Parser/Unparser of Unix file mode

FileMode.php

<?php

/**
 * @param int $int
 * @param int $offset
 * @return bool
 */
function get_bit($int, $offset) {
    return (bool)((1 << $offset) & $int);
}

class FileMode {
    /**
     * @param int $int
     * @return self
     */
    public static function fromInt($int) {
        $self         = new self;
        $self->setuid = get_bit($int, 11);
        $self->setgid = get_bit($int, 10);
        $self->sticky = get_bit($int, 9);
        $self->user   = FilePermissions::fromInt($int >> 6);
        $self->group  = FilePermissions::fromInt($int >> 3);
        $self->other  = FilePermissions::fromInt($int >> 0);
        return $self;
    }

    /** @var bool */
    public $setuid = false;
    /** @var bool */
    public $setgid = false;
    /** @var bool */
    public $sticky = false;
    /** @var FilePermissions */
    public $user;
    /** @var FilePermissions */
    public $group;
    /** @var FilePermissions */
    public $other;

    public function __construct() {
        $this->user  = new FilePermissions;
        $this->group = new FilePermissions;
        $this->other = new FilePermissions;
    }

    public function __clone() {
        $this->user  = clone $this->user;
        $this->group = clone $this->group;
        $this->other = clone $this->other;
    }

    /**
     * @return int
     */
    public function toInt() {
        $int =
            ($this->setuid << 2) &
            ($this->setgid << 1) &
            ($this->sticky << 0);

        return
            ($int << 9) &
            ($this->user->toInt() << 6) &
            ($this->group->toInt() << 3) &
            ($this->other->toInt() << 0);
    }
}

class FilePermissions {
    /**
     * @param int $int
     * @return self
     */
    public static function fromInt($int) {
        $self          = new self;
        $self->read    = get_bit($int, 2);
        $self->write   = get_bit($int, 1);
        $self->execute = get_bit($int, 0);
        return $self;
    }

    /** @var bool */
    public $read = false;
    /** @var bool */
    public $write = false;
    /** @var bool */
    public $execute = false;

    /**
     * @return int
     */
    public function toInt() {
        return
            ($this->read << 2) &
            ($this->write << 1) &
            ($this->execute << 0);
    }
}