使用来自流的 boost binary_iarchive 序列化和反序列化

Posted 2023-02-21

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【中文标题】使用来自流的 boost binary_iarchive 序列化和反序列化【英文标题】：serialize and deserialise using boost binary_iarchive from sstream 【发布时间】：2017-03-28 20:42:35 【问题描述】：

最后，经过一番努力，我找到了一种对std::map<int,map<int,structute values> 进行序列化和反序列化的方法，并且我能够打印这些值。

请您澄清一下我对以下代码的疑问

void serialize(archive & ar, const unsigned int version) 函数是否同时用于序列化和反序列化

我们能否在每个类和结构中为序列化和反序列化设置单独的函数

同样的函数也可以用于创建 xml 吗，或者它是一种为 xml 提供单独的序列化和反序列化功能的好方法

 #include <boost/archive/binary_oarchive.hpp>
 #include <boost/archive/binary_iarchive.hpp>
 #include <boost/serialization/binary_object.hpp>
 #include <boost/serialization/serialization.hpp>
 #include <iostream>
 #include <string>
 #include <iomanip>
 #include <sstream>
 #include <map>
 #include <boost/serialization/map.hpp>
   
struct values

    std::string name;
    std::string sex;
    values():name("dummy"),sex("dummy") ;
    template<class archive>
    void serialize(archive & ar,  const unsigned int version)
    
      ar & name ;
      ar & sex ;
    
;
class Myclass 

public:
    
  Myclass()
  
    values val1;
    e_group.insert( std::make_pair(1,val1) ) ;
    e_group.insert( std::make_pair(2,val1) ) ;
    p_group.insert( std::make_pair(1,e_group) ) ;
    p_group.insert( std::make_pair(2,e_group) ) ;
  
  template<class archive>
  void serialize(archive & ar,  const unsigned int version)
  
    ar & e_group ;
    ar & p_group;
  
  typedef   std::map<int,values> groups;
  typedef   std::map<int,groups> Pgroups;
  groups  e_group;
  Pgroups p_group;
;

int main() 
    char buf[256];

    Myclass obj;

    std::stringstream os(std::ios_base::binary| std::ios_base::out| std::ios_base::in);
    
        boost::archive::binary_oarchive oa(os, boost::archive::no_header);
        oa << obj ;
      // oa << make_binary_object(&e_group, sizeof(e_group));
    
   
   //print binary data
    std::string data = os.str();
    for (uint8_t ch : data) 
        std::cout << std::hex << std::setw(2) << std::setfill('0') << static_cast<int>(ch) << " ";
    
    


    Myclass t2;
           
        memcpy(buf, os.str().data(), os.str().length());
        if(memcmp(buf, os.str().data(), os.str().length()) != 0)
          printf("memcpy error\n");
        std::stringstream is(std::string(buf, buf+os.str().length() ), std::ios_base::binary| std::ios_base::out| std::ios_base::in);
        boost::archive::binary_iarchive ia(is, boost::archive::no_header);
        ia >> t2;
    

   for(auto &i:t2.p_group)
       std::cout<<"\n"<<i.first<<"\n";
        for(auto &j:i.second)
          std::cout<<"\t"<<j.first<<"\t"<<j.second.name<<"\t"<<j.second.sex<<"\n";
        
    
   return 0;

更新：我更新了 Richard 的代码并添加了一个函数来反序列化二进制文件

#include <boost/archive/binary_oarchive.hpp>
#include <boost/archive/xml_oarchive.hpp>
#include <boost/archive/binary_iarchive.hpp>
#include <boost/serialization/binary_object.hpp>
#include <boost/serialization/serialization.hpp>
#include <boost/serialization/nvp.hpp>
#include <iostream>
#include <string>
#include <iomanip>
#include <sstream>
#include <fstream>

#include <map>
#include <boost/serialization/map.hpp>
#include <boost/serialization/split_member.hpp>


struct values

    std::string name;
    std::string sex;
    values():name("dummy"),sex("dummy") ;

    BOOST_SERIALIZATION_SPLIT_MEMBER();

    template<class Archive>
    void save(Archive & ar, const unsigned int version) const
    
        // note, version is always the latest when saving
        ar & BOOST_SERIALIZATION_NVP(name);
        ar & BOOST_SERIALIZATION_NVP(sex);
    
    template<class Archive>
    void load(Archive & ar, const unsigned int version)
    
        ar & BOOST_SERIALIZATION_NVP(name);
        ar & BOOST_SERIALIZATION_NVP(sex);
    
;
class Myclass

public:

    Myclass()
    
        values val1;
        e_group.insert( std::make_pair(1,val1) ) ;
        e_group.insert( std::make_pair(2,val1) ) ;
        p_group.insert( std::make_pair(1,e_group) ) ;
        p_group.insert( std::make_pair(2,e_group) ) ;
    

