PHP Decode

<?php 
class Trans{private $utf8_gb2312; private $utf8_big5; public function __construct(){$this->utf8_gb2312=""; $this->utf8_big5=""; } public function c2t($str){$str_t=''; $len=strlen($str); $a=0; while ($a < $len){if (ord($str{$a}) >= 224 && ord($str{$a}) <= 239){if (($temp=strpos($this->utf8_gb2312, $str{$a} . $str{$a+1} . $str{$a+2})) !== false){$str_t.=$this->utf8_big5{$temp} . $this->utf8_big5{$temp + 1} . $this->utf8_big5{$temp + 2} ; $a += 3; continue; } } $str_t.=$str{$a}; $a += 1; } return $str_t; } public function t2c($str){$str_t=''; $len=strlen($str); $a=0; while ($a < $len){if (ord($str{$a}) >= 224 && ord($str{$a}) <= 239){if (($temp=strpos($this->utf8_big5, $str{$a} . $str{$a+1} . $str{$a+2})) !== false){$str_t.=$this->utf8_gb2312{$temp} . $this->utf8_gb2312{$temp + 1} . $this->utf8_gb2312{$temp + 2} ; $a += 3; continue; } } $str_t.=$str{$a}; $a += 1; } return $str_t; } }  ?>