isbntest.class.php in Biblio Advanced Import 6

File

lib/isbntest.class.php

<?php

/*
 * This class contains a method to do validity checks on ISBNs.
 * it's pretty basic and should require no further docs
 *
 * Updated to be more flexible in the face of new isbn standards
 * 2009-11-19 bugfixes to deal with problems reported in the forums.
 *
 * copyright 1999, 2004, 2008, 2009 Keith Nunn
 * [e-mail]
 * Released under the terms of the GNU General Public License v.2 or later
 */
class ISBNtest {
  private $isbn10 = FALSE;

  // the stripped ISBN-10, includes given checkdigit
  private $isbn13 = FALSE;

  // the stripped ISBN-13 (or Bookland EAN), includes given checkdigit
  private $gtin14 = FALSE;

  // the stripped GTIN-14 (or ISBN-14), includes given checkdigit
  private $error = "";

  // error to return, if required
  private function get_isbn10_checkdigit() {
    if (strlen($this->isbn10) != 10) {
      return FALSE;
      $this->error = "Given ISBN-10 is not 10 digits (" . $this->isbn10 . ")";
    }

    /*
     * this checkdigit calculation could probably be expressed in less
     * space using a lop, but this keeps it very clear what the math
     * involved is
     */
    $checkdigit = 11 - (10 * substr($this->isbn10, 0, 1) + 9 * substr($this->isbn10, 1, 1) + 8 * substr($this->isbn10, 2, 1) + 7 * substr($this->isbn10, 3, 1) + 6 * substr($this->isbn10, 4, 1) + 5 * substr($this->isbn10, 5, 1) + 4 * substr($this->isbn10, 6, 1) + 3 * substr($this->isbn10, 7, 1) + 2 * substr($this->isbn10, 8, 1)) % 11;

    /*
     * convert the numeric check value
     * into the single char version
     */
    switch ($checkdigit) {
      case 10:
        $checkdigit = "X";
        break;
      case 11:
        $checkdigit = 0;
        break;
      default:
    }
    return $checkdigit;
  }

  /***********************************************/
  private function get_isbn13_checkdigit() {
    if (strlen($this->isbn13) != 13) {
      return FALSE;
      $this->error = "Given ISBN-13 is not 10 digits (" . $this->isbn13 . ")";
    }

    /*
     * this checkdigit calculation could probably be expressed in less
     * space using a lop, but this keeps it very clear what the math
     * involved is
     */
    $checkdigit = 10 - (1 * substr($this->isbn13, 0, 1) + 3 * substr($this->isbn13, 1, 1) + 1 * substr($this->isbn13, 2, 1) + 3 * substr($this->isbn13, 3, 1) + 1 * substr($this->isbn13, 4, 1) + 3 * substr($this->isbn13, 5, 1) + 1 * substr($this->isbn13, 6, 1) + 3 * substr($this->isbn13, 7, 1) + 1 * substr($this->isbn13, 8, 1) + 3 * substr($this->isbn13, 9, 1) + 1 * substr($this->isbn13, 10, 1) + 3 * substr($this->isbn13, 11, 1)) % 10;

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

  /***********************************************/
  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;
  }

  /***********************************************/
  public function set_isbn10($isbn) {
    $isbn = ereg_replace("[^0-9X]", "", strtoupper($isbn));

    // strip to the basic ISBN
    if (strlen($isbn) == 10) {
      $this->isbn10 = $isbn;
    }
    else {
      $this->error = "ISBN-10 given is not 10 digits ({$isbn})";
      return FALSE;
    }
  }

  /***********************************************/
  public function set_isbn13($isbn) {
    $isbn = ereg_replace("[^0-9]", "", strtoupper($isbn));

    // strip to the basic ISBN
    if (strlen($isbn) == 13) {
      $this->isbn13 = $isbn;
    }
    else {
      $this->error = "ISBN-13 given is not 13 digits ({$isbn})";
      return FALSE;
    }
  }

  /***********************************************/
  public function set_gtin14($isbn) {
    $isbn = ereg_replace("[^0-9]", "", strtoupper($isbn));

    // strip to the basic ISBN
    if (strlen($isbn) == 14) {
      $this->gtin14 = $isbn;
    }
    else {
      $this->error = "GTIN given is not 14 digits ({$isbn})";
      return FALSE;
    }
  }

  /***********************************************/
  public function set_isbn($isbn) {
    $isbn = ereg_replace("[^0-9X]", "", strtoupper($isbn));

    // strip to the basic ISBN
    if (strlen($isbn) == 14) {
      $this
        ->set_gtin14($isbn);
      return TRUE;
    }
    if (strlen($isbn) == 13) {
      $this
        ->set_isbn13($isbn);
      return TRUE;
    }
    elseif (strlen($isbn) == 10) {
      $this->isbn10 = $isbn;
      return TRUE;
    }
    else {
      $this->error = "ISBN given is not 10, 13, or 14 digits ({$isbn})";
      return FALSE;
    }
  }

