casa-mp-base

Fix g_get_monotonic_time on non-Intel processors

https://bugzilla.gnome.org/show_bug.cgi?id=728123

https://bug728123.bugzilla-attachments.gnome.org/attachment.cgi?id=275596

--- glib/gmain.c.orig   2017-11-13 11:02:33.000000000 -0600

+++ glib/gmain.c    2017-11-22 21:47:59.000000000 -0600

@@ -2759,46 +2759,34 @@

 g_get_monotonic_time (void)

 {

   static mach_timebase_info_data_t timebase_info;

+  static double absolute_to_micro;

   if (timebase_info.denom == 0)

     {

-      /* This is a fraction that we must use to scale

-       * mach_absolute_time() by in order to reach nanoseconds.

-       *

-       * We've only ever observed this to be 1/1, but maybe it could be

-       * 1000/1 if mach time is microseconds already, or 1/1000 if

-       * picoseconds.  Try to deal nicely with that.

+      /* mach_absolute_time() returns "absolute time units", rather than

+         seconds; the mach_timebase_info_data_t struct provides a

+         fraction that can be used to convert these units into seconds.

        */

       mach_timebase_info (&timebase_info);

-

-      /* We actually want microseconds... */

-      if (timebase_info.numer % 1000 == 0)

-        timebase_info.numer /= 1000;

-      else

-        timebase_info.denom *= 1000;

-

-      /* We want to make the numer 1 to avoid having to multiply... */

-      if (timebase_info.denom % timebase_info.numer == 0)

-        {

-          timebase_info.denom /= timebase_info.numer;

-          timebase_info.numer = 1;

-        }

-      else

-        {

-          /* We could just multiply by timebase_info.numer below, but why

-           * bother for a case that may never actually exist...

-           *

-           * Plus -- performing the multiplication would risk integer

-           * overflow.  If we ever actually end up in this situation, we

-           * should more carefully evaluate the correct course of action.

-           */

-          mach_timebase_info (&timebase_info); /* Get a fresh copy for a better message */

-          g_error ("Got weird mach timebase info of %d/%d.  Please file a bug against GLib.",

-                   timebase_info.numer, timebase_info.denom);

-        }

+      absolute_to_micro = 1e-3 * timebase_info.numer / timebase_info.denom;

     }

-  return mach_absolute_time () / timebase_info.denom;

+  if (timebase_info.denom == 1 && timebase_info.numer == 1)

+    {

+      /* On Intel, the fraction has been 1/1 to date, so we can shortcut

+         the conversion into microseconds.

+       */

+      return mach_absolute_time () / 1000;

+    }

+  else

+    {