DeflateStream Constructor (Stream, CompressionMode, Boolean)

using System;
using System.IO;
using System.IO.Compression;

public class Program
{
    public static void Main()
    {
        string directoryPath = @"c:\users\public\reports";

        DirectoryInfo directorySelected = new DirectoryInfo(directoryPath);

        foreach (FileInfo fileToCompress in directorySelected.GetFiles())
        {
            Compress(fileToCompress);
    	}

        foreach (FileInfo fileToDecompress in directorySelected.GetFiles("*.cmp"))
        {
            Decompress(fileToDecompress);
        }
    }

    public static void Compress(FileInfo fileToCompress)
    {
        using (FileStream originalFileStream = fileToCompress.OpenRead())
        {
            if ((File.GetAttributes(fileToCompress.FullName) & FileAttributes.Hidden)
                != FileAttributes.Hidden & fileToCompress.Extension != ".cmp")
            {
                using (FileStream compressedFileStream = File.Create(fileToCompress.FullName + ".cmp"))
                {
                    using (DeflateStream compressionStream = new DeflateStream(compressedFileStream, CompressionMode.Compress))
                    {
                        originalFileStream.CopyTo(compressionStream);

                        Console.WriteLine("Compressed {0} from {1} to {2} bytes.",
                          fileToCompress.Name, fileToCompress.Length.ToString(), compressedFileStream.Length.ToString());
                    }
                }
            }
        }
    }

    public static void Decompress(FileInfo fileToDecompress)
    {
        using (FileStream originalFileStream = fileToDecompress.OpenRead())
        {
            string currentFileName = fileToDecompress.FullName;
            string newFileName = currentFileName.Remove(currentFileName.Length - fileToDecompress.Extension.Length);

            using (FileStream decompressedFileStream = File.Create(newFileName))
        	{
                using (DeflateStream decompressionStream = new DeflateStream(originalFileStream, CompressionMode.Decompress))
        	    {
                    decompressionStream.CopyTo(decompressedFileStream);
                    Console.WriteLine("Decompressed: {0}", fileToDecompress.Name);
        	    }
        	}
        }
    }
}