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fastcsv

A simple and fast c++20 csv library

Basic Example

Data Structure

Create a basic structure that represents the lines of data

struct my_data
{
    int id;
    std::string name;
    std::string description;
};

Mappers

Template specializations of the mappers fastcsv::to_csv<T> and fastcsv::from_csv<T> are required to map data to csv files and vice-versa

Implementations of fastcsv::to_csv<T> must inherit from fastcsv::csv_writer which gives access to the helper write() method

template <>
struct fastcsv::to_csv<my_data> final : fastcsv::csv_writer
{
    void operator()(const my_data & data)
    {
        write(data.id);
        write(data.name);
        write(data.description);
    }
};

Implementations of fastcsv::from_csv<T> must inherit from fastcsv::csv_reader which gives access to the helper read<T>() methods

template <>
struct fastcsv::from_csv<my_data> final : fastcsv::csv_reader
{
    [[nodiscard]] my_data operator()() const
    {
        return my_data{ read<int>), read<std::string>(), read<std::string>() };
    }
};

Headers

using namespace std::string_view_literals;

template <>
struct fastcsv::csv_headers<my_data> final
{
    [[nodiscard]] constexpr std::vector<std::string_view> operator() const noexcept
    {
        return std::vector{ "id"sv, "name"sv, "description"sv };
    }
};

Usage

void example()
{
    std::vector<my_data> data1 = fastcsv::load_csv<my_data>("path/to/data.csv");
    std::vector<my_data> data2 = fastcsv::load_csv<my_data>("path/to/data-no-headers.csv", fastcsv::no_header);

    std::string csv = fastcsv::write_csv(dat1);
    std::string csvNoHeaders = fastcsv::write_csv(dat1, fastcsv::no_header);

    auto data3 = fastcsv::read_csv<my_data>(csv);
    auto data4 = fastcsv::read_csv<my_data>(csv, fastcsv::no_header);

    fastcsv::save_csv("path/to/data.csv", data3);
    fastcsv::save_csv("path/to/data-no-headers.csv", data3, fastcsv::no_header);
}