lib/xtime.h

   1 /* xtime -- extended-resolution integer timestamps
   2
   3    Copyright (C) 2005-2006, 2009-2020 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