[Resolved]VB function to a PHP function

[Pc_Madness]

function mid ($str, $start, $howManyCharsToRetrieve = 0)
{
  $start--;
  if ($howManyCharsToRetrieve === 0)
   $howManyCharsToRetrieve = strlen ($str) - $start;

  return substr ($str, $start, $howManyCharsToRetrieve);
} 


function EncryptText($strText, $strKey) {
   $i = 0;
$c = 0;
$strbuff = '';

if (strlen($strKey) > 0) {
 
 for ($i = 1; $i <= strlen($strText); $i++) {

  $c = ord(mid($strText, $i, 1));
  $c = $c + ord(mid($strText, (fmod($i, strlen($strKey))) + 1, 1));
  
  $strbuff = $strbuff & chr($c And 0xFF);

 }
} else {
 $strbuff = $strText;
}


return $strbuff;
} 

'|-------------------------------VB Version
Private Function EncryptText(strText As String, ByVal strKEY As String)
   Dim i As Integer, c As Integer
   Dim strBuff As String
   
   If Len(strKEY) Then
       For i = 1 To Len(strText)
           c = Asc(Mid$(strText, i, 1))
           c = c + Asc(Mid$(strKEY, (i Mod Len(strKEY)) + 1, 1))
           strBuff = strBuff & Chr$(c And &HFF)
       Next i
   Else
       strBuff = strText
   End If
   EncryptText = strBuff
End Function

I'm trying to convert the VB function to a PHP one, but can't seem to get the things inside the loop right. Anyone able to point me in the right direction?