Implementation of sleepUntilDate:

git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/base/trunk@2790 72102866-910b-0410-8b05-ffd578937521

ChangeLog

@@ -5,6 +5,9 @@ Wed Apr 15 09:54:25 1998  Adam Fedor  <fedor@doc.com>
 	* src/externs.m: Add NSFileOwnerAccountName definition.
 	(patch provided by Marcus Mueller <znek@object-factory.com>)
 
+	* src/NSThread.m (-sleepUntilDate:): Implemented (from
+	Quetzalcoatl Bradley <qbradley@csc.uvic.ca>).
+
 Sun Apr  5 20:07:28 1998  Scott Christley  <scottc@net-community.com>
 
 	* Utilize documentation rules in Makefile Package.

Source/NSThread.m

@@ -168,8 +168,26 @@ static BOOL entered_multi_threaded_state;
 // Delaying a thread
 + (void) sleepUntilDate: (NSDate*)date
 {
-  // xxx Do we need some runtime/OS support for this?
-  [self notImplemented: _cmd];
+  NSTimeInterval delay;
+
+  // delay is always the number of seconds we still need to wait
+  delay = [date timeIntervalSinceNow];
+
+  // Avoid integer overflow by breaking up long sleeps
+  // We assume usleep can accept a value at least 31 bits in length
+  while (delay > 30.0*60.0)
+    {
+      // sleep 30 minutes
+      usleep (30*60*1000000);
+      delay = [date timeIntervalSinceNow];
+    }
+
+  // usleep may return early because of signals
+  while (delay > 0)
+    {
+      usleep (delay*1000000.0);
+      delay = [date timeIntervalSinceNow];
+    }
 }
 
 // Terminating a thread