如何在PHP中检查文件是ASCII还是二进制文件

// return mime type ala mimetype extension
$finfo = finfo_open(FILEINFO_MIME);

//check to see if the mime-type starts with 'text'
return substr(finfo_file($finfo,$filename),4) == 'text';

http://us.php.net/manual/en/ref.fileinfo.php