src/systime.h

   1 /* systime.h - System-dependent definitions for time manipulations.
   2    Copyright (C) 1993-1994, 2002-2012 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Emacs.
   5
   6 GNU Emacs is free software: you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation, either version 3 of the License, or
   9 (at your option) any later version.
  10
  11 GNU Emacs 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
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
  18
  19 #ifndef EMACS_SYSTIME_H
  20 #define EMACS_SYSTIME_H
  21
  22 #include <timespec.h>
  23
  24 #ifdef emacs
  25 # ifdef HAVE_X_WINDOWS
  26 #  include <X11/X.h>
  27 # else
  28 typedef unsigned long Time;
  29 # endif
  30 #endif
  31
  32 /* On some configurations (hpux8.0, X11R4), sys/time.h and X11/Xos.h
  33    disagree about the name of the guard symbol.  */
  34 #ifdef HPUX
  35 #ifdef _STRUCT_TIMEVAL
  36 #ifndef __TIMEVAL__
  37 #define __TIMEVAL__
  38 #endif
  39 #endif
  40 #endif
  41
  42 #include <sys/time.h>   /* for 'struct timeval' */
  43 \f
  44 /* The type to use to represent non-negative temporal intervals.  Its
  45    address can be passed as the timeout argument to the pselect system
  46    call.  */
  47 typedef struct timespec EMACS_TIME;
  48
  49 /* Resolution of EMACS_TIME time stamps (in units per second), and log
  50    base 10 of the resolution.  The log must be a positive integer.  */
  51 enum { EMACS_TIME_RESOLUTION = 1000000000 };
  52 enum { LOG10_EMACS_TIME_RESOLUTION = 9 };
  53
  54 /* EMACS_SECS (TIME) is the seconds component of TIME.
  55    EMACS_NSECS (TIME) is the nanoseconds component of TIME.
  56    emacs_secs_addr (PTIME) is the address of *PTIME's seconds component.  */
  57 static inline time_t EMACS_SECS (EMACS_TIME t) { return t.tv_sec; }
  58 static inline int EMACS_NSECS (EMACS_TIME t) { return t.tv_nsec; }
  59 static inline time_t *emacs_secs_addr (EMACS_TIME *t) { return &t->tv_sec; }
  60
  61 /* Return an Emacs time with seconds S and nanoseconds NS.  */
  62 static inline EMACS_TIME
  63 make_emacs_time (time_t s, int ns)
  64 {
  65   EMACS_TIME r = { s, ns };
  66   return r;
  67 }
  68
  69 /* Return an invalid Emacs time.  */
  70 static inline EMACS_TIME
  71 invalid_emacs_time (void)
  72 {
  73   EMACS_TIME r = { 0, -1 };
  74   return r;
  75 }
  76
  77 /* Return current system time.  */
  78 static inline EMACS_TIME
  79 current_emacs_time (void)
  80 {
  81   EMACS_TIME r;
  82   gettime (&r);
  83   return r;
  84 }
  85
  86 /* Return the result of adding A to B, or of subtracting B from A.
  87    On overflow, store an extremal value: ergo, if time_t is unsigned,
  88    return 0 if the true answer would be negative.
  89
  90    WARNING: These are NOT general-purpose macros for adding or
  91    subtracting arbitrary time values!  They are generally intended to
  92    be used with their first argument an absolute time since the epoch
  93    and the second argument a non-negative offset.  Do NOT use them for
  94    anything else.  */
  95 static inline EMACS_TIME
  96 add_emacs_time (EMACS_TIME a, EMACS_TIME b)
  97 {
  98   return timespec_add (a, b);
  99 }
 100 static inline EMACS_TIME
 101 sub_emacs_time (EMACS_TIME a, EMACS_TIME b)
 102 {
 103   return timespec_sub (a, b);
 104 }
 105
 106 /* Return the sign of the valid time stamp TIME, either -1, 0, or 1.
 107    Note: this can only return a negative value if time_t is a signed
 108    data type.  */
 109 static inline int
 110 EMACS_TIME_SIGN (EMACS_TIME t)
 111 {
 112   return timespec_sign (t);
 113 }
 114
 115 /* Return 1 if TIME is a valid time stamp.  */
 116 static inline int
 117 EMACS_TIME_VALID_P (EMACS_TIME t)
 118 {
 119   return 0 <= t.tv_nsec;
 120 }
 121
 122 /* Convert the double D to the greatest EMACS_TIME not greater than D.
 123    On overflow, return an extremal value; in particular, if time_t is
 124    an unsigned data type and D is negative, return zero.  Return the
 125    minimum EMACS_TIME if D is not a number.  */
 126 static inline EMACS_TIME
 127 EMACS_TIME_FROM_DOUBLE (double d)
 128 {
 129   return dtotimespec (d);
 130 }
 131
 132 /* Convert the Emacs time T to an approximate double value D.  */
 133 static inline double
 134 EMACS_TIME_TO_DOUBLE (EMACS_TIME t)
 135 {
 136   return timespectod (t);
 137 }
 138
 139 /* defined in sysdep.c */
 140 extern int set_file_times (int, const char *, EMACS_TIME, EMACS_TIME);
 141 extern struct timeval make_timeval (EMACS_TIME);
 142
 143 /* defined in keyboard.c */
 144 extern void set_waiting_for_input (EMACS_TIME *);
 145
 146 /* When lisp.h is not included Lisp_Object is not defined (this can
 147    happen when this files is used outside the src directory).
 148    Use GCPRO1 to determine if lisp.h was included.  */
 149 #ifdef GCPRO1
 150 /* defined in editfns.c */
 151 extern Lisp_Object make_lisp_time (EMACS_TIME);
 152 extern int decode_time_components (Lisp_Object, Lisp_Object, Lisp_Object,
 153                                    Lisp_Object, EMACS_TIME *, double *);
 154 extern EMACS_TIME lisp_time_argument (Lisp_Object);
 155 #endif
 156
 157 /* Compare times T1 and T2 for equality, inequality etc.  */
 158 static inline int
 159 EMACS_TIME_EQ (EMACS_TIME t1, EMACS_TIME t2)
 160 {
 161   return timespec_cmp (t1, t2) == 0;
 162 }
 163 static inline int
 164 EMACS_TIME_NE (EMACS_TIME t1, EMACS_TIME t2)
 165 {
 166   return timespec_cmp (t1, t2) != 0;
 167 }
 168 static inline int
 169 EMACS_TIME_GT (EMACS_TIME t1, EMACS_TIME t2)
 170 {
 171   return timespec_cmp (t1, t2) > 0;
 172 }
 173 static inline int
 174 EMACS_TIME_GE (EMACS_TIME t1, EMACS_TIME t2)
 175 {
 176   return timespec_cmp (t1, t2) >= 0;
 177 }
 178 static inline int
 179 EMACS_TIME_LT (EMACS_TIME t1, EMACS_TIME t2)
 180 {
 181   return timespec_cmp (t1, t2) < 0;
 182 }
 183 static inline int
 184 EMACS_TIME_LE (EMACS_TIME t1, EMACS_TIME t2)
 185 {
 186   return timespec_cmp (t1, t2) <= 0;
 187 }
 188
 189 #endif /* EMACS_SYSTIME_H */