ParagonIE_Sodium_Core32_Int32::rotateLeft

    public function rotateLeft($c = 0)
    {
        ParagonIE_Sodium_Core32_Util::declareScalarType($c, 'int', 1);
        /** @var int $c */
        $c = (int) $c;

        $return = new ParagonIE_Sodium_Core32_Int32();
        $return->unsignedInt = $this->unsignedInt;
        $c &= 31;
        if ($c === 0) {
            // NOP, but we want a copy.
            $return->limbs = $this->limbs;
        } else {
            /** @var int $c */

            /** @var int $idx_shift */
            $idx_shift = ($c >> 4) & 1;

            /** @var int $sub_shift */
            $sub_shift = $c & 15;

            /** @var array<int, int> $limbs */
            $limbs =& $return->limbs;

            /** @var array<int, int> $myLimbs */
            $myLimbs =& $this->limbs;

            for ($i = 1; $i >= 0; --$i) {
                /** @var int $j */
                $j = ($i + $idx_shift) & 1;
                /** @var int $k */
                $k = ($i + $idx_shift + 1) & 1;
                $limbs[$i] = (int) (
                    (
                        ((int) ($myLimbs[$j]) << $sub_shift)
                            |
                        ((int) ($myLimbs[$k]) >> (16 - $sub_shift))
                    ) & 0xffff
                );
            }
        }
        return $return;
    }