1  /* xtime -- extended-resolution integer timestamps
       2  
       3     Copyright (C) 2005-2006, 2009-2021 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  #ifndef XTIME_H_
      21  #define XTIME_H_ 1
      22  
      23  #ifndef _GL_INLINE_HEADER_BEGIN
      24   #error "Please include config.h first."
      25  #endif
      26  _GL_INLINE_HEADER_BEGIN
      27  #ifndef XTIME_INLINE
      28  # define XTIME_INLINE _GL_INLINE
      29  #endif
      30  
      31  /* xtime_t is a signed type used for timestamps.  It is an integer
      32     type that is a count of nanoseconds.  */
      33  typedef long long int xtime_t;
      34  #define XTIME_PRECISION 1000000000
      35  
      36  #ifdef  __cplusplus
      37  extern "C" {
      38  #endif
      39  
      40  /* Return an extended time value that contains S seconds and NS
      41     nanoseconds.  S and NS should be nonnegative; otherwise, integer
      42     overflow can occur even if the result is in range.  */
      43  XTIME_INLINE xtime_t
      44  xtime_make (xtime_t s, long int ns)
      45  {
      46    return XTIME_PRECISION * s + ns;
      47  }
      48  
      49  /* The following functions split an extended time value:
      50     T = XTIME_PRECISION * xtime_sec (T) + xtime_nsec (T)
      51     with  0 <= xtime_nsec (T) < XTIME_PRECISION.  */
      52  
      53  /* Return the number of seconds in T, which must be nonnegative.  */
      54  XTIME_INLINE xtime_t
      55  xtime_nonnegative_sec (xtime_t t)
      56  {
      57    return t / XTIME_PRECISION;
      58  }
      59  
      60  /* Return the number of seconds in T.  */
      61  XTIME_INLINE xtime_t
      62  xtime_sec (xtime_t t)
      63  {
      64    return (t + (t < 0)) / XTIME_PRECISION - (t < 0);
      65  }
      66  
      67  /* Return the number of nanoseconds in T, which must be nonnegative.  */
      68  XTIME_INLINE long int
      69  xtime_nonnegative_nsec (xtime_t t)
      70  {
      71    return t % XTIME_PRECISION;
      72  }
      73  
      74  /* Return the number of nanoseconds in T.  */
      75  XTIME_INLINE long int
      76  xtime_nsec (xtime_t t)
      77  {
      78    long int ns = t % XTIME_PRECISION;
      79    if (ns < 0)
      80      ns += XTIME_PRECISION;
      81    return ns;
      82  }
      83  
      84  #ifdef  __cplusplus
      85  }
      86  #endif
      87  
      88  #endif