IntegerTransformation.php

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<?php
 
declare(strict_types=1);
 
namespace ILIAS\Refinery\KindlyTo\Transformation;
 
use ILIAS\Refinery\DeriveApplyToFromTransform;
use ILIAS\Refinery\DeriveInvokeFromTransform;
use ILIAS\Refinery\Transformation;
use ILIAS\Refinery\ConstraintViolationException;
 
class IntegerTransformation implements Transformation
{
    use DeriveApplyToFromTransform;
    use DeriveInvokeFromTransform;
    private const REG_INT = '/^\s*(0|(-?[1-9]\d*))\s*$/';
 
    public function transform($from): int
    {
        if (is_int($from)) {
            return $from;
        }
 
        if ($from !== INF && $from !== -INF && is_float($from) && !is_nan($from)) {
            $from = round($from);
            return (int) $from;
        }
 
        if (is_bool($from)) {
            return (int) $from;
        }
 
        if (is_string($from) && preg_match(self::REG_INT, $from)) {
            $int = (int) $from;
            // This is supposed to guard against PHP_MIN_INT and PHP_MAX_INT.
            // We only return the value if it looks the same when transforming it
            // back to string. This won't be the case for too big or too small
            // values.
            if (trim($from) === (string) $int) {
                return $int;
            }
        }
 
        throw new ConstraintViolationException(
            sprintf('The value "%s" can not be transformed into an integer', var_export($from, true)),
            'not_integer',
            $from
        );
    }
}