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Compressing Streams in .Net



Namespace: System.IO.Compression

There are two types of compression streams, GZip and Deflate. GZip leaves a standard header information block that can be used by the tools like Gzip to decompress the information. Deflate does not leaves any header information thus it is only decompressed by the respective application only.

Both streams can only compress 4GB of uncompressed data.

FileStream source = new FileStream(@“C:\file.dat”);
FileStream destination = new FileStream(@“C:\file.gzip”);

GZipStream Gs = new GZipStream(destination, CompressionMode.Compress);

int b = source.ReadByte();

While(b!=-1)
{
                Gs.WriteByte((byte)b);
                b = source.ReadByte();
}


And to decompress a compressed file:

FileStream source = new FileStream(@“C:\file.gzip”);  //reversed
FileStream destination = new FileStream(@“C:\file.dat”);

GZipStream Gs = new GZipStream(destination, CompressionMode.Decompress);

int b = source.ReadByte();

While(b!=-1)
{
                Gs.WriteByte((byte)b);
                b = source.ReadByte();
}

GZip Properties
Name
Description
BaseStream
Gets a reference to the underlying stream.
CanRead
Gets a value indicating whether the stream supports reading while decompressing a file. (Overrides .CanRead.)
CanSeek
Gets a value indicating whether the stream supports seeking. (Overrides .CanSeek.)
CanTimeout
Gets a value that determines whether the current stream can time out. (Inherited from Stream.)
CanWrite
Gets a value indicating whether the stream supports writing. (Overrides .CanWrite.)
Length
Throws a NotSupportedException.
Position
Throws a NotSupportedException.
ReadTimeout
Gets or sets a value that determines how long the stream will attempt to read before timing out. (Inherited from Stream.)
WriteTimeout
Gets or sets a value that determines how long the stream will attempt to write before timing out. (Inherited from Stream.)

Public Methods:

Name
Description
BeginRead
Begins an asynchronous read operation. (Overrides .BeginRead(Byte[](), Int32, Int32, AsyncCallback, Object).)
BeginWrite
Begins an asynchronous write operation. (Overrides .BeginWrite(Byte[](), Int32, Int32, AsyncCallback, Object).)
Close
Closes the current stream and releases any resources (such as sockets and file handles) associated with the current stream. (Inherited from Stream.)
EndRead
Waits for the pending asynchronous read to complete. (Overrides .EndRead(IAsyncResult).)
EndWrite
Handles the end of an asynchronous write operation. (Overrides .EndWrite(IAsyncResult).)
Flush
Flushes the contents of the internal buffer of the current GZipStream object to the underlying stream. (Overrides .Flush().)
Read
Reads a number of decompressed bytes into the specified byte array. (Overrides .Read(Byte[](), Int32, Int32).)
ReadByte
Reads a byte from the stream and advances the position within the stream by one byte, or returns -1 if at the end of the stream. (Inherited from Stream.)
Seek
Throws a NotSupportedException.
SetLength
Throws a NotSupportedException.
Write
Writes compressed bytes to the underlying stream from the specified byte array. (Overrides .Write(Byte[](), Int32, Int32).)
WriteByte
Writes a byte to the current position in the stream and advances the position within the stream by one byte. (Inherited from Stream.)

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