ParagonIE_Sodium_Core_Curve25519::ge_select( int $pos = 0, int $b = 0 ): ParagonIE_Sodium_Core_Curve25519_Ge_Precomp

1646    public static function ge_select($pos = 0, $b = 0)1647    {1648        static $base = null;1649        if ($base === null) {1650            $base = array();1651            /** @var int $i */1652            foreach (self::$base as $i => $bas) {1653                for ($j = 0; $j < 8; ++$j) {1654                    $base[$i][$j] = new ParagonIE_Sodium_Core_Curve25519_Ge_Precomp(1655                        ParagonIE_Sodium_Core_Curve25519_Fe::fromArray($bas[$j][0]),1656                        ParagonIE_Sodium_Core_Curve25519_Fe::fromArray($bas[$j][1]),1657                        ParagonIE_Sodium_Core_Curve25519_Fe::fromArray($bas[$j][2])1658                    );1659                }1660            }1661        }1662        /** @var array<int, array<int, ParagonIE_Sodium_Core_Curve25519_Ge_Precomp>> $base */1663        if (!is_int($pos)) {1664            throw new InvalidArgumentException('Position must be an integer');1665        }1666        if ($pos < 0 || $pos > 31) {1667            throw new RangeException('Position is out of range [0, 31]');1668        }1669 1670        $bnegative = self::negative($b);1671        $babs = $b - (((-$bnegative) & $b) << 1);1672 1673        $t = self::ge_precomp_0();1674        for ($i = 0; $i < 8; ++$i) {1675            $t = self::cmov(1676                $t,1677                $base[$pos][$i],1678                self::equal($babs, $i + 1)1679            );1680        }1681        $minusT = new ParagonIE_Sodium_Core_Curve25519_Ge_Precomp(1682            self::fe_copy($t->yminusx),1683            self::fe_copy($t->yplusx),1684            self::fe_neg($t->xy2d)1685        );1686        return self::cmov($t, $minusT, $bnegative);1687    }