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emacs/lib/dtotimespec.c
Paul Eggert cd19641ed3 Merge from gnulib
This mostly just updates copyright dates of gnulib files.
It also updates to the latest version of texinfo.tex.
2016-01-18 22:29:10 -08:00

60 lines
1.7 KiB
C

/* Convert double to timespec.
Copyright (C) 2011-2016 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 <http://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)
{
double min_representable = TYPE_MINIMUM (time_t);
double max_representable =
((TYPE_MAXIMUM (time_t) * (double) TIMESPEC_RESOLUTION
+ (TIMESPEC_RESOLUTION - 1))
/ TIMESPEC_RESOLUTION);
if (! (min_representable < sec))
return make_timespec (TYPE_MINIMUM (time_t), 0);
else if (! (sec < max_representable))
return make_timespec (TYPE_MAXIMUM (time_t), TIMESPEC_RESOLUTION - 1);
else
{
time_t s = sec;
double frac = TIMESPEC_RESOLUTION * (sec - s);
long ns = frac;
ns += ns < frac;
s += ns / TIMESPEC_RESOLUTION;
ns %= TIMESPEC_RESOLUTION;
if (ns < 0)
{
s--;
ns += TIMESPEC_RESOLUTION;
}
return make_timespec (s, ns);
}
}