SpeedMeter no longer uses NaN to represent invalid values.

There is no portable way to check for NaN values before the
C++11 standard, so the old code didn't compile on OmniOS 11
and OpenIndiana 151a7.

Closes GH-1212.

ext/common/Utils/SpeedMeter.h

@@ -191,7 +191,7 @@ class SpeedMeter {
 		return count;
 	}
 
-	/** Current speed over the configured window. Returns NaN if less than 2
+	/** Current speed over the configured window. Returns unknownSpeed() if less than 2
 	 * samples have been collected so far.
 	 */
 	double currentSpeed() const {
@@ -221,16 +221,21 @@ class SpeedMeter {
 		}
 		avgWeight /= std::max(1, (int) count - 1 - begin);
 
-		interval = getSample(count - 1).timestamp - getSample(begin).timestamp;
+		interval = getSample((int) count - 1).timestamp - getSample(begin).timestamp;
 		if (interval > 0) {
 			// sum / interval is the speed per average delta interval,
 			// so we extrapolate that over the entire window interval.
 			return (sum / interval) * (window / avgWeight);
 		} else {
-			return numeric_limits<double>::quiet_NaN();
+			return unknownSpeed();
 		}
 	}
 
+	static ValueType unknownSpeed() {
+		assert(numeric_limits<ValueType>::is_iec559);
+		return -numeric_limits<ValueType>::max();
+	}
+
 	#if 1
 		void debug() const {
 			const unsigned long long timeThreshold = getTimeThreshold();

ext/common/Utils/SystemMetricsCollector.h

@@ -45,7 +45,6 @@
 	#include <sys/sysinfo.h>
 	#include <Exceptions.h>
 	#include <Utils/StringScanning.h>
-	#include <Utils/SpeedMeter.h>
 	#include <Utils/IOUtils.h>
 #endif
 #ifdef __APPLE__
@@ -69,6 +68,7 @@
 #include <Utils/StrIntUtils.h>
 #include <Utils/SystemTime.h>
 #include <Utils/AnsiColorConstants.h>
+#include <Utils/SpeedMeter.h>
 
 /*
  * Useful resources
@@ -346,13 +346,13 @@ class SystemMetrics {
 	time_t boottime;
 
 	/** Speed at which processes are created per second.
-	 * NaN if it's not yet known (because too few samples have been taken so far).
+	 * SpeedMeter<>::unknownSpeed() if it's not yet known (because too few samples have been taken so far).
 	 * -1 if there was an error querying this information.
 	 * -2 if the OS does not support this metric.
 	 */
 	double forkRate;
 	/** Speed at which the OS swaps in and swaps out data, in KB/sec.
-	 * NaN if it's not yet known (because too few samples have been taken so far).
+	 * SpeedMeter<>::unknownSpeed() if it's not yet known (because too few samples have been taken so far).
 	 * -1 if there was an error querying this information.
 	 * -2 if the OS does not support this metric.
 	 */
@@ -537,7 +537,7 @@ class SystemMetrics {
 
 			if (forkRate != -2) {
 				stream << "Fork rate         : ";
-				if (std::isnan(forkRate) || forkRate < 0) {
+				if (forkRate == SpeedMeter<>::unknownSpeed() || forkRate < 0) {
 					if (options.colors) {
 						stream << ANSI_COLOR_DGRAY;
 					}
@@ -648,7 +648,7 @@ class SystemMetrics {
 
 			if (swapInRate != -2) {
 				stream << "Swap in           : ";
-				if (std::isnan(swapInRate) || swapInRate < 0) {
+				if (swapInRate == SpeedMeter<>::unknownSpeed() || swapInRate < 0) {
 					if (options.colors) {
 						stream << ANSI_COLOR_DGRAY;
 					}
@@ -668,7 +668,7 @@ class SystemMetrics {
 
 			if (swapOutRate != -2) {
 				stream << "Swap out          : ";
-				if (std::isnan(swapOutRate) || swapOutRate < 0) {
+				if (swapOutRate == SpeedMeter<>::unknownSpeed() || swapOutRate < 0) {
 					if (options.colors) {
 						stream << ANSI_COLOR_DGRAY;
 					}