const size_t tosize = (size_t)(to->tail - to->array);
const size_t reqsize = nused + tosize;
size_t nnext = (size_t)(to->end - to->array) * 2;
const size_t tosize = (size_t)(to->tail - to->array);
const size_t reqsize = nused + tosize;
size_t nnext = (size_t)(to->end - to->array) * 2;