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

BatteryMeter.c

@@ -12,6 +12,7 @@ This meter written by Ian P. Hands ([email protected], [email protected]).
 #include <math.h>
 
 #include "CRT.h"
+#include "Macros.h"
 #include "Object.h"
 #include "Platform.h"
 #include "XUtils.h"
@@ -27,7 +28,7 @@ static void BatteryMeter_updateValues(Meter* this) {
 
    Platform_getBattery(&percent, &isOnAC);
 
-   if (isnan(percent)) {
+   if (!isNonnegative(percent)) {
       this->values[0] = NAN;
       xSnprintf(this->txtBuffer, sizeof(this->txtBuffer), "N/A");
       return;

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);

FileDescriptorMeter.c

@@ -12,14 +12,15 @@ in the source distribution for its full text.
 #include <string.h>
 
 #include "CRT.h"
+#include "Macros.h"
 #include "Meter.h"
 #include "Object.h"
 #include "Platform.h"
 #include "RichString.h"
 #include "XUtils.h"
 
 
-#define FD_EFFECTIVE_UNLIMITED(x) ((x) > (1<<30))
+#define FD_EFFECTIVE_UNLIMITED(x) (!isgreaterequal((double)(1<<30), (x)))
 
 static const int FileDescriptorMeter_attributes[] = {
    FILE_DESCRIPTOR_USED,
@@ -67,9 +68,9 @@ static void FileDescriptorMeter_updateValues(Meter* this) {
       }
    }
 
-   if (isnan(this->values[0])) {
+   if (!isNonnegative(this->values[0])) {
       xSnprintf(this->txtBuffer, sizeof(this->txtBuffer), "unknown/unknown");
-   } else if (isnan(this->values[1]) || FD_EFFECTIVE_UNLIMITED(this->values[1])) {
+   } else if (FD_EFFECTIVE_UNLIMITED(this->values[1])) {
       xSnprintf(this->txtBuffer, sizeof(this->txtBuffer), "%.0lf/unlimited", this->values[0]);
    } else {
       xSnprintf(this->txtBuffer, sizeof(this->txtBuffer), "%.0lf/%.0lf", this->values[0], this->values[1]);
@@ -81,7 +82,7 @@ static void FileDescriptorMeter_display(const Object* cast, RichString* out) {
    char buffer[50];
    int len;
 
-   if (isnan(this->values[0])) {
+   if (!isNonnegative(this->values[0])) {
       RichString_appendAscii(out, CRT_colors[METER_TEXT], "unknown");
       return;
    }
@@ -91,7 +92,7 @@ static void FileDescriptorMeter_display(const Object* cast, RichString* out) {
    RichString_appendnAscii(out, CRT_colors[FILE_DESCRIPTOR_USED], buffer, len);
 
    RichString_appendAscii(out, CRT_colors[METER_TEXT], " max: ");
-   if (isnan(this->values[1]) || FD_EFFECTIVE_UNLIMITED(this->values[1])) {
+   if (FD_EFFECTIVE_UNLIMITED(this->values[1])) {
       RichString_appendAscii(out, CRT_colors[FILE_DESCRIPTOR_MAX], "unlimited");
    } else {
       len = xSnprintf(buffer, sizeof(buffer), "%.0lf", this->values[1]);

Macros.h

@@ -2,6 +2,8 @@
 #define HEADER_Macros
 
 #include <assert.h> // IWYU pragma: keep
+#include <math.h>
+#include <stdbool.h>
 
 #ifndef MINIMUM
 #define MINIMUM(a, b)                  ((a) < (b) ? (a) : (b))
@@ -98,6 +100,24 @@
 #define IGNORE_WCASTQUAL_END
 #endif
 
+/* Cheaper function for checking NaNs. Unlike the standard isnan(), this may
+   throw an FP exception on a "signaling" NaN.
+   (ISO/IEC TS 18661-1 and the C23 standard stated that isnan() throws no
+   exceptions even with a "signaling" NaN) */
+static inline bool isNaN(double x) {
+   return !isgreaterequal(x, x);
+}
+
+/* Checks if x is nonnegative. Returns false if x is NaN. */
+static inline bool isNonnegative(double x) {
+   return isgreaterequal(x, 0.0);
+}
+
+/* Checks if x is positive. Returns false if x is NaN. */
+static inline bool isPositive(double x) {
+   return isgreater(x, 0.0);
+}
+
 /* This subtraction is used by Linux / NetBSD / OpenBSD for calculation of CPU usage items. */
 static inline unsigned long long saturatingSub(unsigned long long a, unsigned long long b) {
    return a > b ? a - b : 0;

