| 1 | /* Convert double to timespec. |
| 2 | |
| 3 | Copyright (C) 2011-2014 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 <http://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 | double min_representable = TYPE_MINIMUM (time_t); |
| 33 | double max_representable = |
| 34 | ((TYPE_MAXIMUM (time_t) * (double) TIMESPEC_RESOLUTION |
| 35 | + (TIMESPEC_RESOLUTION - 1)) |
| 36 | / TIMESPEC_RESOLUTION); |
| 37 | |
| 38 | if (! (min_representable < sec)) |
| 39 | return make_timespec (TYPE_MINIMUM (time_t), 0); |
| 40 | else if (! (sec < max_representable)) |
| 41 | return make_timespec (TYPE_MAXIMUM (time_t), TIMESPEC_RESOLUTION - 1); |
| 42 | else |
| 43 | { |
| 44 | time_t s = sec; |
| 45 | double frac = TIMESPEC_RESOLUTION * (sec - s); |
| 46 | long ns = frac; |
| 47 | ns += ns < frac; |
| 48 | s += ns / TIMESPEC_RESOLUTION; |
| 49 | ns %= TIMESPEC_RESOLUTION; |
| 50 | |
| 51 | if (ns < 0) |
| 52 | { |
| 53 | s--; |
| 54 | ns += TIMESPEC_RESOLUTION; |
| 55 | } |
| 56 | |
| 57 | return make_timespec (s, ns); |
| 58 | } |
| 59 | } |