The comparison functor passed to the constraints hierarchy has a
pointer to the `Constrained_triangulation_plus_2` that contains it.
That means the defaulted move constructor and move assignment operator of `Polyline_constraint_hierarchy_2` cannot be used to
implement the move constructor and move assignment operator of
`Constrained_triangulation_plus_2`.
Add a special constructor for `Polyline_constraint_hierarchy_2`, that is
usee to move the hierarchy and reassign the comparison operator.
It is invalid to try to detect if an iterator is singular or value-initialized.
The only operations allowed with value-initialized iterators are:
- copy the iterator, or
- destroy or assign the iterator.
Comparisons like `vertex_it == Vertex_it{}` are not allowed.
VC++ 19.16 thought there was an ambiguous call to `operator==`
between `skip_iterator` and `skip_iterator` in the internals of `boost::iterator_adaptor` (yet another matching bug) of VC++ 19.16).
I solved it by using the more modern `boost::stl_interfaces::iterator_interface` from Boost.STLintface (Boost>=1.74).
- encapsulate the creation/erasure of constraints in the hierarchy class
- add encapsulation in the hierarchy class, to detect direct uses of members
- add a test of `CDt_plus_2::insert_vertex_in_constraint`, and fix it
- rename `concatenate` and `concatenate2` to
- `concatenate`
- `prepend`
and force a rvalue reference on the argument corresponding to the constraint
that will be swallowed
- rename `split` to `split_tail` and `split2` to `split_head`
- rename `fix_contexts` to give it a longer self-explaning name
Instead of storing the hierarchy as a data member, store it
as a hidden (protected) base class. That allows to forward
member functions easily with using-declarations. That also avoids
mismatches between the names in the triangulation and the hierarchy.
- refactor the member function `enclosing_constraint`
- refactor things around `sc_to_sc_map`, using new member functions
to encapsulate the logic
- remove unused/undocuments functions
The regular expression I used was:
```
((?!(?:^.*(\/\/|\/\*).*|^ *\* .*|^[^"]*"(?:"[^"]*"|[^"])*))^(?:.*[ ,\(]|))(\b(?:(?:[A-Za-z]+::)*)(?:max|min))\b *\(
```
- remove all mentions of `Edge` and `Constraint`
- `Subconstraint_iterator` is renamed `Subconstraint_and_contexts_iterator` (because of its value type)
- a new `Subconstraint_iterator`, with value type `Subconstraint`
- a few unused/untested and uncompilable functions are removed from the code
- a lot of internal renamings
== Breaking changes ==
For `Constrained_triangulation_plus_2`, there are a few breaking changes...
- The value type of `subconstraints_begin()`, `subconstraints_end()`, of the range `subconstraints()` has changed to `Subconstraint` (a simple `std::pair` of vertex handles). That is actually a kind of bug-fix, because it was documented as such in the user manual.
- The new member functions `subconstraints_and_contexts_begin()`, `subconstraints_and_contexts_end()`, `subconstraints_and_contexts()` are created get the old value type (`std::pair<const Subconstraint, std::list<Context>*>`).
- A few range types have changed from `CGAL::Iterator_range<It>` to `unspecified_type`, for efficiency reasons.
- Doc fixes.
== Determinism ==
Even if it was not documented, the range `subconstraints()` is deterministic (used by Mesh_2), and `subconstraints_and_contexts()` is not.
...and `refactor Polyline_constraint_hierarchy_2` to use it.
`CGAL::unordered_flat_map` will be Boost `unordered_flat_map` if availlable, or the standard `std::unordered_map` otherwise.
Laurent Rineau
albert-github
Andreas Fabri
Sébastien Loriot