Chris@16: //////////////////////////////////////////////////////////////////////////////
Chris@16: //
Chris@101: // (C) Copyright Ion Gaztanaga 2005-2014. Distributed under the Boost
Chris@16: // Software License, Version 1.0. (See accompanying file
Chris@16: // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: //
Chris@16: // See http://www.boost.org/libs/interprocess for documentation.
Chris@16: //
Chris@16: //////////////////////////////////////////////////////////////////////////////
Chris@16: 
Chris@16: #ifndef BOOST_INTERPROCESS_OFFSET_PTR_HPP
Chris@16: #define BOOST_INTERPROCESS_OFFSET_PTR_HPP
Chris@16: 
Chris@101: #ifndef BOOST_CONFIG_HPP
Chris@101: #  include <boost/config.hpp>
Chris@101: #endif
Chris@101: #
Chris@101: #if defined(BOOST_HAS_PRAGMA_ONCE)
Chris@16: #  pragma once
Chris@16: #endif
Chris@16: 
Chris@16: #include <boost/interprocess/detail/config_begin.hpp>
Chris@16: #include <boost/interprocess/detail/workaround.hpp>
Chris@16: 
Chris@16: #include <boost/interprocess/interprocess_fwd.hpp>
Chris@16: #include <boost/interprocess/detail/utilities.hpp>
Chris@16: #include <boost/interprocess/detail/cast_tags.hpp>
Chris@16: #include <boost/interprocess/detail/mpl.hpp>
Chris@101: #include <boost/container/detail/type_traits.hpp>  //alignment_of, aligned_storage
Chris@16: #include <boost/assert.hpp>
Chris@101: #include <iosfwd>
Chris@16: 
Chris@16: //!\file
Chris@16: //!Describes a smart pointer that stores the offset between this pointer and
Chris@16: //!target pointee, called offset_ptr.
Chris@16: 
Chris@16: namespace boost {
Chris@16: 
Chris@101: #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
Chris@101: 
Chris@16: //Predeclarations
Chris@16: template <class T>
Chris@16: struct has_trivial_destructor;
Chris@16: 
Chris@101: #endif   //#if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
Chris@101: 
Chris@16: namespace interprocess {
Chris@16: 
Chris@101: #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
Chris@16: namespace ipcdetail {
Chris@16: 
Chris@16:    template<class OffsetType, std::size_t OffsetAlignment>
Chris@16:    union offset_ptr_internal
Chris@16:    {
Chris@16:       explicit offset_ptr_internal(OffsetType off)
Chris@16:          : m_offset(off)
Chris@16:       {}
Chris@16:       OffsetType m_offset; //Distance between this object and pointee address
Chris@101:       typename ::boost::container::container_detail::aligned_storage
Chris@16:          < sizeof(OffsetType)
Chris@16:          , (OffsetAlignment == offset_type_alignment) ?
Chris@101:             ::boost::container::container_detail::alignment_of<OffsetType>::value : OffsetAlignment
Chris@16:          >::type alignment_helper;
Chris@16:    };
Chris@16: 
Chris@16:    //Note: using the address of a local variable to point to another address
Chris@16:    //is not standard conforming and this can be optimized-away by the compiler.
Chris@16:    //Non-inlining is a method to remain illegal but correct
Chris@16: 
Chris@16:    //Undef BOOST_INTERPROCESS_OFFSET_PTR_INLINE_XXX if your compiler can inline
Chris@16:    //this code without breaking the library
Chris@16: 
Chris@16:    ////////////////////////////////////////////////////////////////////////
Chris@16:    //
Chris@16:    //                      offset_ptr_to_raw_pointer
Chris@16:    //
Chris@16:    ////////////////////////////////////////////////////////////////////////
Chris@16:    #define BOOST_INTERPROCESS_OFFSET_PTR_INLINE_TO_PTR
Chris@101:    #if defined(_MSC_VER) && (_MSC_VER >= 1800) && (defined(_M_AMD64) || defined(_M_X64))
Chris@101:       //Visual 2013 x64 optimizes more than we desire, so disable branchless option
Chris@101:    #else
Chris@101:       #define BOOST_INTERPROCESS_OFFSET_PTR_BRANCHLESS_TO_PTR
Chris@101:    #endif
Chris@16:    template<int Dummy>
Chris@16:    #ifndef BOOST_INTERPROCESS_OFFSET_PTR_INLINE_TO_PTR
Chris@101:       BOOST_NOINLINE
Chris@16:    #elif defined(NDEBUG)
Chris@16:       inline
Chris@16:    #endif
Chris@16:    void * offset_ptr_to_raw_pointer(const volatile void *this_ptr, std::size_t offset)
Chris@16:    {
Chris@16:       typedef pointer_size_t_caster<void*> caster_t;
Chris@16:       #ifndef BOOST_INTERPROCESS_OFFSET_PTR_BRANCHLESS_TO_PTR
Chris@16:          if(offset == 1){
Chris@16:             return 0;
Chris@16:          }
Chris@16:          else{
Chris@16:             const caster_t caster((void*)this_ptr);
Chris@16:             return caster_t(caster.size() + offset).pointer();
Chris@16:          }
