Solved

Convert large Hex to Decimal in VB.NET or Excel

Posted on 2007-11-27
9
10,526 Views
Last Modified: 2008-03-21
I found some java code to convert Hex to Decimal -- but I'd like to do the equivilent in VB.NET -- can you do it?

        BigInteger b = new BigInteger(hexStr, 16);
        String s = b.toString();

I also found Microsoft's answer to do it in VBA, Excel, but since the number is too big it gets trucated - don't know if there's another option here to make this work for me: http://www.vbaexpress.com/kb/getarticle.php?kb_id=307

Hex Str: 76c55e6970d6843011fa94e4433304ea
Decimal Str: 157873700884132896764748183476385285354
0
Comment
Question by:starship_wars
  • 4
  • 2
  • 2
  • +1
9 Comments
 
LVL 92

Expert Comment

by:Patrick Matthews
ID: 20363365
Hello starship_wars,

Please explain what you mean by "truncated".  Excel and VBA are limited to a maximum of
15 significant digits, and cannot maintain any greater precision than that with numeric data.

Regards,

Patrick
0
 

Expert Comment

by:kieranjcollins
ID: 20364996
I doubt Excel formula will ever do it as the formula "=HEX2DEC(A1)" is limited to a 10 character Hex string.
0
 

Expert Comment

by:kieranjcollins
ID: 20365059
Try putting this into an Excel  module and trying the formula:
=HEX2DEC("76c55e6970d6843011fa94e4433304ea") in a worksheet in same workbook.



Option Explicit 

 

Public Function HexToDec(Hex As String) As Double 

     

    Dim i               As Long 

    Dim j               As Variant 

    Dim k               As Long 

    Dim n               As Long 

    Dim HexArray()      As Double 

     

    n = Len(Hex) 

    k = -1 

    ReDim HexArray(1 To n) 

    For i = n To 1 Step -1 

        j = Mid(Hex, i, 1) 

        k = k + 1 

        Select Case j 

        Case 0 To 9 

            HexArray(i) = j * 16 ^ (k) 

        Case Is = "A" 

            HexArray(i) = 10 * 16 ^ (k) 

        Case Is = "B" 

            HexArray(i) = 11 * 16 ^ (k) 

        Case Is = "C" 

            HexArray(i) = 12 * 16 ^ (k) 

        Case Is = "D" 

            HexArray(i) = 13 * 16 ^ (k) 

        Case Is = "E" 

            HexArray(i) = 14 * 16 ^ (k) 

        Case Is = "F" 

            HexArray(i) = 15 * 16 ^ (k) 

        End Select 

    Next i 

    HexToDec = Application.WorksheetFunction.Sum(HexArray) 

     

End Function 

Open in new window

0
 

Author Comment

by:starship_wars
ID: 20366538
Yes, I have tried Microsoft's code.  But the problem is that I want the value "157873700884132896764748183476385285354" but instead Excel only shows me: 1.57873700884133E+38

If Excel is limited to 15 digits, does anyone know how I can get the result using VB.NET?
0
6 Surprising Benefits of Threat Intelligence

All sorts of threat intelligence is available on the web. Intelligence you can learn from, and use to anticipate and prepare for future attacks.

 
LVL 81

Accepted Solution

by:
zorvek (Kevin Jones) earned 125 total points
ID: 20367738
I don't get the exact result you listed above but it seems to work correctly:

Public Function GetLargeIntegerFromHex( _
      ByVal HexText As String _
   ) As String
   
   Dim Base2 As String
   Dim Result As String
   Dim Index As Long
   Dim Bit As Long
   Dim Char As Byte
   
   Base2 = "1"
   Result = "0"
   
   HexText = UCase(HexText)
   
   For Index = Len(HexText) To 1 Step -1
      Char = CLng("&H" & Mid(HexText, Index, 1))
      For Bit = 1 To 4
         If IsBitSet(Char, Bit) Then Result = AddString(Result, Base2)
         Base2 = AddString(Base2, Base2)
      Next Bit
   Next Index
   
   GetLargeIntegerFromHex = Result

End Function

Public Function AddString( _
      ByVal Value1 As String, _
      ByVal Value2 As String _
   ) As String

   Dim ResultIndex As Long
   Dim OperandIndex As Long
   Dim Result As String
   Dim Operand As String
   Dim Sum As Long
   Dim Carry As Long
   
   If Len(Value1) > Len(Value2) Then
      Result = Value1
      Operand = Value2
   Else
      Result = Value2
      Operand = Value1
   End If
   
   ResultIndex = Len(Result)
   OperandIndex = Len(Operand)
   Do While OperandIndex > 0
      Sum = CLng(Mid(Result, ResultIndex, 1)) + CLng(Mid(Operand, OperandIndex, 1)) + Carry
      If Sum > 9 Then
         Carry = 1
         Mid(Result, ResultIndex, 1) = Sum - 10
      Else
         Carry = 0
         Mid(Result, ResultIndex, 1) = Sum
      End If
      ResultIndex = ResultIndex - 1
      OperandIndex = OperandIndex - 1
   Loop
   If Carry = 1 Then Result = "1" & Result
   
   AddString = Result

End Function

Public Function IsBitSet( _
      ByVal Value As Variant, _
      ByVal Position As Long _
   ) As Boolean
   
   Select Case VarType(Value)
      Case vbLong, vbInteger, vbByte
         IsBitSet = (CLng(Value) And (2 ^ (Position - 1))) > 0
   End Select

End Function

Kevin
0
 

Author Comment

by:starship_wars
ID: 20405614
Sorry for the delayed response.

Kevin, thank you for the good code example.  Too bad the result is just off a few digits, strange.
0
 
LVL 81

Expert Comment

by:zorvek (Kevin Jones)
ID: 20406567
Are you sure your example is correct? I did some pretty extensive testing with my function.

Kevin
0
 

Author Comment

by:starship_wars
ID: 20413583
OMG - I am SO SORRY!!

You are right, I tried a different value and they came out the same.
The one above were the values someone else gave me, so they made an ass-u-me.

Zorvek - Kevin - you are a genius!  Thank you again!
0
 

Author Comment

by:starship_wars
ID: 20495649
I was revisting this code and couldn't get the values to compute again.  I finally figured out a fix by modifying the AddString function:
        If Len(Value1) < Len(Value2) Then
            'Make values the same length by left padding with zeros
            Value1 = Value1.PadLeft(Len(Value2), "0")
        End If
        'If Len(Value1) > Len(Value2) Then
        Result = Value1
        Operand = Value2
        'Else
        '    Result = Value2
        '    Operand = Value1
        'End If
0

Featured Post

6 Surprising Benefits of Threat Intelligence

All sorts of threat intelligence is available on the web. Intelligence you can learn from, and use to anticipate and prepare for future attacks.

Join & Write a Comment

More often than not, we developers are confronted with a need: a need to make some kind of magic happen via code. Whether it is for a client, for the boss, or for our own personal projects, the need must be satisfied. Most of the time, the Framework…
A long time ago (May 2011), I have written an article showing you how to create a DLL using Visual Studio 2005 to be hosted in SQL Server 2005. That was valid at that time and it is still valid if you are still using these versions. You can still re…
This Micro Tutorial demonstrate the bugs in Microsoft Excel for Mac with Pivot Charts.
This Micro Tutorial will demonstrate in Google Sheets how to use the HYPERLINK function to create live links inside your spreadsheet.

757 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

19 Experts available now in Live!

Get 1:1 Help Now