/* Subtract two struct timespec values.
- Copyright (C) 2011-2019 Free Software Foundation, Inc.
+ Copyright (C) 2011-2023 Free Software Foundation, Inc.
This file is part of the GNU C Library and is also part of gnulib.
Patches to this file should be submitted to both projects.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
- <http://www.gnu.org/licenses/>. */
+ <https://www.gnu.org/licenses/>. */
/* Return the difference between two timespec values A and B. On
overflow, return an extremal value. This assumes 0 <= tv_nsec <
time_t bs = b.tv_sec;
int ns = a.tv_nsec - b.tv_nsec;
int rns = ns;
- time_t tmin = TYPE_MINIMUM (time_t);
- time_t tmax = TYPE_MAXIMUM (time_t);
if (ns < 0)
{
rns = ns + TIMESPEC_HZ;
- if (bs < tmax)
- bs++;
+ time_t bs1;
+ if (!INT_ADD_WRAPV (bs, 1, &bs1))
+ bs = bs1;
else if (- TYPE_SIGNED (time_t) < rs)
rs--;
else
goto low_overflow;
}
- /* INT_SUBTRACT_WRAPV is not appropriate since time_t might be unsigned.
- In theory time_t might be narrower than int, so plain
- INT_SUBTRACT_OVERFLOW does not suffice. */
- if (! INT_SUBTRACT_OVERFLOW (rs, bs) && tmin <= rs - bs && rs - bs <= tmax)
- rs -= bs;
- else
+ if (INT_SUBTRACT_WRAPV (rs, bs, &rs))
{
- if (rs < 0)
+ if (0 < bs)
{
low_overflow:
- rs = tmin;
+ rs = TYPE_MINIMUM (time_t);
rns = 0;
}
else
{
- rs = tmax;
+ rs = TYPE_MAXIMUM (time_t);
rns = TIMESPEC_HZ - 1;
}
}
- return make_timespec (rs, rns);
+ return (struct timespec) { .tv_sec = rs, .tv_nsec = rns };
}