1 files changed, 136 insertions, 0 deletions
diff --git a/lib/timespec.h b/lib/timespec.h
new file mode 100644
index 0000000..cc49668
--- /dev/null
+++ b/lib/timespec.h
@@ -0,0 +1,136 @@
+/* timespec -- System time interface
+
+   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
+   it under the terms of the GNU General Public License as published by
+   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
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   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, see <https://www.gnu.org/licenses/>.  */
+
+#if ! defined TIMESPEC_H
+#define TIMESPEC_H
+
+#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 "arg-nonnull.h"
+#include "verify.h"
+
+/* Inverse resolution of timespec timestamps (in units per second),
+   and log base 10 of the inverse resolution.  */
+
+enum { TIMESPEC_HZ = 1000000000 };
+enum { LOG10_TIMESPEC_HZ = 9 };
+
+/* Obsolescent names for backward compatibility.
+   They are misnomers, because TIMESPEC_RESOLUTION is not a resolution.  */
+
+enum { TIMESPEC_RESOLUTION = TIMESPEC_HZ };
+enum { LOG10_TIMESPEC_RESOLUTION = LOG10_TIMESPEC_HZ };
+
+/* Return a timespec with seconds S and nanoseconds NS.  */
+
+_GL_TIMESPEC_INLINE struct timespec
+make_timespec (time_t s, long int ns)
+{
+  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.
+
+   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)
+{
+  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:
+     https://lists.gnu.org/r/bug-gnulib/2017-10/msg00006.html  */
+  assume (-1 <= a.tv_nsec && a.tv_nsec <= 2 * TIMESPEC_HZ);
+  assume (-1 <= b.tv_nsec && b.tv_nsec <= 2 * TIMESPEC_HZ);
+
+  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;
+}
+
+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;
+}
+
+struct timespec current_timespec (void);
+void gettime (struct timespec *) _GL_ARG_NONNULL ((1));
+int settime (struct timespec const *) _GL_ARG_NONNULL ((1));
+
+#ifdef __cplusplus
+}
+#endif
+
+_GL_INLINE_HEADER_END
+
+#endif