How to: Compress Files
Use the System.IO.Compression.GZipStream class to compress and decompress data. You can also use the System.IO.Compression.DeflateStream class, which uses the same compression algorithm; however, compressed GZipStream objects written to a file that has an extension of .gz can be decompressed using many common compression tools.
This example shows how to compress and decompress a directory of files by using the GZipStream class.
Example
Imports System.IO
Imports System.IO.Compression
Module Module1
Sub Main()
' Path to directory of files to compress.
Dim dirpath As String = "c:\users\public\reports"
Dim di As DirectoryInfo = New DirectoryInfo(dirpath)
' Compress the directory's files.
For Each fi As FileInfo In di.GetFiles()
Compress(fi)
Next
' Decompress all *.gz files in the directory.
For Each fi As FileInfo In di.GetFiles("*.gz")
Decompress(fi)
Next
End Sub
' Method to compress.
Private Sub Compress(ByVal fi As FileInfo)
' Get the stream of the source file.
Using inFile As FileStream = fi.OpenRead()
' Compressing:
' Prevent compressing hidden and already compressed files.
If (File.GetAttributes(fi.FullName) And FileAttributes.Hidden) _
<> FileAttributes.Hidden And fi.Extension <> ".gz" Then
' Create the compressed file.
Using outFile As FileStream = File.Create(fi.FullName + ".gz")
Using Compress As GZipStream = _
New GZipStream(outFile, CompressionMode.Compress)
' Copy the source file into the compression stream.
inFile.CopyTo(Compress)
Console.WriteLine("Compressed {0} from {1} to {2} bytes.", _
fi.Name, fi.Length.ToString(), outFile.Length.ToString())
End Using
End Using
End If
End Using
End Sub
' Method to decompress.
Private Sub Decompress(ByVal fi As FileInfo)
' Get the stream of the source file.
Using inFile As FileStream = fi.OpenRead()
' Get orignial file extension, for example "doc" from report.doc.gz.
Dim curFile As String = fi.FullName
Dim origName = curFile.Remove(curFile.Length - fi.Extension.Length)
' Create the decompressed file.
Using outFile As FileStream = File.Create(origName)
Using Decompress As GZipStream = New GZipStream(inFile, _
CompressionMode.Decompress)
' Copy the decompression stream
' into the output file.
Decompress.CopyTo(outFile)
Console.WriteLine("Decompressed: {0}", fi.Name)
End Using
End Using
End Using
End Sub
End Module
using System;
using System.IO;
using System.IO.Compression;
namespace zip
{
public class Program
{
public static void Main()
{
// Path to directory of files to compress and decompress.
string dirpath = @"c:\users\public\reports";
DirectoryInfo di = new DirectoryInfo(dirpath);
// Compress the directory's files.
foreach (FileInfo fi in di.GetFiles())
{
Compress(fi);
}
// Decompress all *.gz files in the directory.
foreach (FileInfo fi in di.GetFiles("*.gz"))
{
Decompress(fi);
}
}
public static void Compress(FileInfo fi)
{
// Get the stream of the source file.
using (FileStream inFile = fi.OpenRead())
{
// Prevent compressing hidden and
// already compressed files.
if ((File.GetAttributes(fi.FullName)
& FileAttributes.Hidden)
!= FileAttributes.Hidden & fi.Extension != ".gz")
{
// Create the compressed file.
using (FileStream outFile =
File.Create(fi.FullName + ".gz"))
{
using (GZipStream Compress =
new GZipStream(outFile,
CompressionMode.Compress))
{
// Copy the source file into
// the compression stream.
inFile.CopyTo(Compress);
Console.WriteLine("Compressed {0} from {1} to {2} bytes.",
fi.Name, fi.Length.ToString(), outFile.Length.ToString());
}
}
}
}
}
public static void Decompress(FileInfo fi)
{
// Get the stream of the source file.
using (FileStream inFile = fi.OpenRead())
{
// Get original file extension, for example
// "doc" from report.doc.gz.
string curFile = fi.FullName;
string origName = curFile.Remove(curFile.Length -
fi.Extension.Length);
//Create the decompressed file.
using (FileStream outFile = File.Create(origName))
{
using (GZipStream Decompress = new GZipStream(inFile,
CompressionMode.Decompress))
{
// Copy the decompression stream
// into the output file.
Decompress.CopyTo(outFile);
Console.WriteLine("Decompressed: {0}", fi.Name);
}
}
}
}
}
}