EAM - Moving the data inside a struct to an array

struct_to_array.c

// \param p0          The structure to copy in an array.
// \param param_sp    An array of double with space for at least 6 elements (48 bytes).
inline double *tr_sp_array(ParamSP *p, double *param_sp)
{
    param_sp[0] = (double)p->cycle_num;
    param_sp[1] = (double)p->number;
    param_sp[2] = (double)p->ab;
    param_sp[3] = (double)p->pc;
    param_sp[4] = p->input;
    param_sp[5] = p->mass;
}

inline double *tr_array_sp(double *param_sp, ParamSP *p)
{
    p->cycle_num = param_sp[0];
    p->number = param_sp[1];
    p->ab = param_sp[2];
    p->pc = param_sp[3];
    p->input = param_sp[4];
    p->mass = param_sp[5];
}

/*

 // Because the array is so small, you could store it on the stack (faster and no need to free), e.g.:
 double x[6];
 tr_sp_array(p0, x);

 // You can also allocate it on the heap:
 double *x = malloc(6 * sizeof(double));
 tr_sp_array(p0, x);
 // do stuff...
 free(x);

*/