VB 에서 Signed 데이터 Unsigned로 변환하기

출처 : http://support.microsoft.com/kb/189323

 

 

      Option Explicit

      Private Const OFFSET_4 = 4294967296#
      Private Const MAXINT_4 = 2147483647
      Private Const OFFSET_2 = 65536
      Private Const MAXINT_2 = 32767

      Function UnsignedToLong(Value As Double) As Long
        If Value < 0 Or Value >= OFFSET_4 Then Error 6 ' Overflow
        If Value <= MAXINT_4 Then
          UnsignedToLong = Value
        Else
          UnsignedToLong = Value - OFFSET_4
        End If
      End Function

      Function LongToUnsigned(Value As Long) As Double
        If Value < 0 Then
          LongToUnsigned = Value + OFFSET_4
        Else
          LongToUnsigned = Value
        End If
      End Function

      Function UnsignedToInteger(Value As Long) As Integer
        If Value < 0 Or Value >= OFFSET_2 Then Error 6 ' Overflow
        If Value <= MAXINT_2 Then
          UnsignedToInteger = Value
        Else
          UnsignedToInteger = Value - OFFSET_2
        End If
      End Function

      Function IntegerToUnsigned(Value As Integer) As Long
        If Value < 0 Then
          IntegerToUnsigned = Value + OFFSET_2
        Else
          IntegerToUnsigned = Value
        End If
      End Function