Replace isnan() with better comparisons (isgreater(), etc.)

The standard isnan() function is defined to never throw FP exceptions
even when the argument is a "signaling" NaN. This makes isnan() more
expensive than (x != x) expression unless the compiler flag
'-fno-signaling-nans' is given.

Introduce functions isNaN(), isNonnegative(), isPositive(),
sumPositiveValues() and compareRealNumbers(), and replace isnan() in
htop's codebase with the new functions. These functions utilize
isgreater() and isgreaterequal() comparisons, which do not throw FP
exceptions on "quiet" NaNs, which htop uses extensively.

With isnan() removed, there is no need to suppress the warning
'-Wno-c11-extensions' in FreeBSD. Remove the code from 'configure.ac'.

Signed-off-by: Kang-Che Sung <explorer09@gmail.com>

1 files changed, 13 insertions, 13 deletions

diff --git a/CPUMeter.c b/CPUMeter.c
index a946aa7d..c12bb72c 100644
--- a/CPUMeter.c
+++ b/CPUMeter.c
@@ -9,11 +9,11 @@ in the source distribution for its full text.
 
 #include "CPUMeter.h"
 
-#include <math.h>
 #include <stdlib.h>
 #include <string.h>
 
 #include "CRT.h"
+#include "Macros.h"
 #include "Object.h"
 #include "Platform.h"
 #include "ProcessList.h"
@@ -71,7 +71,7 @@ static void CPUMeter_updateValues(Meter* this) {
    }
 
    double percent = Platform_setCPUValues(this, cpu);
-   if (isnan(percent)) {
+   if (!isNonnegative(percent)) {
       xSnprintf(this->txtBuffer, sizeof(this->txtBuffer), "offline");
       return;
    }
@@ -86,17 +86,17 @@ static void CPUMeter_updateValues(Meter* this) {
 
    if (settings->showCPUFrequency) {
       double cpuFrequency = this->values[CPU_METER_FREQUENCY];
-      if (isnan(cpuFrequency)) {
-         xSnprintf(cpuFrequencyBuffer, sizeof(cpuFrequencyBuffer), "N/A");
-      } else {
+      if (isNonnegative(cpuFrequency)) {
          xSnprintf(cpuFrequencyBuffer, sizeof(cpuFrequencyBuffer), "%4uMHz", (unsigned)cpuFrequency);
+      } else {
+         xSnprintf(cpuFrequencyBuffer, sizeof(cpuFrequencyBuffer), "N/A");
       }
    }
 
    #ifdef BUILD_WITH_CPU_TEMP
    if (settings->showCPUTemperature) {
       double cpuTemperature = this->values[CPU_METER_TEMPERATURE];
-      if (isnan(cpuTemperature))
+      if (isNaN(cpuTemperature))
          xSnprintf(cpuTemperatureBuffer, sizeof(cpuTemperatureBuffer), "N/A");
       else if (settings->degreeFahrenheit)
          xSnprintf(cpuTemperatureBuffer, sizeof(cpuTemperatureBuffer), "%3d%sF", (int)(cpuTemperature * 9 / 5 + 32), CRT_degreeSign);
@@ -146,12 +146,12 @@ static void CPUMeter_display(const Object* cast, RichString* out) {
       len = xSnprintf(buffer, sizeof(buffer), "%5.1f%% ", this->values[CPU_METER_SOFTIRQ]);
       RichString_appendAscii(out, CRT_colors[METER_TEXT], "si:");
       RichString_appendnAscii(out, CRT_colors[CPU_SOFTIRQ], buffer, len);
-      if (!isnan(this->values[CPU_METER_STEAL])) {
+      if (isNonnegative(this->values[CPU_METER_STEAL])) {
          len = xSnprintf(buffer, sizeof(buffer), "%5.1f%% ", this->values[CPU_METER_STEAL]);
          RichString_appendAscii(out, CRT_colors[METER_TEXT], "st:");
          RichString_appendnAscii(out, CRT_colors[CPU_STEAL], buffer, len);
       }
-      if (!isnan(this->values[CPU_METER_GUEST])) {
+      if (isNonnegative(this->values[CPU_METER_GUEST])) {
          len = xSnprintf(buffer, sizeof(buffer), "%5.1f%% ", this->values[CPU_METER_GUEST]);
          RichString_appendAscii(out, CRT_colors[METER_TEXT], "gu:");
          RichString_appendnAscii(out, CRT_colors[CPU_GUEST], buffer, len);
@@ -166,7 +166,7 @@ static void CPUMeter_display(const Object* cast, RichString* out) {
       len = xSnprintf(buffer, sizeof(buffer), "%5.1f%% ", this->values[CPU_METER_NICE]);
       RichString_appendAscii(out, CRT_colors[METER_TEXT], "low:");
       RichString_appendnAscii(out, CRT_colors[CPU_NICE_TEXT], buffer, len);
-      if (!isnan(this->values[CPU_METER_IRQ])) {
+      if (isNonnegative(this->values[CPU_METER_IRQ])) {
          len = xSnprintf(buffer, sizeof(buffer), "%5.1f%% ", this->values[CPU_METER_IRQ]);
          RichString_appendAscii(out, CRT_colors[METER_TEXT], "vir:");
          RichString_appendnAscii(out, CRT_colors[CPU_GUEST], buffer, len);
@@ -176,10 +176,10 @@ static void CPUMeter_display(const Object* cast, RichString* out) {
    if (settings->showCPUFrequency) {
       char cpuFrequencyBuffer[10];
       double cpuFrequency = this->values[CPU_METER_FREQUENCY];
-      if (isnan(cpuFrequency)) {
-         len = xSnprintf(cpuFrequencyBuffer, sizeof(cpuFrequencyBuffer), "N/A     ");
-      } else {
+      if (isNonnegative(cpuFrequency)) {
          len = xSnprintf(cpuFrequencyBuffer, sizeof(cpuFrequencyBuffer), "%4uMHz ", (unsigned)cpuFrequency);
+      } else {
+         len = xSnprintf(cpuFrequencyBuffer, sizeof(cpuFrequencyBuffer), "N/A     ");
       }
       RichString_appendAscii(out, CRT_colors[METER_TEXT], "freq: ");
       RichString_appendnWide(out, CRT_colors[METER_VALUE], cpuFrequencyBuffer, len);
@@ -189,7 +189,7 @@ static void CPUMeter_display(const Object* cast, RichString* out) {
    if (settings->showCPUTemperature) {
       char cpuTemperatureBuffer[10];
       double cpuTemperature = this->values[CPU_METER_TEMPERATURE];
-      if (isnan(cpuTemperature)) {
+      if (isNaN(cpuTemperature)) {
          len = xSnprintf(cpuTemperatureBuffer, sizeof(cpuTemperatureBuffer), "N/A");
       } else if (settings->degreeFahrenheit) {
          len = xSnprintf(cpuTemperatureBuffer, sizeof(cpuTemperatureBuffer), "%5.1f%sF", cpuTemperature * 9 / 5 + 32, CRT_degreeSign);