1 /* Convert double to timespec.
2
3 Copyright (C) 2011-2023 Free Software Foundation, Inc.
4
5 This program is free software: you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation, either version 3 of the License, or
8 (at your option) any later version.
9
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
14
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <https://www.gnu.org/licenses/>. */
17
18 /* written by Paul Eggert */
19
20 /* Convert the double value SEC to a struct timespec. Round toward
21 positive infinity. On overflow, return an extremal value. */
22
23 #include <config.h>
24
25 #include "timespec.h"
26
27 #include "intprops.h"
28
29 struct timespec
30 dtotimespec (double sec)
31 {
32 if (! (TYPE_MINIMUM (time_t) < sec))
33 return make_timespec (TYPE_MINIMUM (time_t), 0);
34 else if (! (sec < 1.0 + TYPE_MAXIMUM (time_t)))
35 return make_timespec (TYPE_MAXIMUM (time_t), TIMESPEC_HZ - 1);
36 else
37 {
38 time_t s = sec;
39 double frac = TIMESPEC_HZ * (sec - s);
40 long ns = frac;
41 ns += ns < frac;
42 s += ns / TIMESPEC_HZ;
43 ns %= TIMESPEC_HZ;
44
45 if (ns < 0)
46 {
47 s--;
48 ns += TIMESPEC_HZ;
49 }
50
51 return make_timespec (s, ns);
52 }
53 }