AndreyBarmaley/jsmn-cpp

json wrapper c++

JSON C++ Wrapper

This is a simpe C++ interface over JSMN parser

How to use it

read file content

SWE::JsonContentFile jc(file);

or string content

SWE::JsonContentString jc(str);

determine type array or object

if(jc.isObject())
{
    // JsonObject type
    auto jo = jc.toObject();
}
else
if(jc.isArray())
{
    // JsonArray type
    auto ja = jc.toArray();
}
else
    throw std::runtime_error("not json");

parse primitives for

std::cout << "variant 1 -" << std::endl;
for(auto & key : jo.keys())
{
    auto type = jo.getType(key);
    std::cout << key << ": ";

    switch(type)
    {
        case JsonType::Null:        std::cout << "null"; break;
        case JsonType::Integer:     std::cout << jo.getInteger(key); break;
        case JsonType::Double:      std::cout << jo.getDouble(key); break;
        case JsonType::String:      std::cout << jo.getString(key); break;
        case JsonType::Boolean:     std::cout << std::boolalpha << jo.getBoolean(key); break;
        case JsonType::Object:      std::cout << "skip object"; break;
        case JsonType::Array:       std::cout << "skip array"; break;
        default: break;
    }
    std::cout << std::endl;
}

std::cout << "variant 2 -" << std::endl;
for(auto & key : jo.keys())
{
    auto jv = jo.getValue(key)
    std::cout << key << ": ";

    switch(jv->getType())
    {
        case JsonType::Null:        std::cout << jv->toString(); break;
        case JsonType::Integer:     std::cout << jv->getInteger(); break;
        case JsonType::Double:      std::cout << jv->getDouble(); break;
        case JsonType::String:      std::cout << jv->getString(); break;
        case JsonType::Boolean:     std::cout << std::boolalpha << jv->getBoolean(); break;
        case JsonType::Object:      std::cout << "skip object"; break;
        case JsonType::Array:       std::cout << "skip array"; break;
        default: break;
    }
    std::cout << std::endl;
}

// if the key value is already known
auto val1 = jo.getString("key1", "default value1");
auto val2 = jo.getInteger("key2", 123);
auto val3 = jo.getInteger("key3");

parse primitives for

std::cout << "base variant -" << std::endl;
for(int it = 0; it < ja.size(); ++it)
{
    auto jv = ja.getValue(it);
    switch(jv->getType())
    {
        case JsonType::Null:        std::cout << jv->toString(); break;
        case JsonType::Integer:     std::cout << jv->getInteger(); break;
        case JsonType::Double:      std::cout << jv->getDouble(); break;
        case JsonType::String:      std::cout << jv->getString(); break;
        case JsonType::Boolean:     std::cout << std::boolalpha << jv->getBoolean(); break;
        case JsonType::Object:      std::cout << "skip object"; break;
        case JsonType::Array:       std::cout << "skip array"; break;
        default: break;
    }
    std::cout << std::endl;
}

// convert JsonArray to std::vector
std::cout << "convert to int vector" << std::endl;
for(auto & val : ja.toStdVector<int>())
    std::cout << val ", ";
std::cout << std::endl;

// convert JsonArray to std::list
std::cout << "convert to string list" << std::endl;
for(auto & val : ja.toStdList<std::string>())
    std::cout << val ", ";
std::cout << std::endl;

// stream variant
double val1;
std::string val2;
int val3;
ja >> val1 >> val2 >> val3;

API Documentation: https://andreybarmaley.github.io/jsmn-cpp/html/annotated.html