PHP初记｜中英混合字符串截取

function truncate($string, $len, $wordsafe = FALSE) {
	$slen = strlen($string);
	if ($slen <= $len) {
		return $string;
	}
	if ($wordsafe) {
		while (($string[-- $len] != ' ') && ($len > 0)) {
		};
	}
	if ((ord($string[$len]) < 0x80) || (ord($string[$len]) >= 0xC0)) {
		return substr($string, 0, $len) . "...";
	}
	while (ord($string[-- $len]) < 0xC0) {
	};
	return substr($string, 0, $len) . "...";
}

function truncate($string, $len, $cnCharWidth = 2) {

	$len = $len * $cnCharWidth;
	$suffix = "...";
	$newStr = "";

	for ($i = 0, $j = 0; $i < $len; $i++, $j++) {

		if (!isset($string[$j])) {
			$suffix = "";
			break;
		}

		$start = $j;
		while ($j < ($start +3) && !(ord($string[$j]) < 0x80)) {
			$j++;
		}
		if ($start == $j) {
			$charLen = 1;
		}
		else {
			$i = $i + 1;
			$j--;
			$charLen = 3;
		}

		$newStr .= substr($string, $start, $charLen);
	}

	return $newStr . $suffix;
}