CONVERSION DE NOMBRES EN BASE X

Private Const DICTIONNARY = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"

' Aucune validation n'est faite, ce qui signifie qu'on considère que:
' - Le paramètre Number contient tous des signes valides appartenant au
'   dictionnaire.
' - Les chiffres FromBase et ToBase appartiennent à ]0:Len(Dictionnary)]
Public Function BaseX(ByVal Number As String, ByVal FromBase As Integer, ByVal ToBase As Integer) As String
Dim Number10 As Long ' --- Nombre en base 10 ---------------------------------
Dim Power As Integer ' --- Puissance -----------------------------------------
Dim Idx As Integer   ' --- Index ---------------------------------------------
Dim Sign As Integer  ' --- Chiffre traité ------------------------------------

  ' --- Convertir en base 10 -------------------------------------------------
  If FromBase <> 10 Then
    Power = Len(Number) - 1
    For Idx = 1 To Len(Number)
      Sign = InStr(DICTIONNARY, Mid$(Number, Idx, 1)) - 1
      Number10 = Number10 + (Sign * FromBase ^ Power)
      Power = Power - 1
    Next
  Else
    Number10 = Number
  End If

  ' --- Convertir en base X --------------------------------------------------
  If ToBase <> 0 Then
    Power = 0
    While Number10 > 0
      Sign = Number10 Mod ToBase
      BaseX = Mid$(DICTIONNARY, Sign + 1, 1) & BaseX
      Number10 = (Number10 - Sign) / ToBase
    Wend
  Else
    BaseX = Number10
  End If
End Function