[RESOLVED] multiple range checking algorithm vb6

[flyguille]

Well, then let's see what your recommendations will bring, when I alter it to your wishes...


Ok, done...


... as you wish, master...


Please forgive me, but I've found it this way in posting #10 (from a guy named "flyguille")...
But Ok - I've adapted it now as commanded...



I hope the new code below is to your satisfaction now - but I have to tell you that the changes you demanded,
make it now run factor 2 slower than before... (about 3.3 µsec per call, compared to the former 1.6)
What now?

Wouldn't it be better, when you perhaps write "the ideal code" for the usage of your approach yourself -
and post it here (preferrably within Code-Tags, if that's not too much to ask...).

Option Explicit

Private LookupTable(0 To 255, 0 To 255, 0 To 255, 0 To 31) As Byte

Private Sub Form_Click()
  Dim i As Long, Result As Boolean, T As Single
  T = Timer
    For i = 1 To 100000
      Result = IsInUSA("121.122.123.124")
      If Result Then
        'do something here
      End If
    Next
  Caption = Format$((Timer - T) * 10, "0.0") & " µSec per function-call"
End Sub

Function IsInUSA(RemoteIP As String) As Boolean
  Dim st() As String
      st = Split(RemoteIP, ".")

  IsInUSA = LookupTable(Val(st(0)), Val(st(1)), Val(st(2)), Int(Val(st(3)) / 16) And (Val(st(3)) Mod 16))
End Function

Olaf

ok remove the INT(), btw I didn't know a Split() function, is slower than 7 VB string function which its parameters parsings and all. weird.

oh, BTW? why you chose MOD and / 16, if it is 8 , as per 8 bits per byte?

oh, and you didn't did the BIT inspection, just readed the whole byte as output!.

lets change the: To 31

Private LookupTable(0 To 255, 0 To 255, 0 To 255, 0 To 31) As Byte

and

IsInUSA = LookupTable(Val(st(0)), Val(st(1)), Val(st(2)), Val(st(3)), Val(st(4)) / 8) And (2^(Val(st(4)) Mod 8)

oh, now I see you didn't inspect the fourth value at all!

Ofcourse now it is a bit slower.

But prefferably a lookup table, and not rolling an array with many entries, including it doing binary search would be slower.

Oh, BTW, thanks by your participation.