Boost Pointer Container Library

# Pointer Container Library

# Class `ptr_multimap_adapter`

This class is used to build custom pointer containers with an underlying multimap-like container. The interface of the class is an extension of the interface from `associative_ptr_container`.

Hierarchy:

- reversible_ptr_container
  - associative_ptr_container
    - ptr_set_adapter
    - ptr_multiset_adapter
    - ptr_map_adapter
    - `ptr_multi_map_adapter`
      - ptr_set
      - ptr_multi_set
      - ptr_map
      - ptr_multimap

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Synopsis:

    namespace boost
    {
        template
        <
            T,
            class VoidPtrMultiMap,
            class CloneAllocator = heap_clone_allocator
        >
        class ptr_multimap_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
            iterator  insert( key_type& k, T* x );
            template< class U >
            iterator  insert( const key_type&, compatible-smart-ptr<U> x );

        public: // pointer container requirements
            void      transfer( iterator object, ptr_multimap_adapter& from );
            size_type transfer( iterator first, iterator last, ptr_multimap_adapter& from );
            template< class Range >
            size_type transfer( const Range& r, ptr_multimap_adapter& from );
            void      transfer( ptr_multimap_adapter& from );

        }; //  class 'ptr_multimap_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`.

## Semantics: modifiers

- `iterator insert( key_type& k, T* x );`

  > - Requirements: `x != 0`
  > - Effects: Takes ownership of `x` and returns an iterator pointing to it.
  > - Throws: bad_pointer if `x == 0`
  > - Exception safety: Strong guarantee

- `template< class U > iterator insert( const key_type& k, compatible-smart-ptr<U> x );`

  > - Equivalent to (but without the `const_cast`): `return insert( const_cast<key_type&>(k), x.release() );`

## Semantics: pointer container requirements

- `void transfer( iterator object, ptr_multimap_adapter& from );`

  > - Requirements: `not from.empty()`
  > - Effects: Inserts the object defined by `object` into the container and remove it from `from`.
  > - Postconditions: `size()` is one more, `from.size()` is one less.
  > - Exception safety: Strong guarantee

- `void transfer( iterator first, iterator last, ptr_multimap_adapter& from );`

  > - Requirements: `not from.empty()`
  > - Effects: Inserts the objects defined by the range `[first,last)` into the container and remove it from `from`.
  > - Postconditions: Let `N == std::distance(first,last);` then `size()` is `N` more, `from.size()` is `N` less.
  > - Exception safety: Basic guarantee

- `template< class Range > void transfer( const Range& r, ptr_multimap_adapter& from );`

  > - Effects: `transfer( boost::begin(r), boost::end(r), from );`

- `void transfer( ptr_multimap_adapter& from );`

  > - Effects: `transfer( from.begin(), from.end(), from );`.
  > - Postconditions: `from.empty();`
  > - Exception safety: Basic guarantee

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