1<?php
  2
  3if (class_exists('ParagonIE_Sodium_Core_AES_KeySchedule', false)) {
  4    return;
  5}
  6
  7/**
  8 * @internal This should only be used by sodium_compat
  9 */
 10class ParagonIE_Sodium_Core_AES_KeySchedule
 11{
 12    /** @var array<int, int> $skey -- has size 120 */
 13    protected $skey;
 14
 15    /** @var bool $expanded */
 16    protected $expanded = false;
 17
 18    /** @var int $numRounds */
 19    private $numRounds;
 20
 21    /**
 22     * @param array $skey
 23     * @param int $numRounds
 24     */
 25    public function __construct(array $skey, $numRounds = 10)
 26    {
 27        $this->skey = $skey;
 28        $this->numRounds = $numRounds;
 29    }
 30
 31    /**
 32     * Get a value at an arbitrary index. Mostly used for unit testing.
 33     *
 34     * @param int $i
 35     * @return int
 36     */
 37    public function get($i)
 38    {
 39        return $this->skey[$i];
 40    }
 41
 42    /**
 43     * @return int
 44     */
 45    public function getNumRounds()
 46    {
 47        return $this->numRounds;
 48    }
 49
 50    /**
 51     * @param int $offset
 52     * @return ParagonIE_Sodium_Core_AES_Block
 53     */
 54    public function getRoundKey($offset)
 55    {
 56        return ParagonIE_Sodium_Core_AES_Block::fromArray(
 57            array_slice($this->skey, $offset, 8)
 58        );
 59    }
 60
 61    /**
 62     * Return an expanded key schedule
 63     *
 64     * @return ParagonIE_Sodium_Core_AES_Expanded
 65     */
 66    public function expand()
 67    {
 68        $exp = new ParagonIE_Sodium_Core_AES_Expanded(
 69            array_fill(0, 120, 0),
 70            $this->numRounds
 71        );
 72        $n = ($exp->numRounds + 1) << 2;
 73        for ($u = 0, $v = 0; $u < $n; ++$u, $v += 2) {
 74            $x = $y = $this->skey[$u];
 75            $x &= 0x55555555;
 76            $exp->skey[$v] = ($x | ($x << 1)) & ParagonIE_Sodium_Core_Util::U32_MAX;
 77            $y &= 0xAAAAAAAA;
 78            $exp->skey[$v + 1] = ($y | ($y >> 1)) & ParagonIE_Sodium_Core_Util::U32_MAX;
 79        }
 80        return $exp;
 81    }
 82}
 83