Chris@16:       #else
Chris@16:          const caster_t caster((void*)this_ptr);
Chris@101:          std::size_t target_offset = caster.size() + offset;
Chris@101:          std::size_t mask = -std::size_t(offset != 1);
Chris@101:          target_offset &= mask;
Chris@101:          return caster_t(target_offset).pointer();
Chris@16:       #endif
Chris@16:    }
Chris@16: 
Chris@16:    #ifdef BOOST_INTERPROCESS_OFFSET_PTR_INLINE_TO_PTR
Chris@16:       #undef BOOST_INTERPROCESS_OFFSET_PTR_INLINE_TO_PTR
Chris@16:    #endif
Chris@16:    #ifdef BOOST_INTERPROCESS_OFFSET_PTR_BRANCHLESS_TO_PTR
Chris@16:       #undef BOOST_INTERPROCESS_OFFSET_PTR_BRANCHLESS_TO_PTR
Chris@16:    #endif
Chris@16: 
Chris@16:    ////////////////////////////////////////////////////////////////////////
Chris@16:    //
Chris@16:    //                      offset_ptr_to_offset
Chris@16:    //
Chris@16:    ////////////////////////////////////////////////////////////////////////
Chris@16:    #define BOOST_INTERPROCESS_OFFSET_PTR_INLINE_TO_OFF
Chris@16:    //Branchless seems slower in x86
Chris@16:    #define BOOST_INTERPROCESS_OFFSET_PTR_BRANCHLESS_TO_OFF
Chris@16: 
Chris@16:    template<int Dummy>
Chris@16:    #ifndef BOOST_INTERPROCESS_OFFSET_PTR_INLINE_TO_OFF
Chris@101:       BOOST_NOINLINE
Chris@16:    #elif defined(NDEBUG)
Chris@16:       inline
Chris@16:    #endif
Chris@16:    std::size_t offset_ptr_to_offset(const volatile void *ptr, const volatile void *this_ptr)
Chris@16:    {
Chris@16:       typedef pointer_size_t_caster<void*> caster_t;
Chris@16:       #ifndef BOOST_INTERPROCESS_OFFSET_PTR_BRANCHLESS_TO_OFF
Chris@16:          //offset == 1 && ptr != 0 is not legal for this pointer
Chris@16:          if(!ptr){
Chris@16:             return 1;
Chris@16:          }
Chris@16:          else{
Chris@16:             const caster_t this_caster((void*)this_ptr);
Chris@16:             const caster_t ptr_caster((void*)ptr);
Chris@16:             std::size_t offset = ptr_caster.size() - this_caster.size();
Chris@16:             BOOST_ASSERT(offset != 1);
Chris@16:             return offset;
Chris@16:          }
Chris@16:       #else
Chris@16:          const caster_t this_caster((void*)this_ptr);
Chris@16:          const caster_t ptr_caster((void*)ptr);
Chris@16:          //std::size_t other = -std::size_t(ptr != 0);
Chris@16:          //std::size_t offset = (ptr_caster.size() - this_caster.size()) & other;
Chris@16:          //return offset + !other;
Chris@16:          //
Chris@16:          std::size_t offset = (ptr_caster.size() - this_caster.size() - 1) & -std::size_t(ptr != 0);
Chris@16:          return ++offset;
Chris@16:       #endif
Chris@16:    }
Chris@16: 
Chris@16:    #ifdef BOOST_INTERPROCESS_OFFSET_PTR_INLINE_TO_OFF
Chris@16:       #undef BOOST_INTERPROCESS_OFFSET_PTR_INLINE_TO_OFF
Chris@16:    #endif
Chris@16:    #ifdef BOOST_INTERPROCESS_OFFSET_PTR_BRANCHLESS_TO_OFF
Chris@16:       #undef BOOST_INTERPROCESS_OFFSET_PTR_BRANCHLESS_TO_OFF
Chris@16:    #endif
Chris@16: 
Chris@16:    ////////////////////////////////////////////////////////////////////////
Chris@16:    //
Chris@16:    //                      offset_ptr_to_offset_from_other
Chris@16:    //
Chris@16:    ////////////////////////////////////////////////////////////////////////
Chris@16:    #define BOOST_INTERPROCESS_OFFSET_PTR_INLINE_TO_OFF_FROM_OTHER
Chris@16:    //Branchless seems slower in x86
Chris@16:    #define BOOST_INTERPROCESS_OFFSET_PTR_BRANCHLESS_TO_OFF_FROM_OTHER
Chris@16: 
Chris@16:    template<int Dummy>
Chris@16:    #ifndef BOOST_INTERPROCESS_OFFSET_PTR_INLINE_TO_OFF_FROM_OTHER
Chris@101:       BOOST_NOINLINE
Chris@16:    #elif defined(NDEBUG)
Chris@16:       inline
Chris@16:    #endif
Chris@16:    std::size_t offset_ptr_to_offset_from_other
Chris@16:       (const volatile void *this_ptr, const volatile void *other_ptr, std::size_t other_offset)
Chris@16:    {
Chris@16:       typedef pointer_size_t_caster<void*> caster_t;
Chris@16:       #ifndef BOOST_INTERPROCESS_OFFSET_PTR_BRANCHLESS_TO_OFF_FROM_OTHER
Chris@16:       if(other_offset == 1){
Chris@16:          return 1;
Chris@16:       }
Chris@16:       else{
Chris@16:          const caster_t this_caster((void*)this_ptr);
Chris@16:          const caster_t other_caster((void*)other_ptr);
Chris@16:          std::size_t offset = other_caster.size() - this_caster.size() + other_offset;
Chris@16:          BOOST_ASSERT(offset != 1);
Chris@16:          return offset;
Chris@16:       }
Chris@16:       #else
