Private crcTable(0 To 255) As Long 'crc32
Private Function CRC32(ByRef bArrayIn() As Byte, ByVal lLen As Long, Optional ByVal lcrc As Long = 0) As Long
'bArrayIn adalah array byte dari file yang dibaca
'lLen adalah ukuran atau size file
Dim lCurPos As Long 'Current position untuk iterasi proses array bArrayIn
Dim lTemp As Long 'Variabel temp hasil perhitungan
BuildTable
If lLen = 0 Then Exit Function 'keluar fungsi apabila ukuran file = 0
lTemp = lcrc Xor &HFFFFFFFF
For lCurPos = 0 To lLen
lTemp = (((lTemp And &HFFFFFF00) \ &H100) And &HFFFFFF) Xor (crcTable((lTemp And 255) Xor bArrayIn(lCurPos)))
Next lCurPos
CRC32 = lTemp Xor &HFFFFFFFF
End Function
Private Function BuildTable() As Boolean
Dim i As Long, x As Long, crc As Long
Const limit = &HEDB88320
For i = 0 To 255
crc = i
For x = 0 To 7
If crc And 1 Then
crc = (((crc And &HFFFFFFFE) \ 2) And &H7FFFFFFF) Xor limit
Else
crc = ((crc And &HFFFFFFFE) \ 2) And &H7FFFFFFF
End If
Next
crcTable(i) = crc
Next i
End Function
