C++ reads the sample code for the configuration file

The code address

https://github.com/gongluck/Code-snippet/tree/master/cpp/config

demand

In development, reading configuration file information is essential. The Windows platform is readily available and convenient. However, once the project was moved to Linux, the original code under Windows became invalid. Therefore, the realization of a set of cross-platform configuration file reading function code can save a lot of labor.

implementation

ini_parser, which relies on boost, enables cross-platform reading of configuration files in ini format.

// config.h
/*
 * @Author: gongluck 
 * @Date: 2020-03-23 15:11:50 
 * @Last Modified by: gongluck
 * @Last Modified time: 2020-03-23 15:17:58
 */

// Profile read, dependent on boost

#pragma once

#include <iostream>
#include <vector>
#include <boost/property_tree/ptree.hpp>

namespace gconf
{
class config
{
public:
  int open(const char *configfile);
  template <typename T>
  int read(const char *session, const char *key, T &value, const char *configfile = nullptr)
  {
    if (configfile != nullptr && open(configfile) != 0)
    {
      return -1;
    }

    try
    {
      auto lvbtItems = lvptProperties_.get_child(session);
      value = lvbtItems.get<T>(key);
    }
    catch (std::exception &e)
    {
      std::cerr << __FILE__ << " : " << __LINE__ << " : " << e.what() << std::endl;
      return -1;
    }

    return 0;
  }
  int readall(const char *session,
        std::vector<std::pair<std::string, std::string>> &results,
        const char *configfile = nullptr);

private:
  boost::property_tree::ptree lvptProperties_;
};
} // namespace gconf

// config.cpp
/*
 * @Author: gongluck 
 * @Date: 2020-03-23 15:13:13 
 * @Last Modified by: gongluck
 * @Last Modified time: 2020-03-23 15:17:56
 */

#include "config.h"
#include <boost/property_tree/ini_parser.hpp>

namespace gconf
{
int config::open(const char *configfile)
{
  if (configfile == nullptr)
  {
    return -1;
  }

  try
  {
    boost::property_tree::ini_parser::read_ini(configfile, lvptProperties_);
  }
  catch (std::exception &e)
  {
    std::cerr << __FILE__ << " : " << __LINE__ << " : " << e.what() << std::endl;
    return -1;
  }

  return 0;
}

int config::readall(const char *session,
          std::vector<std::pair<std::string, std::string>> &results,
          const char *configfile /*= nullptr*/)
{
  if (configfile != nullptr && open(configfile) != 0)
  {
    std::cerr << __FILE__ << " : " << __LINE__ << " : "
         << " can not open " << configfile << std::endl;
    return -1;
  }

  try
  {
    auto lvbtItems = lvptProperties_.get_child(session);
    for (const auto &i : lvbtItems)
    {
      results.push_back(std::make_pair(i.first.data(), i.second.data()));
    }
  }
  catch (std::exception &e)
  {
    std::cerr << __FILE__ << " : " << __LINE__ << " : " << e.what() << std::endl;
    return -1;
  }

  return 0;
}
} // namespace gconf

// testcode
#include <iostream>

#include "../config/config.h"

#define CHECKRET(ret)\
if(ret != 0)\
{\
  std::cin.get();\
  return ret;\
}

int main()
{
  gconf::config conf;
  auto ret = conf.open("./config.ini");
  CHECKRET(ret);
  int file = 0;
  ret = conf.read<int>("log", "file", file);
  CHECKRET(ret);
  std::vector<std::pair<std::string, std::string>>kvs;
  ret = conf.readall("log", kvs);
  CHECKRET(ret);
  return 0;
}

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