Перевод из строки в число и обратно

Option Explicit
 
Private Declare Function GetMem2 Lib "msvbvm60" (Src As Any, Dst As Any) As Long
 
Private Sub Form_Load()
    Dim Value() As Byte, Res As String
   
    StrToUI "1234567891011121314151617181920", Value
    
    Res = UIToStr(Value)
    
End Sub
' Перевод беззнакового целого числа из байтового представления в строку
Private Function UIToStr(bValue() As Byte) As String
    Dim i As Long, f As Boolean, loc() As Byte
    loc = bValue
    Do
        i = Div10UI(loc)
        UIToStr = CStr(i) & UIToStr
        f = False
        For i = UBound(loc) To 0 Step -1
            If loc(i) Then f = True: Exit For
        Next
    Loop While f
End Function
' Перевод беззнакового целого числа из строкового представления в массив байт
Private Sub StrToUI(sValue As String, Out() As Byte)
    Dim i As Long, lpStr As Long, v As Integer, b(0) As Byte
    ReDim Out(0)
    If Len(sValue) Then
        lpStr = StrPtr(sValue)
        For i = 0 To Len(sValue) - 1
            GetMem2 ByVal lpStr, v
            v = v - &H30
            If v < 0 Or v > 9 Then Err.Raise 13: Exit Sub
            b(0) = v
            If i Then Mul10UI Out
            AddUI Out, b()
            lpStr = lpStr + 2
        Next
    Else: Err.Raise 5
    End If
End Sub
Private Sub AddUI(Op1() As Byte, Op2() As Byte)
    Dim i As Long, p As Long, o As Long, q As Long
    If UBound(Op1) < UBound(Op2) Then ReDim Preserve Op1(UBound(Op2))
    Do
        If i <= UBound(Op2) Then o = Op2(i) Else o = 0
        q = CLng(Op1(i)) + o + p
        p = (q And &H100&) \ &H100
        Op1(i) = q And &HFF
        i = i + 1
    Loop While CBool(o Or p) And i <= UBound(Op1)
    If p Then ReDim Preserve Op1(i): Op1(i) = p
End Sub
Private Function Div10UI(Value() As Byte) As Long
    Dim i1 As Long, i2 As Long, acc() As Byte, loc() As Byte, q As Long, p As Long
    For i1 = 0 To (UBound(Value) + 1) * 8
        Div10UI = (Div10UI * 2) Or p
        If Div10UI < 10 Then p = 0 Else p = 1: Div10UI = Div10UI - 10
        For i2 = 0 To UBound(Value)
            q = (CLng(Value(i2)) * 2) Or p
            p = (q And &H100) \ &H100
            Value(i2) = q And &HFF&
        Next
    Next
End Function
Private Sub Mul10UI(Value() As Byte)
    Dim i As Long, p As Long, q As Long
    For i = 0 To UBound(Value)
        q = (CLng(Value(i)) * 4 + Value(i)) * 2 + p
        p = (q And &HFF00&) \ &H100
        Value(i) = q And &HFF
    Next
    If p Then ReDim Preserve Value(i): Value(i) = p
End Sub