Moved the haversine code to a subdirectory

haversine/cpp/fscanf.cpp

@@ -0,0 +1,100 @@
+#include "haversine.h"
+#include <bits/types/FILE.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+#define DEBUG 0
+
+#define EARTH_RADIUS_KM 6371.0
+
+#if DEBUG
+#define ITEM_COUNT 2
+#else
+#define ITEM_COUNT 10000000
+#endif
+
+struct Item {
+  double x0;
+  double y0;
+  double x1;
+  double y1;
+};
+
+int main(int argc, char *argv[]) {
+#if DEBUG
+  FILE *fp = fopen("../test_data.json", "rb");
+#else
+  FILE *fp = fopen("../data_10000000_flex.json", "rb");
+#endif
+
+  Item *items = (Item *)malloc(ITEM_COUNT * sizeof(Item));
+  int index = 0;
+
+  clock_t start_time = clock();
+
+  {
+    char buf[256];
+    int read = fread(buf, 1, 256, fp);
+
+    for (int i = 1; i < read; ++i) {
+      if (buf[i] == '{') {
+        fseek(fp, i, SEEK_SET);
+        break;
+      }
+    }
+  }
+
+  while (true) {
+    fscanf(fp, "{\n");
+
+    int scanned = fscanf(fp,
+                         "      \"x0\": %lf,\n      \"y0\": %lf,\n      "
+                         "\"x1\": %lf,\n      \"y1\": %lf\n    },\n    ",
+                         &(items[index].x0), &(items[index].y0),
+                         &(items[index].x1), &(items[index].y1));
+
+    if (scanned == 0) {
+      break;
+    }
+
+    ++index;
+  }
+
+  clock_t mid_time = clock();
+
+  double sum = 0.0;
+
+  for (int i = 0; i < ITEM_COUNT; ++i) {
+    sum += haversine_of_degrees(items[i].x0, items[i].y0, items[i].x1,
+                                items[i].y1, EARTH_RADIUS_KM);
+  }
+
+  double average = sum / ITEM_COUNT;
+
+  clock_t end_time = clock();
+
+  printf("Result: %.16f\n", average);
+  printf("Input = %.16f seconds\n",
+         (double)(mid_time - start_time) / CLOCKS_PER_SEC);
+  printf("Math = %.16f seconds\n",
+         (double)(end_time - mid_time) / CLOCKS_PER_SEC);
+  printf("Total = %.16f seconds\n",
+         (double)(end_time - start_time) / CLOCKS_PER_SEC);
+  printf("Throughput = %.16f haversines/second\n",
+         ITEM_COUNT / ((double)(end_time - start_time) / CLOCKS_PER_SEC));
+
+#if DEBUG
+  for (int i = 0; i < ITEM_COUNT; ++i) {
+    printf("%.16f\n%.16f\n%.16f\n%.16f\n\n", items[i].x0, items[i].y0,
+           items[i].x1, items[i].y1);
+  }
+#endif
+
+  free(items);
+
+  fclose(fp);
+
+  return 0;
+}

haversine/cpp/haversine.cpp

@@ -0,0 +1,24 @@
+#include "haversine.h"
+#include <math.h>
+
+#define PI 3.14159265358979323845
+#define SQUARE(X) ((X) * (X))
+
+double radians(double degrees);
+
+double haversine_of_degrees(double x0, double y0, double x1, double y1,
+                            double radius) {
+  double dy = radians(y1 - y0);
+  double dx = radians(x1 - x0);
+  y0 = radians(y0);
+  y1 = radians(y1);
+
+  double root_term =
+      SQUARE(sin(dy / 2.0)) + cos(y0) * cos(y1) * SQUARE(sin(dx / 2.0));
+
+  double result = 2.0 * radius * asin(sqrt(root_term));
+
+  return result;
+}
+
+double radians(double degrees) { return (degrees * PI) / 180.0; }

haversine/cpp/haversine.h

@@ -0,0 +1,7 @@
+#ifndef HAVERSINE_H
+#define HAVERSINE_H
+
+double haversine_of_degrees(double x0, double y0, double x1, double y1,
+                            double radius);
+
+#endif // !HAVERSINE_H

haversine/cpp/strtok.cpp

@@ -0,0 +1,112 @@
+#include "haversine.h"
+#include <bits/types/FILE.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+#define DEBUG 0
+
+#define EARTH_RADIUS_KM 6371.0
+
+#if DEBUG
+#define ITEM_COUNT 2
+#else
+#define ITEM_COUNT 10000000
+#endif
+
+struct Item {
+  double x0;
+  double y0;
+  double x1;
+  double y1;
+};
+
+int main(int argc, char *argv[]) {
+#if DEBUG
+  FILE *fp = fopen("../test_data.json", "rb");
+#else
+  FILE *fp = fopen("../data_10000000_flex.json", "rb");
+#endif
+
+  Item *items = (Item *)malloc(ITEM_COUNT * sizeof(Item));
+  int index = 0;
+  double *elem = nullptr;
+
+  fseek(fp, 0, SEEK_END);
+
+  long length = (long)ftell(fp);
+
+  fseek(fp, 0, SEEK_SET);
+
+  char *text = (char *)malloc(length + 1);
+  memset(text, 0, length + 1);
+
+  fread(text, 1, length, fp);
+
+  clock_t start_time = clock();
+
+  const char *delim = "{}[]:,\"\n ";
+
+  char *token = strtok(text, delim);
+
+  while (token) {
+    if (strcmp(token, "x0") == 0) {
+      elem = &(items[index].x0);
+    } else if (strcmp(token, "y0") == 0) {
+      elem = &(items[index].y0);
+    } else if (strcmp(token, "x1") == 0) {
+      elem = &(items[index].x1);
+    } else if (strcmp(token, "y1") == 0) {
+      elem = &(items[index].y1);
+      ++index;
+    } else {
+      if (elem) {
+        char *end = &(token[strlen(token)]);
+        *elem = strtod(token, &end);
+        elem = nullptr;
+      }
+    }
+
+    token = strtok(NULL, delim);
+  }
+
+  clock_t mid_time = clock();
+
+  double sum = 0.0;
+
+  for (int i = 0; i < ITEM_COUNT; ++i) {
+    sum += haversine_of_degrees(items[i].x0, items[i].y0, items[i].x1,
+                                items[i].y1, EARTH_RADIUS_KM);
+  }
+
+  double average = sum / ITEM_COUNT;
+
+  clock_t end_time = clock();
+
+  printf("Result: %.16f\n", average);
+  printf("Input = %.16f seconds\n",
+         (double)(mid_time - start_time) / CLOCKS_PER_SEC);
+  printf("Math = %.16f seconds\n",
+         (double)(end_time - mid_time) / CLOCKS_PER_SEC);
+  printf("Total = %.16f seconds\n",
+         (double)(end_time - start_time) / CLOCKS_PER_SEC);
+  printf("Throughput = %.16f haversines/second\n",
+         ITEM_COUNT / ((double)(end_time - start_time) / CLOCKS_PER_SEC));
+
+#if DEBUG
+  int precision = 16;
+  for (int i = 0; i < ITEM_COUNT; ++i) {
+    printf("%.*f\n%.*f\n%.*f\n%.*f\n\n", precision, items[i].x0, precision,
+           items[i].y0, precision, items[i].x1, precision, items[i].y1);
+  }
+#endif
+
+  free(text);
+
+  free(items);
+
+  fclose(fp);
+
+  return 0;
+}