PHP Example of ISO 7064 Mod 11,2 or Modulus 11,2 of the norm ISO/IEC 7064. Is is not very used, that's why I am sharing.

iso7064_mod11_2.php

<?php

class Iso7064mod112 {

    public $code;

    public function encode($code) {
        $this->code = $code;
        $c = $this->computeCheck($this->code);
        if ($c == 10) {
            return $this->code . "X";
        } else {
            return $this->code . $c;
        }
    }

    public function verify($code) {
        $this->code = $code;
        return (computeCheck(substr($this->code, 0, -1)) == getCheckDigit($this->code));
    }

    public function computeCheck($str) {
        $p = 0;
        for ($i = 0; $i < strlen($str); $i++) {
            $c = $str[$i];
            $p = 2 * ($p + $c);
        }
        $p %= 11;
        return (12 - $p) % 11;
    }

    public function getCheckDigit($str) {
        $c = substr($str, -1);
        if ($c == 'X' || $c == 'x') {
            return 10;
        } else {
            return $c;
        }
    }

}

?>