Chris@16:       const caster_t this_caster((void*)this_ptr);
Chris@16:       const caster_t other_caster((void*)other_ptr);
Chris@16:       return ((other_caster.size() - this_caster.size()) & -std::size_t(other_offset != 1)) + other_offset;
Chris@16:       #endif
Chris@16:    }
Chris@16: 
Chris@16:    #ifdef BOOST_INTERPROCESS_OFFSET_PTR_INLINE_TO_OFF_FROM_OTHER
Chris@16:       #undef BOOST_INTERPROCESS_OFFSET_PTR_INLINE_TO_OFF_FROM_OTHER
Chris@16:    #endif
Chris@16:    #ifdef BOOST_INTERPROCESS_OFFSET_PTR_BRANCHLESS_TO_OFF_FROM_OTHER
Chris@16:       #undef BOOST_INTERPROCESS_OFFSET_PTR_BRANCHLESS_TO_OFF_FROM_OTHER
Chris@16:    #endif
Chris@16: 
Chris@16:    ////////////////////////////////////////////////////////////////////////
Chris@16:    //
Chris@16:    // Let's assume cast to void and cv cast don't change any target address
Chris@16:    //
Chris@16:    ////////////////////////////////////////////////////////////////////////
Chris@16:    template<class From, class To>
Chris@16:    struct offset_ptr_maintains_address
Chris@16:    {
Chris@16:       static const bool value =    ipcdetail::is_cv_same<From, To>::value
Chris@16:                                 || ipcdetail::is_cv_same<void, To>::value;
Chris@16:    };
Chris@16: 
Chris@16: }  //namespace ipcdetail {
Chris@101: #endif   //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
Chris@16: 
Chris@16: //!A smart pointer that stores the offset between between the pointer and the
Chris@16: //!the object it points. This allows offset allows special properties, since
Chris@16: //!the pointer is independent from the address address of the pointee, if the
Chris@16: //!pointer and the pointee are still separated by the same offset. This feature
Chris@16: //!converts offset_ptr in a smart pointer that can be placed in shared memory and
Chris@16: //!memory mapped files mapped in different addresses in every process.
Chris@101: //!
Chris@101: //! \tparam PointedType The type of the pointee.
Chris@101: //! \tparam DifferenceType A signed integer type that can represent the arithmetic operations on the pointer
Chris@101: //! \tparam OffsetType An unsigned integer type that can represent the
Chris@101: //!   distance between two pointers reinterpret_cast-ed as unsigned integers. In general this type
Chris@101: //!   should be at least of the same size of std::uintptr_t. In some systems it's possible to communicate
Chris@101: //!   between 32 and 64 bit processes using 64 bit offsets.
Chris@101: //! \tparam OffsetAlignment Alignment of the OffsetType stored inside. In some systems might be necessary
Chris@101: //!   to align it to 64 bits in order to communicate 32 and 64 bit processes using 64 bit offsets.
Chris@16: template <class PointedType, class DifferenceType, class OffsetType, std::size_t OffsetAlignment>
Chris@16: class offset_ptr
Chris@16: {
Chris@101:    #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
Chris@16:    typedef offset_ptr<PointedType, DifferenceType, OffsetType, OffsetAlignment>   self_t;
Chris@16:    void unspecified_bool_type_func() const {}
Chris@16:    typedef void (self_t::*unspecified_bool_type)() const;
Chris@101:    #endif   //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
Chris@16: 
Chris@16:    public:
Chris@16:    typedef PointedType                       element_type;
Chris@16:    typedef PointedType *                     pointer;
Chris@16:    typedef typename ipcdetail::
Chris@16:       add_reference<PointedType>::type       reference;
Chris@16:    typedef typename ipcdetail::
Chris@16:       remove_volatile<typename ipcdetail::
Chris@16:          remove_const<PointedType>::type
Chris@16:             >::type                          value_type;
Chris@16:    typedef DifferenceType                    difference_type;
Chris@16:    typedef std::random_access_iterator_tag   iterator_category;
Chris@16:    typedef OffsetType                        offset_type;
Chris@16: 
Chris@16:    public:   //Public Functions
Chris@16: 
Chris@16:    //!Default constructor (null pointer).
Chris@16:    //!Never throws.
Chris@16:    offset_ptr()
Chris@16:       : internal(1)
Chris@16:    {}
Chris@16: 
Chris@16:    //!Constructor from raw pointer (allows "0" pointer conversion).
Chris@16:    //!Never throws.
Chris@16:    offset_ptr(pointer ptr)
Chris@16:       : internal(static_cast<OffsetType>(ipcdetail::offset_ptr_to_offset<0>(ptr, this)))
Chris@16:    {}
Chris@16: 
Chris@16:    //!Constructor from other pointer.
