<?php
 
$text = 'шшшшшш';
$text = trim($text);
echo strcasecmp($text, strrev($text)), PHP_EOL;
 
function mb_strcasecmp($str1, $str2, $encoding = null) {
    if (null === $encoding) {
    	$encoding = mb_internal_encoding();
    }
    return strcmp(mb_strtolower($str1, $encoding), mb_strtolower($str2, $encoding));
}
 
function utf8_strrev($str){
    preg_match_all('/./us', $str, $matches);
    return join('', array_reverse($matches[0]));
}
 
echo mb_strcasecmp($text, utf8_strrev($text));

PD9waHAKCiR0ZXh0ID0gJ9GI0YjRiNGI0YjRiCc7CiR0ZXh0ID0gdHJpbSgkdGV4dCk7CmVjaG8gc3RyY2FzZWNtcCgkdGV4dCwgc3RycmV2KCR0ZXh0KSksIFBIUF9FT0w7CgpmdW5jdGlvbiBtYl9zdHJjYXNlY21wKCRzdHIxLCAkc3RyMiwgJGVuY29kaW5nID0gbnVsbCkgewogICAgaWYgKG51bGwgPT09ICRlbmNvZGluZykgewogICAgCSRlbmNvZGluZyA9IG1iX2ludGVybmFsX2VuY29kaW5nKCk7CiAgICB9CiAgICByZXR1cm4gc3RyY21wKG1iX3N0cnRvbG93ZXIoJHN0cjEsICRlbmNvZGluZyksIG1iX3N0cnRvbG93ZXIoJHN0cjIsICRlbmNvZGluZykpOwp9CgpmdW5jdGlvbiB1dGY4X3N0cnJldigkc3RyKXsKICAgIHByZWdfbWF0Y2hfYWxsKCcvLi91cycsICRzdHIsICRtYXRjaGVzKTsKICAgIHJldHVybiBqb2luKCcnLCBhcnJheV9yZXZlcnNlKCRtYXRjaGVzWzBdKSk7Cn0KCmVjaG8gbWJfc3RyY2FzZWNtcCgkdGV4dCwgdXRmOF9zdHJyZXYoJHRleHQpKTs=