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#ifndef CAR_HELPERS_H
#define CAR_HELPERS_H
#include <iomanip>
#include <random>
#include <sstream>
#include <vector>
#include <simdjson.h>
struct Car {
std::string make;
std::string model;
int64_t year; // We deliberately do not include the tire pressure.
};
using namespace simdjson;
std::string random_car_json() {
static const std::vector<std::string> makes = {"Toyota", "Honda", "Ford",
"BMW", "Mazda"};
static const std::vector<std::string> models = {"Camry", "Civic", "Focus",
"320i", "3"};
static thread_local std::mt19937 rng{std::random_device{}()};
std::uniform_int_distribution<int> make_dist(0, makes.size() - 1);
std::uniform_int_distribution<int> model_dist(0, models.size() - 1);
std::uniform_int_distribution<int> year_dist(2000, 2025);
std::uniform_real_distribution<double> pressure_dist(30.0, 45.0);
std::ostringstream oss;
oss << R"({ "make": ")" << makes[make_dist(rng)] << R"(", "model": ")"
<< models[model_dist(rng)] << R"(", "year": )" << year_dist(rng)
<< R"(, "tire_pressure": [ )" << std::fixed << std::setprecision(1)
<< pressure_dist(rng) << ", " << pressure_dist(rng) << R"( ] })";
return oss.str();
}
std::string generate_car_json_stream(size_t N) {
std::ostringstream oss;
for (size_t i = 0; i < N; ++i) {
oss << random_car_json();
oss << "\n";
}
return oss.str();
}
std::string generate_car_json_array(size_t N) {
std::ostringstream oss;
oss << "[\n";
for (size_t i = 0; i < N; ++i) {
oss << random_car_json();
if (i < N - 1) {
oss << ",";
}
oss << "\n";
}
oss << "]";
return oss.str();
}
// We want to maximize C++ portability, but this is not needed with static
// reflection (C++26).
template <>
simdjson_inline simdjson_result<Car>
simdjson::ondemand::document::get() & noexcept {
ondemand::object obj;
auto error = get_object().get(obj);
if (error) {
return error;
}
Car car;
if ((error = obj["make"].get_string(car.make))) {
return error;
}
if ((error = obj["model"].get_string(car.model))) {
return error;
}
if ((error = obj["year"].get_int64().get(car.year))) {
return error;
}
return car;
}
template <>
simdjson_inline simdjson_result<Car> simdjson::ondemand::value::get() noexcept {
ondemand::object obj;
auto error = get_object().get(obj);
if (error) {
return error;
}
Car car;
if ((error = obj["make"].get_string(car.make))) {
return error;
}
if ((error = obj["model"].get_string(car.model))) {
return error;
}
if ((error = obj["year"].get_int64().get(car.year))) {
return error;
}
return car;
}
template <>
simdjson_inline simdjson_result<Car>
simdjson::ondemand::document_reference::get() & noexcept {
ondemand::object obj;
auto error = get_object().get(obj);
if (error) {
return error;
}
Car car;
if ((error = obj["make"].get_string(car.make))) {
return error;
}
if ((error = obj["model"].get_string(car.model))) {
return error;
}
if ((error = obj["year"].get_int64().get(car.year))) {
return error;
}
return car;
}
template <>
simdjson_inline simdjson_result<Car>
simdjson::ondemand::document_reference::get() && noexcept {
ondemand::object obj;
auto error = get_object().get(obj);
if (error) {
return error;
}
Car car;
if ((error = obj["make"].get_string(car.make))) {
return error;
}
if ((error = obj["model"].get_string(car.model))) {
return error;
}
if ((error = obj["year"].get_int64().get(car.year))) {
return error;
}
return car;
}
#endif
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