Example: serialization_json_example

Example console output:

{
    "pose" :
    {
        "datatype" : "CPose2D",
        "phi" : 0,
        "version" : 1,
        "x" : 5,
        "y" : 6
    },
    "pose_pdf" :
    {
        "cov" :
        {
            "data" : "[0.000000e+00 0.000000e+00 0.000000e+00 ;0.000000e+00 0.000000e+00 0.000000e+00 ;0.000000e+00 0.000000e+00 0.000000e+00 ]",
            "datatype" : "CMatrixD",
            "ncols" : 3,
            "nrows" : 3,
            "version" : 1
        },
        "datatype" : "CPosePDFGaussian",
        "mean" :
        {
            "datatype" : "CPose2D",
            "phi" : 1.5707963267948966,
            "version" : 1,
            "x" : 1,
            "y" : 2
        },
        "version" : 1
    }
}
read pose:[5.000000 6.000000 0.000000deg]

C++ example source code:

/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2022, Individual contributors, see AUTHORS file     |
   | See: https://www.mrpt.org/Authors - All rights reserved.               |
   | Released under BSD License. See: https://www.mrpt.org/License          |
   +------------------------------------------------------------------------+ */
#include <iostream>  // cout
#include <sstream>  // stringstream

#include <mrpt/poses/CPosePDFGaussian.h>
#include <mrpt/serialization/CSchemeArchive.h>

#include <iostream>  // cout

void WriteAndReadExample()
{
    // Define the MRPT objects to be serialized:
    mrpt::poses::CPosePDFGaussian pdf1{
        mrpt::poses::CPose2D{1.0, 2.0, mrpt::DEG2RAD(90.0)},
        mrpt::math::CMatrixDouble33()};
    mrpt::poses::CPose2D p1{5.0, 6.0, mrpt::DEG2RAD(.0)};

    // --------------------
    // JSON Serialization
    // --------------------
    // Create a JSON archive:
    auto arch = mrpt::serialization::archiveJSON();

    // Writes the objects to the JSON archive:
    arch["pose_pdf"] = pdf1;
    arch["pose"] = p1;

    // Writes the JSON representation to an std::ostream
    std::stringstream ss;
    ss << arch;

    // also, print to cout for illustration purposes:
    std::cout << arch << std::endl;

    // --------------------
    // JSON Deserialization
    // --------------------
    // rewind stream for reading from the start
    ss.seekg(0);

    // Create a new JSON archive for reading
    auto arch2 = mrpt::serialization::archiveJSON();

    // Load the plain text representation into the archive:
    ss >> arch2;

    // Parse the JSON data into an MRPT object:
    mrpt::poses::CPosePDFGaussian pdf2;
    arch2["pose_pdf"].readTo(pdf2);
    mrpt::poses::CPose2D p2;
    arch2["pose"].readTo(p2);

    std::cout << "read pose:" << p2.asString() << std::endl;
}

int main(int argc, char** argv)
{
    try
    {
        WriteAndReadExample();
        return 0;
    }
    catch (const std::exception& e)
    {
        std::cerr << "MRPT error: " << mrpt::exception_to_str(e) << std::endl;
        return -1;
    }
    catch (...)
    {
        printf("Untyped exception!");
        return -1;
    }
}

#if 0  // code disabled, only present as an example for the docs:

#include <json/json.h>

void test()
{
    Json::Value val;
    auto arch = mrpt::serialization::CSchemeArchiveBase(
        std::make_unique<CSchemeArchive<Json::Value>>(val));

    mrpt::poses::CPose2D pt1{1.0, 2.0, 3.0};
    // Store any CSerializable object into the JSON value:
    arch = pt1;
    // Alternative:
    // arch["pose"] = pt1;

    std::stringstream ss;
    ss << val;
    std::cout << val << std::endl;
}


#endif