ReadWriteFile_class_binary.md

Read/write in files

Binary file

For binary reading and writing to files, the type must either have the following methods implemented:

• bool readB(std::ifstream& _input_file)

• void writeB(std::ofstream& _output_file) const

or have the following template functions specialized;

• template bool slv::rw::readB(T& _value, std::ifstream& _input_file);

• template void slv::rw::writeB(const T& _value, std::ofstream& _output_file);

Specializations for common types and containers are provided at this page.

class ClassA {

private:

    float value1 = 20;
    std::string value2 = "foo";

public:

    ClassA() {}

    bool readB(std::ifstream& _input_file) {
        bool l_read = slv::rw::readB(value1, _input_file);
        if (l_read) l_read = slv::rw::readB(value2, _input_file);
        return l_read;
    }

    void writeB(std::ofstream& _output_file) const {
        slv::rw::writeB(value1, _output_file);
        slv::rw::writeB(value2, _output_file);
    }

};

To write and read the instance:

ClassA classA;
SlvFileMgr::write_binary(classA, "classA");//write to file ./classA
SlvFileMgr::read_binary(classA, "classA");//read from file ./classA

The instance is written/read to the file. Then the file is closed. i.e. the file only contains classA output.

More details can be found in sample007_0.cpp.

Remark

The read and write methods being public, they can be called to provide instance read/write independently from file opening/closing. See this example.