--TEST--
Bug #27619 (filters not applied to pre-buffered data)
--FILE--
<?php
    $fp = tmpfile();
    fwrite($fp, "this is a lowercase string.\n");
    rewind($fp);

    /* Echo out the first four bytes 'this' without applying filter
       Remainder will get sucked into the read buffer though. */
    echo fread($fp, 4);

    stream_filter_append($fp, "string.toupper");

    fpassthru($fp);
?>
--EXPECT--
this IS A LOWERCASE STRING.