ( ) : int
return	int

EndInflate() public method

Ends an inflation session.

Call this after successively calling Inflate(). This will cause all buffers to be flushed. After calling this you cannot call Inflate() without a intervening call to one of the InitializeInflate() overloads.

public EndInflate ( ) : int
return	int

Inflate() public method

Inflate the data in the InputBuffer, placing the result in the OutputBuffer.

You must have set InputBuffer and OutputBuffer, NextIn and NextOut, and AvailableBytesIn and AvailableBytesOut before calling this method.

public Inflate ( FlushType flush ) : int
flush	FlushType	The flush to use when inflating.
return	int

InitializeDeflate() public method

Initialize the ZlibCodec for deflation operation.

The codec will use the MAX window bits and the default level of compression.

public InitializeDeflate ( ) : int
return	int

InitializeDeflate() public method

Initialize the ZlibCodec for deflation operation, using the specified CompressionLevel.

The codec will use the maximum window bits (15) and the specified CompressionLevel. It will emit a ZLIB stream as it compresses.

public InitializeDeflate ( CompressionLevel level ) : int
level	CompressionLevel	The compression level for the codec.
return	int

InitializeDeflate() public method

Initialize the ZlibCodec for deflation operation, using the specified CompressionLevel, and the explicit flag governing whether to emit an RFC1950 header byte pair.

The codec will use the maximum window bits (15) and the specified CompressionLevel. If you want to generate a zlib stream, you should specify true for wantRfc1950Header. In this case, the library will emit a ZLIB header, as defined in RFC 1950, in the compressed stream.

public InitializeDeflate ( CompressionLevel level, bool wantRfc1950Header ) : int
level	CompressionLevel	The compression level for the codec.
wantRfc1950Header	bool	whether to emit an initial RFC1950 byte pair in the compressed stream.
return	int

InitializeDeflate() public method

Initialize the ZlibCodec for deflation operation, using the specified CompressionLevel, and the specified number of window bits.

The codec will use the specified number of window bits and the specified CompressionLevel.

public InitializeDeflate ( CompressionLevel level, int bits ) : int
level	CompressionLevel	The compression level for the codec.
bits	int	the number of window bits to use. If you don't know what this means, don't use this method.
return	int

InitializeDeflate() public method

Initialize the ZlibCodec for deflation operation, using the specified CompressionLevel, the specified number of window bits, and the explicit flag governing whether to emit an RFC1950 header byte pair.

public InitializeDeflate ( CompressionLevel level, int bits, bool wantRfc1950Header ) : int
level	CompressionLevel	The compression level for the codec.
bits	int	the number of window bits to use. If you don't know what this means, don't use this method.
wantRfc1950Header	bool	whether to emit an initial RFC1950 byte pair in the compressed stream.
return	int

InitializeInflate() public method

Initialize the inflation state.

It is not necessary to call this before using the ZlibCodec to inflate data; It is implicitly called when you call the constructor.

public InitializeInflate ( ) : int
return	int

InitializeInflate() public method

Initialize the inflation state with an explicit flag to govern the handling of RFC1950 header bytes.

By default, the ZLIB header defined in RFC 1950 is expected. If you want to read a zlib stream you should specify true for expectRfc1950Header. If you have a deflate stream, you will want to specify false. It is only necessary to invoke this initializer explicitly if you want to specify false.

public InitializeInflate ( bool expectRfc1950Header ) : int
expectRfc1950Header	bool	whether to expect an RFC1950 header byte /// pair when reading the stream of data to be inflated.
return	int

InitializeInflate() public method

Initialize the ZlibCodec for inflation, with the specified number of window bits.

public InitializeInflate ( int windowBits ) : int
windowBits	int	The number of window bits to use. If you need to ask what that is, /// then you shouldn't be calling this initializer.
return	int

InitializeInflate() public method

Initialize the inflation state with an explicit flag to govern the handling of RFC1950 header bytes.

