Convert Between Numeric Bases

<?
/****************************************
  convertBase($number, $originalBase, $destinationBase);
  
  Author: Chris Heald
  Email: [email protected]
  Creation date: 1/16/02
  
  License: No restriction, provided this header is left intact. You may
    change the purpose if you update the code - leave the author, email,
    creation date, license, and changelog intact. You may append to the 
    changelog as you make changes.
    
  Purpose:
  Use to convert a number in any base from 2 to 36 to any other base from 2 to 36.
  ie: convertBase("FF",16,10) returns 255. You can also use HEX, BINARY, BASE10, DECIMAL and OCT in place of numeric
  values for the bases. ie: convertBase("FF",HEX,BINARY) returns 11111111.
  
  HEX    : 16
  BASE10 : 10
  DECIMAL: 10
  OCT    :  8
  BINARY :  2
  
  Possible future enhancements:
    Even more bases supported. We could use lower case and upper case letters as seperate digits, but that could get
    confusing. The benefit of this would be a maximum range of 62 bases.
    
  This was an exericse I did in my free time. Please feel free
  to expand or enhance it, and feel free to email me if you have questions.
  
  *** Change Log ***
  01/16/02 - CMH
    Created File. Version 1.00
  ******************
****************************************/

define("HEX",16);
define("BINARY",2);
define("OCT",8);
define("BASE10",10);
define("DECIMAL", 10);
function convertBase($number, $fromBase = 10, $toBase = 2) {
  
  if($toBase > 36 || $toBase < 2)			//check base validity
    return "Invalid originating base.";
  if($fromBase > 36 || $fromBase < 2)
    return "Invalid destination base.";
    
  @list($number, $decimal) = explode(".",$number);
  for($i = 0; $i < strlen($number); $i++) {		//convert to base 10
    $digit = substr($number, $i, 1);
    if(eregi("[a-z]",$digit)) {
      $x = ord($digit) - 65 + 10;
      if($x > $fromBase)
        $x -= 32;
      $digit = $x;
    }
    @$base10 += $digit * (pow($fromBase, strlen($number) - $i - 1));
  }
  $number = $base10;
  if($toBase == 10)
    return $number;
  $q = $number;
  while($q != 0) {		//convert base 10 equivalent to specified base
    $r = $q % $toBase;
    $q = floor($q / $toBase);
    if($r > 9)
      $r = chr(($r - 9) + 64);
    @$baseres = "$r" . "$baseres";
  }
  return $baseres;
}

?>