PHP subistr 截取字符串无码

更新时间：20120102

<?php

/**
 *      [WebodMin] (C)2010-2099 Blank Inc.
 *      This is NOT a freeware, use is subject to license terms
 *
**/

function subistr($string, $length, $dot = ' ...') { 
	global $charset; 
	if(strlen($string) <= $length) { 
		return $string; 
	} 
	$s = ''; 
	if(strtolower($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; 
		} 
		$s = substr($string, 0, $n); 
	} else { 
		for($i = 0; $i < $length; $i++) { 
			$s .= ord($string[$i]) >= 127 ? $string[$i].$string[++$i] : $string[$i]; 
		} 
	}
	return $s.$dot; 
}