Class: CRC32 in Category General VBA/VB6 : Data Integrity from Total Visual SourceBook

' Example of CCRC32 to calculate the 32-bit CRC of a file or string
'
' To try this example, do the following:
' 1. Create a new user form
' 2. Create a command button named 'cmdTest'
' 3. Paste all the code from this example to the new form's module.
' 4. Run the form

' This example assumes that the sample files are located in the folder named by the following constant.
Private Const mcstrSamplePath As String = "C:\TVSBSamp"

' By defining the class WithEvents, you can capture the Progress event to display information to your user.
' To use events, this module must be a class or form/report. If you don't want to capture the Progress event, you can use a regular module.
Private WithEvents mclsCRC32 As CCRC32

Private Sub cmdTest_Click()
  ' Comments: Examples of converting files and strings to a 32-bit Cyclic Redundancy Check (CRC) value; can also be used for Checksum

  Dim lngCRCValue As Long
  Dim strString As String

  ' Initialize class
  Set mclsCRC32 = New CCRC32

  ' Example of creating a 32-bit CRC value for a file
  mclsCRC32.InputFileName = mcstrSamplePath & "\sample.mdb"
  lngCRCValue = mclsCRC32.GetCRCFromFile()

  MsgBox "CRC File Value:" & lngCRCValue

  ' Example of creating a 32-bit CRC value for a string
  strString = "One small step for [a] man; one giant leap for mankind"
  lngCRCValue = mclsCRC32.GetCRCFromString(strString)

  MsgBox "String CRC Value: " & lngCRCValue

  ' Close class
  Set mclsCRC32 = Nothing

End Sub

Private Sub mclsCRC32_Progress(dblPercentage As Double)
  ' Comments: This procedure captures the Progress Event and reveals the percentage completion for the file that's being compressed
  '           This example puts the information on the Immediate Window. You could show the information on a form as text or display a graphic.
  ' Params  : dblPercentage       Percent of completion between 0 and 1

  Debug.Print "Percent done: " & Format$(dblPercentage, "Percent")
End Sub

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