Imported Upstream version 8.17upstream/8.17

1 files changed, 68 insertions, 0 deletions

diff --git a/lib/gethrxtime.c b/lib/gethrxtime.c
new file mode 100644
index 00000000..6e0263d6
--- /dev/null
+++ b/lib/gethrxtime.c
@@ -0,0 +1,68 @@
+/* gethrxtime -- get high resolution real time
+
+   Copyright (C) 2005-2007, 2009-2012 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 <http://www.gnu.org/licenses/>.  */
+
+/* Written by Paul Eggert.  */
+
+#include <config.h>
+
+#include "gethrxtime.h"
+
+#include <sys/time.h>
+#include "timespec.h"
+
+/* Get the current time, as a count of the number of nanoseconds since
+   an arbitrary epoch (e.g., the system boot time).  Prefer a
+   high-resolution clock that is not subject to resetting or
+   drifting.  */
+
+xtime_t
+gethrxtime (void)
+{
+#if HAVE_NANOUPTIME
+  {
+    struct timespec ts;
+    nanouptime (&ts);
+    return xtime_make (ts.tv_sec, ts.tv_nsec);
+  }
+#else
+
+# if defined CLOCK_MONOTONIC && HAVE_CLOCK_GETTIME
+  {
+    struct timespec ts;
+    if (clock_gettime (CLOCK_MONOTONIC, &ts) == 0)
+      return xtime_make (ts.tv_sec, ts.tv_nsec);
+  }
+# endif
+
+# if HAVE_MICROUPTIME
+  {
+    struct timeval tv;
+    microuptime (&tv);
+    return xtime_make (tv.tv_sec, 1000 * tv.tv_usec);
+  }
+
+# else
+  /* No monotonically increasing clocks are available; fall back on a
+     clock that might jump backwards, since it's the best we can do.  */
+  {
+    struct timespec ts;
+    gettime (&ts);
+    return xtime_make (ts.tv_sec, ts.tv_nsec);
+  }
+# endif
+#endif
+}