MemoryMeter.c

@@ -11,6 +11,7 @@ in the source distribution for its full text.
 #include <stddef.h>
 
 #include "CRT.h"
+#include "Macros.h"
 #include "Object.h"
 #include "Platform.h"
 #include "RichString.h"
@@ -42,9 +43,8 @@ static void MemoryMeter_updateValues(Meter* this) {
 
    /* we actually want to show "used + compressed" */
    double used = this->values[MEMORY_METER_USED];
-   if (!isnan(this->values[MEMORY_METER_COMPRESSED])) {
+   if (isPositive(this->values[MEMORY_METER_COMPRESSED]))
       used += this->values[MEMORY_METER_COMPRESSED];
-   }
 
    written = Meter_humanUnit(buffer, used, size);
    METER_BUFFER_CHECK(buffer, size, written);
@@ -71,14 +71,14 @@ static void MemoryMeter_display(const Object* cast, RichString* out) {
    RichString_appendAscii(out, CRT_colors[MEMORY_BUFFERS_TEXT], buffer);
 
    /* shared memory is not supported on all platforms */
-   if (!isnan(this->values[MEMORY_METER_SHARED])) {
+   if (isNonnegative(this->values[MEMORY_METER_SHARED])) {
       Meter_humanUnit(buffer, this->values[MEMORY_METER_SHARED], sizeof(buffer));
       RichString_appendAscii(out, CRT_colors[METER_TEXT], " shared:");
       RichString_appendAscii(out, CRT_colors[MEMORY_SHARED], buffer);
    }
 
    /* compressed memory is not supported on all platforms */
-   if (!isnan(this->values[MEMORY_METER_COMPRESSED])) {
+   if (isNonnegative(this->values[MEMORY_METER_COMPRESSED])) {
       Meter_humanUnit(buffer, this->values[MEMORY_METER_COMPRESSED], sizeof(buffer));
       RichString_appendAscii(out, CRT_colors[METER_TEXT], " compressed:");
       RichString_appendAscii(out, CRT_colors[MEMORY_COMPRESSED], buffer);
@@ -89,7 +89,7 @@ static void MemoryMeter_display(const Object* cast, RichString* out) {
    RichString_appendAscii(out, CRT_colors[MEMORY_CACHE], buffer);
 
    /* available memory is not supported on all platforms */
-   if (!isnan(this->values[MEMORY_METER_AVAILABLE])) {
+   if (isNonnegative(this->values[MEMORY_METER_AVAILABLE])) {
       Meter_humanUnit(buffer, this->values[MEMORY_METER_AVAILABLE], sizeof(buffer));
       RichString_appendAscii(out, CRT_colors[METER_TEXT], " available:");
       RichString_appendAscii(out, CRT_colors[METER_VALUE], buffer);

Meter.c

@@ -333,10 +333,7 @@ static void GraphMeterMode_draw(Meter* this, int x, int y, int w) {
       if (Meter_comprisedValues(this)) {
          data->values[nValues - 1] = (this->curItems > 0) ? this->values[this->curItems - 1] : 0.0;
       } else {
-         double value = 0.0;
-         for (uint8_t i = 0; i < this->curItems; i++)
-            value += !isnan(this->values[i]) ? this->values[i] : 0;
-         data->values[nValues - 1] = value;
+         data->values[nValues - 1] = sumPositiveValues(this->values, this->curItems);
       }
    }
 

Process.c

@@ -759,7 +759,7 @@ void Process_printRate(RichString* str, double rate, bool coloring) {
       processMegabytesColor = CRT_colors[PROCESS];
    }
 
-   if (isnan(rate)) {
+   if (!isNonnegative(rate)) {
       RichString_appendAscii(str, shadowColor, "        N/A ");
    } else if (rate < 0.005) {
       int len = snprintf(buffer, sizeof(buffer), "%7.2f B/s ", rate);
@@ -791,8 +791,8 @@ void Process_printLeftAlignedField(RichString* str, int attr, const char* conten
    RichString_appendChr(str, attr, ' ', width + 1 - columns);
 }
 
