Regarding the utf8_substr function from lmak: The pattern '/./u' doesn't match newline characters. This means that the substring from 0 to the total length of the string will miss the number of characters in the end matching the number of newlines in the string. To fix this one can add the s modifier (PCRE_DOTALL) in the pattern:

<?php
function utf8_substr($str,$start)
{
   preg_match_all("/./su", $str, $ar);

   if(func_num_args() >= 3) {
       $end = func_get_arg(2);
       return join("",array_slice($ar[0],$start,$end));
   } else {
       return join("",array_slice($ar[0],$start));
   }
}
?>