Determine if url or path is relative or absolute in php

Here is the Php functions to check whether paths and urls are relative, absolute.

function isAbsolutePath($url)
{
    $pattern = "/^(?:ftp|https?|feed):\/\/(?:(?:(?:[\w\.\-\+!$&'\(\)*\+,;=]|%[0-9a-f]{2})+:)*
    (?:[\w\.\-\+%!$&'\(\)*\+,;=]|%[0-9a-f]{2})+@)?(?:
    (?:[a-z0-9\-\.]|%[0-9a-f]{2})+|(?:\[(?:[0-9a-f]{0,4}:)*(?:[0-9a-f]{0,4})\]))(?::[0-9]+)?(?:[\/|\?]
    (?:[\w#!:\.\?\+=&@$'~*,;\/\(\)\[\]\-]|%[0-9a-f]{2})*)?$/xi";

    return (bool) preg_match($pattern, $url);
}