  /***********************************************/
  public function valid_isbn10($isbn = "") {
    if ($isbn != "") {

      // If we've been given a new ISBN then use it.
      $this
        ->set_isbn10($isbn);
    }
    if (FALSE === $this->isbn10 && FALSE !== $this->isbn13) {
      if (TRUE === $this
        ->valid_isbn13()) {
        $this
          ->get_isbn10();
      }
    }
    if (FALSE === $this->isbn10 || strlen($this->isbn10) != 10) {
      $this->error = "ISBN-10 is not set";
      return FALSE;
    }
    if ((string) substr($this->isbn10, 9, 1) === (string) $this
      ->get_isbn10_checkdigit()) {
      return TRUE;
    }
    else {
      $this->error = "Checkdigit failure";
      return FALSE;
    }
  }

  /***********************************************/
  public function valid_isbn13($isbn = "") {
    if ($isbn != "") {

      // if we've been given an isbn here, use it
      $this
        ->set_isbn13($isbn);
    }
    if (FALSE === $this->isbn13 && FALSE !== $this->isbn10) {
      if (TRUE === $this
        ->valid_isbn10()) {
        $this
          ->get_isbn13();
      }
    }
    if (FALSE === $this->isbn13 || strlen($this->isbn13) != 13) {
      $this->error = "ISBN-13 is not set";
      return FALSE;
    }
    if ((string) substr($this->isbn13, 12, 1) === (string) $this
      ->get_isbn13_checkdigit()) {
      return TRUE;
    }
    else {
      $this->error = "Checkdigit failure";
      return FALSE;
    }
  }

  /***********************************************/
  public function valid_gtin14($isbn = "") {
    if ($isbn != "") {

      // if we've been given an ISBN here, use it
      $this
        ->set_gtin14($isbn);
    }
    if (FALSE === $this->gtin14 || strlen($this->gtin14) != 14) {
      $this->error = "GTIN-14 is not set";
      return FALSE;
    }
    if (substr($this->gtin14, 13, 1) === $this
      ->get_gtin14_checkdigit()) {
      return TRUE;
    }
    else {
      $this->error = "Checkdigit failure";
      return FALSE;
    }
  }

  /***********************************************/
  public function valid_isbn($isbn = "") {
    if ($isbn != "") {

      // if we've been given an ISBN then use it
      $this
        ->set_isbn($isbn);
    }
    if (isset($this->gtin14) && $this
      ->valid_gtin14() == TRUE || isset($this->isbn13) && $this
      ->valid_isbn13() == TRUE || isset($this->isbn10) && $this
      ->valid_isbn10() == TRUE) {

      // in this routine, we don't care what kind it is, only that it's valid.
      return TRUE;
    }
    else {
      $this->error = "Checkdigit failure";
      return FALSE;
    }
  }

  /***********************************************/
  public function get_isbn10() {
    if ($this->isbn10 != FALSE) {
      return $this->isbn10;
    }
    elseif ($this
      ->valid_isbn13() != FALSE) {
      if (eregi("979", $this->isbn13)) {
        $this->error = "979 Bookland EAN values can't be converted to ISBN-10";
        return FALSE;

        // if it's a 979 prefix it can't be downgraded
      }
      else {
        $this
          ->set_isbn10(substr($this->isbn13, 3, 10));

        // invalid ISBN used as a temp value for next step
        $checkdigit = $this
          ->get_isbn10_checkdigit();
        $this
          ->set_isbn10(substr($this->isbn13, 3, 9) . $checkdigit);

        // true value (I hope)
        return $this->isbn10;
      }
    }
    else {
      $this->error = "No ISBN-10 value set or calculable";
      return FALSE;
    }
  }

  /*********************************************/
  public function get_isbn13() {
    if ($this->isbn13 != FALSE) {
      return $this->isbn13;
    }
    elseif ($this
      ->valid_isbn10() != FALSE) {
      $this
        ->set_isbn13("978" . substr($this->isbn10, 0, 9) . "0");

      // invalid ISBN used as a temp value for next step
      $checkdigit = (string) $this
        ->get_isbn13_checkdigit();
      $this
        ->set_isbn13("978" . substr($this->isbn10, 0, 9) . $checkdigit);

      // true value (I hope)
      return $this->isbn13;
    }
    else {
      $this->error = "No ISBN-10 value set or calculable";
      return FALSE;
    }
  }

  /*********************************************/
  public function get_gtin14() {
    if ($this->gtin14 != FALSE) {
      return $this->gtin14;
    }
    else {
      $this->error = "No GTIN-14 value set or calculable";
      return FALSE;
    }
  }

  /*********************************************/
  public function get_error() {
    return $this->error;
  }

}

Classes

Name	Description
ISBNtest