hexadecimal validation

Part of my project I needed hexadecimal validation so I write these function. You guys may need this too enjoy! Suggestion are welcome.

<?php // ------------------------------------------------------------------------ /**

• Hexadecimal validation function

• Useful for validating hexadecimal value

• @access public

• @param string input string.

• @return Boolean /
  function is_hex($entry) { $validChar=array('0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F');// characters allowed in hex $stringlen=strlen($entry); $entry=strtoupper($entry); // lowercase characters? make uppercase // Now scan string for illegal characters for ($i=0;$i<$stringlen;$i++){ if(!in_array(charAt($entry,$i),$validChar)){
  return false;} } // end scanning loop return true; } /*

• Javascript simalr charAt function

• Pick the string from the define position

• @access public

• @param string input string.

• @return 1 Character */
  function charAt($str, $pos) { return (substr($str, $pos, 1)); } ?>