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70 lines
1.7 KiB
C
70 lines
1.7 KiB
C
/* Convert double to timespec.
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Copyright (C) 2011-2012 Free Software Foundation, Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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/* written by Paul Eggert */
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/* Convert the double value SEC to a struct timespec. Round toward
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positive infinity. On overflow, return an extremal value. */
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#include <config.h>
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#include "timespec.h"
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#include "intprops.h"
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struct timespec
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dtotimespec (double sec)
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{
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enum { BILLION = 1000 * 1000 * 1000 };
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double min_representable = TYPE_MINIMUM (time_t);
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double max_representable =
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((TYPE_MAXIMUM (time_t) * (double) BILLION + (BILLION - 1))
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/ BILLION);
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struct timespec r;
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if (! (min_representable < sec))
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{
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r.tv_sec = TYPE_MINIMUM (time_t);
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r.tv_nsec = 0;
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}
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else if (! (sec < max_representable))
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{
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r.tv_sec = TYPE_MAXIMUM (time_t);
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r.tv_nsec = BILLION - 1;
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}
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else
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{
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time_t s = sec;
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double frac = BILLION * (sec - s);
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long ns = frac;
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ns += ns < frac;
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s += ns / BILLION;
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ns %= BILLION;
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if (ns < 0)
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{
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s--;
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ns += BILLION;
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}
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r.tv_sec = s;
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r.tv_nsec = ns;
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}
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return r;
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}
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