[math] Floating point equality with relative epsilon comparisons

src/float_utils.c

@@ -0,0 +1,29 @@
+#include "float_utils.h"
+
+inline bool float_equals_epsilon(float a, float b, float epsilon) {
+    float diff = fabsf(a - b);
+    a = fabsf(a);
+    b = fabsf(b);
+
+    float largest = (b > a) ? b : a;
+
+    return (diff <= largest * epsilon);
+}
+
+inline bool float_equals(float a, float b) {
+    return float_equals_epsilon(a, b, FLT_EPSILON);
+}
+
+inline bool double_equals_epsilon(double a, double b, double epsilon) {
+    double diff = fabs(a - b);
+    a = fabs(a);
+    b = fabs(b);
+
+    double largest = (b > a) ? b : a;
+
+    return (diff <= largest * epsilon);
+}
+
+inline bool double_equals(double a, double b) {
+    return double_equals_epsilon(a, b, DBL_EPSILON);
+}

src/float_utils.h

@@ -0,0 +1,16 @@
+#ifndef FLOAT_UTILS_H
+#define FLOAT_UTILS_H
+
+#include <stdlib.h>
+#include <stdbool.h>
+#include <float.h>
+#include <math.h>
+
+bool float_equals(float a, float b);
+bool float_equals_epsilon(float a, float b, float epsilon);
+
+bool double_equals(double a, double b);
+bool double_equals_epsilon(double a, double b, double epsilon);
+
+#endif
+