glibc/support/timespec-add.c
Florian Weimer 91ae020f5a support: Remove #include <config.h>
This is not needed: include/intprops.h has its own detection logic.
It makes building these files outside of glibc easer.

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2024-08-16 16:05:19 +02:00

65 lines
1.8 KiB
C

/* Add two struct timespec values.
Copyright (C) 2011-2024 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 "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 (struct timespec) { .tv_sec = rs, .tv_nsec = rns };
}