#include "sleep.h"

#include <time.h>
#include <errno.h>

namespace benchmark {
#ifdef OS_WINDOWS

// Window's _sleep takes milliseconds argument.
void SleepForMilliseconds(int milliseconds) {
  _sleep(milliseconds);
}
void SleepForSeconds(double seconds) {
  SleepForMilliseconds(static_cast<int>(seconds * 1000));
}

#else  // OS_WINDOWS

static const int64_t kNumMillisPerSecond = 1000LL;
static const int64_t kNumMicrosPerMilli = 1000LL;
static const int64_t kNumMicrosPerSecond = kNumMillisPerSecond * 1000LL;
static const int64_t kNumNanosPerMicro = 1000LL;

void SleepForMicroseconds(int64_t microseconds) {
  struct timespec sleep_time;
  sleep_time.tv_sec = microseconds / kNumMicrosPerSecond;
  sleep_time.tv_nsec = (microseconds % kNumMicrosPerSecond) * kNumNanosPerMicro;
  while (nanosleep(&sleep_time, &sleep_time) != 0 && errno == EINTR)
    ;  // Ignore signals and wait for the full interval to elapse.
}

void SleepForMilliseconds(int milliseconds) {
  SleepForMicroseconds(static_cast<int64_t>(milliseconds) * kNumMicrosPerMilli);
}

void SleepForSeconds(double seconds) {
  SleepForMicroseconds(static_cast<int64_t>(seconds * kNumMicrosPerSecond));
}

#endif  // OS_WINDOWS
}  // end namespace benchmark