Chris@16:    //!Never throws.
Chris@16:    template <class T>
Chris@16:    offset_ptr( T *ptr
Chris@16:              , typename ipcdetail::enable_if< ipcdetail::is_convertible<T*, PointedType*> >::type * = 0)
Chris@16:       : internal(static_cast<OffsetType>
Chris@16:          (ipcdetail::offset_ptr_to_offset<0>(static_cast<PointedType*>(ptr), this)))
Chris@16:    {}
Chris@16: 
Chris@16:    //!Constructor from other offset_ptr
Chris@16:    //!Never throws.
Chris@16:    offset_ptr(const offset_ptr& ptr)
Chris@16:       : internal(static_cast<OffsetType>
Chris@16:          (ipcdetail::offset_ptr_to_offset_from_other<0>(this, &ptr, ptr.internal.m_offset)))
Chris@16:    {}
Chris@16: 
Chris@16:    //!Constructor from other offset_ptr. If pointers of pointee types are
Chris@16:    //!convertible, offset_ptrs will be convertibles. Never throws.
Chris@16:    template<class T2>
Chris@16:    offset_ptr( const offset_ptr<T2, DifferenceType, OffsetType, OffsetAlignment> &ptr
Chris@16:              #ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
Chris@101:              , typename ipcdetail::enable_if_c< ipcdetail::is_convertible<T2*, PointedType*>::value
Chris@16:                && ipcdetail::offset_ptr_maintains_address<T2, PointedType>::value
Chris@16:              >::type * = 0
Chris@16:              #endif
Chris@16:              )
Chris@16:       : internal(static_cast<OffsetType>
Chris@16:          (ipcdetail::offset_ptr_to_offset_from_other<0>(this, &ptr, ptr.get_offset())))
Chris@16:    {}
Chris@16: 
Chris@16:    #ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
Chris@16: 
Chris@16:    //!Constructor from other offset_ptr. If pointers of pointee types are
Chris@16:    //!convertible, offset_ptrs will be convertibles. Never throws.
Chris@16:    template<class T2>
Chris@16:    offset_ptr( const offset_ptr<T2, DifferenceType, OffsetType, OffsetAlignment> &ptr
Chris@16:              , typename ipcdetail::enable_if_c< ipcdetail::is_convertible<T2*, PointedType*>::value
Chris@16:                && !ipcdetail::offset_ptr_maintains_address<T2, PointedType>::value
Chris@16:              >::type * = 0)
Chris@16:       : internal(static_cast<OffsetType>
Chris@16:          (ipcdetail::offset_ptr_to_offset<0>(static_cast<PointedType*>(ptr.get()), this)))
Chris@16:    {}
Chris@16: 
Chris@16:    #endif
Chris@16: 
Chris@16:    //!Emulates static_cast operator.
Chris@16:    //!Never throws.
Chris@16:    template<class T2, class P2, class O2, std::size_t A2>
Chris@16:    offset_ptr(const offset_ptr<T2, P2, O2, A2> & r, ipcdetail::static_cast_tag)
Chris@16:       : internal(static_cast<OffsetType>
Chris@16:          (ipcdetail::offset_ptr_to_offset<0>(static_cast<PointedType*>(r.get()), this)))
Chris@16:    {}
Chris@16: 
Chris@16:    //!Emulates const_cast operator.
Chris@16:    //!Never throws.
Chris@16:    template<class T2, class P2, class O2, std::size_t A2>
Chris@16:    offset_ptr(const offset_ptr<T2, P2, O2, A2> & r, ipcdetail::const_cast_tag)
Chris@16:       : internal(static_cast<OffsetType>
Chris@16:          (ipcdetail::offset_ptr_to_offset<0>(const_cast<PointedType*>(r.get()), this)))
Chris@16:    {}
Chris@16: 
Chris@16:    //!Emulates dynamic_cast operator.
Chris@16:    //!Never throws.
Chris@16:    template<class T2, class P2, class O2, std::size_t A2>
Chris@16:    offset_ptr(const offset_ptr<T2, P2, O2, A2> & r, ipcdetail::dynamic_cast_tag)
Chris@16:       : internal(static_cast<OffsetType>
Chris@16:          (ipcdetail::offset_ptr_to_offset<0>(dynamic_cast<PointedType*>(r.get()), this)))
Chris@16:    {}
Chris@16: 
Chris@16:    //!Emulates reinterpret_cast operator.
Chris@16:    //!Never throws.
Chris@16:    template<class T2, class P2, class O2, std::size_t A2>
Chris@16:    offset_ptr(const offset_ptr<T2, P2, O2, A2> & r, ipcdetail::reinterpret_cast_tag)
Chris@16:       : internal(static_cast<OffsetType>
Chris@16:       (ipcdetail::offset_ptr_to_offset<0>(reinterpret_cast<PointedType*>(r.get()), this)))
Chris@16:    {}
Chris@16: 
Chris@16:    //!Obtains raw pointer from offset.
Chris@16:    //!Never throws.
Chris@16:    pointer get() const
Chris@16:    {  return (pointer)ipcdetail::offset_ptr_to_raw_pointer<0>(this, this->internal.m_offset);   }
Chris@16: 
Chris@16:    offset_type get_offset() const
Chris@16:    {  return this->internal.m_offset;  }
Chris@16: 
Chris@16:    //!Pointer-like -> operator. It can return 0 pointer.
