X-Git-Url: https://git.gag.com/?a=blobdiff_plain;f=lib%2Ftimespec.h;h=cc49668f42a6d455e3c556be97293854445e6aaf;hb=92249085071a973e2c0621b0415b93d2e48bb00d;hp=388ddb83a76120814003276f18966a4f7a904faf;hpb=4ee107046a0ffd91f6c60c787326a5e27b799f6d;p=debian%2Fgzip diff --git a/lib/timespec.h b/lib/timespec.h index 388ddb8..cc49668 100644 --- a/lib/timespec.h +++ b/lib/timespec.h @@ -1,6 +1,6 @@ /* timespec -- System time interface - Copyright (C) 2000, 2002, 2004-2005, 2007, 2009-2012 Free Software + 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 @@ -14,16 +14,54 @@ 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 . */ + along with this program. If not, see . */ #if ! defined TIMESPEC_H -# define TIMESPEC_H +#define TIMESPEC_H -# include +#include + +#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 time stamp T, this code assumes that either: + 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 @@ -31,52 +69,68 @@ * 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. + 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 "(int) (a.tv_nsec - b.tv_nsec)" with something like + 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. + overflow. */ - The (int) cast avoids a gcc -Wconversion warning. */ - -static inline int +_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 - : (int) (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: + 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. */ -static inline int +_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); -struct timespec timespec_sub (struct timespec, struct timespec); -struct timespec dtotimespec (double); +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'. */ -static inline 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 *); +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