test_simdjson.cpp

#include <iostream>
#include <libnotify.h>

#include "simdjson.h"

#ifdef __clang__
static constexpr auto COMPILER = "clang++";
#else
static constexpr auto COMPILER = "g++";
#endif

using namespace std;

struct coordinate_t {
  double x;
  double y;
  double z;

  auto operator<=>(const coordinate_t &) const = default;

  friend ostream &operator<<(ostream &out, const coordinate_t &point) {
    out << "coordinate_t {x: " << point.x << ", y: " << point.y
        << ", z: " << point.z << "}";
    return out;
  }
};

using namespace simdjson;

class on_demand {
public:
  bool run(const padded_string &json);
  coordinate_t my_point{};
  size_t count{};

private:
  ondemand::parser parser{};
};

bool on_demand::run(const padded_string &json) {
  count = 0;
  auto doc = parser.iterate(json);
  for (ondemand::object point_object : doc["coordinates"]) {
    my_point.x += double(point_object["x"]);
    my_point.y += double(point_object["y"]);
    my_point.z += double(point_object["z"]);
    count++;
  }
  return true;
}

coordinate_t calc(const padded_string &json) {
  on_demand reader;
  reader.run(json);
  reader.my_point.x /= reader.count;
  reader.my_point.y /= reader.count;
  reader.my_point.z /= reader.count;
  return reader.my_point;
}

int main() {
  auto right = coordinate_t{2.0, 0.5, 0.25};
  // The _padded suffix creates a simdjson::padded_string instance
  for (const padded_string &v :
       {R"({"coordinates":[{"x":2.0,"y":0.5,"z":0.25}]})"_padded,
        R"({"coordinates":[{"y":0.5,"x":2.0,"z":0.25}]})"_padded}) {
    auto left = calc(v);
    if (left != right) {
      cerr << left << " != " << right << endl;
      exit(EXIT_FAILURE);
    }
  }

  padded_string text;
  const auto &error = padded_string::load("/tmp/1.json").get(text);
  if (error) {
    cerr << "could not load file" << endl;
    return EXIT_FAILURE;
  }

  const auto &results = notifying_invoke(
      [&]() { return calc(text); }, "C++/{} (simdjson On-Demand)", COMPILER);

  cout << results << endl;
}