1  /* Convert double to timespec.
       2     Copyright (C) 2011-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library and is also part of gnulib.
       4     Patches to this file should be submitted to both projects.
       5  
       6     The GNU C Library is free software; you can redistribute it and/or
       7     modify it under the terms of the GNU Lesser General Public
       8     License as published by the Free Software Foundation; either
       9     version 2.1 of the License, or (at your option) any later version.
      10  
      11     The GNU C Library is distributed in the hope that it will be useful,
      12     but WITHOUT ANY WARRANTY; without even the implied warranty of
      13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      14     Lesser General Public License for more details.
      15  
      16     You should have received a copy of the GNU Lesser General Public
      17     License along with the GNU C Library; if not, see
      18     <https://www.gnu.org/licenses/>.  */
      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 <support/timespec.h>
      24  #include <intprops.h>
      25  
      26  struct timespec
      27  dtotimespec (double sec)
      28  {
      29    if (sec <= TYPE_MINIMUM (time_t))
      30      return make_timespec (TYPE_MINIMUM (time_t), 0);
      31    else if (sec >= 1.0 + TYPE_MAXIMUM (time_t))
      32      return make_timespec (TYPE_MAXIMUM (time_t), TIMESPEC_HZ - 1);
      33    else
      34      {
      35        time_t s = sec;
      36        double frac = TIMESPEC_HZ * (sec - s);
      37        long ns = frac;
      38        ns += ns < frac;
      39        s += ns / TIMESPEC_HZ;
      40        ns %= TIMESPEC_HZ;
      41  
      42        if (ns < 0)
      43          {
      44            s--;
      45            ns += TIMESPEC_HZ;
      46          }
      47  
      48        return make_timespec (s, ns);
      49      }
      50  }