用php实现gb2312和unicode间的编码转换

is=substr($gb,0,2);
          $gb=substr($gb,2,strlen($gb)-2);
          $utf8.=u2utf8(hexdec($codetable[hexdec(bin2hex($this))-0x8080]));
        }else{
            $this=substr($gb,0,1);
            $gb=substr($gb,1,strlen($gb)-1);
            $utf8.=u2utf8($this);
        }
    }
    return $utf8;
}

function u2utf8($c){
    $str="";
    if ($c < 0x80) {
         $str.=$c;
    } else if ($c < 0x800) {
         $str.=chr(0xC0 | $c>>6);
         $str.=chr(0x80 | $c & 0x3F);
    } else if ($c < 0x10000) {
         $str.=chr(0xE0 | $c>>12);
         $str.=chr(0x80 | $c>>6 & 0x3F);
         $str.=chr(0x80 | $c & 0x3F);
    } else if ($c < 0x200000) {
         $str.=chr(0xF0 | $c>>18);
         $str.=chr(0x80 | $c>>12 & 0x3F);
         $str.=chr(0x80 | $c>>6 & 0x3F);
         $str.=chr(0x80 | $c & 0x3F);
    }
    return $str;
}

?>