Is there any better approach to private inheriting from the STL containers?

M

Michael Tsang

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

I'm writing 2 classes which is intended to be used like any other STL
containers:

// begin code
class Lrv {
public:
Lrv();
Lrv(const Lrv &rhs);
explicit Lrv(int number);
Lrv &operator=(const Lrv &trailer);
operator bool() const;
const int &phase;
const int &number;
const bool &trailer;
bool is_compatible_with(const Lrv &trailer) const;
bool matches(unsigned constraint) const;
private:
int _phase, _number;
bool _trailer;
};

class Fleet : private vector<Lrv> {
typedef vector<Lrv> Base;
public:
// types
using Base::reference;
using Base::const_reference;
using Base::iterator;
using Base::const_iterator;
using Base::size_type;
using Base::difference_type;
using Base::value_type;
using Base::allocator_type;
using Base::pointer;
using Base::const_pointer;
using Base::reverse_iterator;
using Base::const_reverse_iterator;
// statics
const static unsigned new_lrv = 1, phase_3_lrv = 2, couple = 4, renewed =
8;
// constructors and destructors
Fleet();
Fleet(const Fleet &rhs);
// operators
Fleet &operator=(const Fleet &rhs);
const_reference operator[](size_type n) const;
// other functions
using Base::get_allocator;
const_iterator begin() const;
const_iterator end() const;
const_reverse_iterator rbegin() const;
const_reverse_iterator rend() const;
using Base::size;
using Base::max_size;
using Base::capacity;
using Base::empty;
const_reference at(size_type n) const;
const_reference front() const;
const_reference back() const;
pair<Lrv, Lrv> get(unsigned constraint);
void put(const pair<Lrv, Lrv> &set);
private:
pair<Lrv, Lrv> get_internal(iterator first, iterator last);
};

class Timetable : private map<int, pair<Lrv, Lrv> > {
typedef map<int, pair<Lrv, Lrv> > Base;
public:
// types
using Base::key_type;
using Base::mapped_type;
using Base::value_type;
using Base::key_compare;
using Base::allocator_type;
using Base::reference;
using Base::const_reference;
using Base::iterator;
using Base::const_iterator;
using Base::size_type;
using Base::difference_type;
using Base::pointer;
using Base::const_pointer;
using Base::reverse_iterator;
using Base::const_reverse_iterator;
using Base::value_compare;
// constructors and destructors
Timetable();
Timetable(const Timetable &rhs);
explicit Timetable(int weekday);
template<class Iterator> Timetable(Iterator first, Iterator last);
template<class Iterator>
Timetable(int weekday, Iterator first, Iterator last);
// operators
Timetable &operator=(const Timetable &rhs);
using Base::eek:perator[];
// other functions;
using Base::get_allocator;
using Base::begin;
using Base::end;
using Base::rbegin;
using Base::rend;
using Base::empty;
using Base::size;
using Base::max_size;
using Base::insert;
using Base::erase;
using Base::swap;
using Base::clear;
using Base::key_comp;
using Base::value_comp;
using Base::find;
using Base::count;
using Base::lower_bound;
using Base::upper_bound;
using Base::equal_range;
void allocate(Fleet &fleet);
private:
enum {depot_single = -1, depot_couple = -2};
map<int, unsigned> constraints;
list<pair<int, int> >reforms;
};

bool operator==(const Fleet &lhs, const Fleet &rhs);
bool operator!=(const Fleet &lhs, const Fleet &rhs);
bool operator==(const Timetable &lhs, const Timetable &rhs);
bool operator!=(const Timetable &lhs, const Timetable &rhs);
bool operator<(const Timetable &lhs, const Timetable &rhs);
bool operator<=(const Timetable &lhs, const Timetable &rhs);
bool operator>(const Timetable &lhs, const Timetable &rhs);
bool operator>=(const Timetable &lhs, const Timetable &rhs);
void swap(Timetable &a, Timetable &b);

// end code

I don't want any automatic conversion from these classes to the STL base
classes because the bases are not virtual, however, I want them to behave
identically to STL classes. (The Fleet class should be a read-only container
that can only be modified by the member functions get and put; the Timetable
class should be read/writeable.) If I use composition instead, I need to get
through the headaches wrapping every public member function from the STL
classes. As the classes represent real-life objects, I also don't want to
write global functions operating on these classes (as the constructors are
very complex)



-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.11 (GNU/Linux)

iEYEARECAAYFAk23zIgACgkQZ1Turg5KUCmqaACfdSr45IlriGpvoy9qFUM+W15l
iyQAn11dNIV5ovifbFshoul50kizfcUQ
=Ro/c
-----END PGP SIGNATURE-----
 

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments. After that, you can post your question and our members will help you out.

Ask a Question

Members online

No members online now.

Forum statistics

Threads
473,744
Messages
2,569,484
Members
44,903
Latest member
orderPeak8CBDGummies

Latest Threads

Top