Attempting error correction by single digit insertion.\n"); } elseif (strlen($clean) == 8) { echo("
This string has an error in at least one position.
\n"); echo("Attempting error correction by single character " . "replacement or pairwise transposition.\n"); } else { echo("
This string has an extraneous character.
\n"); echo("Attempting error correction by single character deletion.\n"); } echo("
\n"); $corrections = generate_issn_corrections($clean); if (sizeof($corrections) == 0) { echo("Sorry, no correction is possible.\n
"); } else { echo("The following valid ISSNs have been generated.
\n"); echo("The string is ISSN-checksum correct!
\n"); $canon = canonical_ISSN($clean); if ((strlen($original) > 8) && (str_replace("x", "X", $original) != $canon)) { echo("Hyphenation error: hyphenation ignored.
\n"); } echo("Try the bibp link: bibp:ISSN/' . $canon . "!
\n"); } ?> Error in ISSN\n"); echo("ISSN string under analysis: $clean
\n"); if ($class == "single_error") error_repair_and_report($clean); else { echo("This string "); if ($class == "short") echo("is too short to be an ISSN.\n"); elseif ($class == "short/invalid") echo("is too short to be an ISSN and contains invalid characters.\n"); elseif ($class == "long") echo("is too long to be an ISSN.\n"); elseif ($class == "long/invalid") echo("is too long to be an ISSN and contains invalid characters.\n"); elseif ($class == "invalid") echo("contains two or more invalid ISSN characters.\n"); echo("There are too many errors for error correction to be attempted.
\n"); } echo("An ISSN consists of 7 significant digits and a check digit.\n"); echo("The check digit may be 'X' or 'x' to represent a checksum of 10.\n"); echo("An optional embedded hyphen may appear between the fourth and " . "fifth digits.\n"); echo("
"); } } ?>