php截取中文函数

<?php//截取中文字符函数一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;}?>