libs/ptr_container/doc/ptr_map_adapter.rst
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|Boost| Pointer Container Library
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.. |Boost| image:: boost.png
Class ``ptr_map_adapter``
-------------------------
This class is used to build custom pointer containers with
an underlying map-like container. The interface of the class is an extension
of the interface from ``associative_ptr_container``.
**Hierarchy:**
- `reversible_ptr_container <reversible_ptr_container.html>`_
- `associative_ptr_container <associative_ptr_container.html>`_
- `ptr_set_adapter <ptr_set_adapter.html>`_
- `ptr_multiset_adapter <ptr_multiset_adapter.html>`_
- ``ptr_map_adapter``
- `ptr_multi_map_adapter <ptr_multimap_adapter.html>`_
- `ptr_set <ptr_set.html>`_
- `ptr_multi_set <ptr_multiset.html>`_
- `ptr_map <ptr_map.html>`_
- `ptr_multimap <ptr_multimap.html>`_
**Navigate:**
- `home <ptr_container.html>`_
- `reference <reference.html>`_
**Synopsis:**
.. parsed-literal::
namespace boost
{
template
<
class T,
class VoidPtrMap,
class CloneAllocator = heap_clone_allocator
>
class ptr_map_adapter
{
public: // `typedefs`_
typedef VoidPtrMap::key_type key_type;
typedef T* mapped_type;
typedef T& mapped_reference;
typedef const T& const_mapped_reference;
typedef ... value_type;
typedef ... reference;
typedef ... const_reference;
typedef ... pointer;
typedef ... const_pointer;
public: // `modifiers`_
std::pair<iterator,bool> insert( key_type& k, T* x );
template< class U >
std::pair<iterator,bool> insert( const key_type& k, std::auto_ptr<U> x );
public; // `lookup`_
T& operator[]( const key_type& key );
T& at( const key_type& key );
const T& at( const key_type& key ) const;
public: // `pointer container requirements`_
bool transfer( iterator object, ptr_map_adapter& from );
size_type transfer( iterator first, iterator last, ptr_map_adapter& from );
template< class Range >
size_type transfer( const Range& r, ptr_map_adapter& from );
size_type transfer( ptr_map_adapter& from );
}; // class 'ptr_map_adapter'
} // namespace 'boost'
Semantics
---------
.. _`typedefs`:
Semantics: typedefs
^^^^^^^^^^^^^^^^^^^
The following types are implementation defined::
typedef ... value_type;
typedef ... reference;
typedef ... const_reference;
typedef ... pointer;
typedef ... const_pointer;
However, the structure of the type mimics ``std::pair`` s.t. one
can use ``first`` and ``second`` members. The reference-types
are not real references and the pointer-types are not real pointers.
However, one may still write ::
map_type::value_type a_value = *m.begin();
a_value.second->foo();
map_type::reference a_reference = *m.begin();
a_reference.second->foo();
map_type::const_reference a_creference = *const_begin(m);
map_type::pointer a_pointer = &*m.begin();
a_pointer->second->foo();
map_type::const_pointer a_cpointer = &*const_begin(m);
The difference compared to ``std::map<Key,T*>`` is that constness
is propagated to the pointer (that is, to ``second``) in ``const_itertor``.
.. _`modifiers`:
Semantics: modifiers
^^^^^^^^^^^^^^^^^^^^
- ``std::pair<iterator,bool> insert( key_type& k, value_type x );``
- Requirements: ``x != 0``
- Effects: Takes ownership of ``x`` and insert it iff there is no equivalent of it already. The bool part of the return value indicates insertion and the iterator points to the element with key ``x``.
- Throws: bad_pointer if ``x == 0``
- Exception safety: Strong guarantee
- ``template< class U > std::pair<iterator,bool> insert( const key_type& k, std::auto_ptr<U> x );``
- Equivalent to (but without the ``const_cast``): ``return insert( const_cast<key_type&>(k), x.release() );``
..
- ``std::pair<iterator,bool> insert( key_type& k, const_reference x );``
- Effects: ``return insert( allocate_clone( x ) );``
- Exception safety: Strong guarantee
.. _`lookup`:
Semantics: lookup
^^^^^^^^^^^^^^^^^
- ``T& operator[]( const key_type& key );``
- Effects: returns the object with key ``key`` if it exists; otherwise a new object is allocated and inserted and its reference returned.
- Exception-safety: Strong guarantee
- ``T& at( const key_type& key );``
- ``const T& at( const key_type& jey ) const;``
- Requirement: the key exists
- Throws: ``bad_ptr_container_operation`` if the key does not exist
.. _`pointer container requirements`:
Semantics: pointer container requirements
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
- ``bool transfer( iterator object, ptr_map_adapter& from );``
- Requirements: ``not from.empty()``
- Effects: Inserts the object defined by ``object`` into the container and remove it from ``from``
iff no equivalent object exists.
- Returns: whether the object was transfered
- Exception safety: Strong guarantee
- ``size_type transfer( iterator first, iterator last, ptr__set_adapter& from );``
- Requirements: ``not from.empty()``
- Effects: Inserts the objects defined by the range ``[first,last)`` into the container and remove it from ``from``.
An object is only transferred if no equivalent object exists.
- Returns: the number of transfered objects
- Exception safety: Basic guarantee
- ``template< class Range > void transfer( const Range& r, ptr_map_adapter& from );``
- Effects: ``return transfer( boost::begin(r), boost::end(r), from );``
- ``size_type transfer( ptr_set_adapter& from );``
- Effects: ``return transfer( from.begin(), from.end(), from );``.
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:Copyright: Thorsten Ottosen 2004-2006. Use, modification and distribution is subject to the Boost Software License, Version 1.0 (see LICENSE_1_0.txt__).
__ http://www.boost.org/LICENSE_1_0.txt
