Chip 2002 September/Chip_2002-09_cd1.bin/zkuste/vbasic/Data/Utils/XZipNet.msi/Data1.cab/StreamDemo.vb

Text File | 2002-02-04 | 5.7 KB | 183 lines

'Xceed Zip for .NET - StreamDemo for VB.NET Sample Application
'Copyright (c) 2000-2002 - Xceed Software Inc
'
'[StreamDemo.vb]
'
'This console application demonstrates how touse the CompressedStream class
'to compress/decompress data as it is written to/read from a Stream.
'
'This file is part of Xceed Zip for .NET. The source code in this file
'is only intended as a supplement to the documentation and is provided "as is"
'without warranty of any kind, either expresed or implied.

Imports System
Imports System.IO
Imports Xceed.Compression


Module Module1

#Region " Compression Methods "

  'Compress sourceFile into destFile using the default compression algorithm (deflate).
  'sourceFile is the name of the file to compress.
  'destFile is the name of the output file.
  '
  'If destFile exists, it will be overwritten.
  Private Sub DoCompress(ByVal sourceFile As String, ByVal destFile As String)
    Console.WriteLine("Compressing file {0} to {1} ...", sourceFile, destFile)
    Console.WriteLine()

    'Open the source file into a FileStream
    Dim sourceStream As New FileStream(sourceFile, FileMode.Open, FileAccess.Read)

    'Open the destination file into a FileStream
    Dim destStream As New FileStream(destFile, FileMode.Create, FileAccess.Write)

    'Creates a CompressedStream around the destination FileStream so that
    'all data written to that stream will be compressed.
    Dim compStream As New CompressedStream(destStream)

    'Copy the stream
    StreamCopy(sourceStream, compStream)
  End Sub
#End Region

#Region " Decompression Methods "

  'Decompress sourceFile into destFile using the default compression algorithm (deflate).
  'sourceFile is the name of the file to decompress.
  'destFile is the name of the output file.
  '
  'If destFile exists, it will be overwritten.
  Private Sub DoDecompress(ByVal sourceFile As String, ByVal destFile As String)
    Console.WriteLine("Decompression file {0} to {1} ...", sourceFile, destFile)
    Console.WriteLine()

    'Open the source file into a FileStream
    Dim sourceStream As New FileStream(sourceFile, FileMode.Open, FileAccess.Read)

    'Open the destination file into a FileStream
    Dim destStream As New FileStream(destFile, FileMode.Create, FileAccess.Write)

    'Creates a CompressedStream around the source FileStream so that all
    'data read from that stream will be decompressed.
    Dim compStream As New CompressedStream(sourceStream)

    'Copy the stream
    StreamCopy(compStream, destStream)
  End Sub
#End Region

#Region " Private Utility Methods "

  'Copies the contents of sourceStream into destStream.
  'sourceStream is the input stream.
  'destStream is the output stream.
  '
  'When done, this function closes both streams.
  Private Sub StreamCopy(ByVal sourceStream As Stream, ByVal destStream As Stream)
    Try
      Dim bytesRead As Integer
      Dim buffer(32768) As Byte

      bytesRead = sourceStream.Read(buffer, 0, buffer.Length)

      While (bytesRead > 0)
        destStream.Write(buffer, 0, bytesRead)
        bytesRead = sourceStream.Read(buffer, 0, buffer.Length)
      End While

    Finally
      sourceStream.Close()
      destStream.Close()
    End Try
  End Sub
#End Region

#Region " Entry-point and non-compress related methods "

  'Entry point for the console application.
  'The arguments are supplied on the command line
  Sub Main()
    Try
      Console.WriteLine()
      Console.WriteLine("Xceed Zip for .BET - VB.NET StreamDemo")
      Console.WriteLine("======================================")
      Console.WriteLine()

      Dim args() As String = GetCommandLineArgs()

      If args.Length <> 3 Then
        PrintUsage()
        Return
      End If

      Select Case args(0)
        Case "-c"
          DoCompress(args(1), args(2))
        Case "-d"
          DoDecompress(args(1), args(2))
        Case Else
          PrintUsage()
          Return
      End Select
    Catch except As Exception
      Console.WriteLine()
      Console.WriteLine("ERROR: The following exception occured:")
      Console.WriteLine(except.ToString())
      Console.WriteLine()
    End Try

    Console.WriteLine("Done!")
  End Sub

  'Displays usage guidelines for the command-line application
  Private Sub PrintUsage()
    Console.WriteLine("Usage: StreamDemoVB.exe [-c | -d] sourceFile destFile")
    Console.WriteLine()
    Console.WriteLine("   -c : Compress sourceFile into destFile")
    Console.WriteLine("   -d : Decompress sourceFile into destFile")
  End Sub

  'Get the command-line arguments in a function that returns
  'them in an object containing an array.
  Function GetCommandLineArgs() As String()
    Dim commandLine As String = Microsoft.VisualBasic.Command()
    Dim argument As String
    Dim stringOpened As Boolean = False
    Dim I As Long
    Dim args(0) As String

    argument = ""
    For I = 0 To commandLine.Length - 1
      If commandLine.Chars(I) = " " And Not stringOpened Then
        If argument.Length > 0 Then
          ReDim Preserve args(UBound(args) + 1)
          args(UBound(args) - 1) = argument.ToString()
          argument = ""
        End If
      Else
        If commandLine.Chars(I) = """" Then
          stringOpened = Not stringOpened
        Else
          argument = argument & commandLine.Chars(I)
        End If
      End If
    Next

    If (argument.Length > 0) Then
      ReDim Preserve args(UBound(args) + 1)
      args(UBound(args) - 1) = argument.ToString()
    End If

    If UBound(args) > 1 Then
      ReDim Preserve args(UBound(args) - 1)
    End If

    Return args
  End Function
#End Region

End Module