CODEWITHSUNDEEP
c++xmlboost
harshini
harshini

Reputation: 59

xml parsing using boost

I am parsing below xml file using BOOST library- 

<da>
        <m_day Type="int">15</m_day>
        <m_month Type="int">8</m_month>
        <m_year Type="int">1947</m_year>
</da>

My cpp code is :

    #include <boost/archive/xml_oarchive.hpp> 
    #include <boost/archive/xml_iarchive.hpp>
    #include <iostream> 
    #include <fstream> 

    typedef struct date { 
        unsigned int m_day;
        unsigned int m_month;
        unsigned int m_year;
        date( int d,  int m,  int y) : m_day(d), m_month(m), m_year(y) 
        {}
        date() : m_day(1), m_month(1), m_year(2000) 
        {}
        friend std::ostream& operator << (std::ostream& out, date& d) 
        {
            out << "day: " << d.m_day 
                  << " month: " << d.m_month
        << " year: " << d.m_year;
            return out;
        }
        template<class Archive>
        void serialize(Archive& archive, const unsigned int version)
        {
        archive & BOOST_SERIALIZATION_NVP(m_day);
            archive & BOOST_SERIALIZATION_NVP(m_month);
            archive & BOOST_SERIALIZATION_NVP(m_year);
        }
    } date;

    BOOST_CLASS_IMPLEMENTATION(date, boost::serialization::object_serializable);//object_serializable);

    unsigned int flags =   boost::archive::no_header;


    int main()
    {

     std::ifstream file1("archive.xml");
     boost::archive::xml_iarchive ia(file1,flags);
     date dr;
     ia >> BOOST_SERIALIZATION_NVP(dr);


     std::ofstream file("archive2.xml");
      boost::archive::xml_oarchive oa(file,flags);
    //  date da(15, 8, 1947);
      oa & BOOST_SERIALIZATION_NVP(dr);


    return 0;
    }

I am getting below error :

terminate called after throwing an instance of 'boost::archive::archive_exception' what(): input stream error Aborted (core dumped)

for Normal xml without attributes(as mentioned below) the above code is working fine

<da>
        <m_day>15</m_day>
        <m_month>8</m_month>
        <m_year>1947</m_year>
</da>

But for previous xml file ,Is there any problem in code ? could you please let me know if it is possible with boost.i have searched so much to find the answer but failed to get any. Thanks in Advance !!!

Upvotes: 2

Views: 1891

Answers (2)

sehe
sehe

Reputation: 392931

Boost Serialization is not an XML library.

Boost Archive xml_[io]archive isn't an XML library either.

Heck, not even Boost Property Tree is an XML library.

In short: Boost Does Not Contain An XML Library.

Slightly longer: you can use Boost Property Tree to parse your XML. It's using a derivative of RapidXML under the hood and you can read/write fairly generic XML documents using Boost Property Tree.

In reality, the Property Tree interface is quite specific and often leads to confusion. There's not a lot of control.

If you care about your XML support (namespaces? whitespace? ordering? PCDATA? Processing instructions? XPath? Encodings? ...) please consider using an XML library (What XML parser should I use in C++?)

Bonus: sample with Boost Property Tree

Here's how to do it with Boost Property Tree

Live On Coliru

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

typedef struct date { 
    unsigned int m_day;
    unsigned int m_month;
    unsigned int m_year;
    date( int d=1,  int m=1,  int y=2000) : m_day(d), m_month(m), m_year(y) {}

    friend std::ostream& operator << (std::ostream& out, date& d) {
        return out << "day: " << d.m_day << " month: " << d.m_month << " year: " << d.m_year;
    }

    void load(boost::property_tree::ptree const& pt)
    {
        m_day = pt.get("da.m_day", 1);
        m_month = pt.get("da.m_month", 1);
        m_year = pt.get("da.m_year", 2000);
    }
} date;

#include <sstream>

int main() {
    std::istringstream iss("<da>\n"
                "<m_day Type=\"int\">15</m_day>\n"
                "<m_month Type=\"int\">8</m_month>\n"
                "<m_year Type=\"int\">1947</m_year>\n"
                "</da>\n");

    boost::property_tree::ptree pt;
    read_xml(iss, pt);

    date d;
    d.load(pt);

    std::cout << d << "\n";
}

Prints

day: 15 month: 8 year: 1947

Upvotes: 3

John Zwinck
John Zwinck

Reputation: 249143

Boost Serialization does not support writing XML attributes, and apparently doesn't support reading them either, or even ignoring them. One of the authors wrote about this here: http://boost.2283326.n4.nabble.com/serialization-How-to-serialize-as-an-XML-attribute-td2557918.html

You could pre-process the XML before loading it, using another XML library like Expat or whatever.

Upvotes: 1

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