Recursive rename encoded cyrillic files (like #U0411...) to UTF-8 (wordpress problem)

rename.php

<?php

function utf8_urldecode($str) {
	$str = preg_replace("/%u([0-9a-f]{3,4})/i","&#x\\1;",urldecode($str));
	$str = html_entity_decode($str,null,'UTF-8');
	//$str = iconv('UTF-8', 'windows-1251', $str);
	return $str;
}

$str = utf8_urldecode($str);

$directory = new RecursiveDirectoryIterator(__DIR__);
$flattened = new RecursiveIteratorIterator($directory);

$files = new RegexIterator($flattened, '#^.*(\#U\d\d\d\d[^/]+)\.*#i');
foreach($files as $file) {
	$newFileName = utf8_urldecode(str_replace('#', '%', $file));
	rename($file, $newFileName);
    echo $file . PHP_EOL;
}