px4_atomic.h

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#pragma once

#ifdef __cplusplus

#include <stdbool.h>
#include <stdint.h>

namespace px4
{

template <typename T>
class atomic
{
public:

#ifdef __PX4_NUTTX
    // Ensure that all operations are lock-free, so that 'atomic' can be used from
    // IRQ handlers. This might not be required everywhere though.
    static_assert(__atomic_always_lock_free(sizeof(T), 0), "atomic is not lock-free for the given type T");
#endif


    explicit atomic(T value) : _value(value) {}

    inline T load() const
    {
        return __atomic_load_n(&_value, __ATOMIC_SEQ_CST);
    }

    inline void store(T value)
    {
        __atomic_store(&_value, &value, __ATOMIC_SEQ_CST);
    }

    inline T fetch_add(T num)
    {
        return __atomic_fetch_add(&_value, num, __ATOMIC_SEQ_CST);
    }

    inline T fetch_sub(T num)
    {
        return __atomic_fetch_sub(&_value, num, __ATOMIC_SEQ_CST);
    }

    inline T fetch_and(T num)
    {
        return __atomic_fetch_and(&_value, num, __ATOMIC_SEQ_CST);
    }

    inline T fetch_xor(T num)
    {
        return __atomic_fetch_xor(&_value, num, __ATOMIC_SEQ_CST);
    }

    inline T fetch_or(T num)
    {
        return __atomic_fetch_or(&_value, num, __ATOMIC_SEQ_CST);
    }

    inline T fetch_nand(T num)
    {
        return __atomic_fetch_nand(&_value, num, __ATOMIC_SEQ_CST);
    }

    inline bool compare_exchange(T *expected, T num)
    {
        return __atomic_compare_exchange(&_value, expected, num, false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST);
    }

private:
    T _value;
};

using atomic_int = atomic<int>;
using atomic_int32_t = atomic<int32_t>;
using atomic_bool = atomic<bool>;

} /* namespace px4 */

#endif /* __cplusplus */