class LengthValidator

LengthValidatorTest.php in drupal/core/vendor/symfony/validator/Symfony/Component/Validator/Tests/Constraints/LengthValidatorTest.php

class LengthValidator extends ConstraintValidator {

  /**
   * {@inheritDoc}
   */
  public function validate($value, Constraint $constraint) {
    if (null === $value || '' === $value) {
      return;
    }
    if (!is_scalar($value) && !(is_object($value) && method_exists($value, '__toString'))) {
      throw new UnexpectedTypeException($value, 'string');
    }
    $stringValue = (string) $value;
    if (function_exists('grapheme_strlen') && 'UTF-8' === $constraint->charset) {
      $length = grapheme_strlen($stringValue);
    }
    elseif (function_exists('mb_strlen')) {
      $length = mb_strlen($stringValue, $constraint->charset);
    }
    else {
      $length = strlen($stringValue);
    }
    if ($constraint->min == $constraint->max && $length != $constraint->min) {
      $this->context
        ->addViolation($constraint->exactMessage, array(
        '{{ value }}' => $stringValue,
        '{{ limit }}' => $constraint->min,
      ), $value, (int) $constraint->min);
      return;
    }
    if (null !== $constraint->max && $length > $constraint->max) {
      $this->context
        ->addViolation($constraint->maxMessage, array(
        '{{ value }}' => $stringValue,
        '{{ limit }}' => $constraint->max,
      ), $value, (int) $constraint->max);
      return;
    }
    if (null !== $constraint->min && $length < $constraint->min) {
      $this->context
        ->addViolation($constraint->minMessage, array(
        '{{ value }}' => $stringValue,
        '{{ limit }}' => $constraint->min,
      ), $value, (int) $constraint->min);
    }
  }

}