字符串处理 兼容UTF8 GBK

/**
 * 处理字符串类，旨在练习字符串等
 */
class ProcessString {

    var $string;
    var $slice_array = array();
    var $charset = array();
    var $CHARSET=array(
        "UTF-8",
        "GBK",
        "ACSII"
    );
    var $length;

    function __construct($string) {
        $this->string = $string;
        $this->length = array(
            strlen($this->string),
            strlen($this->string)
        );
        $this->slice();
    }

    /*通过魔术方法调用系统函数,省略系统函数指定字符串的参数
     * strstr('hello','h');
     * ----->
     * $ps=new ProcessString('hello');
     * echo $ps->strstr('h');
     */
    public function __call($function, $args) {
        if (function_exists($function)) {
            array_unshift($args, $this->string);
            return call_user_func_array($function, $args);
        } else {
            echo "Called method/function ：$function not exists! Params：";
            print_r($args);
        }
    }

    public function slice() {
        $len=$I = 0;
        $String=$this->string;
        $Length = $this->length[1];
        while ($len++ < $Length) {
            $StringTMP = substr($String, $I, 1);
            if (ord($StringTMP) >= 224) {
                $StringTMP = substr($String, $I, 3);
                $I = $I + 3;
                $this->length[1]-=2;
                $this->hasCharset($this->CHARSET[0]);
            } elseif (ord($StringTMP) >= 192) {
                $StringTMP = substr($String, $I, 2);
                $I = $I + 2;
                $this->length[1]-=1;
                $this->hasCharset($this->CHARSET[1]);
            } else {
                $I = $I + 1;
                $this->hasCharset($this->CHARSET[2]);
            }
            $Length=$this->length[1];
            $this->slice_array[] = $StringTMP;
        }
    }

    public function hasCharset($charset){
        if(!in_array($charset, $this->charset)){
            array_push($this->charset, $charset);
        }
    }

    public function get_str($length,$omit=true,$tipstring='...'){
        $res_arr = $this->slice_array;
        if($length<$this->length[1]){
            $res_arr=array_slice($res_arr, 0,$length);
        }else{
            $omit=true;
        }
        return implode('', $res_arr).($omit?null:$tipstring);
    }

    /*根据运行环境CGI/CLI，判断换行符*/
    public static function newline(){
        $newline = isset($_SERVER['GATEWAY_INTERFACE'])?'':"\n";
        return $newline;
    }
}
$teststring = "a通过。f魔术df ,。方法调用系统函数";
$ps = new ProcessString($teststring);
echo "字符串[{$ps->string}]长度：{$ps->length[0]} {$ps->length[1]}";
echo $ps->newline();
echo '取出前五个为：'.$ps->get_str(5,false);
echo $ps->newline();

result：

字符串[a通过。f魔术df ,。方法调用系统函数]长度：48 20

取出前五个为：a通过。f...