[GENERAL] sum 2 arrays of general int type

[Leonardo Francalanci]

I wrote a function to sum arrays.
It works, but I had to cast the data pointer to int64 (because my arrays 
are 'int8[]'):

int64* ptr1 = ARR_DATA_PTR(v1);
What if I want to write a more general function that adds values of 2 
arrays of every int type? How could I do it?

Here is the function (if you find any errors tell me...):
PG_FUNCTION_INFO_V1(array_sum);
Datum
array_add(PG_FUNCTION_ARGS)
{
        Oid     element_type;
        ArrayType  *result, *v1, *v2;
        char       *dat1,  *dat2;
        int ndatabytes, ndims1, ndims2;
        
        
        v1 = PG_GETARG_ARRAYTYPE_P(0);
        v2 = PG_GETARG_ARRAYTYPE_P(1);
        ndims1 = ARR_NDIM(v1);
        ndims2 = ARR_NDIM(v2);
        dat1 = ARR_DATA_PTR(v1);
        dat2 = ARR_DATA_PTR(v2);
        int dim1 = ARR_DIMS(v1)[0];
        int dim2 = ARR_DIMS(v2)[0];
        int *lbs = ARR_LBOUND(v1);
        ndatabytes = ARR_SIZE(v1) - ARR_OVERHEAD(ndims1);
                        
        
        int nbytes = ndatabytes + ARR_OVERHEAD(ndims1);
        result = (ArrayType *) palloc(nbytes);
        element_type = ARR_ELEMTYPE(v1);
        result->size = ARR_SIZE(v1);//nbytes;
        result->ndim = ARR_NDIM(v1);
        result->flags = 0;
        result->elemtype = element_type;
        memcpy(ARR_DIMS(result), &dim1, sizeof(int));
        memcpy(ARR_LBOUND(result), lbs, sizeof(int));   
        int64* ptr = ARR_DATA_PTR(result);
        int64* ptr1 = ARR_DATA_PTR(v1);
        int64* ptr2 = ARR_DATA_PTR(v2);
        int i = 0;
        for (; i < dim1; i++)
        {
                ptr[i]=ptr1[i]+ptr2[i]; 
        }
        PG_RETURN_ARRAYTYPE_P(result);
}
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