X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fnanosleep.c;h=17572dcef1b09764da0c5b37c43ff7d0b474ed2d;hb=5518d301980bdc0f60b1b5d58b140004dfda490e;hp=7a7cc02fd987c9cf8d77ec0f0533b11b6ce80c20;hpb=e97e3a48d3a23446cf334e288aa6f138a6f9bae5;p=gnulib.git

diff --git a/lib/nanosleep.c b/lib/nanosleep.c
index 7a7cc02fd..17572dcef 100644
--- a/lib/nanosleep.c
+++ b/lib/nanosleep.c
@@ -1,7 +1,6 @@
 /* Provide a replacement for the POSIX nanosleep function.
 
-   Copyright (C) 1999, 2000, 2002, 2004, 2005, 2006, 2007, 2008 Free
-   Software Foundation, Inc.
+   Copyright (C) 1999-2000, 2002, 2004-2010 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
@@ -16,14 +15,16 @@
    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 Jim Meyering */
+/* written by Jim Meyering
+   and Bruno Haible for the Woe32 part */
 
 #include <config.h>
 
 #include <time.h>
 
+#include "intprops.h"
 #include "sig-handler.h"
-#include "timespec.h"
+#include "verify.h"
 
 #include <stdbool.h>
 #include <stdio.h>
@@ -36,65 +37,149 @@
 
 #include <unistd.h>
 
-#undef nanosleep
 
 enum { BILLION = 1000 * 1000 * 1000 };
 
 #if HAVE_BUG_BIG_NANOSLEEP
 
-static void
-getnow (struct timespec *t)
+int
+nanosleep (const struct timespec *requested_delay,
+           struct timespec *remaining_delay)
+#undef nanosleep
 {
-# if defined CLOCK_MONOTONIC && HAVE_CLOCK_GETTIME
-  if (clock_gettime (CLOCK_MONOTONIC, t) == 0)
-    return;
-# endif
-  gettime (t);
+  /* nanosleep mishandles large sleeps due to internal overflow
+     problems.  The worst known case of this is cygwin 1.5.x, which
+     can't sleep more than 49.7 days (2**32 milliseconds).  Solve this
+     by breaking the sleep up into smaller chunks.  Verify that time_t
+     is large enough.  */
+  verify (TYPE_MAXIMUM (time_t) / 49 / 24 / 60 / 60);
+  const time_t limit = 49 * 24 * 60 * 60;
+  time_t seconds = requested_delay->tv_sec;
+  struct timespec intermediate;
+  intermediate.tv_nsec = 0;
+
+  while (limit < seconds)
+    {
+      int result;
+      intermediate.tv_sec = limit;
+      result = nanosleep (&intermediate, remaining_delay);
+      seconds -= limit;
+      if (result)
+        {
+          if (remaining_delay)
+            {
+              remaining_delay->tv_sec += seconds;
+              remaining_delay->tv_nsec += requested_delay->tv_nsec;
+              if (BILLION <= requested_delay->tv_nsec)
+                {
+                  remaining_delay->tv_sec++;
+                  remaining_delay->tv_nsec -= BILLION;
+                }
+            }
+          return result;
+        }
+    }
+  intermediate.tv_sec = seconds;
+  intermediate.tv_nsec = requested_delay->tv_nsec;
+  return nanosleep (&intermediate, remaining_delay);
 }
 
+#elif (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
+/* Windows platforms.  */
+
+# define WIN32_LEAN_AND_MEAN
+# include <windows.h>
+
+/* The Win32 function Sleep() has a resolution of about 15 ms and takes
+   at least 5 ms to execute.  We use this function for longer time periods.
+   Additionally, we use busy-looping over short time periods, to get a
+   resolution of about 0.01 ms.  In order to measure such short timespans,
+   we use the QueryPerformanceCounter() function.  */
+
 int
-rpl_nanosleep (const struct timespec *requested_delay,
-	       struct timespec *remaining_delay)
+nanosleep (const struct timespec *requested_delay,
+           struct timespec *remaining_delay)
 {
-  /* nanosleep mishandles large sleeps due to internal overflow
-     problems, so check that the proper amount of time has actually
-     elapsed.  */
+  static bool initialized;
+  /* Number of performance counter increments per nanosecond,
+     or zero if it could not be determined.  */
+  static double ticks_per_nanosecond;
+
+  if (requested_delay->tv_nsec < 0 || BILLION <= requested_delay->tv_nsec)
+    {
+      errno = EINVAL;
+      return -1;
+    }
 
