Semantics: typedefs

Notice how these two types differ:

• typedef T* value_type;

  • notice this has pointer type

• typedef T& reference;

  • notice this is not a pointer type

This is done to be able to add pointers directly to the container, but to hide the pointers externally.

Also notice that

• typedef ... iterator

allows one to iterate over T& objects, not T*. Note that:

iterator i = ...;
i.base();

returns an iterator that allows one to iterate over void* elements (this is very rarely needed and you should not use the functionality unless you know what you are doing).

• typedef ... auto_type

This declaration hides a pointer pointer type. You can rely on the following operations

T* operator->() const;
T& operator*() const;
T* release();
~auto_type();
operator implementation-defined bool();

The destructor will delete the stored object using the clone allocator of the container (this explains why we cannot use std::auto_ptr<T> nor std::unique_ptr<T>). It might help to think it is just a compatible-smart-ptr<T>. You can also return the pointer from a function or assign it to another pointer via the move() function

auto_type ptr   = ...;
auto_type other = boost::ptr_container::move( ptr );
return boost::ptr_container::move( other );

Semantics: construct/copy/destroy

• reversible_ptr_container();

  • Effects: Constructs an empty container
  • Postconditions: size() == 0

• explicit reversible_ptr_container( const reversible_ptr_container& r );

  • Effects: Constructs a container by cloning all elements of r

• template< class Derived > explicit reversible_ptr_container( const reversible_ptr_container<Derived>& r );

  • Effects: Constructs a container by cloning all elements of r
  • Requirements: Derived is derived from T

• explicit reversible_ptr_container( compatible-smart-ptr< reversible_ptr_container > r );

  • Effects: Constructs a container by taking ownership of the supplied pointers

• template< class InputIterator > reversible_ptr_container( InputIterator first, InputIterator last );

  • Requirements: (first,last] is a valid range
  • Effects: Constructs a container with a cloned range of (first,last]
  • Postconditions: size() == std::distance( first, last )

• ~reversible_ptr_container();

  • Effects: Deletes the stored objects via the clone allocator
  • Throws: Nothing

• reversible_ptr_container& operator=( const reversible_ptr_container& r );

  • Effects: Assigns a clone of r
  • Exception safety: strong guarantee

• template<class Derived> reversible_ptr_container& operator=( const reversible_ptr_container<Derived>& r );

  • Effects: Assigns a clone of r
  • Requirements: Derived is derived from T
  • Exception safety: Strong guarantee

• reversible_ptr_container& operator=( compatible-smart-ptr<reversible_ptr_container> r );

  • Effects: Deletes the stored objects and then takes ownership of the supplied pointers
  • Throws: Nothing

• allocator_type get_allocator() const;

  • Effects: Returns a copy of the allocator of the container object

Semantics: iterators

See also: iterator invalidation

• iterator begin();

• const_iterator begin() const;

  • Effects: Returns a mutable/non-mutable iterator with value_type T
  • Throws: Nothing

• iterator end();

• const_iterator end() const;

  • Effects: Returns a mutable/non-mutable iterator with value_type T
  • Throws: Nothing

• reverse_iterator rbegin();

• const_reverse_iterator rbegin() const;

  • Effects: Returns a mutable/non-mutable reverse iterator with value_type T
  • Throws: Nothing

• reverse_iterator rend();

• const_reverse_iterator rend() const;

  • Effects: Returns a mutable/non-mutable reverse iterator with value_type T
  • Throws: Nothing

Semantics: capacity

• size_type size() const;

  • Effects: Returns the number of stored elements
  • Throws: Nothing

• size_type max_size() const;

  • Effects: Returns the maximum number of stored elements
  • Throws: Nothing

• bool empty() const;

  • Effects: Returns whether the container is empty or not
  • Throws: Nothing

Semantics: modifiers

• void swap( reversible_ptr_container& r );

  • Effects: Swaps the content of the two containers
  • Throws: Nothing

• void clear();

  • Effects: Destroys all object of the container
  • Postconditions: empty() == true
  • Throws: Nothing

• VoidPtrContainer& base();

• const VoidPtrContainer& base() const;

  • Returns: a reference to the wrapped container

Semantics: pointer container requirements

• auto_type replace( iterator position, T* x );

  • Requirements: not empty() and x != 0
  • Effects: returns the object pointed to by position and replaces it with x.
  • Throws: bad_ptr_container_operation if the container is empty and bad_pointer if x == 0.
  • Exception safety: Strong guarantee

• template< class U > auto_type replace( iterator position, compatible-smart-ptr<U> x );

  • Effects: return replace( position, x.release() );

• compatible-smart-ptr< reversible_ptr_container > clone() const;

  • Effects: Returns a deep copy of the container
  • Throws: std::bad_alloc if there is not enough memory to make a clone of the container
  • Complexity: Linear

• compatible-smart-ptr< reversible_ptr_container > release();

  • Effects: Releases ownership of the container. This is a useful way of returning a container from a function.
  • Postconditions: empty() == true
  • Throws: std::bad_alloc if the return value cannot be allocated
  • Exception safety: Strong guarantee

• auto_type release( iterator position );

  • Requirements: not empty();
  • Effects: Releases ownership of the pointer referred to by position
  • Postconditions: size() is one less
  • Throws: bad_ptr_container_operation if the container is empty
  • Exception safety: Strong guarantee

Semantics: comparison

These functions compare the underlying range of objects. So

operation( const ptr_container& l, const ptr_container& r );

has the effect one would expect of normal standard containers. Hence objects are compared and not the pointers to objects.

Semantics: cloneability

• template< class T, class CloneAllocator > reversible_ptr_container<T,CA,VPC>* new_clone( const reversible_ptr_container<T,CA,VPC>& r );

  • Effects: return r.clone().release();
  • Remarks: This function is only defined for concrete pointer containers, but not for pointer container adapters.

Semantics: null predicate

• template< class Iterator > bool is_null( Iterator i );

  • Requirements: i is a valid dereferencable iterator
  • Returns: *i.base() == 0;

Semantics: serialization

All containers can be serialized by means of Boost.Serialization. For an overview, see Serialization of Pointer Containers.

template<class Archive, class T, class CA, class VPC>
void serialize( Archive& ar, reversible_ptr_container<T,CA,VPC>& c, const unsigned int version );

• Effects: Saves or loads the container to/from the archive.
• Remarks: This function is called automatically be stream operators in Boost.Serialization
• Exception safety: Loading gives the basic guarantee

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Copyright:	Thorsten Ottosen 2004-2007. Use, modification and distribution is subject to the Boost Software License, Version 1.0 (see LICENSE_1_0.txt).