<?php

/**

 * Class ParagonIE_Sodium_Core32_Int32

 *

 * Encapsulates a 32-bit integer.

 *

 * These are immutable. It always returns a new instance.

 */

class ParagonIE_Sodium_Core32_Int32

{

    /**

     * @var array<int, int> - two 16-bit integers

     *

     * 0 is the higher 16 bits

     * 1 is the lower 16 bits

     */

    public $limbs = array(0, 0);

    /**

     * @var int

     */

    public $overflow = 0;

    /**

     * @var bool

     */

    public $unsignedInt = false;

    /**

     * ParagonIE_Sodium_Core32_Int32 constructor.

     * @param array $array

     * @param bool $unsignedInt

     */

    public function __construct($array = array(0, 0), $unsignedInt = false)

    {

        $this->limbs = array(

            (int) $array[0],

            (int) $array[1]

        );

        $this->overflow = 0;

        $this->unsignedInt = $unsignedInt;

    }

    /**

     * Adds two int32 objects

     *

     * @param ParagonIE_Sodium_Core32_Int32 $addend

     * @return ParagonIE_Sodium_Core32_Int32

     */

    public function addInt32(ParagonIE_Sodium_Core32_Int32 $addend)

    {

        $i0 = $this->limbs[0];

        $i1 = $this->limbs[1];

        $j0 = $addend->limbs[0];

        $j1 = $addend->limbs[1];

        $r1 = $i1 + ($j1 & 0xffff);

        $carry = $r1 >> 16;

        $r0 = $i0 + ($j0 & 0xffff) + $carry;

        $carry = $r0 >> 16;

        $r0 &= 0xffff;

        $r1 &= 0xffff;

        $return = new ParagonIE_Sodium_Core32_Int32(

            array($r0, $r1)

        );

        $return->overflow = $carry;

        $return->unsignedInt = $this->unsignedInt;

        return $return;

    }

    /**

     * Adds a normal integer to an int32 object

     *

     * @param int $int

     * @return ParagonIE_Sodium_Core32_Int32

     * @throws SodiumException

     * @throws TypeError

     */

    public function addInt($int)

    {

        ParagonIE_Sodium_Core32_Util::declareScalarType($int, 'int', 1);

        /** @var int $int */

        $int = (int) $int;

        $int = (int) $int;

        $i0 = $this->limbs[0];

        $i1 = $this->limbs[1];

        $r1 = $i1 + ($int & 0xffff);

        $carry = $r1 >> 16;

        $r0 = $i0 + (($int >> 16) & 0xffff) + $carry;

        $carry = $r0 >> 16;

        $r0 &= 0xffff;

        $r1 &= 0xffff;

        $return = new ParagonIE_Sodium_Core32_Int32(

            array($r0, $r1)

        );

        $return->overflow = $carry;

        $return->unsignedInt = $this->unsignedInt;

        return $return;

    }

    /**

     * @param int $b

     * @return int

     */

    public function compareInt($b = 0)

    {

        $gt = 0;

        $eq = 1;

        $i = 2;

        $j = 0;

        while ($i > 0) {

            --$i;

            /** @var int $x1 */

            $x1 = $this->limbs[$i];

            /** @var int $x2 */

            $x2 = ($b >> ($j << 4)) & 0xffff;

            /** @var int $gt */

            $gt |= (($x2 - $x1) >> 8) & $eq;

            /** @var int $eq */

            $eq &= (($x2 ^ $x1) - 1) >> 8;

        }

        return ($gt + $gt - $eq) + 1;

    }

    /**

     * @param int $m

     * @return ParagonIE_Sodium_Core32_Int32

     */

    public function mask($m = 0)

    {

        /** @var int $hi */

        $hi = ((int) $m >> 16);

        $hi &= 0xffff;

        /** @var int $lo */

        $lo = ((int) $m) & 0xffff;

        return new ParagonIE_Sodium_Core32_Int32(

            array(

                (int) ($this->limbs[0] & $hi),

                (int) ($this->limbs[1] & $lo)

