Q200649: HOWTO: Use LZCopy to Copy Files

Article: Q200649
Product(s): Microsoft Visual Basic for Windows
Version(s): 5.0,6.0
Operating System(s): 
Keyword(s): kbAPI kbFileIO kbSDKWin32 kbVBp500 kbVBp600 kbGrpDSVB kbDSupport
Last Modified: 18-MAY-2001

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The information in this article applies to:

- Microsoft Visual Basic Enterprise Edition for Windows, versions 5.0, 6.0 
- Microsoft Visual Basic Professional Edition for Windows, versions 5.0, 6.0 
- Microsoft Visual Basic Learning Edition for Windows, versions 5.0, 6.0 
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SUMMARY
=======

This article demonstrates how to use the LZOpenFile, LZCopy, and LZClose
functions from the LZ Expand/Compress library (LZ32.dll). You can use these
functions to make a copy of an existing file. The LZCopy function creates a
decompressed destination file if the source file is compressed with the
Microsoft File Compression Utility (Compress.exe).

MORE INFORMATION
================

Step-by-Step Example
--------------------

These steps demonstrate how to use the functions from the LZ Expand/Compress
library to copy files to and from locations on a local or network drive.

1. Create a new Standard EXE project. Form1 is created by default.

2. Add two Labels, two TextBoxes, and a CommandButton to Form1.

3. Position Label1 and Label2 above Text1 and Text2, respectively.

4. Add the following code to the General Declarations section of Form1:

  Option Explicit

  Const OF_CREATE = &H1000
  Const OF_READ = &H0
  Const OFS_MAXPATHNAME = 128

  Private Type OFSTRUCT
      cBytes As Byte
      fFixedDisk As Byte
      nErrCode As Integer
      Reserved1 As Integer
      Reserved2 As Integer
      szPathName(OFS_MAXPATHNAME) As Byte
  End Type

  Private Declare Sub LZClose Lib "lz32.dll" _
          (ByVal hfFile As Long)
  Private Declare Function LZCopy Lib "lz32.dll" _
          (ByVal hfSource As Long, ByVal hfDest As Long) As Long
  Private Declare Function LZOpenFile Lib "lz32.dll" Alias "LZOpenFileA" _
          (ByVal lpszFile As String, lpOf As OFSTRUCT, ByVal style As Long) _
          As Long

  Public Sub CopyFile(Source As String, Destination As String)
      Dim hsource As Long
      Dim hdest As Long
      Dim iret As Long
      Dim OpenStruct As OFSTRUCT

      ' Open the source and destination files.
      hsource = LZOpenFile(Source, OpenStruct, OF_READ)
      hdest = LZOpenFile(Destination, OpenStruct, OF_CREATE)
      ' Copy the source file to the destination location, and
      ' decompress the Source file if it was compressed.
      iret = LZCopy(hsource, hdest)
      ' Close the files.
      LZClose hdest
      LZClose hsource
      If iret = -1 Then
          MsgBox "File transfer failed"
      Else
          MsgBox "Transfer successful: " _
          & Format$(iret, "###,###,###,###") _
          & " bytes were transferred."
      End If
  End Sub

  Private Sub Command1_Click()
      CopyFile Text1.Text, Text2.Text
  End Sub

  Private Sub Form_Load()
      Label1.Caption = "Source Directory and Filename"
      Label2.Caption = "Target Directory and Filename"
      Command1.Caption = "Copy"
  End Sub

5. Run the project. In the Source TextBox, type the full path and file name of
  the file that you want to copy.

6. In the Target TextBox, type the full path and file name of the destination
  file, and then click Copy.

7. In Windows Explorer, confirm that the file copied successfully.

REFERENCES
==========

For more information about these functions, see the following MSDN
documentation:

  LZOpenFile
  http://msdn.microsoft.com/library/psdk/winbase/datadcmp_1tyd.htm

  LZCopy
  http://msdn.microsoft.com/library/psdk/winbase/datadcmp_9b3t.htm

  LZClose
  http://msdn.microsoft.com/library/psdk/winbase/datadcmp_8skl.htm

Additional query words: decompress

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Keywords          : kbAPI kbFileIO kbSDKWin32 kbVBp500 kbVBp600 kbGrpDSVB kbDSupport 
Technology        : kbVBSearch kbAudDeveloper kbPTNotAssigned kbZNotKeyword2 kbWord600Mac kbGraph500
Version           : :5.0,6.0
Issue type        : kbhowto

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