Chris@16:    //!Never throws.
Chris@16:    pointer operator->() const
Chris@16:    {  return this->get(); }
Chris@16: 
Chris@16:    //!Dereferencing operator, if it is a null offset_ptr behavior
Chris@16:    //!   is undefined. Never throws.
Chris@16:    reference operator* () const
Chris@16:    {
Chris@16:       pointer p = this->get();
Chris@16:       reference r = *p;
Chris@16:       return r;
Chris@16:    }
Chris@16: 
Chris@16:    //!Indexing operator.
Chris@16:    //!Never throws.
Chris@16:    reference operator[](difference_type idx) const
Chris@16:    {  return this->get()[idx];  }
Chris@16: 
Chris@16:    //!Assignment from pointer (saves extra conversion).
Chris@16:    //!Never throws.
Chris@16:    offset_ptr& operator= (pointer from)
Chris@16:    {
Chris@16:       this->internal.m_offset =
Chris@16:          static_cast<OffsetType>(ipcdetail::offset_ptr_to_offset<0>(from, this));
Chris@16:       return *this;
Chris@16:    }
Chris@16: 
Chris@16:    //!Assignment from other offset_ptr.
Chris@16:    //!Never throws.
Chris@16:    offset_ptr& operator= (const offset_ptr & ptr)
Chris@16:    {
Chris@16:       this->internal.m_offset =
Chris@16:          static_cast<OffsetType>(ipcdetail::offset_ptr_to_offset_from_other<0>(this, &ptr, ptr.internal.m_offset));
Chris@16:       return *this;
Chris@16:    }
Chris@16: 
Chris@16:    //!Assignment from related offset_ptr. If pointers of pointee types
Chris@16:    //!   are assignable, offset_ptrs will be assignable. Never throws.
Chris@16:    template<class T2>
Chris@16:    #ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
Chris@16:    typename ipcdetail::enable_if_c< ipcdetail::is_convertible<T2*, PointedType*>::value
Chris@16:                                     && ipcdetail::offset_ptr_maintains_address<T2, PointedType>::value
Chris@16:                                   , offset_ptr&>::type
Chris@16:    #else
Chris@16:    offset_ptr&
Chris@16:    #endif
Chris@16:       operator= (const offset_ptr<T2, DifferenceType, OffsetType, OffsetAlignment> &ptr)
Chris@16:    {
Chris@16:       this->internal.m_offset =
Chris@16:          static_cast<OffsetType>(ipcdetail::offset_ptr_to_offset_from_other<0>(this, &ptr, ptr.get_offset()));
Chris@16:       return *this;
Chris@16:    }
Chris@16: 
Chris@16:    #ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
Chris@16:    template<class T2>
Chris@101:    typename ipcdetail::enable_if_c<ipcdetail::is_convertible<T2*, PointedType*>::value
Chris@16:                                    && !ipcdetail::offset_ptr_maintains_address<T2, PointedType>::value
Chris@16:                                  , offset_ptr&>::type
Chris@16:       operator= (const offset_ptr<T2, DifferenceType, OffsetType, OffsetAlignment> &ptr)
Chris@16:    {
Chris@16:       this->internal.m_offset =
Chris@16:          static_cast<OffsetType>(ipcdetail::offset_ptr_to_offset<0>(static_cast<PointedType*>(ptr.get()), this));
Chris@16:       return *this;
Chris@16:    }
Chris@16:    #endif
Chris@16: 
Chris@16:    //!offset_ptr += difference_type.
Chris@16:    //!Never throws.
Chris@16:    offset_ptr &operator+= (difference_type offset)
Chris@16:    {  this->inc_offset(offset * sizeof (PointedType));   return *this;  }
Chris@16: 
Chris@16:    //!offset_ptr -= difference_type.
Chris@16:    //!Never throws.
Chris@16:    offset_ptr &operator-= (difference_type offset)
Chris@16:    {  this->dec_offset(offset * sizeof (PointedType));   return *this;  }
Chris@16: 
Chris@16:    //!++offset_ptr.
Chris@16:    //!Never throws.
Chris@16:    offset_ptr& operator++ (void)
Chris@16:    {  this->inc_offset(sizeof (PointedType));   return *this;  }
Chris@16: 
Chris@16:    //!offset_ptr++.
Chris@16:    //!Never throws.
Chris@16:    offset_ptr operator++ (int)
Chris@16:    {
Chris@16:       offset_ptr tmp(*this);
Chris@16:       this->inc_offset(sizeof (PointedType));
Chris@16:       return tmp;
Chris@16:    }
Chris@16: 
Chris@16:    //!--offset_ptr.
Chris@16:    //!Never throws.
Chris@16:    offset_ptr& operator-- (void)
Chris@16:    {  this->dec_offset(sizeof (PointedType));   return *this;  }
Chris@16: 
Chris@16:    //!offset_ptr--.
Chris@16:    //!Never throws.
