cgal/TDS_3/doc/TDS_3/Concepts/TriangulationDSCellBase_3.h

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/*!
\ingroup PkgTDS3Concepts
\cgalConcept
\cgalRefines TriangulationDataStructure_3::Cell
The concept `TriangulationDSCellBase_3` describes the requirements for
the cell base class of a `CGAL::Triangulation_data_structure_3<Vb,Cb>`.
Note that if the `CGAL::Triangulation_data_structure_3`
is plugged into a triangulation class,
the face base class may have additional geometric
requirements depending on the triangulation class.
At the base level
(see the Software Design sections of the Chapters \ref Triangulation3secdesign "Triangulation"
and \ref TDS3secdesign "Triangulation Datastructure"),
a cell stores handles to its four vertices and to its four neighbor cells.
The vertices and neighbors are indexed 0, 1, 2 and 3. Neighbor `i`
lies opposite to vertex `i`.
Since the Triangulation data structure is the class which defines the handle
types, the cell base class has to be somehow parameterized by the Triangulation
data structure. But since it is itself parameterized by the cell and vertex
base classes, there is a cycle in the definition of these classes. In order
to break the cycle, the base classes for vertex and cell which are given as
arguments for the Triangulation data structure use `void` as Triangulation
data structure parameter, and the Triangulation data structure then uses a
<I>rebind</I>-like mechanism (similar to the one specified in
`std::allocator`) in order to put itself as parameter to the vertex and
cell classes. The <I>rebound</I> base classes so obtained are the classes
which are used as base classes for the final vertex and cell classes.
More information can be found in Section \ref TDS3secdesign.
\cgalHasModel `CGAL::Triangulation_ds_cell_base_3<TDS>`
\sa `TriangulationDSVertexBase_3`
\sa `CGAL::Triangulation_data_structure_3<Vb,Cb>`
*/
class TriangulationDSCellBase_3
{
public:
/// \name Types
/// A model of the concept `TriangulationDSCellBase_3` has to provide the following types.
/// @{
/*!
This template class has to define a type `Rebind_TDS<TDS3>::%Other` which is the
<I>rebound</I> cell, that is, the one whose `Triangulation_data_structure`
will be the actually used one. `Rebind_TDS<TDS3>::%Other` will be the real base
class of `Triangulation_data_structure_3::Cell`.
\note It can be implemented using a nested template class.
\sa Section \ref tds3cyclic
*/
template <typename TDS3>
using Rebind_TDS = unspecified_type;
/*!
*/
typedef TriangulationDataStructure_3 Triangulation_data_structure;
/*!
*/
typedef TriangulationDataStructure_3::Vertex_handle Vertex_handle;
/*!
*/
typedef TriangulationDataStructure_3::Cell_handle Cell_handle;
/// @}
/// \name Creation
/// @{
/*!
Default constructor
*/
TriangulationDSCellBase_3();
/*!
Initializes the vertices with `v0, v1, v2, v3`. Neighbors are
initialized to the default constructed handle.
*/
TriangulationDSCellBase_3( Vertex_handle v0, Vertex_handle v1,
Vertex_handle v2, Vertex_handle v3);
/*!
Initializes the vertices with `v0, v1, v2, v3` and the neighbors with
`n0, n1, n2, n3`.
*/
TriangulationDSCellBase_3( Vertex_handle v0, Vertex_handle v1,
Vertex_handle v2, Vertex_handle v3,
Cell_handle n0, Cell_handle n1,
Cell_handle n2, Cell_handle n3);
/// @}
/// \name Checking
/// @{
/*!
Performs any desired geometric test on a cell.
\cgalDebugFunction
\cgalDebugBegin
When `verbose` is set to `true`, messages are printed to give
a precise indication of the kind of invalidity encountered. `level`
increases the level of testing.
\cgalDebugEnd
*/
bool is_valid(bool verbose = false, int level = 0) const;
/// @}
/// \name Members for Compact_container
/// \cgalAdvancedBegin
/// These member functions are required by
/// `CGAL::Triangulation_data_structure_3` because it uses
/// `CGAL::Compact_container` to store its cells. See the documentation of
/// `CGAL::Compact_container` for the exact requirements.
/// \cgalAdvancedEnd
/// @{
/*!
*/
void * for_compact_container() const;
/*!
*/
void * & for_compact_container();
/// @}
/// \name I/O
/// @{
/*!
Inputs the possible non combinatorial information given by the cell.
*/
istream& operator>> (istream& is, TriangulationDSCellBase_3 & c);
/*!
Outputs the possible non combinatorial information given by the cell.
*/
ostream& operator<< (ostream& os, const TriangulationDSCellBase_3 & c);
/// @}
}; /* end TriangulationDSCellBase_3 */