Class: CRC16 in Category General VBA/VB6 : Data Integrity from Total Visual SourceBook

' Example of CCRC16 to calculate the 16-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 mclsCRC16 As CCRC16

Private Sub cmdTest_Click()
  ' Comments: Examples of converting files and strings to a 16-bit Cyclic Redundancy Check (CRC) value; can also be used for Checksum

  Dim intCRCValue As Integer
  Dim strString As String

  ' Initialize
  Set mclsCRC16 = New CCRC16

  ' Example of creating a 16-bit CRC value for a file
  mclsCRC16.InputFileName = mcstrSamplePath & "\sample.mdb"
  intCRCValue = mclsCRC16.GetCRCFromFile()
  MsgBox "File CRC Value:" & intCRCValue

  ' Example of creating a 16-bit CRC value for a string
  strString = "One small step for [a] man; one giant leap for mankind"
  intCRCValue = mclsCRC16.GetCRCFromString(strString)
  MsgBox "String CRC Value: " & intCRCValue

  ' Example
  intCRCValue = mclsCRC16.GetCRCFromStringAscii(strString)
  MsgBox "Ascii String CRC Value: " & intCRCValue

  ' Clean up
  Set mclsCRC16 = Nothing

End Sub

Private Sub mclsCRC16_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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