Merge a94f8f0e32 into 661329877f

helpers/latlon.c

@@ -0,0 +1,36 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+
+#define R 6371
+#define TO_RAD (3.1415926536 / 180)
+double dist(double th1, double ph1, double th2, double ph2)
+{
+	double dx, dy, dz;
+	ph1 -= ph2;
+	ph1 *= TO_RAD, th1 *= TO_RAD, th2 *= TO_RAD;
+
+	dz = sin(th1) - sin(th2);
+	dx = cos(ph1) * cos(th1) - cos(th2);
+	dy = sin(ph1) * cos(th1);
+	return asin(sqrt(dx * dx + dy * dy + dz * dz) / 2) * 2 * R;
+}
+
+int main(int argc, const char * argv[])
+{
+	if(argc < 5 || argc > 5){
+		return 1;
+	}
+	float coords[4];
+	for(int i=1;i<5;i++){
+		if(atof(argv[i]) == 0){
+			return 1;
+		}
+		coords[i] = atof(argv[i]);
+	}
+	
+	double d = dist(coords[1], coords[2], coords[3], coords[4]);
+	printf("%.1f\n", d);
+
+	return 0;
+}

helpers/tools/.gitignore

@@ -1 +0,0 @@
-latlon

helpers/tools/Makefile

@@ -1,24 +0,0 @@
-bin := latlon
-
-CC = gcc
-
-CFLAGS += -Wall
-CFLAGS += -Wextra
-CFLAGS += -Wpedantic
-CFLAGS += -std=c23
-CFLAGS += -O3
-
-LDFLAGS += -lm
-
-PREFIX ?= $(HOME)/.local/share/dzgui
-
-all: $(bin)
-
-install: $(bin)
-	install -Dm 755 $(bin) $(PREFIX)
-
-$(bin): latlon.c
-	$(CC) $(CFLAGS) $^ -o $@ $(LDFLAGS)
-
-clean:
-	rm -f $(bin)

helpers/tools/latlon.c

@@ -1,77 +0,0 @@
-// This small program computes the distance between two points on the Earths
-// surface. The algorithm used for computing is called haversine formula.
-// Source for the algorithm can be found here:
-// https://en.wikipedia.org/wiki/Haversine_formula
-
-#include <math.h>
-#include <stdlib.h>
-#include <stdio.h>
-
-// Earth's radius in meters.
-#define RADIUS ((12756L / 2.0L) * 1000L)
-
-// PI natural constant
-#define PI 3.1415926536L
-
-// coordinates struct for storing points
-struct Coordinate {
-    double latitude;
-    double longitude;
-};
-
-/**
- * @brief Calculates a radian value from an angle
- */
-double radian_from(const double angle) {
-    return (angle * PI) / 180;
-}
-
-/**
- * @brief Calculate the haversine function from an angle in radian
- */
-double haversine(const double angle) { return ((1.0L - cos(angle)) / 2); }
-
-/**
- * @brief Calculate the distance between two coordinates
- */
-double great_circle_distance(const struct Coordinate a,
-                             const struct Coordinate b) {
-
-    // calculate longitude and latitude differences
-    struct Coordinate diff_coord = {
-        .longitude = a.longitude - b.longitude,
-        .latitude  = a.latitude - b.latitude,
-    };
-
-    // calculate haversine(theta) value, where theta is the angle between the
-    // two coordinates
-    double hav_theta = haversine(diff_coord.latitude)
-                       + cos(a.latitude) * cos(b.latitude) * haversine(diff_coord.longitude);
-
-    // calculate distance from radius, and haversine(theta) values 
-    double distance = 2 * RADIUS * asin(sqrt(hav_theta));
-
-    return distance;
-}
-
-int main(int argc, const char* argv[]) {
-    if (argc < 5 || argc > 5) {
-        return 1;
-    }
-
-    const struct Coordinate a = {
-        .latitude  = radian_from(atof(argv[1])),
-        .longitude = radian_from(atof(argv[2])),
-    };
-    const struct Coordinate b = {
-        .latitude  = radian_from(atof(argv[3])),
-        .longitude = radian_from(atof(argv[4])),
-    };
-
-    // Returns the distance in meters.
-    // To pretty-print the result in a consumer of this module, it is
-    // recommended to divide the result by 1,000 and round it.
-    printf("%.1f\n", great_circle_distance(a, b));
-
-    return 0;
-}