php截取中文函數

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<?php  
//截取中文字符函數一  
function cutstr($string, $length, $dot = ' ...' ,$charset = 'utf-8') {  
    if(strlen($string) <= $length) {  
        return $string;  
    }  
  
    $string = str_replace(array('&', '"', '<', '>'), array('&', '"', '<', '>'), $string);  
  
    $strcut = '';  
    if(strtolower($charset) == 'utf-8') {  
  
        $n = $tn = $noc = 0;  
        while($n < strlen($string)) {  
  
            $t = ord($string[$n]);  
            if($t == 9 || $t == 10 || (32 <= $t && $t <= 126)) {  
                $tn = 1; $n++; $noc++;  
            } elseif(194 <= $t && $t <= 223) {  
                $tn = 2; $n += 2; $noc += 2;  
            } elseif(224 <= $t && $t < 239) {  
                $tn = 3; $n += 3; $noc += 2;  
            } elseif(240 <= $t && $t <= 247) {  
                $tn = 4; $n += 4; $noc += 2;  
            } elseif(248 <= $t && $t <= 251) {  
                $tn = 5; $n += 5; $noc += 2;  
            } elseif($t == 252 || $t == 253) {  
                $tn = 6; $n += 6; $noc += 2;  
            } else {  
                $n++;  
            }  
  
            if($noc >= $length) {  
                break;  
            }  
  
        }  
        if($noc > $length) {  
            $n -= $tn;  
        }  
  
        $strcut = substr($string, 0, $n);  
  
    } else {  
        for($i = 0; $i < $length; $i++) {  
            $strcut .= ord($string[$i]) > 127 ? $string[$i].$string[++$i] : $string[$i];  
        }  
    }  
  
    $strcut = str_replace(array('&', '"', '<', '>'), array('&', '"', '<', '>'), $strcut);  
  
    return $strcut.$dot;  
}  
?>  

原文地址;http://blog.csdn.net/zhaoxuejie/article/details/7474229