wp-includes/sodium_compat/src/Core/Base64/UrlSafe.php:200Uses bitwise operators instead of table-lookups to turn 6-bit integers into 8-bit integers.
$srcintint protected static function decode6Bits($src) { $ret = -1; // if ($src > 0x40 && $src < 0x5b) $ret += $src - 0x41 + 1; // -64 $ret += (((0x40 - $src) & ($src - 0x5b)) >> 8) & ($src - 64); // if ($src > 0x60 && $src < 0x7b) $ret += $src - 0x61 + 26 + 1; // -70 $ret += (((0x60 - $src) & ($src - 0x7b)) >> 8) & ($src - 70); // if ($src > 0x2f && $src < 0x3a) $ret += $src - 0x30 + 52 + 1; // 5 $ret += (((0x2f - $src) & ($src - 0x3a)) >> 8) & ($src + 5); // if ($src == 0x2c) $ret += 62 + 1; $ret += (((0x2c - $src) & ($src - 0x2e)) >> 8) & 63; // if ($src == 0x5f) ret += 63 + 1; $ret += (((0x5e - $src) & ($src - 0x60)) >> 8) & 64; return $ret; }Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/sodium_compat/src/Core/Base64/UrlSafe.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.