If you want to read a zlib stream you should specify true for expectRfc1950Header. In this case, the library will expect to find a ZLIB header, as defined in RFC 1950, in the compressed stream. If you will be reading a DEFLATE or GZIP stream, which does not have such a header, you will want to specify false.

public InitializeInflate ( int windowBits, bool expectRfc1950Header ) : int
windowBits	int	The number of window bits to use. If you need to ask what that is, /// then you shouldn't be calling this initializer.
expectRfc1950Header	bool	whether to expect an RFC1950 header byte pair when reading /// the stream of data to be inflated.
return	int

ResetDeflate() public method

Reset a codec for another deflation session.

Call this to reset the deflation state. For example if a thread is deflating non-consecutive blocks, you can call Reset() after the Deflate(Sync) of the first block and before the next Deflate(None) of the second block.

public ResetDeflate ( ) : void
return	void

SetDeflateParams() public method

Set the CompressionStrategy and CompressionLevel for a deflation session.

public SetDeflateParams ( CompressionLevel level, CompressionStrategy strategy ) : int
level	CompressionLevel	the level of compression to use.
strategy	CompressionStrategy	the strategy to use for compression.
return	int

SetDictionary() public method

Set the dictionary to be used for either Inflation or Deflation.

public SetDictionary ( byte dictionary ) : int
dictionary	byte	The dictionary bytes to use.
return	int

SyncInflate() public method

I don't know what this does!

public SyncInflate ( ) : int
return	int

ZlibCodec() public method

Create a ZlibCodec.

If you use this default constructor, you will later have to explicitly call InitializeInflate() or InitializeDeflate() before using the ZlibCodec to compress or decompress.

public ZlibCodec ( ) : System
return	System

ZlibCodec() public method

Create a ZlibCodec that either compresses or decompresses.

public ZlibCodec ( CompressionMode mode ) : System
mode	CompressionMode	/// Indicates whether the codec should compress (deflate) or decompress (inflate). ///
return	System

Property Details

AvailableBytesIn public_oe property

The number of bytes available in the InputBuffer, starting at NextIn.

Generally you should set this to InputBuffer.Length before the first Inflate() or Deflate() call. The class will update this number as calls to Inflate/Deflate are made.

public int AvailableBytesIn
return	int

AvailableBytesOut public_oe property

The number of bytes available in the OutputBuffer, starting at NextOut.

Generally you should set this to OutputBuffer.Length before the first Inflate() or Deflate() call. The class will update this number as calls to Inflate/Deflate are made.

public int AvailableBytesOut
return	int

CompressLevel public_oe property

The compression level to use in this codec. Useful only in compression mode.

public CompressionLevel CompressLevel
return	CompressionLevel

InputBuffer public_oe property

The buffer from which data is taken.

public byte[] InputBuffer
return	byte[]

Message public_oe property

used for diagnostics, when something goes wrong!

public String,System Message
return	System.String

NextIn public_oe property

An index into the InputBuffer array, indicating where to start reading.

public int NextIn
return	int

NextOut public_oe property

An index into the OutputBuffer array, indicating where to start writing.

public int NextOut
return	int

OutputBuffer public_oe property

Buffer to store output data.

public byte[] OutputBuffer
return	byte[]

Strategy public_oe property

The compression strategy to use.

This is only effective in compression. The theory offered by ZLIB is that different strategies could potentially produce significant differences in compression behavior for different data sets. Unfortunately I don't have any good recommendations for how to set it differently. When I tested changing the strategy I got minimally different compression performance. It's best to leave this property alone if you don't have a good feel for it. Or, you may want to produce a test harness that runs through the different strategy options and evaluates them on different file types. If you do that, let me know your results.

public CompressionStrategy Strategy
return	CompressionStrategy

TotalBytesIn public_oe property

Total number of bytes read so far, through all calls to Inflate()/Deflate().

public long TotalBytesIn
return	long

TotalBytesOut public_oe property

Total number of bytes written to the output so far, through all calls to Inflate()/Deflate().

public long TotalBytesOut
return	long

WindowBits public_oe property

The number of Window Bits to use.

This gauges the size of the sliding window, and hence the compression effectiveness as well as memory consumption. It's best to just leave this setting alone if you don't know what it is. The maximum value is 15 bits, which implies a 32k window.

public int WindowBits
return	int