-  struct timespec delay = *requested_delay;
-  struct timespec t0;
-  getnow (&t0);
+  /* For requested delays of one second or more, 15ms resolution is
+     sufficient.  */
+  if (requested_delay->tv_sec == 0)
+    {
+      if (!initialized)
+        {
+          /* Initialize ticks_per_nanosecond.  */
+          LARGE_INTEGER ticks_per_second;
+
+          if (QueryPerformanceFrequency (&ticks_per_second))
+            ticks_per_nanosecond =
+              (double) ticks_per_second.QuadPart / 1000000000.0;
+
+          initialized = true;
+        }
+      if (ticks_per_nanosecond)
+        {
+          /* QueryPerformanceFrequency worked.  We can use
+             QueryPerformanceCounter.  Use a combination of Sleep and
+             busy-looping.  */
+          /* Number of milliseconds to pass to the Sleep function.
+             Since Sleep can take up to 8 ms less or 8 ms more than requested
+             (or maybe more if the system is loaded), we subtract 10 ms.  */
+          int sleep_millis = (int) requested_delay->tv_nsec / 1000000 - 10;
+          /* Determine how many ticks to delay.  */
+          LONGLONG wait_ticks = requested_delay->tv_nsec * ticks_per_nanosecond;
+          /* Start.  */
+          LARGE_INTEGER counter_before;
+          if (QueryPerformanceCounter (&counter_before))
+            {
+              /* Wait until the performance counter has reached this value.
+                 We don't need to worry about overflow, because the performance
+                 counter is reset at reboot, and with a frequency of 3.6E6
+                 ticks per second 63 bits suffice for over 80000 years.  */
+              LONGLONG wait_until = counter_before.QuadPart + wait_ticks;
+              /* Use Sleep for the longest part.  */
+              if (sleep_millis > 0)
+                Sleep (sleep_millis);
+              /* Busy-loop for the rest.  */
+              for (;;)
+                {
+                  LARGE_INTEGER counter_after;
+                  if (!QueryPerformanceCounter (&counter_after))
+                    /* QueryPerformanceCounter failed, but succeeded earlier.
+                       Should not happen.  */
+                    break;
+                  if (counter_after.QuadPart >= wait_until)
+                    /* The requested time has elapsed.  */
+                    break;
+                }
+              goto done;
+            }
+        }
+    }
+  /* Implementation for long delays and as fallback.  */
+  Sleep (requested_delay->tv_sec * 1000 + requested_delay->tv_nsec / 1000000);
 
-  for (;;)
+ done:
+  /* Sleep is not interruptible.  So there is no remaining delay.  */
+  if (remaining_delay != NULL)
     {
-      int r = nanosleep (&delay, remaining_delay);
-      if (r == 0)
-	{
-	  time_t secs_sofar;
-	  struct timespec now;
-	  getnow (&now);
-
-	  secs_sofar = now.tv_sec - t0.tv_sec;
-	  if (requested_delay->tv_sec < secs_sofar)
-	    return 0;
-	  delay.tv_sec = requested_delay->tv_sec - secs_sofar;
-	  delay.tv_nsec = requested_delay->tv_nsec - (now.tv_nsec - t0.tv_nsec);
-	  if (delay.tv_nsec < 0)
-	    {
-	      if (delay.tv_sec == 0)
-		return 0;
-	      delay.tv_nsec += BILLION;
-	      delay.tv_sec--;
-	    }
-	  else if (BILLION <= delay.tv_nsec)
-	    {
-	      delay.tv_nsec -= BILLION;
-	      delay.tv_sec++;
-	    }
-	}
+      remaining_delay->tv_sec = 0;
+      remaining_delay->tv_nsec = 0;
     }
+  return 0;
 }
 
 #else
+/* Unix platforms lacking nanosleep. */
 
 /* Some systems (MSDOS) don't have SIGCONT.
    Using SIGTERM here turns the signal-handling code below
@@ -125,12 +210,12 @@ my_usleep (const struct timespec *ts_delay)
     {
       time_t t1 = tv_delay.tv_sec + 1;
       if (t1 < tv_delay.tv_sec)
-	tv_delay.tv_usec = 1000000 - 1; /* close enough */
+        tv_delay.tv_usec = 1000000 - 1; /* close enough */
       else
-	{
-	  tv_delay.tv_sec = t1;
-	  tv_delay.tv_usec = 0;
-	}
+        {
+          tv_delay.tv_sec = t1;
+          tv_delay.tv_usec = 0;
+        }
     }
   select (0, NULL, NULL, NULL, &tv_delay);
 }
@@ -139,11 +224,17 @@ my_usleep (const struct timespec *ts_delay)
    *REMAINING_DELAY part isn't implemented yet.  */
 
 int
-rpl_nanosleep (const struct timespec *requested_delay,
-	       struct timespec *remaining_delay)
+nanosleep (const struct timespec *requested_delay,
+           struct timespec *remaining_delay)
 {
   static bool initialized;
 
+  if (requested_delay->tv_nsec < 0 || BILLION <= requested_delay->tv_nsec)
+    {
+      errno = EINVAL;
+      return -1;
+    }
+
   /* set up sig handler */
   if (! initialized)
     {
@@ -151,14 +242,14 @@ rpl_nanosleep (const struct timespec *requested_delay,
 
       sigaction (SIGCONT, NULL, &oldact);
       if (get_handler (&oldact) != SIG_IGN)
-	{
-	  struct sigaction newact;
-
-	  newact.sa_handler = sighandler;
-	  sigemptyset (&newact.sa_mask);
-	  newact.sa_flags = 0;
-	  sigaction (SIGCONT, &newact, NULL);
-	}
+        {
+          struct sigaction newact;
+
+          newact.sa_handler = sighandler;
+          sigemptyset (&newact.sa_mask);
+          newact.sa_flags = 0;
+          sigaction (SIGCONT, &newact, NULL);
+        }
       initialized = true;
     }
 
@@ -170,7 +261,7 @@ rpl_nanosleep (const struct timespec *requested_delay,
     {
       /* Calculate time remaining.  */
       /* FIXME: the code in sleep doesn't use this, so there's no
-	 rush to implement it.  */
+         rush to implement it.  */
 
       errno = EINTR;
     }