/* timespec -- System time interface
- Copyright (C) 2000, 2002, 2004, 2005 Free Software Foundation, Inc.
+ Copyright (C) 2000, 2002, 2004-2005, 2007, 2009-2018 Free Software
+ Foundation, Inc.
- This program is free software; you can redistribute it and/or modify
+ This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2, or (at your option)
- any later version.
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software Foundation,
- Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
+ along with this program. If not, see <https://www.gnu.org/licenses/>. */
#if ! defined TIMESPEC_H
# define TIMESPEC_H
-# include <sys/types.h>
-# if TIME_WITH_SYS_TIME
-# include <sys/time.h>
-# include <time.h>
-# else
-# if HAVE_SYS_TIME_H
-# include <sys/time.h>
-# else
-# include <time.h>
-# endif
-# endif
-
-# if ! HAVE_STRUCT_TIMESPEC
-/* Some systems don't define this struct, e.g., AIX 4.1, Ultrix 4.3. */
-struct timespec
+# include <time.h>
+
+#ifndef _GL_INLINE_HEADER_BEGIN
+ #error "Please include config.h first."
+#endif
+_GL_INLINE_HEADER_BEGIN
+#ifndef _GL_TIMESPEC_INLINE
+# define _GL_TIMESPEC_INLINE _GL_INLINE
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "verify.h"
+
+/* Resolution of timespec timestamps (in units per second), and log
+ base 10 of the resolution. */
+
+enum { TIMESPEC_RESOLUTION = 1000000000 };
+enum { LOG10_TIMESPEC_RESOLUTION = 9 };
+
+/* Return a timespec with seconds S and nanoseconds NS. */
+
+_GL_TIMESPEC_INLINE struct timespec
+make_timespec (time_t s, long int ns)
{
- time_t tv_sec;
- long tv_nsec;
-};
-# endif
+ struct timespec r;
+ r.tv_sec = s;
+ r.tv_nsec = ns;
+ return r;
+}
/* Return negative, zero, positive if A < B, A == B, A > B, respectively.
- Assume the nanosecond components are in range, or close to it. */
-static inline int
+
+ For each timestamp T, this code assumes that either:
+
+ * T.tv_nsec is in the range 0..999999999; or
+ * T.tv_sec corresponds to a valid leap second on a host that supports
+ leap seconds, and T.tv_nsec is in the range 1000000000..1999999999; or
+ * T.tv_sec is the minimum time_t value and T.tv_nsec is -1; or
+ T.tv_sec is the maximum time_t value and T.tv_nsec is 2000000000.
+ This allows for special struct timespec values that are less or
+ greater than all possible valid timestamps.
+
+ In all these cases, it is safe to subtract two tv_nsec values and
+ convert the result to integer without worrying about overflow on
+ any platform of interest to the GNU project, since all such
+ platforms have 32-bit int or wider.
+
+ Replacing "a.tv_nsec - b.tv_nsec" with something like
+ "a.tv_nsec < b.tv_nsec ? -1 : a.tv_nsec > b.tv_nsec" would cause
+ this function to work in some cases where the above assumption is
+ violated, but not in all cases (e.g., a.tv_sec==1, a.tv_nsec==-2,
+ b.tv_sec==0, b.tv_nsec==999999999) and is arguably not worth the
+ extra instructions. Using a subtraction has the advantage of
+ detecting some invalid cases on platforms that detect integer
+ overflow. */
+
+_GL_TIMESPEC_INLINE int _GL_ATTRIBUTE_PURE
timespec_cmp (struct timespec a, struct timespec b)
{
- return (a.tv_sec < b.tv_sec ? -1
- : a.tv_sec > b.tv_sec ? 1
- : a.tv_nsec - b.tv_nsec);
+ if (a.tv_sec < b.tv_sec)
+ return -1;
+ if (a.tv_sec > b.tv_sec)
+ return 1;
+
+ /* Pacify gcc -Wstrict-overflow (bleeding-edge circa 2017-10-02). See:
+ http://lists.gnu.org/r/bug-gnulib/2017-10/msg00006.html */
+ assume (-1 <= a.tv_nsec && a.tv_nsec <= 2 * TIMESPEC_RESOLUTION);
+ assume (-1 <= b.tv_nsec && b.tv_nsec <= 2 * TIMESPEC_RESOLUTION);
+
+ return a.tv_nsec - b.tv_nsec;
+}
+
+/* Return -1, 0, 1, depending on the sign of A. A.tv_nsec must be
+ nonnegative. */
+_GL_TIMESPEC_INLINE int _GL_ATTRIBUTE_PURE
+timespec_sign (struct timespec a)
+{
+ return a.tv_sec < 0 ? -1 : a.tv_sec || a.tv_nsec;
}
-# if ! HAVE_DECL_NANOSLEEP
-/* Don't specify a prototype here. Some systems (e.g., OSF) declare
- nanosleep with a conflicting one (const-less first parameter). */
-int nanosleep ();
-# endif
+struct timespec timespec_add (struct timespec, struct timespec)
+ _GL_ATTRIBUTE_CONST;
+struct timespec timespec_sub (struct timespec, struct timespec)
+ _GL_ATTRIBUTE_CONST;
+struct timespec dtotimespec (double)
+ _GL_ATTRIBUTE_CONST;
+
+/* Return an approximation to A, of type 'double'. */
+_GL_TIMESPEC_INLINE double
+timespectod (struct timespec a)
+{
+ return a.tv_sec + a.tv_nsec / 1e9;
+}
void gettime (struct timespec *);
int settime (struct timespec const *);
+#ifdef __cplusplus
+}
+#endif
+
+_GL_INLINE_HEADER_END
+
#endif
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