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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 17:39:29 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-27 17:39:29 +0000 |
commit | 8ffec2a3aba6f114784e11f89ef1d57a096ae540 (patch) | |
tree | ccebcbad06203e8241a8e7249f8e6c478a3682ea /lib/timespec.h | |
parent | Initial commit. (diff) | |
download | coreutils-8ffec2a3aba6f114784e11f89ef1d57a096ae540.tar.xz coreutils-8ffec2a3aba6f114784e11f89ef1d57a096ae540.zip |
Adding upstream version 8.32.upstream/8.32upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'lib/timespec.h')
-rw-r--r-- | lib/timespec.h | 136 |
1 files changed, 136 insertions, 0 deletions
diff --git a/lib/timespec.h b/lib/timespec.h new file mode 100644 index 0000000..02684ce --- /dev/null +++ b/lib/timespec.h @@ -0,0 +1,136 @@ +/* timespec -- System time interface + + Copyright (C) 2000, 2002, 2004-2005, 2007, 2009-2020 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 |