Chris@16:    offset_ptr operator-- (int)
Chris@16:    {
Chris@16:       offset_ptr tmp(*this);
Chris@16:       this->dec_offset(sizeof (PointedType));
Chris@16:       return tmp;
Chris@16:    }
Chris@16: 
Chris@16:    //!safe bool conversion operator.
Chris@16:    //!Never throws.
Chris@16:    operator unspecified_bool_type() const
Chris@16:    {  return this->internal.m_offset != 1? &self_t::unspecified_bool_type_func : 0;   }
Chris@16: 
Chris@16:    //!Not operator. Not needed in theory, but improves portability.
Chris@16:    //!Never throws
Chris@16:    bool operator! () const
Chris@16:    {  return this->internal.m_offset == 1;   }
Chris@16: 
Chris@16:    //!Compatibility with pointer_traits
Chris@16:    //!
Chris@16:    template <class U>
Chris@16:    struct rebind
Chris@16:    {  typedef offset_ptr<U, DifferenceType, OffsetType, OffsetAlignment> other;  };
Chris@16: 
Chris@16:    //!Compatibility with pointer_traits
Chris@16:    //!
Chris@16:    static offset_ptr pointer_to(reference r)
Chris@16:    { return offset_ptr(&r); }
Chris@16: 
Chris@16:    //!difference_type + offset_ptr
Chris@16:    //!operation
Chris@16:    friend offset_ptr operator+(difference_type diff, offset_ptr right)
Chris@16:    {  right += diff;  return right;  }
Chris@16: 
Chris@16:    //!offset_ptr + difference_type
Chris@16:    //!operation
Chris@16:    friend offset_ptr operator+(offset_ptr left, difference_type diff)
Chris@16:    {  left += diff;  return left; }
Chris@16: 
Chris@16:    //!offset_ptr - diff
Chris@16:    //!operation
Chris@16:    friend offset_ptr operator-(offset_ptr left, difference_type diff)
Chris@16:    {  left -= diff;  return left; }
Chris@16: 
Chris@16:    //!offset_ptr - diff
Chris@16:    //!operation
Chris@16:    friend offset_ptr operator-(difference_type diff, offset_ptr right)
Chris@16:    {  right -= diff; return right; }
Chris@16: 
Chris@16:    //!offset_ptr - offset_ptr
Chris@16:    //!operation
Chris@16:    friend difference_type operator-(const offset_ptr &pt, const offset_ptr &pt2)
Chris@16:    {  return difference_type(pt.get()- pt2.get());   }
Chris@16: 
Chris@16:    //Comparison
Chris@16:    friend bool operator== (const offset_ptr &pt1, const offset_ptr &pt2)
Chris@16:    {  return pt1.get() == pt2.get();  }
Chris@16: 
Chris@16:    friend bool operator!= (const offset_ptr &pt1, const offset_ptr &pt2)
Chris@16:    {  return pt1.get() != pt2.get();  }
Chris@16: 
Chris@16:    friend bool operator<(const offset_ptr &pt1, const offset_ptr &pt2)
Chris@16:    {  return pt1.get() < pt2.get();  }
Chris@16: 
Chris@16:    friend bool operator<=(const offset_ptr &pt1, const offset_ptr &pt2)
Chris@16:    {  return pt1.get() <= pt2.get();  }
Chris@16: 
Chris@16:    friend bool operator>(const offset_ptr &pt1, const offset_ptr &pt2)
Chris@16:    {  return pt1.get() > pt2.get();  }
Chris@16: 
Chris@16:    friend bool operator>=(const offset_ptr &pt1, const offset_ptr &pt2)
Chris@16:    {  return pt1.get() >= pt2.get();  }
Chris@16: 
Chris@16:    //Comparison to raw ptr to support literal 0
Chris@16:    friend bool operator== (pointer pt1, const offset_ptr &pt2)
Chris@16:    {  return pt1 == pt2.get();  }
Chris@16: 
Chris@16:    friend bool operator!= (pointer pt1, const offset_ptr &pt2)
Chris@16:    {  return pt1 != pt2.get();  }
Chris@16: 
Chris@16:    friend bool operator<(pointer pt1, const offset_ptr &pt2)
Chris@16:    {  return pt1 < pt2.get();  }
Chris@16: 
Chris@16:    friend bool operator<=(pointer pt1, const offset_ptr &pt2)
Chris@16:    {  return pt1 <= pt2.get();  }
Chris@16: 
Chris@16:    friend bool operator>(pointer pt1, const offset_ptr &pt2)
Chris@16:    {  return pt1 > pt2.get();  }
Chris@16: 
Chris@16:    friend bool operator>=(pointer pt1, const offset_ptr &pt2)
Chris@16:    {  return pt1 >= pt2.get();  }
Chris@16: 
Chris@16:    //Comparison
Chris@16:    friend bool operator== (const offset_ptr &pt1, pointer pt2)
Chris@16:    {  return pt1.get() == pt2;  }
Chris@16: 
Chris@16:    friend bool operator!= (const offset_ptr &pt1, pointer pt2)
Chris@16:    {  return pt1.get() != pt2;  }
Chris@16: 
Chris@16:    friend bool operator<(const offset_ptr &pt1, pointer pt2)
Chris@16:    {  return pt1.get() < pt2;  }
Chris@16: 
Chris@16:    friend bool operator<=(const offset_ptr &pt1, pointer pt2)
Chris@16:    {  return pt1.get() <= pt2;  }
Chris@16: 
Chris@16:    friend bool operator>(const offset_ptr &pt1, pointer pt2)
Chris@16:    {  return pt1.get() > pt2;  }
Chris@16: 
Chris@16:    friend bool operator>=(const offset_ptr &pt1, pointer pt2)
