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emacs/lib/dtotimespec.c
2024-01-02 09:47:10 +08:00

54 lines
1.5 KiB
C

/* Convert double to timespec.
Copyright (C) 2011-2024 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 3 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/>. */
/* written by Paul Eggert */
/* Convert the double value SEC to a struct timespec. Round toward
positive infinity. On overflow, return an extremal value. */
#include <config.h>
#include "timespec.h"
#include "intprops.h"
struct timespec
dtotimespec (double sec)
{
if (! (TYPE_MINIMUM (time_t) < sec))
return make_timespec (TYPE_MINIMUM (time_t), 0);
else if (! (sec < 1.0 + TYPE_MAXIMUM (time_t)))
return make_timespec (TYPE_MAXIMUM (time_t), TIMESPEC_HZ - 1);
else
{
time_t s = sec;
double frac = TIMESPEC_HZ * (sec - s);
long ns = frac;
ns += ns < frac;
s += ns / TIMESPEC_HZ;
ns %= TIMESPEC_HZ;
if (ns < 0)
{
s--;
ns += TIMESPEC_HZ;
}
return make_timespec (s, ns);
}
}