Function select

include/jsoncons_ext/jsonpath/path_node.hpp:227–266

    template <typename Json>
    Json* select(Json& root, const basic_path_node<typename Json::char_type>& path)
    {
        using path_node_type = basic_path_node<typename Json::char_type>;

        std::vector<const path_node_type*> nodes(path.size(), nullptr);
        std::size_t len = nodes.size();
        const path_node_type* p = std::addressof(path);
        while (p != nullptr)
        {
            nodes[--len] = p;
            p = p->parent();
        }

        Json* current = std::addressof(root);
        for (auto node : nodes)
        {
            if (node->node_kind() == path_node_kind::index)
            {
                if (current->type() != json_type::array || node->index() >= current->size())
                {
                    return nullptr; 
                }
                current = std::addressof(current->at(node->index()));
            }
            else if (node->node_kind() == path_node_kind::name)
            {
                if (current->type() != json_type::object)
                {
                    return nullptr;
                }
                auto it = current->find(node->name());
                if (it == current->object_range().end())
                {
                    return nullptr;
                }
                current = std::addressof((*it).value());
            }
        }
        return current;
    }

    template <typename CharT,typename Allocator=std::allocator<CharT>>
    std::basic_string<CharT,std::char_traits<CharT>,Allocator> to_basic_string(const basic_path_node<CharT>& path, const Allocator& alloc=Allocator())