glibc/support/timespec-add.c
Adhemerval Zanella c1dac8f83e Sync timespec-{add,sub} with gnulib
It sync with gnulib commit 06011ed74e978613422aca43c0bd92dc44213933.

Reviewed-by: Paul Eggert <eggert@cs.ucla.edu>
2019-10-31 17:03:04 -03:00

66 lines
1.8 KiB
C

/* Add two struct timespec values.
Copyright (C) 2011-2019 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.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
/* Return the sum of two timespec values A and B. On overflow, return
an extremal value. This assumes 0 <= tv_nsec < TIMESPEC_HZ. */
#include <config.h>
#include "timespec.h"
#include "intprops.h"
struct timespec
timespec_add (struct timespec a, struct timespec b)
{
time_t rs = a.tv_sec;
time_t bs = b.tv_sec;
int ns = a.tv_nsec + b.tv_nsec;
int nsd = ns - TIMESPEC_HZ;
int rns = ns;
if (0 <= nsd)
{
rns = nsd;
time_t bs1;
if (!INT_ADD_WRAPV (bs, 1, &bs1))
bs = bs1;
else if (rs < 0)
rs++;
else
goto high_overflow;
}
if (INT_ADD_WRAPV (rs, bs, &rs))
{
if (bs < 0)
{
rs = TYPE_MINIMUM (time_t);
rns = 0;
}
else
{
high_overflow:
rs = TYPE_MAXIMUM (time_t);
rns = TIMESPEC_HZ - 1;
}
}
return make_timespec (rs, rns);
}