[PHP] - pdf 속성 추출

function get_pdf_prop( $file ) {
  $f = fopen($file,'rb');
  if( !$f ) return false;

  //Read the last 16KB
  fseek( $f, -16384, SEEK_END );
  $s = fread( $f, 16384 );

  //Extract cross-reference table and trailer
  if( !preg_match( "/xref[\r\n]+(.*)trailer(.*)startxref/s", $s, $a ) ) return false;
  $xref    = $a[1];
  $trailer = $a[2];

  //Extract Info object number
  if( !preg_match( '/Info ([0-9]+) /', $trailer, $a ) ) return false;
  $object_no = $a[1];

  //Extract Info object offset
  $lines = preg_split( "/[\r\n]+/", $xref );
  $line = $lines[1 + $object_no];
  $offset = (int)$line;
  if( $offset == 0 ) return false;

  //Read Info object
  fseek( $f, $offset, SEEK_SET );
  $s = fread( $f, 1024 );
  fclose( $f );

  //Extract properties
  if( !preg_match( '/<<(.*)>>/Us', $s, $a ) )
      return false;
  $n = preg_match_all( '|/([a-z]+) ?\((.*)\)|Ui', $a[1], $a );
  $prop = array();
  for( $i=0; $i<$n; $i++ ) {
      $prop[$a[1][$i]] = $a[2][$i];
  }
  return $prop;
}

출처 - http://www.fpdf.org/en/script/script59.php