            ),

            $this->unsignedInt

        );

    }

    /**

     * @param array<int, int> $a

     * @param array<int, int> $b

     * @param int $baseLog2

     * @return array<int, int>

     */

    public function multiplyLong(array $a, array $b, $baseLog2 = 16)

    {

        $a_l = count($a);

        $b_l = count($b);

        /** @var array<int, int> $r */

        $r = array_fill(0, $a_l + $b_l + 1, 0);

        $base = 1 << $baseLog2;

        for ($i = 0; $i < $a_l; ++$i) {

            $a_i = $a[$i];

            for ($j = 0; $j < $a_l; ++$j) {

                $b_j = $b[$j];

                $product = ($a_i * $b_j) + $r[$i + $j];

                $carry = ((int) $product >> $baseLog2 & 0xffff);

                $r[$i + $j] = ((int) $product - (int) ($carry * $base)) & 0xffff;

                $r[$i + $j + 1] += $carry;

            }

        }

        return array_slice($r, 0, 5);

    }

    /**

     * @param int $int

     * @return ParagonIE_Sodium_Core32_Int32

     */

    public function mulIntFast($int)

    {

        // Handle negative numbers

        $aNeg = ($this->limbs[0] >> 15) & 1;

        $bNeg = ($int >> 31) & 1;

        $a = array_reverse($this->limbs);

        $b = array(

            $int & 0xffff,

            ($int >> 16) & 0xffff

        );

        if ($aNeg) {

            for ($i = 0; $i < 2; ++$i) {

                $a[$i] = ($a[$i] ^ 0xffff) & 0xffff;

            }

            ++$a[0];

        }

        if ($bNeg) {

            for ($i = 0; $i < 2; ++$i) {

                $b[$i] = ($b[$i] ^ 0xffff) & 0xffff;

            }

            ++$b[0];

        }

        // Multiply

        $res = $this->multiplyLong($a, $b);

        // Re-apply negation to results

        if ($aNeg !== $bNeg) {

            for ($i = 0; $i < 2; ++$i) {

                $res[$i] = (0xffff ^ $res[$i]) & 0xffff;

            }

            // Handle integer overflow

            $c = 1;

            for ($i = 0; $i < 2; ++$i) {

                $res[$i] += $c;

                $c = $res[$i] >> 16;

                $res[$i] &= 0xffff;

            }

        }

        // Return our values

        $return = new ParagonIE_Sodium_Core32_Int32();

        $return->limbs = array(

            $res[1] & 0xffff,

            $res[0] & 0xffff

        );

        if (count($res) > 2) {

            $return->overflow = $res[2] & 0xffff;

        }

        $return->unsignedInt = $this->unsignedInt;

        return $return;

    }

    /**

     * @param ParagonIE_Sodium_Core32_Int32 $right

     * @return ParagonIE_Sodium_Core32_Int32

     */

    public function mulInt32Fast(ParagonIE_Sodium_Core32_Int32 $right)

    {

        $aNeg = ($this->limbs[0] >> 15) & 1;

        $bNeg = ($right->limbs[0] >> 15) & 1;

        $a = array_reverse($this->limbs);

        $b = array_reverse($right->limbs);

        if ($aNeg) {

            for ($i = 0; $i < 2; ++$i) {

                $a[$i] = ($a[$i] ^ 0xffff) & 0xffff;

            }

            ++$a[0];

        }

        if ($bNeg) {

            for ($i = 0; $i < 2; ++$i) {

                $b[$i] = ($b[$i] ^ 0xffff) & 0xffff;

            }

            ++$b[0];

        }

        $res = $this->multiplyLong($a, $b);

        if ($aNeg !== $bNeg) {

            if ($aNeg !== $bNeg) {

                for ($i = 0; $i < 2; ++$i) {

                    $res[$i] = ($res[$i] ^ 0xffff) & 0xffff;

                }

                $c = 1;

                for ($i = 0; $i < 2; ++$i) {

                    $res[$i] += $c;

                    $c = $res[$i] >> 16;

                    $res[$i] &= 0xffff;

