/* header files are included here */

PCI_card card;

int main(void)
{
    card.init_card(0);

    return 0;
}

#ifndef __PCI_CARD_H
#define __PCI_CARD_H

/* header files are included here */

typedef struct {
    int32_t card_index;
    int32_t user_counter;
} card_dev_t;

class PCI_card {
public:
    PCI_card() : dev_descriptor(-1) { enlarge_vector(); }

    int32_t init_card(int32_t card_num);

private:
    int32_t dev_descriptor;

public:
    static int32_t enlarge_vector();

private:
    static int32_t card_amount;
    static std::vector<card_dev_t> cards;
};

#endif

/* header files are included here */

int32_t PCI_card::card_amount = -1;
std::vector<card_dev_t> PCI_card::cards;

int32_t PCI_card::init_card(int32_t card_num)
{
    if (card_num >= card_amount || card_num < 0)
        return -1;

    card_dev_t new_card = {
        .card_index = card_num,
        .user_counter = 1
    };

    cards[card_num] = new_card;
    dev_descriptor = card_num;

    return 0;
}

int32_t PCI_card::enlarge_vector()
{
    card_amount = 10;
    card_dev_t null_card = {
        .card_index = -1,
        .user_counter = -1
    };

    cards.resize(card_amount, null_card);

    return card_amount;
}