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author | Lorry Tar Creator <lorry-tar-importer@lorry> | 2016-01-20 10:55:18 +0000 |
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committer | Lorry Tar Creator <lorry-tar-importer@lorry> | 2016-01-20 10:55:18 +0000 |
commit | 70e9163c9c18e995515598085cb824e554eb7ae7 (patch) | |
tree | a42dc8b2a6c031354bf31472de888bfc8a060132 /lib/timespec.h | |
parent | cbf5993c43f49281173f185863577d86bfac6eae (diff) | |
download | coreutils-tarball-master.tar.gz |
coreutils-8.25HEADcoreutils-8.25master
Diffstat (limited to 'lib/timespec.h')
-rw-r--r-- | lib/timespec.h | 95 |
1 files changed, 85 insertions, 10 deletions
diff --git a/lib/timespec.h b/lib/timespec.h index cce2d66..601394b 100644 --- a/lib/timespec.h +++ b/lib/timespec.h @@ -1,11 +1,12 @@ /* timespec -- System time interface - Copyright (C) 2000, 2002, 2004, 2005, 2007 Free Software Foundation, Inc. + Copyright (C) 2000, 2002, 2004-2005, 2007, 2009-2016 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 @@ -13,25 +14,99 @@ 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 <http://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 + +/* Resolution of timespec time stamps (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) +{ + 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 time stamp 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 time stamps. + + 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 "(int) (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. + + The (int) cast avoids a gcc -Wconversion warning. */ + +_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); + : a.tv_sec > b.tv_sec ? 1 + : (int) (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; } void gettime (struct timespec *); int settime (struct timespec const *); +_GL_INLINE_HEADER_END + #endif |