SubscriptionArray.hpp

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#pragma once

#include <uORB/Subscription.hpp>

class SubscriptionArray
{
public:
    SubscriptionArray() = default;
    ~SubscriptionArray();

    template<class T>
    bool get(const struct orb_metadata *meta, uORB::Subscription<T> *&subscription, unsigned instance = 0);

    void update();

    void forcedUpdate();

private:
    void cleanup();

    bool resizeSubscriptions();

    uORB::SubscriptionNode **_subscriptions{nullptr};
    int _subscriptions_count{0}; 
    int _subscriptions_size{0}; 
};


template<class T>
bool SubscriptionArray::get(const struct orb_metadata *meta, uORB::Subscription<T> *&subscription, unsigned instance)
{
    // does it already exist?
    for (int i = 0; i < _subscriptions_count; ++i) {
        if (_subscriptions[i]->getMeta() == meta && _subscriptions[i]->getInstance() == instance) {
            // we know the type must be correct, so we can use reinterpret_cast (dynamic_cast is not available)
            subscription = reinterpret_cast<uORB::Subscription<T>*>(_subscriptions[i]);
            return true;
        }
    }

    // resize if needed
    if (_subscriptions_count >= _subscriptions_size) {
        if (!resizeSubscriptions()) {
            subscription = nullptr;
            return false;
        }
    }

    subscription = new uORB::Subscription<T>(meta, 0, instance);

    if (!subscription) {
        return false;
    }

    _subscriptions[_subscriptions_count++] = subscription;
    return true;
}