C++读取配置文件

代码地址

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

需求

开发中，读取配置文件信息必不可少。Windows平台有现成的API可用，也很方便。但是一旦项目迁移到Linux平台下，原先在Windows平台下的代码就全部作废。所以，实现一套跨平台的配置文件读取功能代码可以节省不少的劳动力。

实现

依赖于boost的ini_parser，可以实现跨平台读取ini格式的配置文件。

// 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;
}