UserClass operator() () /* non-const */ {
// return a default-constructed UserClass intialized
// to the next sequential value
return UserClass ();
}
// exercise vector<>::capacity() and vector<>::reserve()
// focus on the complexity of the function
void test_capacity (Vector::size_type nelems)
{
// create a vector with nelems elements
Vector v (nelems);
const Vector::size_type cap = v.capacity ();
const Vector::size_type size = v.size ();
Vector::const_pointer begin = size ? &v [0] : 0;
UserClass::reset_totals ();
// call reserve capacity that is less than or equal to the current value
v.reserve (cap / 2);
// verify that the call had no effect
rw_assert (v.capacity () == cap, 0, __LINE__,
"vector<UserClass>(%zu).reserve(%zu); capacity() == %zu, "
"got %zu", nelems, cap / 2, cap, v.capacity ());
if (size) {
// verify that no reallocation took place
rw_assert (begin == &v [0], 0, __LINE__,
"vector<UserClass>(%zu).reserve(%zu) unexpectedly "
"reallocated", nelems, cap / 2);
}
// call reserve the same capacity as the current value
v.reserve (cap);
// verify that the call had no effect
rw_assert (v.capacity () == cap, 0, __LINE__,
"vector<UserClass>(%zu).reserve(%zu); capacity() == %zu, "
"got %zu", nelems, cap / 2, cap, v.capacity ());
if (size) {
// verify that no reallocation took place
rw_assert (begin == &v [0], 0, __LINE__,
"vector<UserClass>(%zu).reserve(%zu) unexpectedly "
"reallocated", nelems, cap / 2);
}
// call reserve with a larger capacity then is available
v.reserve (cap + 1);
// 23.2.4.2, p2: After reserve (), capacity () is greater or equal
// to the reserve value if reallocation happens
rw_assert (v.capacity () >= cap + 1, 0, __LINE__,
"vector<UserClass>(%zu).reserve(%zu); capacity() > %zu, got %zu",
nelems, cap + 1, cap, v.capacity ());
// 23.2.3.2, p3: reserve shall not change the size of the sequence
rw_assert (v.size () == size, 0, __LINE__,
"vector<UserClass>(%zu).reserve(); size() == %zu, got %zu",
nelems, size, v.size ());
// 23.2.3.2, p3: takes at most linear time in the size of the sequence
rw_assert (UserClass::n_total_copy_ctor_ == v.size (), 0, __LINE__,
"vector<UserClass>(%zu).reserve(%zu) complexity: "
"copy ctor called %zu times when size() = %zu",
nelems, cap + 1, UserClass::n_total_copy_ctor_, v.size ());
if (size) {
begin = &v [0];
// verify 23.2.4.2, p5: no reallocation takes place until
// the size of the container would exceed its capacity
for (Vector::size_type i = 0; i != v.capacity () - size; ++i) {
v.push_back (UserClass ());
rw_assert (begin == &v [0], 0, __LINE__,
"vector<UserClass>(%zu).reserve(%zu); insertion of "
"element %zu unexpectedly reallocated; size() = %zu",
nelems, cap + 1, v.size ());
}
}
if (rw_opt_no_exceptions)
return;
#ifndef _RWSTD_NO_EXCEPTIONS
// exercise reserve exception
const char *caught = 0;
Vector::size_type too_much = v.max_size () + 1;
if (!too_much)
too_much = v.max_size ();
try {
v.reserve (too_much);
}
catch (std::length_error) {
caught = "";
}
catch (...) {
caught = "unknown exception";
}
rw_assert (0 != caught, 0, __LINE__,
"vector<UserClass>(%zu).reserve(%zu) "
"expected exception not thrown",
nelems, too_much);
if (caught)
rw_assert ('\0' == *caught, 0, __LINE__,
"vector<UserClass>(%zu).reserve(%zu) "
"expected length_error, got %s",
nelems, too_much, caught);
#endif // _RWSTD_NO_EXCEPTIONS
}
