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 *.cmp files in the directory.
        For Each fi As FileInfo In di.GetFiles("*.cmp")
            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 <> ".cmp" Then
                ' Create the compressed file.
                Using outFile As FileStream = File.Create(fi.FullName + ".cmp")
                    Using Compress As DeflateStream = New DeflateStream(outFile, _
                                                        CompressionMode.Compress)
                        ' Copy the source file into the compression stream.
                        Dim buffer As Byte() = New Byte(4096) {}
                        Dim numRead As Integer
                        numRead = inFile.Read(buffer, 0, buffer.Length)
                        Do While numRead <> 0
                            Compress.Write(buffer, 0, numRead)
                            numRead = inFile.Read(buffer, 0, buffer.Length)
                        Loop

                        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.cmp.
            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 DeflateStream = New DeflateStream(inFile, _
                                                        CompressionMode.Decompress)
                    ' Copy the compressed file into the decompression stream.
                    Dim buffer As Byte() = New Byte(4096) {}
                    Dim numRead As Integer
                    numRead = Decompress.Read(buffer, 0, buffer.Length)
                    Do While numRead <> 0
                        outFile.Write(buffer, 0, numRead)
                        numRead = Decompress.Read(buffer, 0, buffer.Length)
                    Loop
                    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;

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 *.cmp files in the directory.
        foreach (FileInfo fi in di.GetFiles("*.cmp"))
        {
            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 != ".cmp")
            {
                // Create the compressed file.
                using (FileStream outFile = 
                        File.Create(fi.FullName + ".cmp"))
                {
                    using (DeflateStream Compress = 
                        new DeflateStream(outFile, 
                        CompressionMode.Compress))
                    {
                        // Copy the source file into 
                        // the compression stream.
                        byte[] buffer = new byte[4096];
                        int numRead;
                        while ((numRead = inFile.Read(buffer, 
                                0, buffer.Length)) != 0)
                        {
                            Compress.Write(buffer, 0, numRead);
                        }
                        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.cmp.
            string curFile = fi.FullName;
            string origName = curFile.Remove(curFile.Length 
                    - fi.Extension.Length);

            //Create the decompressed file.
            using (FileStream outFile = File.Create(origName))
            {
                using (DeflateStream Decompress = new DeflateStream(inFile,
                    CompressionMode.Decompress))
                {
                    //Copy the decompression stream into the output file.
                    byte[] buffer = new byte[4096];
                    int numRead;
                    while ((numRead = 
                        Decompress.Read(buffer, 0, buffer.Length)) != 0)
                    {
                        outFile.Write(buffer, 0, numRead);
                    }
                    Console.WriteLine("Decompressed: {0}", fi.Name);
                }
            }
        }
    }
}