$files = array (
             'c:\1.jpg',
             'c:\1.png',
             'c:\1.gif',
             'c:\1.rar',
             'c:\1.zip',
             'c:\1.exe',
         );
foreach ( $files AS $file )
{
	$fp = fopen ( $file, "rb" );
	$bin = fread ( $fp, 2 ); //只读2字节
	fclose ( $fp );
	$str_info = @unpack ( "C2chars", $bin );
	$type_code = intval ( $str_info['chars1'].$str_info['chars2'] );
	$file_type = '';
	switch ( $type_code )
	{
	case 7790:
		$file_type = 'exe';
		break;
	case 7784:
		$file_type = 'midi';
		break;
	case 8075:
		$file_type = 'zip';
		break;
	case 8297:
		$file_type = 'rar';
		break;
	case 255216:
		$file_type = 'jpg';
		break;
	case 7173:
		$file_type = 'gif';
		break;
	case 6677:
		$file_type = 'bmp';
		break;
	case 13780:
		$file_type = 'png';
		break;
	default:
		$file_type = 'unknown';
		break;
	}

	echo $file , ' type: ', $file_type, ' code:', $type_code, '
	';

}