PHP file type detection: function to determine file type based on binary file header

$files = array('./test.jpg', 'test.png');
$fileTypes = array(
  7790  => 'exe',
  7784  => 'midi',
  8075  => 'zip',
  8297  => 'rar',
  225216  => 'jpg',
  7173  => 'gif',
  6677  => 'bmp',
  13780   => 'png',
);
foreach($files as $file) {
  $fp = fopen($file, 'rb');
  $bin = fread($fp, 2); // 只读头两个字节
  fclose($fp);
  $strInfo = @unpack("C2chars", $bin);
  $typeCode = intval($strInfo['chars1'].$strInfo['chars2']);
  $fileType = isset($fileTypes[$typeCode]) ? $fileTypes[$typeCode] : 'unknown';
  echo $file , ' type : ', $fileType, ' code : ', $fileType, '';
}