    BOOST_SERIALIZATION_SPLIT_MEMBER();

    template<class Archive>
    void save(Archive & ar, const unsigned int version) const
    
        // note, version is always the latest when saving
        ar & BOOST_SERIALIZATION_NVP(e_group);
        ar & BOOST_SERIALIZATION_NVP(p_group);
    
    template<class Archive>
    void load(Archive & ar, const unsigned int version)
    
        ar & BOOST_SERIALIZATION_NVP(e_group);
        ar & BOOST_SERIALIZATION_NVP(p_group);
    

    typedef   std::map<int,values> groups;
    typedef   std::map<int,groups> Pgroups;
    groups  e_group;
    Pgroups p_group;
;

template<class Archive, class Object>
std::string serialise_to_string(Object const& assetlist)

    auto os = std::ostringstream(std::ios::binary);
    Archive arch  os, boost::archive::no_header ;
    arch << BOOST_SERIALIZATION_NVP(assetlist);
    return os.str();
;


std::ostream& dump(std::ostream& os, std::string const& s)

    const char *sep = "";
    for (uint8_t ch : s) 
        std::cout << sep << std::hex << std::setw(2) << std::setfill('0') << static_cast<int>(ch);
        sep = " ";
    
    return os;


template<class Archive , class Object>
void deserialise_to_obj(std::string const &s1,Object &outObj)

    std::stringstream is( s1, std::ios_base::binary| std::ios_base::out| std::ios_base::in);
    Archive arch  is, boost::archive::no_header ;
    arch >> BOOST_SERIALIZATION_NVP(outObj);
;


int main() 
    
    Myclass obj ;
    std::string  s1 = serialise_to_string<boost::archive::binary_oarchive>(obj);
    dump(std::cout, s1) << std::endl << std::endl;
    
    auto s2 = serialise_to_string<boost::archive::xml_oarchive>(obj);
   
   //Save xml to a file
    std::ofstream ofs("output.xml");
    ofs << s2 << std::endl << std::endl;
    
    //Deserialize the binary data to object
    Myclass outObj;
    deserialise_to_obj<boost::archive::binary_iarchive>(s1,outObj); 
    
    //Print the object 
    for(auto &i:outObj.p_group)
       std::cout<<"\n"<<i.first<<"\n";
        for(auto &j:i.second)
          std::cout<<"\t"<<j.first<<"\t"<<j.second.name<<"\t"<<j.second.sex<<"\n";

使用coliru编译的代码

请建议。如果我的方法是错误的，请告诉我

我要感谢 @sehe 和 @richard 帮助我提升。

谢谢光辉

【问题讨论】：

【参考方案1】：

首先，不要这样做：

    memcpy(buf, os.str().data(), os.str().length());
    if(memcmp(buf, os.str().data(), os.str().length()) != 0)

这只是创建了 4 个单独的字符串副本。

现在问题：

是 void serialize(archive & ar, const unsigned int version) 函数同时用于序列化和反序列化

是的

我们能否在每个类和结构中为序列化和反序列化设置单独的函数

是的

同样的函数也可以用于创建 xml 吗，或者它是一种为 xml 提供单独的序列化和反序列化功能的好方法

是的

您需要xml_oarchive 和宏BOOST_SERIALIZATION_SPLIT_MEMBER 和BOOST_SERIALIZATION_NVP

#include <boost/archive/binary_oarchive.hpp>
#include <boost/archive/xml_oarchive.hpp>
#include <boost/archive/binary_iarchive.hpp>
#include <boost/serialization/binary_object.hpp>
#include <boost/serialization/serialization.hpp>
#include <boost/serialization/nvp.hpp>
#include <iostream>
#include <string>
#include <iomanip>
#include <sstream>
#include <map>
#include <boost/serialization/map.hpp>
#include <boost/serialization/split_member.hpp>


struct values

    std::string name;
    std::string sex;
    values():name("dummy"),sex("dummy") ;

    BOOST_SERIALIZATION_SPLIT_MEMBER();

    template<class Archive>
    void save(Archive & ar, const unsigned int version) const
    
        // note, version is always the latest when saving
        ar & BOOST_SERIALIZATION_NVP(name);
        ar & BOOST_SERIALIZATION_NVP(sex);
    
    template<class Archive>
    void load(Archive & ar, const unsigned int version)
    
        ar & BOOST_SERIALIZATION_NVP(name);
        ar & BOOST_SERIALIZATION_NVP(sex);
    
;
class Myclass

public:

    Myclass()
    
        values val1;
        e_group.insert( std::make_pair(1,val1) ) ;
        e_group.insert( std::make_pair(2,val1) ) ;
        p_group.insert( std::make_pair(1,e_group) ) ;
        p_group.insert( std::make_pair(2,e_group) ) ;
    

