ParagonIE_Sodium_Compat::add( string $val, string $addv ): void

166    public static function add(167        #[\SensitiveParameter]168        &$val,169        #[\SensitiveParameter]170        $addv171    ) {172        $val_len = ParagonIE_Sodium_Core_Util::strlen($val);173        $addv_len = ParagonIE_Sodium_Core_Util::strlen($addv);174        if ($val_len !== $addv_len) {175            throw new SodiumException('values must have the same length');176        }177        $A = ParagonIE_Sodium_Core_Util::stringToIntArray($val);178        $B = ParagonIE_Sodium_Core_Util::stringToIntArray($addv);179 180        $c = 0;181        for ($i = 0; $i < $val_len; $i++) {182            $c += ($A[$i] + $B[$i]);183            $A[$i] = ($c & 0xff);184            $c >>= 8;185        }186        $val = ParagonIE_Sodium_Core_Util::intArrayToString($A);187    }