mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-08 14:20:07 +00:00
7c1ec1b7d0
This saves a few instructions. BORROW cannot be -1, since NSEC_DIFF is at most 999999999. Idea taken from Gnulib, here: https://git.savannah.gnu.org/cgit/gnulib.git/commit/?id=fe33f943054b93af8b965ce6564b8713b0979a21
37 lines
1.3 KiB
C
37 lines
1.3 KiB
C
/* struct timespec subtraction.
|
|
Copyright (C) 1991-2024 Free Software Foundation, Inc.
|
|
|
|
This program is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU General Public License
|
|
as published by the Free Software Foundation; either version 2
|
|
of the License, or (at your option) any later version.
|
|
|
|
This program is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
GNU General Public License for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with this program; if not, see <https://www.gnu.org/licenses/>.
|
|
*/
|
|
#include <stdckdint.h>
|
|
#include <time.h>
|
|
|
|
/* Put into *R the difference between X and Y.
|
|
Return true if overflow occurs, false otherwise. */
|
|
|
|
bool
|
|
timespec_subtract (struct timespec *r,
|
|
struct timespec x, struct timespec y)
|
|
{
|
|
/* Compute nanoseconds, setting @var{borrow} to 1 or 0
|
|
for propagation into seconds. */
|
|
long int nsec_diff = x.tv_nsec - y.tv_nsec;
|
|
bool borrow = nsec_diff < 0;
|
|
r->tv_nsec = nsec_diff + 1000000000 * borrow;
|
|
|
|
/* Compute seconds, returning true if this overflows. */
|
|
bool v = ckd_sub (&r->tv_sec, x.tv_sec, y.tv_sec);
|
|
return v ^ ckd_sub (&r->tv_sec, r->tv_sec, borrow);
|
|
}
|