Chris@16:    {  return pt1.get() >= pt2;  }
Chris@16: 
Chris@16:    friend void swap(offset_ptr &left, offset_ptr &right)
Chris@16:    {
Chris@16:       pointer ptr = right.get();
Chris@16:       right = left;
Chris@16:       left = ptr;
Chris@16:    }
Chris@16: 
Chris@16:    private:
Chris@101:    #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
Chris@16:    void inc_offset(DifferenceType bytes)
Chris@16:    {  internal.m_offset += bytes;   }
Chris@16: 
Chris@16:    void dec_offset(DifferenceType bytes)
Chris@16:    {  internal.m_offset -= bytes;   }
Chris@16: 
Chris@16:    ipcdetail::offset_ptr_internal<OffsetType, OffsetAlignment> internal;
Chris@101:    #endif   //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
Chris@16: };
Chris@16: 
Chris@16: //!operator<<
Chris@16: //!for offset ptr
Chris@16: template<class E, class T, class W, class X, class Y, std::size_t Z>
Chris@16: inline std::basic_ostream<E, T> & operator<<
Chris@16:    (std::basic_ostream<E, T> & os, offset_ptr<W, X, Y, Z> const & p)
Chris@16: {  return os << p.get_offset();   }
Chris@16: 
Chris@16: //!operator>>
Chris@16: //!for offset ptr
Chris@16: template<class E, class T, class W, class X, class Y, std::size_t Z>
Chris@16: inline std::basic_istream<E, T> & operator>>
Chris@16:    (std::basic_istream<E, T> & is, offset_ptr<W, X, Y, Z> & p)
Chris@16: {  return is >> p.get_offset();  }
Chris@16: 
Chris@16: //!Simulation of static_cast between pointers. Never throws.
Chris@16: template<class T1, class P1, class O1, std::size_t A1, class T2, class P2, class O2, std::size_t A2>
Chris@16: inline boost::interprocess::offset_ptr<T1, P1, O1, A1>
Chris@16:    static_pointer_cast(const boost::interprocess::offset_ptr<T2, P2, O2, A2> & r)
Chris@16: {
Chris@16:    return boost::interprocess::offset_ptr<T1, P1, O1, A1>
Chris@16:             (r, boost::interprocess::ipcdetail::static_cast_tag());
Chris@16: }
Chris@16: 
Chris@16: //!Simulation of const_cast between pointers. Never throws.
Chris@16: template<class T1, class P1, class O1, std::size_t A1, class T2, class P2, class O2, std::size_t A2>
Chris@16: inline boost::interprocess::offset_ptr<T1, P1, O1, A1>
Chris@16:    const_pointer_cast(const boost::interprocess::offset_ptr<T2, P2, O2, A2> & r)
Chris@16: {
Chris@16:    return boost::interprocess::offset_ptr<T1, P1, O1, A1>
Chris@16:             (r, boost::interprocess::ipcdetail::const_cast_tag());
Chris@16: }
Chris@16: 
Chris@16: //!Simulation of dynamic_cast between pointers. Never throws.
Chris@16: template<class T1, class P1, class O1, std::size_t A1, class T2, class P2, class O2, std::size_t A2>
Chris@16: inline boost::interprocess::offset_ptr<T1, P1, O1, A1>
Chris@16:    dynamic_pointer_cast(const boost::interprocess::offset_ptr<T2, P2, O2, A2> & r)
Chris@16: {
Chris@16:    return boost::interprocess::offset_ptr<T1, P1, O1, A1>
Chris@16:             (r, boost::interprocess::ipcdetail::dynamic_cast_tag());
Chris@16: }
Chris@16: 
Chris@16: //!Simulation of reinterpret_cast between pointers. Never throws.
Chris@16: template<class T1, class P1, class O1, std::size_t A1, class T2, class P2, class O2, std::size_t A2>
Chris@16: inline boost::interprocess::offset_ptr<T1, P1, O1, A1>
Chris@16:    reinterpret_pointer_cast(const boost::interprocess::offset_ptr<T2, P2, O2, A2> & r)
Chris@16: {
Chris@16:    return boost::interprocess::offset_ptr<T1, P1, O1, A1>
Chris@16:             (r, boost::interprocess::ipcdetail::reinterpret_cast_tag());
Chris@16: }
Chris@16: 
Chris@16: }  //namespace interprocess {
Chris@16: 
Chris@101: #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
Chris@16: 
Chris@101: ///has_trivial_destructor<> == true_type specialization for optimizations
Chris@16: template <class T, class P, class O, std::size_t A>
Chris@101: struct has_trivial_destructor< ::boost::interprocess::offset_ptr<T, P, O, A> >
Chris@16: {
Chris@16:    static const bool value = true;
Chris@16: };
Chris@16: 
Chris@101: namespace move_detail {
Chris@101: 
Chris@16: ///has_trivial_destructor<> == true_type specialization for optimizations
Chris@16: template <class T, class P, class O, std::size_t A>
Chris@101: struct is_trivially_destructible< ::boost::interprocess::offset_ptr<T, P, O, A> >
Chris@16: {
Chris@16:    static const bool value = true;
Chris@16: };
Chris@16: 
Chris@101: }  //namespace move_detail {
Chris@16: 
Chris@16: namespace interprocess {
Chris@16: 
Chris@16: //!to_raw_pointer() enables boost::mem_fn to recognize offset_ptr.
