<?php

$str = '<b>Sort By\u00a0-\u00a0</b><a href="http://p...content-available-to-author-only...d.com/files/9704/Dil Dhadakne Do (2015) Mp3 Songs/atoz/1.html">A to Z\u00a0|\u00a0</a><a href="http://p...content-available-to-author-only...d.com/files/9704/Dil Dhadakne Do (2015) Mp3 Songs/recent/1.html">Recently Added\u00a0|\u00a0</a><a href="http://p...content-available-to-author-only...d.com/files/9704/Dil Dhadakne Do (2015) Mp3 Songs/downloads/1.html">Most Downloaded</a>';


echo unicodeString($str);
function unicodeString($str, $encoding=null) {
    if (is_null($encoding)) $encoding = ini_get('mbstring.internal_encoding');
    return preg_replace_callback('/\\\\u([0-9a-fA-F]{4})/u', create_function('$match', 'return mb_convert_encoding(pack("H*", $match[1]), '.var_export($encoding, true).', "UTF-16BE");'), $str);
}
