php 文件流与二进制流

// 根据二进制流获取文件类型

function getFileType($file, &$fileType)

{

// 文件头标识 (2 bytes)

$bin = substr($file,0,2);

$strInfo = @unpack("C2chars", $bin);;

$typeCode = intval($strInfo['chars1'].$strInfo['chars2']);

$fileType = "";

switch($typeCode)

{

case 255216 :

$fileType = "image/jpeg";

$ret = 0;

break;

case 7173 :

$fileType = "image/gif";

$ret = 0;

break;

case 13780 :

$fileType = "image/png";

$ret = 0;

break;

case 6677:

$fileType = 'image/bmp';

$ret = 0;

break;

case 7790:

$fileType = 'exe';

$ret = 0;

break;

case 7784:

$fileType = 'midi';

$ret = 0;

break;

case 8297:

$fileType = 'rar';

$ret = 0;

break;

default :

$fileType = "unknow";

$ret = -1;

break;

}

return $ret;

}