'Subnet Calculator V1
'Script by MJP 2010

'usage cscript VBScriptSubnetCalcV2 > output.txt


   'force script to run in cscript mode
   Set objShell = CreateObject("WScript.Shell") 
   If Instr(1, WScript.FullName, "CScript", vbTextCompare) = 0 Then
      objShell.Run "%comspec% /k cscript //nologo """ & WScript.ScriptFullName & """", 1, False
      WScript.Quit
   End If



   
   'a bit of test code to feed a range of addresses into script for testing
'   snm="255.255.192.0"

'   for iCount=0 to 255
'      ip="172.16.17."&iCount
'      CalcSubnet ip, snm
'   next


   strIP=inputbox("Enter IP", "MJP Subnet Calc", "172.16.98.53")
   strSN=inputbox("Enter Subnet Mask", "MJP Subnet Calc", "255.255.224.0")
 
   CalcSubnet strIP, strSN

   wscript.quit


'-----------------------------------------------------------

function CalcSubnet(strIP,strSNM)

   binSNM=str2bin(strSNM) 
   binIP=str2bin(strIP) 


   'IP <AND> SN to find Network addresses
   for c=32 to 1 step -1
      temp=(cint(mid(binIP,c, 1)) and cint(mid(binSNM,c, 1))) & temp
   next
   netwAdd=temp : temp=""



   'IP <OR> SN to find blocks of all "ones" - these addresss are broadcast addresses
   for c=32 to 1 step -1
      temp=(cint(mid(binIP,c, 1)) or cint(mid(binSNM,c, 1))) & temp
   next
   bcCheck=temp : temp=""




   'Calc 1st. host address in range (Network Address + 1)
   ist=binAdd(netwAdd,string(31, "0")&"1")

   'Calc Last host address in range (111111...1 - bcCheck + IP - 0...000001)
   lst=binSub(string(32,"1"),bcCheck) 
   lst=binadd(lst,binIP)
   lst=binsub(lst,string(31, "0")&"1" )


   wscript.echo "IP    "&binIP&" "&bin2str(binIP)&vbcrlf&_
             "SNM   "&binSNM&" "&bin2str(binSNM)&vbcrlf&_
             "SN    "&netwAdd&" "&bin2str(netwAdd)&vbcrlf&_
             "1st   "&ist &" "& bin2str(ist) &vbcrlf&_
             "Last  "&lst &" "& bin2str(lst) &vbcrlf&_
             "Hosts "&binsub(lst,ist) &" "& Bin2Dec(binsub(lst,ist)) &vbcrlf


end function


'-----------------------------------------------------------


Function Bin2Dec(strBin)
'Plain old binary to decimal function

   result = 0
   for intIndex = len(strBin) to 1 step -1
      strDigit = mid(strBin, intIndex, 1)

      if strDigit = "0" then
         'do nothing
      elseif strDigit = "1" then
         result = result + (2 ^ (len(strBin)-intIndex))
      else
         Bin2Dec = 0
         exit for
      end if
   next

   Bin2Dec = result

End Function



'-----------------------------------------------------------


Function bin2str(strBinary)
'special binary to decimal function
'input 32bit binary number
'output 4 octet ip address 

   For iPosOct = 1 To 4 
      strOctBin = Right(Left(strBinary, iPosOct * 8), 8) 
      intOctet = 0 
      intValue = 1 
      For iPosBin = 1 To Len(strOctBin) 
         If Left(Right(strOctBin, iPosBin), 1) = "1" Then 
            intOctet = intOctet + intValue 
         end if
         intValue = intValue * 2 
      Next 
      If bin2str = Empty Then 
         bin2str = CStr(intOctet) 
      Else 
         bin2str = bin2str & "." & CStr(intOctet)
      end if 
   Next 

End Function 


'-----------------------------------------------------------


Function str2bin(strAddress) 
'special decimal to binary function
'input 4 octet ip address 
'output 32bit binary number


   objAddress = Split(strAddress, ".") 
   For Each strOctet In objAddress 

      intOctet = CInt(strOctet)
      strOctBin = "" 
      For x = 1 To 8 
         If intOctet Mod 2 > 0 Then 
            strOctBin = "1" & strOctBin 
         Else 
            strOctBin = "0" & strOctBin 
         End If 
         intOctet = Int(intOctet / 2) 
      Next 
      str2bin = str2bin & strOctBin 
   Next 

End Function 


'-----------------------------------------------------------


function binSub(binA,binB)
'subtract one 32bit binary number from another
'binA must be biggest

   c=0
   for i=32 to 1 step-1
      a=cint(mid(binA,i,1))
      b=cint(mid(binB,i,1))

      if a=0 and b=0 and c=0 then 
         subt=0  : c=0 
      elseif a=1 and b=0 and c=0 then 
         subt=1  : c=0 
      elseif a=0 and b=1 and c=0 then 
         subt=1  : c=1 
      elseif a=1 and b=1 and c=0 then 
         subt=0  : c=0 
      elseif a=1 and b=1 and c=1 then 
        subt=1  : c=1
      elseif a=1 and b=0 and c=1 then 
         subt=0  : c=0
      elseif a=0 and b=1 and c=1 then 
         subt=0  : c=0 
      elseif a=0 and b=0 and c=1 then 
         subt=1  : c=1
      else
         msgbox "This function is only for subtracting 2 32bit binary numbers"
         binSub=0 : exit function
      end if            
    
      total=subt&total
      'wscript.echo "a-"&BinA&" "&a&vbcrlf&"b-"&BinB&" "&b&vbcrlf&"subtraction "&subt&vbcrlf&"carry "& c&vbcrlf&"x-"&total&vbcrlf&cvcrlf

   next

   if c=1 then 
      msgbox "Error you are subtracting a larger number from a smaller number"&vbcrlf&binA&vbcrlf&binB
   end if
   
   binsub=total

end function


'-----------------------------------------------------------


function binAdd(binA,binB)
'add two 32bit binary numbers together

   c=0
   for i=32 to 1 step-1
      a=cint(mid(binA,i,1))
      b=cint(mid(binB,i,1))
      if a=0 and b=0 and c=0 then 
         add=0  : c=0 
      elseif a=1 and b=0 and c=0 then 
         add=1  : c=0 
      elseif a=0 and b=1 and c=0 then 
         add=1  : c=0 
      elseif a=1 and b=1 and c=0 then 
         add=0  : c=1 
      elseif a=1 and b=1 and c=1 then 
        add=1  : c=1
      elseif a=1 and b=0 and c=1 then 
         add=0  : c=1
      elseif a=0 and b=1 and c=1 then 
         add=0  : c=1 
      elseif a=0 and b=0 and c=1 then 
         add=1  : c=0
      else
         msgbox "Error this function is only for adding 2 32bit binary numbers together"
         binAdd=0 : exit function
      end if
    
      total=add&total
      'wscript.echo "a-"&BinA&" "&a&vbcrlf&"b-"&BinB&" "&b&vbcrlf&"addition "&add&vbcrlf&"carry "& c&vbcrlf&"x-"&total

   next

   binAdd=total

end function


'-----------------------------------------------------------