众所周知，PHP 自带的 strlen 与 substr 函数没法处理中文字符，于是，我们会用 mb_ 系列函数替代。但是，没有 mbstring 库怎么办？这就需要我们自己写一个来替代了，废话不多说，先上代码:
代码如下:
nes 1-3
| [\xF1-\xF3][\x80-\xBF]{3} # planes 4-15
| \xF4[\x80-\x8F][\x80-\xBF]{2} # plane 16
)%xs',$text,$out);
}else{
return strlen($text);
}
}
}
/* from Internet,author unkNown */ if (!function_exists('mb_substr')) { function mb_substr($str,$start,$len = '',$encoding="UTF-8"){ $limit = strlen($str);
for ($s = 0; $start > 0;--$start) {// found the real start
if ($s >= $limit)
break;
if ($str[$s] <= "\x7F")
++$s;
else {
++$s; // skip length
while ($str[$s] >= "\x80" && $str[$s] <= "\xBF")
++$s;
}
}
if ($len == '')
return substr($str,$s);
else
for ($e = $s; $len > 0; --$len) {//found the real end
if ($e >= $limit)
break;
if ($str[$e] <= "\x7F")
++$e;
else {
++$e;//skip length
while ($str[$e] >= "\x80" && $str[$e] <= "\xBF" && $e < $limit)
++$e;
}
}
return substr($str,$s,$e - $s);
}
}
