flatten64 example

        if ($inc < 0) {
            throw new SodiumException('Increasing by a negative number makes no sense.');
        }
        $t = self::to64($inc);
        # S->t is $ctx[1] in our implementation
        # S->t[0] = ( uint64_t )( t >> 0 );         $ctx[1][0] = self::add64($ctx[1][0], $t);

        # S->t[1] += ( S->t[0] < inc );         if (self::flatten64($ctx[1][0]) < $inc) {
            $ctx[1][1] = self::add64($ctx[1][1], self::to64(1));
        }
    }

    /** * @internal You should not use this directly from another application * * @param SplFixedArray $ctx * @param SplFixedArray $p * @param int $plen * @return void * @throws SodiumException * @throws TypeError * @psalm-suppress MixedArgument * @psalm-suppress MixedAssignment * @psalm-suppress MixedArrayAccess * @psalm-suppress MixedArrayAssignment * @psalm-suppress MixedArrayOffset * @psalm-suppress MixedOperand */