-void Process_printPercentage(float val, char* buffer, int n, uint8_t width, int* attr) {
-   if (val >= 0) {
+void Process_printPercentage(float val, char* buffer, size_t n, uint8_t width, int* attr) {
+   if (isNonnegative(val)) {
       if (val < 0.05F)
          *attr = CRT_colors[PROCESS_SHADOW];
       else if (val >= 99.9F)
@@ -1184,7 +1184,7 @@ int Process_compareByKey_Base(const Process* p1, const Process* p2, ProcessField
    switch (key) {
    case PERCENT_CPU:
    case PERCENT_NORM_CPU:
-      return SPACESHIP_NUMBER(p1->percent_cpu, p2->percent_cpu);
+      return compareRealNumbers(p1->percent_cpu, p2->percent_cpu);
    case PERCENT_MEM:
       return SPACESHIP_NUMBER(p1->m_resident, p2->m_resident);
    case COMM:

Process.h

@@ -380,7 +380,7 @@ void Process_fillStarttimeBuffer(Process* this);
 
 void Process_printLeftAlignedField(RichString* str, int attr, const char* content, unsigned int width);
 
-void Process_printPercentage(float val, char* buffer, int n, uint8_t width, int* attr);
+void Process_printPercentage(float val, char* buffer, size_t n, uint8_t width, int* attr);
 
 void Process_display(const Object* cast, RichString* out);
 

SwapMeter.c

@@ -13,6 +13,7 @@ in the source distribution for its full text.
 #include <stddef.h>
 
 #include "CRT.h"
+#include "Macros.h"
 #include "Object.h"
 #include "Platform.h"
 #include "RichString.h"
@@ -51,13 +52,13 @@ static void SwapMeter_display(const Object* cast, RichString* out) {
    RichString_appendAscii(out, CRT_colors[METER_TEXT], " used:");
    RichString_appendAscii(out, CRT_colors[METER_VALUE], buffer);
 
-   if (!isnan(this->values[SWAP_METER_CACHE])) {
+   if (isNonnegative(this->values[SWAP_METER_CACHE])) {
       Meter_humanUnit(buffer, this->values[SWAP_METER_CACHE], sizeof(buffer));
       RichString_appendAscii(out, CRT_colors[METER_TEXT], " cache:");
       RichString_appendAscii(out, CRT_colors[SWAP_CACHE], buffer);
    }
 
-   if (!isnan(this->values[SWAP_METER_FRONTSWAP])) {
+   if (isNonnegative(this->values[SWAP_METER_FRONTSWAP])) {
       Meter_humanUnit(buffer, this->values[SWAP_METER_FRONTSWAP], sizeof(buffer));
       RichString_appendAscii(out, CRT_colors[METER_TEXT], " frontswap:");
       RichString_appendAscii(out, CRT_colors[SWAP_FRONTSWAP], buffer);

XUtils.c

@@ -12,13 +12,15 @@ in the source distribution for its full text.
 #include <assert.h>
 #include <errno.h>
 #include <fcntl.h>
+#include <math.h>
 #include <stdarg.h>
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
 
 #include "CRT.h"
+#include "Macros.h"
 
 
 void fail(void) {
@@ -337,3 +339,25 @@ ssize_t full_write(int fd, const void* buf, size_t count) {
 
    return written;
 }
+
+/* Compares floating point values for ordering data entries. In this function,
+   NaN is considered "less than" any other floating point value (regardless of
+   sign), and two NaNs are considered "equal" regardless of payload. */
+int compareRealNumbers(double a, double b) {
+   int result = isgreater(a, b) - isgreater(b, a);
+   if (result)
+      return result;
+   return !isNaN(a) - !isNaN(b);
+}
+
+/* Computes the sum of all positive floating point values in an array.
+   NaN values in the array are skipped. The returned sum will always be
+   nonnegative. */
+double sumPositiveValues(const double* array, size_t count) {
+   double sum = 0.0;
+   for (size_t i = 0; i < count; i++) {
+      if (isPositive(array[i]))
+         sum += array[i];
+   }
+   return sum;
+}

XUtils.h

@@ -82,4 +82,14 @@ ssize_t xReadfileat(openat_arg_t dirfd, const char* pathname, void* buffer, size
 ATTR_ACCESS3_R(2, 3)
 ssize_t full_write(int fd, const void* buf, size_t count);
 
+/* Compares floating point values for ordering data entries. In this function,
+   NaN is considered "less than" any other floating point value (regardless of
+   sign), and two NaNs are considered "equal" regardless of payload. */
+int compareRealNumbers(double a, double b);
+
+/* Computes the sum of all positive floating point values in an array.
+   NaN values in the array are skipped. The returned sum will always be
+   nonnegative. */
+double sumPositiveValues(const double* array, size_t count);
+
 #endif