<?
$str = str_repeat('ウィキ', 99) . 'б';

function utf8_strrev($str) {
    return iconv("UTF-16LE", "UTF-8", strrev(iconv("UTF-8", "UTF-16BE", $str)));
}

$start = microtime(true);
for ($i = 0; $i <= 10000; $i++) {
    utf8_strrev($str);
}

echo "iconv:\t" . round(microtime(true) - $start, 5) . " s\n";


function utf8_strrev_mb($str) {
    return mb_convert_encoding(strrev(mb_convert_encoding($str, "UTF-8", "UTF-16BE")), "UTF-16LE", "UTF-8");
}

$start = microtime(true);
for ($i = 0; $i <= 10000; $i++) {
    utf8_strrev_mb($str);
}
echo "mb:\t" . round(microtime(true) - $start, 5) . " s\n";

function utf8_strrev_cycle($str) {
    $out = '';

    for ($l = strlen($str), $i = 0; $i<$l;) {
        $ch = ord($str[$i]);

        $len = ($ch & 0b10000000) ?
            ($ch & 0b11110000) == 0b11110000 ? 4 :
            (
                ($ch & 0b11100000) == 0b11100000 ? 3 : (
                    ($ch & 0b11000000) == 0b11000000 ? 2 : 1
                )
            ) : 1;

        $out = substr($str, $i, $len) . $out;
        $i += $len;

    }
    return $out;
}

$start = microtime(true);
for ($i = 0; $i <= 10000; $i++) {
    utf8_strrev_cycle($str);
}

echo "cycle:\t" . round(microtime(true) - $start, 5) . " s\n";

function utf8_rev_another_cycle($text) {
    $result = "";
   for ($index = 0; $index < strlen($text); $index ++)
   {
     $item = $text[$index];
     $byte = ord($item);
     if ($byte < 0x80)
     {
       $result = $item . $result;
       continue;
     }
     if (($byte & 0xc0) == 0x80)
     {
       $sequence .= $item;
       $count --;
       if ($count == 0)
         $result = $sequence . $result;
       continue;
     }
     for ($count = 1; $count <= 6; $count ++)
     {
       $mask = (0xfc0 >> $count) & 0xff;
       $mark = (0xf80 >> $count) & 0xff;
       if (($byte & $mask) == $mark)
         break;
     }
     $sequence = $item;
   }

   return $result;
}


$start = microtime(true);
for ($i = 0; $i <= 10000; $i++) {
    utf8_rev_another_cycle($str);
}

echo "an cyc:\t" . round(microtime(true) - $start, 5) . " sec\n";