去除utf8的bom

removebom.php

function checkBOM ($filename) {  

       global $auto;  

       $contents = file_get_contents($filename);  

        $charset[1] = substr($contents, 0, 1);  

       $charset[2] = substr($contents, 1, 1);  

       $charset[3] = substr($contents, 2, 1);  

       if (ord($charset[1]) == 239 && ord($charset[2]) == 187 && ord($charset[3]) == 191) {  

           if ($auto == 1) {  

              $rest = substr($contents, 3);  

              rewrite ($filename, $rest);  

              return ("<font color=red>BOM found, automatically removed.</font>");  

           }else {  

              return ("<font color=red>BOM found.</font>");  

           }  

       }else return ("BOM Not Found.");  

    }  

echo transfer_time(1393487787);
//$time必须为Unix时间戳，如果不是请先用strtotime()将其转换成Unix时间戳。
function transfer_time($time)
{
    $rtime = date("m-d H:i",$time);
    $htime = date("H:i",$time);

    $time = time() - $time;

    if ($time < 60)
    {
        $str = '刚刚';
    }
    elseif ($time < 60 * 60)
    {
        $min = floor($time/60);
        $str = $min.'分钟前';
    }
    elseif ($time < 60 * 60 * 24)
    {
        $h = floor($time/(60*60));
        $str = $h.'小时前 '.$htime;
    }
    elseif ($time < 60 * 60 * 24 * 3)
    {
        $d = floor($time/(60*60*24));
        if($d==1)
            $str = '昨天 '.$rtime;
        else
            $str = '前天 '.$rtime;
    }
    else
    {
        $str = $rtime;
    }
    return $str;
}
function mbstrlen($str)
{
	echo $len = strlen($str);//17
	
	if ($len <= 0)
	{
		return 0;
	}
	
	$count  = 0;
	
	for ($i = 0; $i < $len; $i++)
	{
		$count++;
		if (ord($str{$i}) >= 0x80)
		{
			$i += 2;//利用单字节字符的ASCII码小于0x80。至于要跳过几个字节
		}
	}
	
	return $count;
}
 echo "output: " . mbstrlen("中国so强大！") . "\n";//7