                }

            }

        }

        $return = new ParagonIE_Sodium_Core32_Int32();

        $return->limbs = array(

            $res[1] & 0xffff,

            $res[0] & 0xffff

        );

        if (count($res) > 2) {

            $return->overflow = $res[2];

        }

        return $return;

    }

    /**

     * @param int $int

     * @param int $size

     * @return ParagonIE_Sodium_Core32_Int32

     * @throws SodiumException

     * @throws TypeError

     */

    public function mulInt($int = 0, $size = 0)

    {

        ParagonIE_Sodium_Core32_Util::declareScalarType($int, 'int', 1);

        ParagonIE_Sodium_Core32_Util::declareScalarType($size, 'int', 2);

        if (ParagonIE_Sodium_Compat::$fastMult) {

            return $this->mulIntFast((int) $int);

        }

        /** @var int $int */

        $int = (int) $int;

        /** @var int $size */

        $size = (int) $size;

        if (!$size) {

            $size = 31;

        }

        /** @var int $size */

        $a = clone $this;

        $return = new ParagonIE_Sodium_Core32_Int32();

        $return->unsignedInt = $this->unsignedInt;

        // Initialize:

        $ret0 = 0;

        $ret1 = 0;

        $a0 = $a->limbs[0];

        $a1 = $a->limbs[1];

        /** @var int $size */

        /** @var int $i */

        for ($i = $size; $i >= 0; --$i) {

            $m = (int) (-($int & 1));

            $x0 = $a0 & $m;

            $x1 = $a1 & $m;

            $ret1 += $x1;

            $c = $ret1 >> 16;

            $ret0 += $x0 + $c;

            $ret0 &= 0xffff;

            $ret1 &= 0xffff;

            $a1 = ($a1 << 1);

            $x1 = $a1 >> 16;

            $a0 = ($a0 << 1) | $x1;

            $a0 &= 0xffff;

            $a1 &= 0xffff;

            $int >>= 1;

        }

        $return->limbs[0] = $ret0;

        $return->limbs[1] = $ret1;

        return $return;

    }

    /**

     * @param ParagonIE_Sodium_Core32_Int32 $int

     * @param int $size

     * @return ParagonIE_Sodium_Core32_Int32

     * @throws SodiumException

     * @throws TypeError

     */

    public function mulInt32(ParagonIE_Sodium_Core32_Int32 $int, $size = 0)

    {

        ParagonIE_Sodium_Core32_Util::declareScalarType($size, 'int', 2);

        if (ParagonIE_Sodium_Compat::$fastMult) {

            return $this->mulInt32Fast($int);

        }

        if (!$size) {

            $size = 31;

        }

        /** @var int $size */

        $a = clone $this;

        $b = clone $int;

        $return = new ParagonIE_Sodium_Core32_Int32();

        $return->unsignedInt = $this->unsignedInt;

        // Initialize:

        $ret0 = 0;

        $ret1 = 0;

        $a0 = $a->limbs[0];

        $a1 = $a->limbs[1];

        $b0 = $b->limbs[0];

        $b1 = $b->limbs[1];

        /** @var int $size */

        /** @var int $i */

        for ($i = $size; $i >= 0; --$i) {

            $m = (int) (-($b1 & 1));

            $x0 = $a0 & $m;

            $x1 = $a1 & $m;

            $ret1 += $x1;

            $c = $ret1 >> 16;

            $ret0 += $x0 + $c;

            $ret0 &= 0xffff;

            $ret1 &= 0xffff;

            $a1 = ($a1 << 1);

            $x1 = $a1 >> 16;

            $a0 = ($a0 << 1) | $x1;

            $a0 &= 0xffff;

            $a1 &= 0xffff;

            $x0 = ($b0 & 1) << 16;

            $b0 = ($b0 >> 1);

            $b1 = (($b1 | $x0) >> 1);

            $b0 &= 0xffff;

            $b1 &= 0xffff;

        }

        $return->limbs[0] = $ret0;

        $return->limbs[1] = $ret1;

        return $return;