Function limitrange

zic.c:2618–2658

  ptrdiff_t leapbase, leapcount;
  bool leapexpiry;
};

static struct timerange
limitrange(struct timerange r, zic_t lo, zic_t hi,
	   zic_t const *ats, unsigned char const *types)
{
  /* Omit ordinary transitions < LO.  */
  while (0 < r.count && ats[r.base] < lo) {
    r.defaulttype = types[r.base];
    r.count--;
    r.base++;
  }

  /* Omit as many initial leap seconds as possible, such that the
     first leap second in the truncated list is <= LO, and is a
     positive leap second if and only if it has a positive correction.
     This supports common TZif readers that assume that the first leap
     second is positive if and only if its correction is positive.  */
  while (1 < r.leapcount && leap[r.leapbase + 1].trans <= lo) {
    r.leapcount--;
    r.leapbase++;
  }
  while (0 < r.leapbase
	 && ((leap[r.leapbase - 1].corr < leap[r.leapbase].corr)
	     != (0 < leap[r.leapbase].corr))) {
    r.leapcount++;
    r.leapbase--;
  }


  /* Omit ordinary and leap second transitions greater than HI + 1.  */
  if (hi < max_time) {
    while (0 < r.count && hi + 1 < ats[r.base + r.count - 1])
      r.count--;
    while (0 < r.leapcount && hi + 1 < leap[r.leapbase + r.leapcount - 1].trans)
      r.leapcount--;
  }

  /* Determine whether to append an expiration to the leap second table.  */
  r.leapexpiry = 0 <= leapexpires && leapexpires - 1 <= hi;

  return r;
}