X-Git-Url: http://nitlanguage.org

diff --git a/lib/realtime.nit b/lib/realtime.nit
index dc24c99..39c5a27 100644
--- a/lib/realtime.nit
+++ b/lib/realtime.nit
@@ -10,7 +10,7 @@
 # You  are  allowed  to  redistribute it and sell it, alone or is a part of
 # another product.
 
-# Provides the Clock utility class to keep time of real time flow
+# Services to keep time of the wall clock time
 module realtime is ldflags "-lrt"
 
 in "C header" `{
@@ -21,6 +21,28 @@ in "C header" `{
 #include <time.h>
 `}
 
+in "C" `{
+
+#ifdef __MACH__
+/* OS X does not have clock_gettime, mascarade it and use clock_get_time
+ * cf http://stackoverflow.com/questions/11680461/monotonic-clock-on-osx
+*/
+#include <mach/clock.h>
+#include <mach/mach.h>
+#define CLOCK_REALTIME CALENDAR_CLOCK
+#define CLOCK_MONOTONIC SYSTEM_CLOCK
+void clock_gettime(clock_t clock_name, struct timespec *ts) {
+	clock_serv_t cclock;
+	mach_timespec_t mts;
+	host_get_clock_service(mach_host_self(), clock_name, &cclock);
+	clock_get_time(cclock, &mts);
+	mach_port_deallocate(mach_task_self(), cclock);
+	ts->tv_sec = mts.tv_sec;
+	ts->tv_nsec = mts.tv_nsec;
+}
+#endif
+`}
+
 # Elapsed time representation.
 extern class Timespec `{struct timespec*`}
 
@@ -51,13 +73,16 @@ extern class Timespec `{struct timespec*`}
 		clock_gettime(CLOCK_MONOTONIC, self);
 	`}
 
-	# Substract a Timespec from `self`.
-	fun - ( o : Timespec ) : Timespec
+	# Subtract `other` from `self`
+	fun -(other: Timespec): Timespec
 	do
-		var s = sec - o.sec
-		var ns = nanosec - o.nanosec
-		if ns > nanosec then s += 1
-		return new Timespec( s, ns )
+		var s = sec - other.sec
+		var ns = nanosec - other.nanosec
+		if ns < 0 then
+			s -= 1
+			ns += 1000000000
+		end
+		return new Timespec(s, ns)
 	end
 
 	# Number of whole seconds of elapsed time.
@@ -105,7 +130,18 @@ class Clock
 	# Smallest time frame reported by clock
 	fun resolution : Timespec `{
 		struct timespec* tv = malloc( sizeof(struct timespec) );
+#ifdef __MACH__
+		clock_serv_t cclock;
+		int nsecs;
+		mach_msg_type_number_t count;
+		host_get_clock_service(mach_host_self(), SYSTEM_CLOCK, &cclock);
+		clock_get_attributes(cclock, CLOCK_GET_TIME_RES, (clock_attr_t)&nsecs, &count);
+		mach_port_deallocate(mach_task_self(), cclock);
+		tv->tv_sec = 0;
+		tv->tv_nsec = nsecs;
+#else
 		clock_getres( CLOCK_MONOTONIC, tv );
+#endif
 		return tv;
 	`}
 
@@ -123,4 +159,15 @@ class Clock
 		time_at_last_lapse = nt
 		return dt
 	end
+
+	# Seconds since the last call to `lapse`, without resetting the lapse counter
+	fun peek_lapse: Float
+	do
+		var nt = new Timespec.monotonic_now
+		var dt = nt - time_at_last_lapse
+		var r = dt.to_f
+		nt.free
+		dt.free
+		return r
+	end
 end