多个PHP中文字符串截取函数

代码如下:
<?php
function sysSubStr($string,$length,$append = false)
{
    if(strlen($string) <= $length )
    {
        return $string;
    }
    else
    {
        $i = 0;
        while ($i < $length)
        {
            $stringTMP = substr($string,$i,1);
            if ( ord($stringTMP) >=224 )
            {
                $stringTMP = substr($string,$i,3);
                $i = $i + 3;
            }
            elseif( ord($stringTMP) >=192 )
            {
                $stringTMP = substr($string,$i,2);
                $i = $i + 2;
            }
            else
            {
                $i = $i + 1;
            }
            $stringLast[] = $stringTMP;
        }
        $stringLast = implode("",$stringLast);
        if($append)
        {
            $stringLast .= "...";
        }
        return $stringLast;
    }
}

$string = "简明现代魔法 —— 专注于互联网主流的各种技术";
$length = "27";
$append = true;
echo sysSubStr($string,$length,$append);
// 输出
// 简明现代魔法 —— 专...
?>

截取GB2312中文字符串：
代码如下:
<?php
//截取中文字符串
function mysubstr($str, $start, $len) {
    $tmpstr = "";
    $strlen = $start + $len;
    for($i = 0; $i < $strlen; $i++) {
        if(ord(substr($str, $i, 1)) > 0xa0) {