#include "traffic_lights.h"

void init(unsigned char *lights)
{
    *lights <<= 4;
}

void turn_on(unsigned char *lights, unsigned char light_num)
{
    *lights |= 1 << (light_num - 1);
}

void turn_off(unsigned char *lights, unsigned char light_num)
{
    *lights &= ~(1 << (light_num - 1));
}

void next_step(unsigned char *lights)
{
    *lights <<= 1;
    *lights += *lights >> 4;
}

void reverse(unsigned char *lights)
{
    *lights = ~*lights;
}

void swap(unsigned char *lights_1, unsigned char *lights_2)
{
    if (lights_1 == lights_2)
    {
        return;
    }
    *lights_1 = *lights_2 ^ *lights_1;
    *lights_2 = *lights_1 ^ *lights_2;
    *lights_1 = *lights_2 ^ *lights_1;
}