As of mailparse-2.1.5, it can return 7bit, 8bit, base64 and qprint. False on mbstring failure.
(PECL mailparse >= 0.9.0)
mailparse_determine_best_xfer_encoding — Gets the best way of encoding
$fp
) : stringFigures out the best way of encoding the content read from the given file pointer.
fpA valid file pointer, which must be seek-able.
Returns one of the character encodings supported by the mbstring module.
Example #1 mailparse_determine_best_xfer_encoding() example
<?php
$fp = fopen('somemail.eml', 'r');
echo 'Best encoding: ' . mailparse_determine_best_xfer_encoding($fp);
?>
以上例程的输出类似于：
Best encoding: 7bit
As of mailparse-2.1.5, it can return 7bit, 8bit, base64 and qprint. False on mbstring failure.
As far as I can tell, this only returns one of two strings: 'Quoted-Printable' or '7bit'