Excel VBA UDF Function XOR Operation.

Question

Hi there,

I need to perform XOR  operation on two hex values in excel.

Value 1:- 

0000198000010048 Value 2:-  04546E7FFFFEFFB7 Output:-  045477FFFFFFFFFF Can somebody please help me to create a function in VBA to calculate this value performing XOR operation on value 1 and value 2. Any help would be appreciable. Thanks

Answer 1

You're posting in the forum for Microsoft Access, not Excel, but the VBA for this sort of thing should be the same. But what sort of values do you intend to XOR?  Are they numeric values -- and if so, of what type and size? Strings of hexadecimal characters intended as representations of bit strings?  Bit values represented as characters?

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Dirk Goldgar, MS Access MVP
Access tips: www.datagnostics.com/tips.html

Answer 2

If your hex values are in the form of character strings of hexadecimal digits, here's a quickie function to XOR them and return the result as a hex string:

Function XorHexStrings(ByVal V1 As String, ByVal V2 As String, Optional PadRight As Boolean) As String

    ' XOR two hexadecimal strings, returning the result as a hexadecimal string.
    ' If one of the argument strings is shorter than the other, that string
    ' will be padded with zeros; by default, padded on the left, but the
    ' optional argument PadRight may be used to specify padding on the right.

    Dim L1 As Long      ' length of first hex string
    Dim L2 As Long      ' length of second hex string
    Dim D1 As String    ' hex digit extracted from first string
    Dim D2 As String    ' hex digit extracted from second string
    Dim R As String     ' result string
    Dim I As Long       ' digit iterator

    If V1 Like "*[!0-9A-F]*" Then
        Err.Raise 5
    End If

    If V2 Like "*[!0-9A-F]*" Then
        Err.Raise 5
    End If
    
    L1 = Len(V1)
    L2 = Len(V2)

    If L1 < L2 Then
        If PadRight Then
            V1 = V1 & String(L2 - L1, "0")
        Else
            V1 = String(L2 - L1, "0") & V1
        End If
        L1 = L2
    ElseIf L2 < L1 Then
        If PadRight Then
            V2 = V2 & String(L1 - L2, "0")
        Else
            V2 = String(L1 - L2, "0") & V2
        End If
        L2 = L1
    End If

    For I = 1 To L1
        D1 = Mid$(V1, I, 1)
        D2 = Mid$(V2, I, 1)
        R = R & Hex(Val("&H" & D1) Xor Val("&H" & D2))
    Next I

    XorHexStrings = R

End Function

I make no promises as to performance, but it seems to work.

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Dirk Goldgar, MS Access MVP
Access tips: www.datagnostics.com/tips.html