PHP decrypts Unicode and Escape encrypted strings, unicodeescape_PHP tutorial

<&#63;php  
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;  
}  
  
$str='%u5927%u5BB6%u597D%uFF0C我是孤魂！<br />\u8FD9\u662F\u6D4B\u8BD5\u6587\u672C\uFF01';  
echo uni_decode($str); // 大家好，我是孤魂！这是测试文本！  

function phpescape($str){ 
  preg_match_all("/[\x80-\xff].|[\x01-\x7f]+/",$str,$newstr); 
  $ar = $newstr[0]; 
  foreach($ar as $k=>$v){ 
    if(ord($ar[$k])>=127){ 
      $tmpString=bin2hex(iconv("GBK","ucs-2",$v)); 
      if (!eregi("WIN",PHP_OS)){ 
        $tmpString = substr($tmpString,2,2).substr($tmpString,0,2); 
      } 
      $reString.="%u".$tmpString; 
    } else { 
      $reString.= rawurlencode($v); 
    } 
  } 
  return $reString; 
}