Chris@16: //!Never throws.
Chris@16: template <class T, class P, class O, std::size_t A>
Chris@16: inline T * to_raw_pointer(boost::interprocess::offset_ptr<T, P, O, A> const & p)
Chris@16: {  return ipcdetail::to_raw_pointer(p);   }
Chris@16: 
Chris@16: }  //namespace interprocess
Chris@16: 
Chris@16: 
Chris@101: #endif   //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
Chris@16: }  //namespace boost {
Chris@16: 
Chris@101: #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
Chris@16: 
Chris@16: namespace boost{
Chris@16: 
Chris@16: //This is to support embedding a bit in the pointer
Chris@16: //for intrusive containers, saving space
Chris@16: namespace intrusive {
Chris@16: 
Chris@16: //Predeclaration to avoid including header
Chris@16: template<class VoidPointer, std::size_t N>
Chris@16: struct max_pointer_plus_bits;
Chris@16: 
Chris@16: template<std::size_t OffsetAlignment, class P, class O, std::size_t A>
Chris@16: struct max_pointer_plus_bits<boost::interprocess::offset_ptr<void, P, O, A>, OffsetAlignment>
Chris@16: {
Chris@16:    //The offset ptr can embed one bit less than the alignment since it
Chris@16:    //uses offset == 1 to store the null pointer.
Chris@16:    static const std::size_t value = ::boost::interprocess::ipcdetail::ls_zeros<OffsetAlignment>::value - 1;
Chris@16: };
Chris@16: 
Chris@16: //Predeclaration
Chris@16: template<class Pointer, std::size_t NumBits>
Chris@16: struct pointer_plus_bits;
Chris@16: 
Chris@16: template<class T, class P, class O, std::size_t A, std::size_t NumBits>
Chris@16: struct pointer_plus_bits<boost::interprocess::offset_ptr<T, P, O, A>, NumBits>
Chris@16: {
Chris@16:    typedef boost::interprocess::offset_ptr<T, P, O, A>      pointer;
Chris@16:    typedef ::boost::interprocess::pointer_size_t_caster<T*> caster_t;
Chris@16:    //Bits are stored in the lower bits of the pointer except the LSB,
Chris@16:    //because this bit is used to represent the null pointer.
Chris@16:    static const std::size_t Mask = ((std::size_t(1) << NumBits) - 1) << 1u;
Chris@16: 
Chris@16:    static pointer get_pointer(const pointer &n)
Chris@16:    {
Chris@16:       caster_t caster(n.get());
Chris@16:       return pointer(caster_t(caster.size() & ~Mask).pointer());
Chris@16:    }
Chris@16: 
Chris@16:    static void set_pointer(pointer &n, const pointer &p)
Chris@16:    {
Chris@16:       caster_t n_caster(n.get());
Chris@16:       caster_t p_caster(p.get());
Chris@16:       BOOST_ASSERT(0 == (p_caster.size() & Mask));
Chris@16:       n = caster_t(p_caster.size() | (n_caster.size() & Mask)).pointer();
Chris@16:    }
Chris@16: 
Chris@16:    static std::size_t get_bits(const pointer &n)
Chris@16:    {  return (caster_t(n.get()).size() & Mask) >> 1u;  }
Chris@16: 
Chris@16:    static void set_bits(pointer &n, std::size_t b)
Chris@16:    {
Chris@16:       BOOST_ASSERT(b < (std::size_t(1) << NumBits));
Chris@16:       caster_t n_caster(n.get());
Chris@16:       n = caster_t((n_caster.size() & ~Mask) | (b << 1u)).pointer();
Chris@16:    }
Chris@16: };
Chris@16: 
Chris@16: }  //namespace intrusive
Chris@16: 
Chris@16: //Predeclaration
Chris@16: template<class T, class U>
Chris@16: struct pointer_to_other;
Chris@16: 
Chris@16: //Backwards compatibility with pointer_to_other
Chris@16: template <class PointedType, class DifferenceType, class OffsetType, std::size_t OffsetAlignment, class U>
Chris@16: struct pointer_to_other
Chris@16:    < ::boost::interprocess::offset_ptr<PointedType, DifferenceType, OffsetType, OffsetAlignment>, U >
Chris@16: {
Chris@16:    typedef ::boost::interprocess::offset_ptr<U, DifferenceType, OffsetType, OffsetAlignment> type;
Chris@16: };
Chris@16: 
Chris@16: }  //namespace boost{
Chris@101: #endif   //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
Chris@16: 
Chris@16: #include <boost/interprocess/detail/config_end.hpp>
Chris@16: 
Chris@16: #endif //#ifndef BOOST_INTERPROCESS_OFFSET_PTR_HPP