arr.c

array.c

pure_array* write_arr(int idx, elem x, pure_array* arr,
                      void (*io_write)(int, elem, io_vector),
                      io_vector (*io_clone)(io_vector),
                      elem (*io_read)(int, io_vector))
{
    elem old_val;
    pure_array* new_arr = (pure_array*)malloc(sizeof(pure_array));
    switch (arr->rep.tag)
    {
        case 0:
        {
            old_val = io_read(idx, arr->rep.uni.head.vector);
            io_write(idx, x, arr->rep.uni.head.vector);
            memcpy(new_arr, arr, sizeof(pure_array));
            break;
        }
        case 1:
        {
            io_vector vec = to_vector(arr, io_write, io_clone);
            old_val = io_read(idx, vec);
            io_write(idx, x, vec);
            new_arr->size = arr->size;
            new_arr->rep.tag = 0;
            new_arr->rep.uni.head.vector = vec;
            break;
        }
        default:
            exit(122);
    }
    arr->rep.tag = 1;
    arr->rep.uni.log.index = idx;
    arr->rep.uni.log.new_value = old_val;
    arr->rep.uni.log.new_array = new_arr;
    return new_arr;
}