Saving and loading a class state from and to steam c++ - c++

Question

I'm trying to figure out how to save and load an objects state to a binary stream. For context, we currently have this working but only a 'save-to-file' implementation. However, we want the serialization done in-memory to better interact with some parallelization libraries. I'm hoping this will be quite simple but my current implementation doesn't do much - can anybody spot what I'm doing wrong?
class ForSerializationAsBinary {
public:
ForSerializationAsBinary() = default;
explicit ForSerializationAsBinary(int number)
: number_(number) {}
std::ostringstream toBinaryStream() {
std::ostringstream out(std::ios::binary);
out.write((char *) &number_, sizeof(int));
return out;
}
static void fromBinaryStream(ForSerializationAsBinary &obj, std::ostringstream &os) {
int n;
std::istringstream is(std::ios::binary);
is.basic_ios<char>::rdbuf(os.rdbuf());
is.read((char *) &n, sizeof(int));
std::cout << "n: " << n << std::endl;
obj.number_ = n;
}
int number_;
};
TEST(Serialisation, SimpleSerialization) {
ForSerializationAsBinary serializationAsBinary(4);
auto o = serializationAsBinary.toBinaryStream();
ForSerializationAsBinary loaded;
ForSerializationAsBinary::fromBinaryStream(loaded, o);
std::cout << "loaded.number_: " << loaded.number_ << std::endl;
}
And the current output of the test
n: 0
loaded.number_: 0

Answer 1

Looks like I found the answer : just use a std::stringstream instead of the o or i versions:
class ForSerializationAsBinary {
public:
ForSerializationAsBinary() = default;
explicit ForSerializationAsBinary(int number)
: number_(number) {}
std::stringstream toBinaryStream() {
std::stringstream out(std::ios::binary);
out.write((const char *) &number_, sizeof(int));
return out;
}
static void fromBinaryStream(ForSerializationAsBinary &obj, std::stringstream &os) {
int n;
os.read((char *) &n, sizeof(int));
std::cout << "n: " << n << std::endl;
obj.number_ = n;
}
int number_;
};