#pragma once

#ifdef __cplusplus
extern "C" {
#endif

// Advance to the next tick. Should be called periodically.
void rt_tick_advance(void);

// Return the current tick.
unsigned long rt_tick_count(void);

static inline void rt_tick_elapse(unsigned long *ticks,
                                  unsigned long *start_tick)
{
    const unsigned long now = rt_tick_count();
    const unsigned long elapsed = now - *start_tick;
    const unsigned long prev = *ticks;
    *ticks = (elapsed > prev) ? 0 : (prev - elapsed);
    *start_tick = now;
}

#ifdef __cplusplus
}
#endif