reversible_ptr_container.hpp

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//
// Boost.Pointer Container
//
//  Copyright Thorsten Ottosen 2003-2005. Use, modification and
//  distribution is subject to the Boost Software License, Version
//  1.0. (See accompanying file LICENSE_1_0.txt or copy at
//  http://www.boost.org/LICENSE_1_0.txt)
//
// For more information, see http://www.boost.org/libs/ptr_container/
//


#ifndef BOOST_PTR_CONTAINER_DETAIL_REVERSIBLE_PTR_CONTAINER_HPP
#define BOOST_PTR_CONTAINER_DETAIL_REVERSIBLE_PTR_CONTAINER_HPP

#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif

#include <boost/ptr_container/detail/throw_exception.hpp>
#include <boost/ptr_container/detail/scoped_deleter.hpp>
#include <boost/ptr_container/detail/static_move_ptr.hpp>
#include <boost/ptr_container/exception.hpp>
#include <boost/ptr_container/clone_allocator.hpp>
#include <boost/ptr_container/nullable.hpp>

#ifdef BOOST_NO_SFINAE
#else
#include <boost/range/functions.hpp>
#endif

#include <boost/config.hpp>
#include <boost/iterator/reverse_iterator.hpp>
#include <boost/range/iterator.hpp>
#include <boost/utility/enable_if.hpp>
#include <boost/type_traits/is_pointer.hpp>
#include <boost/type_traits/is_integral.hpp>
#include <typeinfo>
#include <memory>

#if BOOST_WORKAROUND(BOOST_MSVC, >= 1400)  
#pragma warning(push)  
#pragma warning(disable:4127)
#endif  

namespace boost
{

namespace ptr_container_detail
{
    template< class CloneAllocator >
    struct clone_deleter
    {
        template< class T >
        void operator()( const T* p ) const
        {
            CloneAllocator::deallocate_clone( p );
        }
    };

    template< class T >
    struct is_pointer_or_integral
    {
        BOOST_STATIC_CONSTANT(bool, value = is_pointer<T>::value || is_integral<T>::value );
    };

    struct is_pointer_or_integral_tag {};
    struct is_range_tag {};
    struct sequence_tag {};
    struct fixed_length_sequence_tag : sequence_tag {};
    struct associative_container_tag {};
    struct ordered_associative_container_tag : associative_container_tag {};
    struct unordered_associative_container_tag : associative_container_tag {};
    

    
    template
    < 
        class Config, 
        class CloneAllocator
    >
    class reversible_ptr_container 
    {
    private:
        BOOST_STATIC_CONSTANT( bool, allow_null = Config::allow_null );
        
        typedef BOOST_DEDUCED_TYPENAME Config::value_type Ty_;

        template< bool allow_null_values >
        struct null_clone_allocator
        {
            template< class Iter >
            static Ty_* allocate_clone_from_iterator( Iter i )
            { 
                return allocate_clone( Config::get_const_pointer( i ) );
            }
            
            static Ty_* allocate_clone( const Ty_* x )
            {
                if( allow_null_values )
                {
                    if( x == 0 )
                        return 0;
                }
                else
                {
                    BOOST_ASSERT( x != 0 && "Cannot insert clone of null!" );
                }

                Ty_* res = CloneAllocator::allocate_clone( *x );
                BOOST_ASSERT( typeid(*res) == typeid(*x) &&
                              "CloneAllocator::allocate_clone() does not clone the "
                              "object properly. Check that new_clone() is implemented"
                              " correctly" );
                return res;
            }
            
            static void deallocate_clone( const Ty_* x )
            {
                if( allow_null_values )
                {
                    if( x == 0 )
                        return;
                }

                CloneAllocator::deallocate_clone( x );
            }
        };

        typedef BOOST_DEDUCED_TYPENAME Config::void_container_type  Cont;
#if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564))    
        typedef  null_clone_allocator<reversible_ptr_container::allow_null> 
                                                                    null_cloner_type;
#else
        typedef null_clone_allocator<allow_null>                    null_cloner_type;
#endif        
        typedef clone_deleter<null_cloner_type>                     Deleter;

        Cont      c_;

    public:
        Cont&       base()               { return c_; }
    protected: // having this public could break encapsulation
        const Cont& base() const         { return c_; }        
        
    public: // typedefs
        typedef  Ty_*          value_type;
        typedef  Ty_*          pointer;
        typedef  Ty_&          reference;
        typedef  const Ty_&    const_reference;
        
        typedef  BOOST_DEDUCED_TYPENAME Config::iterator 
                                   iterator;
        typedef  BOOST_DEDUCED_TYPENAME Config::const_iterator
                                   const_iterator;
        typedef  boost::reverse_iterator< iterator > 
                                   reverse_iterator;  
        typedef  boost::reverse_iterator< const_iterator >     
                                   const_reverse_iterator;
        typedef  BOOST_DEDUCED_TYPENAME Cont::difference_type
                                   difference_type; 
        typedef  BOOST_DEDUCED_TYPENAME Cont::size_type
                                   size_type;
        typedef  BOOST_DEDUCED_TYPENAME Config::allocator_type
                                   allocator_type;
        typedef CloneAllocator     clone_allocator_type;
        typedef ptr_container_detail::static_move_ptr<Ty_,Deleter> 
                                   auto_type;
            
    protected: 
            
