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//
// Copyright (c) 2021 Peter Dimov
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
// Official repository: https://github.com/boostorg/json
//
//
// An example that compares the performance of json::parse and
// json::parse_into, using https://github.com/kostya/benchmarks#json
//
// Typical results:
//
// 1.json: 115075437 bytes
// boost::json::parse: 721 ms
// x: -5.00335e-30, y: 5.00428e+30, z: 0.499722: 121 ms
// parse_into coordinates: 398 ms
// x: -5.00335e-30, y: 5.00428e+30, z: 0.499722: 3 ms
// parse_into coordinates2: 326 ms
// x: -5.00335e-30, y: 5.00428e+30, z: 0.499722: 0 ms
//
#include <boost/json.hpp>
#include <iostream>
#if !defined(BOOST_DESCRIBE_CXX14)
#include <boost/config/pragma_message.hpp>
BOOST_PRAGMA_MESSAGE( "This example requires C++14" )
int main() {}
#else
#include <boost/describe.hpp>
#include <chrono>
#include <fstream>
#include <iterator>
#include <map>
#include <vector>
// An std::map<std::string, std::pair<int, bool>> replacement
// We don't need to store the options
struct options
{
using mapped_type = std::pair<int, bool>;
using value_type = std::pair<std::string, mapped_type>;
using iterator = value_type*;
std::pair<iterator, bool>
emplace( value_type const& );
void
emplace( std::string const&, mapped_type const& )
{
}
iterator
begin();
iterator
end();
void
clear()
{ }
};
struct coordinate
{
double x{}, y{}, z{};
std::string name;
options opts;
};
BOOST_DESCRIBE_STRUCT(coordinate, (), (x, y, z, name, opts))
struct coordinates1
{
std::vector<coordinate> coordinates;
std::string info;
};
BOOST_DESCRIBE_STRUCT(coordinates1, (), (coordinates, info))
// std::vector<coordinate> replacement that just
// keeps a running sum
struct accumulator
{
using value_type = coordinate;
using iterator = coordinate*;
std::size_t len = 0;
double x = 0;
double y = 0;
double z = 0;
void push_back( coordinate const& v )
{
x += v.x;
y += v.y;
z += v.z;
++len;
}
iterator
begin() { return nullptr; }
iterator
end() { return nullptr; }
void
clear()
{ }
};
struct coordinates2
{
accumulator coordinates;
std::string info;
};
BOOST_DESCRIBE_STRUCT(coordinates2, (), (coordinates, info))
using namespace std::chrono_literals;
int main()
{
// https://github.com/kostya/benchmarks/blob/master/json/generate_json.rb
std::ifstream is( "/tmp/1.json" );
std::string json( std::istreambuf_iterator<char>( is ), std::istreambuf_iterator<char>{} );
std::cout << "1.json: " << json.size() << " bytes\n";
// https://github.com/kostya/benchmarks/blob/master/json/test_boost_json.cpp
{
auto tp1 = std::chrono::steady_clock::now();
boost::json::value jv = boost::json::parse( json );
auto tp2 = std::chrono::steady_clock::now();
std::cout << "boost::json::parse: " << (tp2 - tp1) / 1ms << " ms\n";
auto x = 0.0, y = 0.0, z = 0.0;
auto len = 0;
auto &obj = jv.get_object();
for( auto& v: obj["coordinates"].get_array() )
{
++len;
auto& coord = v.get_object();
x += coord["x"].get_double();
y += coord["y"].get_double();
z += coord["z"].get_double();
}
x /= len;
y /= len;
z /= len;
auto tp3 = std::chrono::steady_clock::now();
std::cout << " x: " << x << ", y: " << y << ", z: " << z << ": " << (tp3 - tp2) / 1ms << " ms\n";
}
{
auto tp1 = std::chrono::steady_clock::now();
coordinates1 w;
boost::system::error_code ec;
boost::json::parse_into( w, json, ec );
if( ec.failed() )
{
std::cout << "Error: " << ec.what() << std::endl;
}
auto tp2 = std::chrono::steady_clock::now();
std::cout << "parse_into coordinates: " << (tp2 - tp1) / 1ms << " ms\n";
auto x = 0.0, y = 0.0, z = 0.0;
auto len = 0;
for( auto const& v: w.coordinates )
{
x += v.x;
y += v.y;
z += v.z;
++len;
}
x /= len;
y /= len;
z /= len;
auto tp3 = std::chrono::steady_clock::now();
std::cout << " x: " << x << ", y: " << y << ", z: " << z << ": " << (tp3 - tp2) / 1ms << " ms\n";
}
{
auto tp1 = std::chrono::steady_clock::now();
coordinates2 w;
boost::system::error_code ec;
boost::json::parse_into( w, json, ec );
if( ec.failed() )
{
std::cout << "Error: " << ec.what() << std::endl;
}
auto tp2 = std::chrono::steady_clock::now();
std::cout << "parse_into coordinates2: " << (tp2 - tp1) / 1ms << " ms\n";
double x = w.coordinates.x / w.coordinates.len;
double y = w.coordinates.y / w.coordinates.len;
double z = w.coordinates.z / w.coordinates.len;
auto tp3 = std::chrono::steady_clock::now();
std::cout << " x: " << x << ", y: " << y << ", z: " << z << ": " << (tp3 - tp2) / 1ms << " ms\n";
}
}
#endif
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