Algorithms

'---------------------------------------------------------------------------------------------------'
'|
'| Date Created: Feb, 27 2015
'| BY: Daniel Couillard
'| Written In: Microsoft Visual Basic for Applications (VBA) 7.0
'|
'| Revisions:
'|
'| Date Revised: Dec, 21 2015
'| BY: Daniel Couillard
'| Revision:
'|  - Created Mathmatical formula to shorten code.
'|  - Re-commented with respect to the changes.
'|
'| .-------------------------------------.
'| | Function  -  ConvertStringToDecimal |
'| `-------------------------------------`
'|
'|  PARAMETERS:
'|
'|       * str - Contains the value to be converted to decimal.
'|
'|       * def - Contains the definition that describes the value's
'|               format.
'|
'|               For example, HEX's definition would be: "0123456789ABCDEF"
'|
'|  RETURN:
'|
'|      * variant - _
'|
'|          The return value is a variant because it can contain one of the two following results:
'|
'|              1. (STRING) Error Message.
'|              2. (DECIMAL) Calculated Value.
'|                 We use the Decimal data type because of its abillity to store such a large number.
'|
'|
'|  NOTE:
'|
'|      FURTHER EXPLAINATION CAN BE FOUND WITHIN THE FUNCTION
'|
'---------------------------------------------------------------------------------------------------'


Public Function ConvertStringToDecimal(ByVal str As String, _
                                       ByVal def As String) As Variant


    ' ------------------------------------- '
    '           Prep Parameters.            '
    ' ------------------------------------- '
    str = Trim(str & vbNullString)
    def = Trim(def & vbNullString)
    ' ------------------------------------- '

    ' ------------------------------------- '
    '           Parse Parameters.           '
    ' ------------------------------------- '
    If Len(str) = 0 Then: ConvertStringToDecimal = "No value has been entered.": Exit Function
    If Len(def) < 2 Then: ConvertStringToDecimal = "Number definition must have 2 or more characters.": Exit Function
    ' ------------------------------------- '

    ' ------------------------------------- '
    ' Variable Declaration & Initialization '
    ' ------------------------------------- '
    Dim LD As Integer: LD = Len(def)        ' - Length of Definition
    Dim LV As Integer: LV = Len(str)        ' - Length of Value
    Dim N As Variant: N = CDec(0)           ' - The sum of the calculations.
    Dim I As Integer                        ' - Increment.
    Dim P As Integer                        ' - Position of Value[i] in Reverse Definition.
    ' ------------------------------------- '

    ' Reverse string for correct digit position calculation allows for
    ' minimization in calculations when traversing through string position
    ' & Or simplifies visualiztion of the code for the reader.
    str = ReverseString(str)

    ' Traverse through the characters(digits) of the string in
    ' an incremental order.
    For I = 1 To LV

        P = InStr(1, def, Mid(str, I, 1))

        If P > 0 Then: N = N + CDec((P - 1) * (LD ^ (I - 1)))

    Next

    ' Return the calculated value.
    ConvertStringToDecimal = N


End Function

Public Function ConvertNumberToDefinition(ByVal number As String, _
                                          ByVal def As String) As String
    
    Dim length_of_def As Integer: length_of_def = Len(def)
    Dim dec_number As Variant: dec_number = CDec(number)
    
    Dim I As Variant: I = CDec(0)
    Dim j As Variant: j = CDec(0)
    
    Dim val As String
    Dim temp As Variant: temp = CDec(0)
    Dim index_value As Variant: index_value = CDec(0)
    
    For I = 0 To dec_number
        
        If (length_of_def ^ I > dec_number) Then
            
            For j = I - 1 To 0 Step -1
                
                index_value = length_of_def ^ j
                
                temp = dec_number Mod index_value
                
                val = val & Mid(def, ((dec_number - temp) / index_value) + 1, 1)
                
                dec_number = temp
                
            Next
            
            Exit For
        End If
        
    Next
    
    ConvertNumberToDefinition = val
    
End Function