        typedef ptr_container_detail::scoped_deleter<Ty_,null_cloner_type>
                                   scoped_deleter;
        typedef BOOST_DEDUCED_TYPENAME Cont::iterator
                                   ptr_iterator; 
        typedef BOOST_DEDUCED_TYPENAME Cont::const_iterator
                                   ptr_const_iterator; 
    private:

        template< class InputIterator >  
        void copy( InputIterator first, InputIterator last ) 
        {
            std::copy( first, last, begin() );
        }
        
        void copy( const reversible_ptr_container& r )
        { 
            copy( r.begin(), r.end() );
        }
        
        void copy_clones_and_release( scoped_deleter& sd ) // nothrow
        {
            BOOST_ASSERT( size_type( std::distance( sd.begin(), sd.end() ) ) == c_.size() );
            std::copy( sd.begin(), sd.end(), c_.begin() );
            sd.release(); 
        }
        
        template< class ForwardIterator >
        void clone_assign( ForwardIterator first, 
                           ForwardIterator last ) // strong 
        {
            BOOST_ASSERT( first != last );
            scoped_deleter sd( first, last );      // strong
            copy_clones_and_release( sd );         // nothrow
        }

        template< class ForwardIterator >
        void clone_back_insert( ForwardIterator first,
                                ForwardIterator last )
        {
            BOOST_ASSERT( first != last );
            scoped_deleter sd( first, last );
            insert_clones_and_release( sd, end() );
        }
        
        void remove_all() 
        {
            remove( begin(), end() ); 
        }

    protected:

        void insert_clones_and_release( scoped_deleter& sd, 
                                        iterator where ) // strong
        {
            //
            // 'c_.insert' always provides the strong guarantee for T* elements
            // since a copy constructor of a pointer cannot throw
            //
            c_.insert( where.base(), 
                       sd.begin(), sd.end() ); 
            sd.release();
        }

        void insert_clones_and_release( scoped_deleter& sd ) // strong
        {
            c_.insert( sd.begin(), sd.end() );
            sd.release();
        }

        template< class I >
        void remove( I i )
        { 
            null_policy_deallocate_clone( Config::get_const_pointer(i) );
        }

        template< class I >
        void remove( I first, I last ) 
        {
            for( ; first != last; ++first )
                remove( first );
        }

        static void enforce_null_policy( const Ty_* x, const char* msg )
        {
            if( !allow_null )
            {
                BOOST_PTR_CONTAINER_THROW_EXCEPTION( 0 == x && "null not allowed", 
                                                     bad_pointer, msg );
            }
        }

        static Ty_* null_policy_allocate_clone( const Ty_* x )
        {
            return null_cloner_type::allocate_clone( x );
        }

        static void null_policy_deallocate_clone( const Ty_* x )
        {
            null_cloner_type::deallocate_clone( x );
        }

    private:
        template< class ForwardIterator >
        ForwardIterator advance( ForwardIterator begin, size_type n ) 
        {
            ForwardIterator iter = begin;
            std::advance( iter, n );
            return iter;
        }        

        template< class I >
        void constructor_impl( I first, I last, std::input_iterator_tag ) // basic
        {
            while( first != last )
            {
                insert( end(), null_cloner_type::allocate_clone_from_iterator(first) );
                ++first;
            }
        }

        template< class I >
        void constructor_impl( I first, I last, std::forward_iterator_tag ) // strong
        {
            if( first == last )
                return;
            clone_back_insert( first, last );
        }

        template< class I >
        void associative_constructor_impl( I first, I last ) // strong
        {
            if( first == last )
                return;

            scoped_deleter sd( first, last );
            insert_clones_and_release( sd );             
        }

    public: // foundation! should be protected!
        reversible_ptr_container()
        { }

        template< class SizeType >
        reversible_ptr_container( SizeType n, unordered_associative_container_tag )
          : c_( n )
        { }

        template< class SizeType >
        reversible_ptr_container( SizeType n, fixed_length_sequence_tag )
          : c_( n )
        { }

        template< class SizeType >
        reversible_ptr_container( SizeType n, const allocator_type& a, 
                                  fixed_length_sequence_tag )
          : c_( n, a )
        { }
        
        explicit reversible_ptr_container( const allocator_type& a ) 
         : c_( a )
        { }
        
        template< class PtrContainer >
        explicit reversible_ptr_container( std::auto_ptr<PtrContainer> clone )                
        { 
            swap( *clone ); 
        }

        reversible_ptr_container( const reversible_ptr_container& r ) 
        {
            constructor_impl( r.begin(), r.end(), std::forward_iterator_tag() ); 
        }

        template< class C, class V >
        reversible_ptr_container( const reversible_ptr_container<C,V>& r ) 
        {
            constructor_impl( r.begin(), r.end(), std::forward_iterator_tag() ); 
        }

        template< class PtrContainer >
        reversible_ptr_container& operator=( std::auto_ptr<PtrContainer> clone ) // nothrow
        {
            swap( *clone );
            return *this;
        }

        reversible_ptr_container& operator=( reversible_ptr_container r ) // strong 
        {
            swap( r );
            return *this;
        }
        
        // overhead: null-initilization of container pointer (very cheap compared to cloning)
        // overhead: 1 heap allocation (very cheap compared to cloning)
        template< class InputIterator >
        reversible_ptr_container( InputIterator first, 
                                  InputIterator last,
                                  const allocator_type& a = allocator_type() ) // basic, strong
          : c_( a )
        { 
            constructor_impl( first, last, 
#if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564))
#else