PHP实现获取中文的首页字母方法

function getfirstchar($s0) {
	$fchar = ord(substr($s0, 0, 1));
	if (($fchar >= ord("a") and $fchar <= ord("z"))or($fchar >= ord("A") and $fchar <= ord("Z"))) return strtoupper(chr($fchar));
	$s = iconv("UTF-8", "gb2312", $s0);
	$asc = ord($s{0}) * 256 + ord($s{1})-65536;
	if ($asc >= -20319 and $asc <= -20284)return "A";
	if ($asc >= -20283 and $asc <= -19776)return "B";
	if ($asc >= -19775 and $asc <= -19219)return "C";
	if ($asc >= -19218 and $asc <= -18711)return "D";
	if ($asc >= -18710 and $asc <= -18527)return "E";
	if ($asc >= -18526 and $asc <= -18240)return "F";
	if ($asc >= -18239 and $asc <= -17923)return "G";
	if ($asc >= -17922 and $asc <= -17418)return "I";
	if ($asc >= -17417 and $asc <= -16475)return "J";
	if ($asc >= -16474 and $asc <= -16213)return "K";
	if ($asc >= -16212 and $asc <= -15641)return "L";
	if ($asc >= -15640 and $asc <= -15166)return "M";
	if ($asc >= -15165 and $asc <= -14923)return "N";
	if ($asc >= -14922 and $asc <= -14915)return "O";
	if ($asc >= -14914 and $asc <= -14631)return "P";
	if ($asc >= -14630 and $asc <= -14150)return "Q";
	if ($asc >= -14149 and $asc <= -14091)return "R";
	if ($asc >= -14090 and $asc <= -13319)return "S";
	if ($asc >= -13318 and $asc <= -12839)return "T";
	if ($asc >= -12838 and $asc <= -12557)return "W";
	if ($asc >= -12556 and $asc <= -11848)return "X";
	if ($asc >= -11847 and $asc <= -11056)return "Y";
	if ($asc >= -11055 and $asc <= -10247)return "Z";
	return null;
}