    BOOST_SERIALIZATION_SPLIT_MEMBER();

    template<class Archive>
    void save(Archive & ar, const unsigned int version) const
    
        // note, version is always the latest when saving
        ar & BOOST_SERIALIZATION_NVP(e_group);
        ar & BOOST_SERIALIZATION_NVP(p_group);
    
    template<class Archive>
    void load(Archive & ar, const unsigned int version)
    
        ar & BOOST_SERIALIZATION_NVP(e_group);
        ar & BOOST_SERIALIZATION_NVP(p_group);
    

    typedef   std::map<int,values> groups;
    typedef   std::map<int,groups> Pgroups;
    groups  e_group;
    Pgroups p_group;
;

template<class Archive, class Object>
std::string serialise_to_string(Object const& o)

    auto os = std::ostringstream(std::ios::binary);
    Archive arch  os, boost::archive::no_header ;
    arch << BOOST_SERIALIZATION_NVP(o);
    return os.str();
;

std::ostream& dump(std::ostream& os, std::string const& s)

    const char *sep = "";
    for (uint8_t ch : s) 
        std::cout << sep << std::hex << std::setw(2) << std::setfill('0') << static_cast<int>(ch);
        sep = " ";
    
    return os;


int main() 
    char buf[256];

    Myclass obj;

    auto s1 = serialise_to_string<boost::archive::binary_oarchive>(obj);
    dump(std::cout, s1) << std::endl << std::endl;

    auto s2 = serialise_to_string<boost::archive::xml_oarchive>(obj);
    std::cout<< s2 << std::endl << std::endl;

    return 0;

示例输出：

00 00 00 00 00 00 00 00 00 00 02 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 00 00 00 00 00 00 00 05 00 00 00 00 00 00 00 64 75 6d 6d 79 05 00 00 00 00 00 00 00 64 75 6d 6d 79 02 00 00 00 05 00 00 00 00 00 00 00 64 75 6d 6d 79 05 00 00 00 00 00 00 00 64 75 6d 6d 79 00 00 00 00 00 02 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 01 00 00 00 02 00 00 00 00 00 00 00 00 00 00 00 01 00 00 00 05 00 00 00 00 00 00 00 64 75 6d 6d 79 05 00 00 00 00 00 00 00 64 75 6d 6d 79 02 00 00 00 05 00 00 00 00 00 00 00 64 75 6d 6d 79 05 00 00 00 00 00 00 00 64 75 6d 6d 79 02 00 00 00 02 00 00 00 00 00 00 00 00 00 00 00 01 00 00 00 05 00 00 00 00 00 00 00 64 75 6d 6d 79 05 00 00 00 00 00 00 00 64 75 6d 6d 79 02 00 00 00 05 00 00 00 00 00 00 00 64 75 6d 6d 79 05 00 00 00 00 00 00 00 64 75 6d 6d 79

<o class_id="0" tracking_level="0" version="0">
    <e_group class_id="1" tracking_level="0" version="0">
        <count>2</count>
        <item_version>0</item_version>
        <item class_id="2" tracking_level="0" version="0">
            <first>1</first>
            <second class_id="3" tracking_level="0" version="0">
                <name>dummy</name>
                <sex>dummy</sex>
            </second>
        </item>
        <item>
            <first>2</first>
            <second>
                <name>dummy</name>
                <sex>dummy</sex>
            </second>
        </item>
    </e_group>
    <p_group class_id="4" tracking_level="0" version="0">
        <count>2</count>
        <item_version>0</item_version>
        <item class_id="5" tracking_level="0" version="0">
            <first>1</first>
            <second>
                <count>2</count>
                <item_version>0</item_version>
                <item>
                    <first>1</first>
                    <second>
                        <name>dummy</name>
                        <sex>dummy</sex>
                    </second>
                </item>
                <item>
                    <first>2</first>
                    <second>
                        <name>dummy</name>
                        <sex>dummy</sex>
                    </second>
                </item>
            </second>
        </item>
        <item>
            <first>2</first>
            <second>
                <count>2</count>
                <item_version>0</item_version>
                <item>
                    <first>1</first>
                    <second>
                        <name>dummy</name>
                        <sex>dummy</sex>
                    </second>
                </item>
                <item>
                    <first>2</first>
                    <second>
                        <name>dummy</name>
                        <sex>dummy</sex>
                    </second>
                </item>
            </second>
        </item>
    </p_group>
</o>

【讨论】：

为什么要拆分加载/保存？实现是相同的，这使得它不必要的开销 @sehe 我认为这就是他要求的 - 是的，问题 2。他问“是否用于序列化和反序列化的 void serialize(archive & ar, const unsigned int version) 函数” - 答案是“是” 我也真的困惑你从哪里得到他“想要”xml档案的想法。（我碰巧从其他问题中知道他也想要这个，但这不是问题所在？） @sehe 那是 q1，我没有回答。

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