--- /dev/null
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Validator\Constraints;
+
+use Symfony\Component\Validator\Context\ExecutionContextInterface;
+use Symfony\Component\Validator\Constraint;
+use Symfony\Component\Validator\ConstraintValidator;
+use Symfony\Component\Validator\Exception\UnexpectedTypeException;
+
+/**
+ * Validates whether the value is a valid ISSN.
+ *
+ * @author Antonio J. GarcĂa Lagar <aj@garcialagar.es>
+ * @author Bernhard Schussek <bschussek@gmail.com>
+ *
+ * @see https://en.wikipedia.org/wiki/Issn
+ */
+class IssnValidator extends ConstraintValidator
+{
+ /**
+ * {@inheritdoc}
+ */
+ public function validate($value, Constraint $constraint)
+ {
+ if (!$constraint instanceof Issn) {
+ throw new UnexpectedTypeException($constraint, __NAMESPACE__.'\Issn');
+ }
+
+ if (null === $value || '' === $value) {
+ return;
+ }
+
+ if (!is_scalar($value) && !(is_object($value) && method_exists($value, '__toString'))) {
+ throw new UnexpectedTypeException($value, 'string');
+ }
+
+ $value = (string) $value;
+ $canonical = $value;
+
+ // 1234-567X
+ // ^
+ if (isset($canonical[4]) && '-' === $canonical[4]) {
+ // remove hyphen
+ $canonical = substr($canonical, 0, 4).substr($canonical, 5);
+ } elseif ($constraint->requireHyphen) {
+ if ($this->context instanceof ExecutionContextInterface) {
+ $this->context->buildViolation($constraint->message)
+ ->setParameter('{{ value }}', $this->formatValue($value))
+ ->setCode(Issn::MISSING_HYPHEN_ERROR)
+ ->addViolation();
+ } else {
+ $this->buildViolation($constraint->message)
+ ->setParameter('{{ value }}', $this->formatValue($value))
+ ->setCode(Issn::MISSING_HYPHEN_ERROR)
+ ->addViolation();
+ }
+
+ return;
+ }
+
+ $length = strlen($canonical);
+
+ if ($length < 8) {
+ if ($this->context instanceof ExecutionContextInterface) {
+ $this->context->buildViolation($constraint->message)
+ ->setParameter('{{ value }}', $this->formatValue($value))
+ ->setCode(Issn::TOO_SHORT_ERROR)
+ ->addViolation();
+ } else {
+ $this->buildViolation($constraint->message)
+ ->setParameter('{{ value }}', $this->formatValue($value))
+ ->setCode(Issn::TOO_SHORT_ERROR)
+ ->addViolation();
+ }
+
+ return;
+ }
+
+ if ($length > 8) {
+ if ($this->context instanceof ExecutionContextInterface) {
+ $this->context->buildViolation($constraint->message)
+ ->setParameter('{{ value }}', $this->formatValue($value))
+ ->setCode(Issn::TOO_LONG_ERROR)
+ ->addViolation();
+ } else {
+ $this->buildViolation($constraint->message)
+ ->setParameter('{{ value }}', $this->formatValue($value))
+ ->setCode(Issn::TOO_LONG_ERROR)
+ ->addViolation();
+ }
+
+ return;
+ }
+
+ // 1234567X
+ // ^^^^^^^ digits only
+ if (!ctype_digit(substr($canonical, 0, 7))) {
+ if ($this->context instanceof ExecutionContextInterface) {
+ $this->context->buildViolation($constraint->message)
+ ->setParameter('{{ value }}', $this->formatValue($value))
+ ->setCode(Issn::INVALID_CHARACTERS_ERROR)
+ ->addViolation();
+ } else {
+ $this->buildViolation($constraint->message)
+ ->setParameter('{{ value }}', $this->formatValue($value))
+ ->setCode(Issn::INVALID_CHARACTERS_ERROR)
+ ->addViolation();
+ }
+
+ return;
+ }
+
+ // 1234567X
+ // ^ digit, x or X
+ if (!ctype_digit($canonical[7]) && 'x' !== $canonical[7] && 'X' !== $canonical[7]) {
+ if ($this->context instanceof ExecutionContextInterface) {
+ $this->context->buildViolation($constraint->message)
+ ->setParameter('{{ value }}', $this->formatValue($value))
+ ->setCode(Issn::INVALID_CHARACTERS_ERROR)
+ ->addViolation();
+ } else {
+ $this->buildViolation($constraint->message)
+ ->setParameter('{{ value }}', $this->formatValue($value))
+ ->setCode(Issn::INVALID_CHARACTERS_ERROR)
+ ->addViolation();
+ }
+
+ return;
+ }
+
+ // 1234567X
+ // ^ case-sensitive?
+ if ($constraint->caseSensitive && 'x' === $canonical[7]) {
+ if ($this->context instanceof ExecutionContextInterface) {
+ $this->context->buildViolation($constraint->message)
+ ->setParameter('{{ value }}', $this->formatValue($value))
+ ->setCode(Issn::INVALID_CASE_ERROR)
+ ->addViolation();
+ } else {
+ $this->buildViolation($constraint->message)
+ ->setParameter('{{ value }}', $this->formatValue($value))
+ ->setCode(Issn::INVALID_CASE_ERROR)
+ ->addViolation();
+ }
+
+ return;
+ }
+
+ // Calculate a checksum. "X" equals 10.
+ $checkSum = 'X' === $canonical[7]
+ || 'x' === $canonical[7]
+ ? 10
+ : $canonical[7];
+
+ for ($i = 0; $i < 7; ++$i) {
+ // Multiply the first digit by 8, the second by 7, etc.
+ $checkSum += (8 - $i) * $canonical[$i];
+ }
+
+ if (0 !== $checkSum % 11) {
+ if ($this->context instanceof ExecutionContextInterface) {
+ $this->context->buildViolation($constraint->message)
+ ->setParameter('{{ value }}', $this->formatValue($value))
+ ->setCode(Issn::CHECKSUM_FAILED_ERROR)
+ ->addViolation();
+ } else {
+ $this->buildViolation($constraint->message)
+ ->setParameter('{{ value }}', $this->formatValue($value))
+ ->setCode(Issn::CHECKSUM_FAILED_ERROR)
+ ->addViolation();
+ }
+ }
+ }
+}