<?php

if (class_exists('ParagonIE_Sodium_Core32_HChaCha20', false)) {

    return;

}

/**

 * Class ParagonIE_Sodium_Core_HChaCha20

 */

class ParagonIE_Sodium_Core32_HChaCha20 extends ParagonIE_Sodium_Core32_ChaCha20

{

    /**

     * @param string $in

     * @param string $key

     * @param string|null $c

     * @return string

     * @throws SodiumException

     * @throws TypeError

     */

    public static function hChaCha20($in = '', $key = '', $c = null)

    {

        $ctx = array();

        if ($c === null) {

            $ctx[0] = new ParagonIE_Sodium_Core32_Int32(array(0x6170, 0x7865));

            $ctx[1] = new ParagonIE_Sodium_Core32_Int32(array(0x3320, 0x646e));

            $ctx[2] = new ParagonIE_Sodium_Core32_Int32(array(0x7962, 0x2d32));

            $ctx[3] = new ParagonIE_Sodium_Core32_Int32(array(0x6b20, 0x6574));

        } else {

            $ctx[0] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($c, 0, 4));

            $ctx[1] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($c, 4, 4));

            $ctx[2] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($c, 8, 4));

            $ctx[3] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($c, 12, 4));

        }

        $ctx[4]  = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 0, 4));

        $ctx[5]  = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 4, 4));

        $ctx[6]  = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 8, 4));

        $ctx[7]  = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 12, 4));

        $ctx[8]  = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 16, 4));

        $ctx[9]  = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 20, 4));

        $ctx[10] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 24, 4));

        $ctx[11] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($key, 28, 4));

        $ctx[12] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($in, 0, 4));

        $ctx[13] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($in, 4, 4));

        $ctx[14] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($in, 8, 4));

        $ctx[15] = ParagonIE_Sodium_Core32_Int32::fromReverseString(self::substr($in, 12, 4));

        return self::hChaCha20Bytes($ctx);

    }

    /**

     * @param array $ctx

     * @return string

     * @throws SodiumException

     * @throws TypeError

     */

    protected static function hChaCha20Bytes(array $ctx)

    {

        /** @var ParagonIE_Sodium_Core32_Int32 $x0 */

        $x0  = $ctx[0];

        /** @var ParagonIE_Sodium_Core32_Int32 $x1 */

        $x1  = $ctx[1];

        /** @var ParagonIE_Sodium_Core32_Int32 $x2 */

        $x2  = $ctx[2];

        /** @var ParagonIE_Sodium_Core32_Int32 $x3 */

        $x3  = $ctx[3];

        /** @var ParagonIE_Sodium_Core32_Int32 $x4 */

        $x4  = $ctx[4];

        /** @var ParagonIE_Sodium_Core32_Int32 $x5 */

        $x5  = $ctx[5];

        /** @var ParagonIE_Sodium_Core32_Int32 $x6 */

        $x6  = $ctx[6];

        /** @var ParagonIE_Sodium_Core32_Int32 $x7 */

        $x7  = $ctx[7];

        /** @var ParagonIE_Sodium_Core32_Int32 $x8 */

        $x8  = $ctx[8];

        /** @var ParagonIE_Sodium_Core32_Int32 $x9 */

        $x9  = $ctx[9];

        /** @var ParagonIE_Sodium_Core32_Int32 $x10 */

        $x10 = $ctx[10];

        /** @var ParagonIE_Sodium_Core32_Int32 $x11 */

        $x11 = $ctx[11];

        /** @var ParagonIE_Sodium_Core32_Int32 $x12 */

        $x12 = $ctx[12];

        /** @var ParagonIE_Sodium_Core32_Int32 $x13 */

        $x13 = $ctx[13];

        /** @var ParagonIE_Sodium_Core32_Int32 $x14 */

        $x14 = $ctx[14];

        /** @var ParagonIE_Sodium_Core32_Int32 $x15 */

        $x15 = $ctx[15];

        for ($i = 0; $i < 10; ++$i) {

            # QUARTERROUND( x0,  x4,  x8,  x12)

            list($x0, $x4, $x8, $x12) = self::quarterRound($x0, $x4, $x8, $x12);

            # QUARTERROUND( x1,  x5,  x9,  x13)

            list($x1, $x5, $x9, $x13) = self::quarterRound($x1, $x5, $x9, $x13);

            # QUARTERROUND( x2,  x6,  x10,  x14)

            list($x2, $x6, $x10, $x14) = self::quarterRound($x2, $x6, $x10, $x14);

            # QUARTERROUND( x3,  x7,  x11,  x15)

            list($x3, $x7, $x11, $x15) = self::quarterRound($x3, $x7, $x11, $x15);

            # QUARTERROUND( x0,  x5,  x10,  x15)

            list($x0, $x5, $x10, $x15) = self::quarterRound($x0, $x5, $x10, $x15);

            # QUARTERROUND( x1,  x6,  x11,  x12)

            list($x1, $x6, $x11, $x12) = self::quarterRound($x1, $x6, $x11, $x12);

            # QUARTERROUND( x2,  x7,  x8,  x13)

            list($x2, $x7, $x8, $x13) = self::quarterRound($x2, $x7, $x8, $x13);

            # QUARTERROUND( x3,  x4,  x9,  x14)

            list($x3, $x4, $x9, $x14) = self::quarterRound($x3, $x4, $x9, $x14);

        }

        return $x0->toReverseString() .

            $x1->toReverseString() .

            $x2->toReverseString() .

            $x3->toReverseString() .

            $x12->toReverseString() .

            $x13->toReverseString() .

            $x14->toReverseString() .

            $x15->toReverseString();

    }

}