1 files changed, 150 insertions, 0 deletions
diff --git a/lib/gettimeofday.c b/lib/gettimeofday.c
new file mode 100644
index 0000000..1bd50fa
--- /dev/null
+++ b/lib/gettimeofday.c
@@ -0,0 +1,150 @@
+/* Provide gettimeofday for systems that don't have it or for which it's broken.
+
+   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
+   the Free Software Foundation; either version 3, 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/>.  */
+
+/* written by Jim Meyering */
+
+#include <config.h>
+
+/* Specification.  */
+#include <sys/time.h>
+
+#include <time.h>
+
+#if defined _WIN32 && ! defined __CYGWIN__
+# define WINDOWS_NATIVE
+# include <windows.h>
+#endif
+
+#include "localtime-buffer.h"
+
+#ifdef WINDOWS_NATIVE
+
+/* Avoid warnings from gcc -Wcast-function-type.  */
+# define GetProcAddress \
+   (void *) GetProcAddress
+
+/* GetSystemTimePreciseAsFileTime was introduced only in Windows 8.  */
+typedef void (WINAPI * GetSystemTimePreciseAsFileTimeFuncType) (FILETIME *lpTime);
+static GetSystemTimePreciseAsFileTimeFuncType GetSystemTimePreciseAsFileTimeFunc = NULL;
+static BOOL initialized = FALSE;
+
+static void
+initialize (void)
+{
+  HMODULE kernel32 = LoadLibrary ("kernel32.dll");
+  if (kernel32 != NULL)
+    {
+      GetSystemTimePreciseAsFileTimeFunc =
+        (GetSystemTimePreciseAsFileTimeFuncType) GetProcAddress (kernel32, "GetSystemTimePreciseAsFileTime");
+    }
+  initialized = TRUE;
+}
+
+#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.
+   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
+#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 (&current_time);
+  else
+    GetSystemTimeAsFileTime (&current_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
+
+#  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
+  int result = gettimeofday (tv, (struct timezone *) tz);
+#  endif
+
+#  if GETTIMEOFDAY_CLOBBERS_LOCALTIME
+  *localtime_buffer_addr = save;
+#  endif
+
+  return result;
+
+# else
+
+#  if !defined OK_TO_USE_1S_CLOCK
+#   error "Only 1-second nominal clock resolution found.  Is that intended?" \
+          "If so, compile with the -DOK_TO_USE_1S_CLOCK option."
+#  endif
+  tv->tv_sec = time (NULL);
+  tv->tv_usec = 0;
+
+  return 0;
+
+# endif
+#endif
+}