/* Provide gettimeofday for systems that don't have it or for which it's broken.
- Copyright (C) 2001-2003, 2005-2007, 2009-2016 Free Software Foundation, Inc.
+ Copyright (C) 2001-2003, 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
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 <http://www.gnu.org/licenses/>. */
+ along with this program; if not, see <https://www.gnu.org/licenses/>. */
/* written by Jim Meyering */
#include <time.h>
-#if HAVE_SYS_TIMEB_H
-# include <sys/timeb.h>
+#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+# define WINDOWS_NATIVE
+# include <windows.h>
#endif
-#if GETTIMEOFDAY_CLOBBERS_LOCALTIME || TZSET_CLOBBERS_LOCALTIME
+#include "localtime-buffer.h"
-/* Work around the bug in some systems whereby gettimeofday clobbers
- the static buffer that localtime uses for its return value. The
- gettimeofday function from Mac OS X 10.0.4 (i.e., Darwin 1.3.7) has
- this problem. The tzset replacement is necessary for at least
- Solaris 2.5, 2.5.1, and 2.6. */
-
-static struct tm tm_zero_buffer;
-static struct tm *localtime_buffer_addr = &tm_zero_buffer;
-
-# undef localtime
-extern struct tm *localtime (time_t const *);
-
-# undef gmtime
-extern struct tm *gmtime (time_t const *);
-
-/* This is a wrapper for localtime. It is used only on systems for which
- gettimeofday clobbers the static buffer used for localtime's result.
+#ifdef WINDOWS_NATIVE
- On the first call, record the address of the static buffer that
- localtime uses for its result. */
-
-struct tm *
-rpl_localtime (time_t const *timep)
-{
- struct tm *tm = localtime (timep);
-
- if (localtime_buffer_addr == &tm_zero_buffer)
- localtime_buffer_addr = tm;
-
- return tm;
-}
+/* GetSystemTimePreciseAsFileTime was introduced only in Windows 8. */
+typedef void (WINAPI * GetSystemTimePreciseAsFileTimeFuncType) (FILETIME *lpTime);
+static GetSystemTimePreciseAsFileTimeFuncType GetSystemTimePreciseAsFileTimeFunc = NULL;
+static BOOL initialized = FALSE;
-/* Same as above, since gmtime and localtime use the same buffer. */
-struct tm *
-rpl_gmtime (time_t const *timep)
+static void
+initialize (void)
{
- struct tm *tm = gmtime (timep);
-
- if (localtime_buffer_addr == &tm_zero_buffer)
- localtime_buffer_addr = tm;
-
- return tm;
+ HMODULE kernel32 = LoadLibrary ("kernel32.dll");
+ if (kernel32 != NULL)
+ {
+ GetSystemTimePreciseAsFileTimeFunc =
+ (GetSystemTimePreciseAsFileTimeFuncType) GetProcAddress (kernel32, "GetSystemTimePreciseAsFileTime");
+ }
+ initialized = TRUE;
}
-#endif /* GETTIMEOFDAY_CLOBBERS_LOCALTIME || TZSET_CLOBBERS_LOCALTIME */
-
-#if TZSET_CLOBBERS_LOCALTIME
-
-# undef tzset
-extern void tzset (void);
-
-/* This is a wrapper for tzset, for systems on which tzset may clobber
- the static buffer used for localtime's result. */
-void
-rpl_tzset (void)
-{
- /* Save and restore the contents of the buffer used for localtime's
- result around the call to tzset. */
- struct tm save = *localtime_buffer_addr;
- tzset ();
- *localtime_buffer_addr = save;
-}
#endif
/* This is a wrapper for gettimeofday. It is used only on systems
that lack this function, or whose implementation of this function
- causes problems. */
+ causes problems.
+ Work around the bug in some systems whereby gettimeofday clobbers
+ the static buffer that localtime uses for its return value. The
+ gettimeofday function from Mac OS X 10.0.4 (i.e., Darwin 1.3.7) has
+ this problem. */
int
gettimeofday (struct timeval *restrict tv, void *restrict tz)
{
#undef gettimeofday
-#if HAVE_GETTIMEOFDAY
-# if GETTIMEOFDAY_CLOBBERS_LOCALTIME
+#ifdef WINDOWS_NATIVE
+
+ /* On native Windows, there are two ways to get the current time:
+ GetSystemTimeAsFileTime
+ <https://msdn.microsoft.com/en-us/library/ms724397.aspx>
+ or
+ GetSystemTimePreciseAsFileTime
+ <https://msdn.microsoft.com/en-us/library/hh706895.aspx>.
+ GetSystemTimeAsFileTime produces values that jump by increments of
+ 15.627 milliseconds (!) on average.
+ Whereas GetSystemTimePreciseAsFileTime values usually jump by 1 or 2
+ microseconds.
+ More discussion on this topic:
+ <http://www.windowstimestamp.com/description>. */
+ FILETIME current_time;
+
+ if (!initialized)
+ initialize ();
+ if (GetSystemTimePreciseAsFileTimeFunc != NULL)
+ GetSystemTimePreciseAsFileTimeFunc (¤t_time);
+ else
+ GetSystemTimeAsFileTime (¤t_time);
+
+ /* Convert from FILETIME to 'struct timeval'. */
+ /* FILETIME: <https://msdn.microsoft.com/en-us/library/ms724284.aspx> */
+ ULONGLONG since_1601 =
+ ((ULONGLONG) current_time.dwHighDateTime << 32)
+ | (ULONGLONG) current_time.dwLowDateTime;
+ /* Between 1601-01-01 and 1970-01-01 there were 280 normal years and 89 leap
+ years, in total 134774 days. */
+ ULONGLONG since_1970 =
+ since_1601 - (ULONGLONG) 134774 * (ULONGLONG) 86400 * (ULONGLONG) 10000000;
+ ULONGLONG microseconds_since_1970 = since_1970 / (ULONGLONG) 10;
+ tv->tv_sec = microseconds_since_1970 / (ULONGLONG) 1000000;
+ tv->tv_usec = microseconds_since_1970 % (ULONGLONG) 1000000;
+
+ return 0;
+
+#else
+
+# if HAVE_GETTIMEOFDAY
+# if GETTIMEOFDAY_CLOBBERS_LOCALTIME
/* Save and restore the contents of the buffer used for localtime's
result around the call to gettimeofday. */
struct tm save = *localtime_buffer_addr;
-# endif
+# endif
-# if defined timeval /* 'struct timeval' overridden by gnulib? */
-# undef timeval
+# if defined timeval /* 'struct timeval' overridden by gnulib? */
+# undef timeval
struct timeval otv;
int result = gettimeofday (&otv, (struct timezone *) tz);
if (result == 0)
tv->tv_sec = otv.tv_sec;
tv->tv_usec = otv.tv_usec;
}
-# else
+# else
int result = gettimeofday (tv, (struct timezone *) tz);
-# endif
+# endif
-# if GETTIMEOFDAY_CLOBBERS_LOCALTIME
+# if GETTIMEOFDAY_CLOBBERS_LOCALTIME
*localtime_buffer_addr = save;
-# endif
+# endif
return result;
-#else
-
-# if HAVE__FTIME
-
- struct _timeb timebuf;
- _ftime (&timebuf);
- tv->tv_sec = timebuf.time;
- tv->tv_usec = timebuf.millitm * 1000;
-
# else
# if !defined OK_TO_USE_1S_CLOCK
tv->tv_sec = time (NULL);
tv->tv_usec = 0;
-# endif
-
return 0;
+# endif
#endif
}
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