PHPMailer\PHPMailer

PHPMailer::encodeQ() │ public │ WP 1.0

Encode a string using Q encoding.

Method of the class: PHPMailer{}

No Hooks.

Return

String.

Usage

$PHPMailer = new PHPMailer();
$PHPMailer->encodeQ( $str, $position );
$str(string) (required)
the text to encode
$position(string)
Where the text is going to be used, see the RFC for what that means
Default: 'text'

Notes

PHPMailer::encodeQ() code WP 6.6.1

wp-includes/PHPMailer/PHPMailer.php 
public function encodeQ($str, $position = 'text')
{
    //There should not be any EOL in the string
    $pattern = '';
    $encoded = str_replace(["\r", "\n"], '', $str);
    switch (strtolower($position)) {
        case 'phrase':
            //RFC 2047 section 5.3
            $pattern = '^A-Za-z0-9!*+\/ -';
            break;
        /*
         * RFC 2047 section 5.2.
         * Build $pattern without including delimiters and []
         */
        /* @noinspection PhpMissingBreakStatementInspection */
        case 'comment':
            $pattern = '\(\)"';
        /* Intentional fall through */
        case 'text':
        default:
            //RFC 2047 section 5.1
            //Replace every high ascii, control, =, ? and _ characters
            $pattern = '\000-\011\013\014\016-\037\075\077\137\177-\377' . $pattern;
            break;
    }
    $matches = [];
    if (preg_match_all("/[{$pattern}]/", $encoded, $matches)) {
        //If the string contains an '=', make sure it's the first thing we replace
        //so as to avoid double-encoding
        $eqkey = array_search('=', $matches[0], true);
        if (false !== $eqkey) {
            unset($matches[0][$eqkey]);
            array_unshift($matches[0], '=');
        }
        foreach (array_unique($matches[0]) as $char) {
            $encoded = str_replace($char, '=' . sprintf('%02X', ord($char)), $encoded);
        }
    }
    //Replace spaces with _ (more readable than =20)
    //RFC 2047 section 4.2(2)
    return str_replace(' ', '_', $encoded);
}