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WordPress

PHPMailer::encodeQ( string $str, string $position = 'text' ): string

Source
wp-includes/PHPMailer/PHPMailer.php:3943
Encode a string using Q encoding.

Compatibility

WordPress
core
PHP
7.4–8.6-dev
  • 6.7.7
  • 6.8.8
  • 6.9.7
  • 7.0.4
  • 7.1.0

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$strstring
the text to encode
$positionstringoptional
Where the text is going to be used, see the RFC for what that meansDefault: 'text'

Return value

string

Performance profile

How much work a call to PHPMailer::encodeQ() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class
Light

Touches nothing outside its own arguments.

Scaling
Scales with input

The body loops, so the work grows with what you pass in.

Instructions
25–53

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 68.

Plugin surface
None

Nothing here hands control to plugin code.

Called by
0

Nothing in core calls this; the cost is only what you spend yourself.

What it touches

  • regexregular expression over the whole inputpreg_match_all()called directly

What one call costs · 3 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost PHPMailer::encodeQ() can have, taken from its control-flow graph on PHP 8.5.

WhenInstructionsCalls it makes
!preg_match_all()25–30strtolower(), preg_match_all()
preg_match_all() && $eqkey === false40–46strtolower(), preg_match_all(), array_search(), array_unique()
preg_match_all() && $eqkey !== false47–53strtolower(), preg_match_all(), array_search(), array_unshift(), array_unique()

Across PHP versions

PHPCompiledExecutedBranchesNotes
8.6-dev6825–537
8.56825–537
8.46825–53710 fewer instructions than PHP 8.3
8.37832–607
8.27832–607
8.17832–607
7.47832–607

An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.

Source code

    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);    }

Changelog

Unchanged from 6.7.7 through 7.1.0.

  1. 6.7.7
  2. 6.8.8
  3. 6.9.7
  4. 7.0.4
  5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data
Generated from the wordpress-develop 7.1.0 tag, from src/wp-includes/PHPMailer/PHPMailer.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.
Corrections
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