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#include "elevator.h"

// FIXME

// FIXME

// FIXME

void debug_puts (const char* s)

{

#ifndef _NDEBUG

    puts (s);

#endif

}

// FIXME

// FIXME

// FIXME

Elevator::Elevator (int num_floors) : num_floors(num_floors)

{

    this->terminate = false;

    this->pause = false;

    this->direction = IDLE;

    this->current_floor = 1.0;

    this->stop_at_floors = std::vector<bool> (num_floors+1, false);

}

Elevator::~Elevator ()

{

    this->pause = false;

    this->terminate = true;

}

int Elevator::get_direction ()

{

    return this->direction;

}

/**

 * Return the number of floors above the current one that

 * are queued to be stopped at.

 */

int Elevator::floors_above_current ()

{

    int i = ((int)current_floor) + 1;

    int count = 0;

    for (/* see above */; i<num_floors+1; i++)

        if (stop_at_floors[i])

            count++;

    return count;

}

/**

 * Return the number of floors below the current one that

 * are queued to be stopped at.

 */

int Elevator::floors_below_current ()

{

    int i;

    int count = 0;

    if (near_a_floor ())

        i = (int)current_floor - 1;

    else

        i = (int)current_floor;

    for (/* see above */; i>0; i--)

        if (stop_at_floors[i])

            count++;

    return count;

}

void Elevator::push_button (int floor)

{

    assert (floor <= num_floors && floor > 0);

    this->stop_at_floors[floor] = true;

}

/**

 * This function is the entry point for a thread.

 *

 * You must pass the object in, since this is a static function

 * and we aren't allowed to access the this pointer.

 */

void Elevator::thread_entry (const Elevator *me)

{

    Elevator *pthis = (Elevator*)me;

    while (!pthis->terminate)

    {

        /* Implement "pausing" */

        while (pthis->pause)

        {

            usleep (ELEVATOR_TIME_PAUSE_USEC);

        }

        pthis->run_elevator_logic ();

        std::cout << "Current Elevator Position: " << pthis->current_floor << std::endl;

        usleep (ELEVATOR_TIME_DELAY_USEC);

    }

}

void Elevator::run_elevator_logic ()

{

    int i;

    /* Decide what to do */

    switch (direction)

    {

        case IDLE:

            /* Move towards the direction that has more floors to stop at.

             * Prefer DOWN if there is a tie. */

            if (has_floors_to_stop_at ())

            {

                direction = (floors_above_current () > floors_below_current ()) ? MOVE_UP : MOVE_DOWN;

                printf ("changed direction to: %s\n", (direction == MOVE_UP) ? "MOVE_UP" : "MOVE_DOWN");

            }

            break;

        case MOVE_UP:

            /* Decide if we should stop at the floor we're at */

            if (should_stop_at_current_floor ())

            {

                debug_puts ("stop at a floor -- while going up");

                stop_at_floors[(int)current_floor] = false;

            }

            /* Decide to sit idle if we have no more floors to stop at */

            if (!has_floors_to_stop_at ())

            {

                debug_puts ("decides to sit idle");

                direction = IDLE;

            }

            /* Decide to switch directions if we have no more floors to stop

             * at in the current direction, but we have floors in the

             * opposite direction to stop at. */

            else if (floors_below_current () && !floors_above_current ())

            {

                debug_puts ("decides to switch direction to down");

                direction = MOVE_DOWN;

            }

            /* Since nothing else applies, we should keep moving in the

             * current direction, up. */

            else

            {

                current_floor += ELEVATOR_TIME_MOVE_AMOUNT;

                debug_puts ("moving up");

                // TODO: Add a check here to make sure we don't go too high

            }

            break;

        case MOVE_DOWN:

            /* Decide if we should stop at the floor we're at */

            if (should_stop_at_current_floor ())

            {

                debug_puts ("stop at floor -- while going down");

                stop_at_floors[(int)current_floor] = false;

            }

            /* Decide to sit idle if we have no more floors to stop at */

            if (!has_floors_to_stop_at ())

            {

                debug_puts ("decides to sit idle");

                direction = IDLE;

            }

            /* Decide to switch directions if we have no more floors to stop

             * at in the current direction, but we have floors in the

             * opposite direction to stop at. */

            else if (floors_above_current () && !floors_below_current ())

            {

                debug_puts ("decides to switch direction to up");

                direction = MOVE_UP;

            }

            /* Since nothing else applies, we should keep moving in the

             * current direction, down. */

            else

            {

                current_floor -= ELEVATOR_TIME_MOVE_AMOUNT;

                debug_puts ("moving down");

                // TODO: Add a check here to make sure we don't go too low

            }

            break;

        default:

            debug_puts ("bad value of direction");

            break;

    }

}

/**

 * Call this to stop the thread from running.

 */

void Elevator::thread_exit ()

{

    this->terminate = true;

}

/**

 * Call this to pause the thread without exiting it.

 */

void Elevator::thread_pause ()

{

    this->pause = true;

}

/**

 * Call this to unpause the thread.

 */

void Elevator::thread_unpause ()

{

    this->pause = false;

}

bool Elevator::near_a_floor ()

{

    const float range = ELEVATOR_TIME_MOVE_AMOUNT / 4.0;

    /* This seems somewhat counter-intuitive, but it's really not.

     * If we are near a floor, then one of the two of these will fail.

     *

     * Example:

     * current_floor = 3.001;

     * first part is: 3 == 3   (true)

     * second part is: 3 == 2  (false)

     *

     * Therefore we return true

     */

    if ((int)current_floor == (int)(current_floor + range) &&

        (int)current_floor == (int)(current_floor - range))

    {

        return false;

    }

    return true;

}

bool Elevator::near_floor (int floor)

{

    if (near_a_floor () && floor == (int)current_floor)

        return true;

    return false;

}

bool Elevator::has_floors_to_stop_at ()

{

    int i;

    for (i=1; i<=num_floors; i++)

        if (stop_at_floors[i])

            return true;

    return false;

}

bool Elevator::should_stop_at_current_floor ()

{

    int i;

    for (i=1; i<= num_floors; i++)

        if (near_floor (i) && stop_at_floors[i] == true)

            return true;

    return false;

}

bool Elevator::button_is_pushed (int floor)

{

    assert (floor <= num_floors);

    assert (floor > 0);

    return stop_at_floors[floor];

}

float Elevator::get_current_floor ()

{

    return current_floor;

}