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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.
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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'
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.
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() );
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
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 );.
Copyright: | Thorsten Ottosen 2004-2006. Use, modification and distribution is subject to the Boost Software License, Version 1.0 (see LICENSE_1_0.txt). |
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