private function ISBNtest::get_gtin14_checkdigit in Biblio Advanced Import 7

Same name and namespace in other branches

1. 6 lib/isbntest.class.php \ISBNtest::get_gtin14_checkdigit()

1 call to ISBNtest::get_gtin14_checkdigit()

ISBNtest::valid_gtin14 in lib/isbntest.class.php

File

lib/isbntest.class.php, line 79

Class

ISBNtest

Code

private function get_gtin14_checkdigit() {
  if (strlen($this->gtin14) != 14) {
    return FALSE;
    $this->error = "Given GTIN is not 14 digits (" . $this->gtin14 . ")";
  }
  $checkdigit = 10 - (3 * substr($this->gtin14, 0, 1) + 1 * substr($this->gtin14, 1, 1) + 3 * substr($this->gtin14, 2, 1) + 1 * substr($this->gtin14, 3, 1) + 3 * substr($this->gtin14, 4, 1) + 1 * substr($this->gtin14, 5, 1) + 3 * substr($this->gtin14, 6, 1) + 1 * substr($this->gtin14, 7, 1) + 3 * substr($this->gtin14, 8, 1) + 1 * substr($this->gtin14, 9, 1) + 3 * substr($this->gtin14, 10, 1) + 1 * substr($this->gtin14, 11, 1) + 3 * substr($this->gtin14, 12, 1)) % 10;

  /*
   * convert the numeric check value
   * into the single char version
   */
  if ($checkdigit == 10) {
    $checkdigit = "0";
  }
  return $checkdigit;
}