js-deflate issue #15 fix in PHP

<?php
function cp_to_utf8($text) {
    $out='';
    $size=strlen($text);
    $pos=0;
    $count=0;
    $nb=0;
    $nb2=0;
    $nb3=0;
    $nb4=0;
    $c='';
    while($pos<$size) {
        $nb=ord($text[$pos]);
        if($nb<=0x7F) {
            //UTF8 1byte
            $out.=chr($nb);
            ++$pos;
        }
        else if(($nb & 0xE0) == 0xC0) {
            // 110x xxxx
            $nb2=ord($text[$pos+1]);
            assert( ($nb2&0xBF)==$nb2 ) or die('error2');
            $c=( ($nb & 0x1F) << 6 ) | ($nb2 & 0x3F);
            assert( $c<256 || ( (($c>>8)==0xFF) & ($c&0xFFFF00FF<256) ) );
            $out.=chr($c);
            $pos+=2;
        }
        else if(($nb & 0xF0) == 0xE0) {
            // 1110 xxxx
            $nb2=ord($text[$pos+1]);
            $nb3=ord($text[$pos+2]);
            assert( ($nb2&0xBF)==$nb2 ) or die('error3a');
            assert( ($nb3&0xBF)==$nb3 ) or die('error3b');
            $c=( ($nb & 0x1F) << 12 ) | ( ($nb2 & 0x3F) << 6 ) | ($nb3 & 0x3F);
            assert( ($c<256) || ( (($c>>8)==0xFF) && (($c&0xFFFF00FF)<256) ) ) or die(var_dump($c, true));
            $out.=chr($c);
            $pos+=3;
        }
        else if(($nb & 0xF8) == 0xF0) {
            // 1111 0xxx
            $nb2=ord($text[$pos+1]);
            $nb3=ord($text[$pos+2]);
            $nb4=ord($text[$pos+3]);
            assert( ($nb2&0xBF)==$nb2 ) or die('error4a');
            assert( ($nb3&0xBF)==$nb3 ) or die('error4b');
            assert( ($nb4&0xBF)==$nb4 ) or die('error4c');
            $c=( ($nb & 0x1F) << 18 ) | ( ($nb2 & 0x3F) << 12 ) | ( ($nb3 & 0x3F) << 6 ) | ($nb4 & 0x3F);
            assert( ($c<256) || ( (($c>>8)==0xFF) && (($c&0xFFFF00FF)<256) ) ) or die(var_dump($c, true));
            $out.=chr($c);
            $pos+=3;
        }
    }
    return $out;
}
?>