<?php
$url = "http://www.lrytas.lt/lietuvos-diena/aktualijos/viesulas-sugriove-po-20-metu-issipildziusia-svajone-201307112034.htm";
$providers = array("delfi.lt", "lrytas.lt", "15min.lt");
$provider = 'Unknown';
foreach ($providers as $knownProvider)
{
// this is quite lazy - it would be best to get the domain and check it against the array of known providers
$provider = (stripos($url, $knownProvider) === false ? $provider : $knownProvider);
}
echo $provider;