Symfony2 duration datatransformer

DurationTransformer.php

<?php

namespace AppBundle\Form\DataTransformer;

use Symfony\Component\Form\DataTransformerInterface;
use Symfony\Component\Form\Exception\TransformationFailedException;

class DurationTransformer implements DataTransformerInterface
{
    /**
     * Transform seconds in duration
     * 4340 => 1h12m20s
     * 
     * @param  integer $seconds
     * 
     * @return string
     */
    public function transform($seconds)
    {
        return ltrim(gmdate("H\hi\ms\s", $seconds), "0hm");
    }

    /**
     * Tranform a duration in seconds
     * 1h12m20s => 4340
     * 
     * @param  string $duration
     *
     * @return integer
     */
    public function reverseTransform($duration)
    {
        $pattern = '/^(?:([\d]{1,2})h)?(?:([\d]{1,2})m)?(?:([\d]{1,2})s)?$/';

        preg_match($pattern , $duration, $matches);

        $seconds = @$matches[1] * 3600 + @$matches[2] * 60 + @$matches[3];

        return $seconds;
    }
}