알짜게시판

<?php
function get_filetype($filename)
{
   $types = [
       'jpg' => [0, "\xFF\xD8\xFF"],
       'png' => [0, "\x89\x50\x4E\x47\x0D\x0A\x1A\x0A"],
       'bmp' => [0, "\x42\x4D"],
       'gif' => [0, "\x47\x49\x46\x38"],
       'mp4' => [4, "\x66\x74\x79\x70\x69\x73\x6F\x6D"],
       'webp' => [8, "\x57\x45\x42\x50"]
   ];
  $rst = false;

  if(is_file($filename) && $hnd = fopen($filename, 'rb'))
  {
      $buf = fread($hnd, 16);

      foreach($types as $type => $patt)
      {
          if(strcmp($patt[1], substr($buf, $patt[0], strlen($patt[1]))) == 0)
          {
              $rst = $type;
              break;
          }
      }

      fclose($hnd);
  }

  return $rst;
}