Android Code Snippet [B4X] Useful Features for PharmaCode Barcodes

Public Sub PharmacodeDigitVerifier(Value As String) As String
    Dim Result As String
 
    If Not (Regex.IsMatch("[0-9]+", Value)) Then Return Result 'Invalid
    If Not (Value.Length < 9) Then Return Result 'too long
 
    Dim Base32Value As StringBuilder
    Base32Value.Initialize
 
    For Each s As String In Regex.Split("", Value)
        Base32Value.Append(s)
    Next
 
    'Fill with zeros
    For i = 1 To 8 - Base32Value.Length
        Base32Value.Insert(0,"0")
    Next
 
    ' Calculate digit
    Dim CheckValue() As String, CheckSum As Int, Checkpart As Int
    CheckValue = Regex.Split("", Base32Value.ToString)
    For i = 0 To 3
        Checkpart = CheckValue(i * 2)
        CheckSum  = CheckSum + Checkpart
        Checkpart = CheckValue((i * 2) + 1) * 2
        If Checkpart >= 10 Then
            CheckSum = CheckSum + (Checkpart - 10) + 1
        Else
            CheckSum = CheckSum + Checkpart
        End If
    Next
 
    ' Add digit
    Dim Digit As Int = CheckSum Mod 10
    Result = Base32Value.Append(Digit).ToString
    Return Result
End Sub

Public Sub DecimalToBase32(DecimalValue As Int) As String
    Dim Base32Chars As String = "0123456789BCDFGHJKLMNPQRSTUVWXYZ"
    Dim Base32Value As StringBuilder
    Base32Value.Initialize
    Do While DecimalValue > 0
        Dim Remainder As Int = DecimalValue Mod 32
        Base32Value.Insert(0,Base32Chars.CharAt(Remainder))
        DecimalValue = DecimalValue / 32
    Loop
    Return Base32Value.ToString
End Sub

Public Sub Base32ToDecimal(Base32Value As String) As Long
    Dim Base32Chars As String = "0123456789BCDFGHJKLMNPQRSTUVWXYZ"
    Dim DecimalValue As Long
    Dim Exponent As Long
    For i = Base32Value.Length - 1 To 0 Step - 1
        DecimalValue = DecimalValue + (Base32Chars.IndexOf(Base32Value.CharAt(i)) * Power(32, Exponent))
        Exponent = Exponent + 1
    Next
    Return DecimalValue
End Sub

Public Sub TestBase32
    Dim Value As String = 123456
 
    Value = PharmacodeDigitVerifier(Value)
    Log("A" & Value)
 
    Value = DecimalToBase32(Value)
    Log(Value)
 
    Value = Base32ToDecimal(Value)
    Log(Value)
End Sub