PHP解密Unicode及Escape加密字符串函数

<?    
function uni_decode($s) {    
    preg_match_all('/\&\#([0-9]{2,5})\;/', $s, $html_uni);    
    preg_match_all('/[\\\%]u([0-9a-f]{4})/ie', $s, $js_uni);    
    $source = array_merge($html_uni[0], $js_uni[0]);    
    $js = array();    
    for($i=0;$i<count($js_uni[1]);$i++) {    
        $js[] = hexdec($js_uni[1][$i]);    
    }    
    $utf8 = array_merge($html_uni[1], $js);    
    $code = $s;    
    for($j=0;$j<count($utf8);$j++) {    
        $code = str_replace($source[$j], unicode2utf8($utf8[$j]), $code);    
    }    
    return $code;//$s;//preg_replace('/\\\u([0-9a-f]{4})/ie', "chr(hexdec('\\1'))",  $s);    
}    
   
function unicode2utf8($c) {    
    $str="";    
    if ($c < 0x80) {    
         $str.=chr($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;    
}    
   
$str='%u5927%u5BB6%u597D%uFF0C<br />\u8FD9\u662F\u6D4B\u8BD5\u6587\u672C\uFF01';    
echo uni_decode($str); //    
?>