How to serialize unique_ptr<char[]> in struct - c++

Question

I haven't been able to find any docs on how to serialize a unique_ptr to an array. Any help would be great.
struct Counter{
int index;
unique_ptr<char []> name;
template<class Archive>
void serialize(Archive & archive){
archive(index, name ); // serialize things by passing them to the archive
}
};
How it is assigned.
auto buffer = std::unique_ptr<char[]>(new char[BUFFER_SIZE]);
instance.name = std::move(buffer);

Answer 1

You can do it, but it needs some extra work. It differs depending on the type of the archive.
For text-based archives (e.g., XMLOutputArchive/XMLInputArchive and JSONOutputArchive/JSONInputArchive) you can use the saveBinaryValue() / loadBinaryValue() (http://uscilab.github.io/cereal/assets/doxygen/classcereal_1_1JSONOutputArchive.html).
Here's a complete example:
#include <iostream>
#include <memory>
#include <cereal/archives/xml.hpp>
#include <cereal/cereal.hpp>
struct Counter
{
static constexpr std::size_t BUFFER_SIZE = 12;
int index{};
std::unique_ptr<char[]> name;
Counter() = default;
Counter(int i)
: index{i},
name{new char[BUFFER_SIZE]}
{}
template<class Archive>
void load(Archive& archive)
{
archive(index);
name.reset(new char[BUFFER_SIZE]);
archive.loadBinaryValue(name.get(), BUFFER_SIZE * sizeof(decltype(name[0])));
}
template<class Archive>
void save(Archive& archive) const
{
archive(index);
archive.saveBinaryValue(name.get(), BUFFER_SIZE * sizeof(decltype(name[0])));
}
};
int main()
{
cereal::XMLOutputArchive archive(std::cout);
Counter c(42);
archive(CEREAL_NVP(c));
}
If you are using BinaryOutputArchive / BinaryInputArchive or PortableBinaryOutputArchive / PortableBinaryInputArchive the functions become saveBinary() and loadBinary() (http://uscilab.github.io/cereal/assets/doxygen/classcereal_1_1PortableBinaryOutputArchive.html).
For those, you can also wrap your array using binary_data():
template<class Archive>
void save(Archive& archive) const
{
archive(index, cereal::binary_data(name.get(), BUFFER_SIZE));
}