EVOLUTION-MANAGER

Edit File: intersegment_ptr.hpp

//////////////////////////////////////////////////////////////////////////////
//
// (C) Copyright Ion Gaztanaga 2005-2012. Distributed under 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)
//
// See http://www.boost.org/libs/interprocess for documentation.
//
//////////////////////////////////////////////////////////////////////////////

#ifndef BOOST_INTERPROCESS_INTERSEGMENT_PTR_HPP
#define BOOST_INTERPROCESS_INTERSEGMENT_PTR_HPP

#ifndef BOOST_CONFIG_HPP
# include <boost/config.hpp>
#endif
#
#if defined(BOOST_HAS_PRAGMA_ONCE)
# pragma once
#endif

#include <boost/interprocess/detail/config_begin.hpp>
#include <boost/interprocess/detail/workaround.hpp>
// interprocess
#include <boost/interprocess/interprocess_fwd.hpp>
#include <boost/interprocess/sync/scoped_lock.hpp>
#include <boost/interprocess/sync/interprocess_mutex.hpp>
#include <boost/interprocess/containers/flat_map.hpp>
#include <boost/interprocess/containers/vector.hpp> //vector
#include <boost/interprocess/containers/set.hpp> //set
// interprocess/detail
#include <boost/interprocess/detail/multi_segment_services.hpp>
#include <boost/interprocess/detail/utilities.hpp>
#include <boost/interprocess/detail/math_functions.hpp>
#include <boost/interprocess/detail/cast_tags.hpp>
#include <boost/interprocess/detail/mpl.hpp>
// other boost
#include <boost/core/no_exceptions_support.hpp>
#include <boost/static_assert.hpp> //BOOST_STATIC_ASSERT
#include <boost/integer/static_log2.hpp>
#include <boost/assert.hpp> //BOOST_ASSERT
// std
#include <climits> //CHAR_BIT

//!\file
//!
namespace boost {

//Predeclarations
template <class T>
struct has_trivial_constructor;

template <class T>
struct has_trivial_destructor;

namespace interprocess {

template <class T>
struct is_multisegment_ptr;

struct intersegment_base
{
 typedef intersegment_base self_t;
 BOOST_STATIC_ASSERT((sizeof(std::size_t) == sizeof(void*)));
 BOOST_STATIC_ASSERT((sizeof(void*)*CHAR_BIT == 32 || sizeof(void*)*CHAR_BIT == 64));
 static const std::size_t size_t_bits = (sizeof(void*)*CHAR_BIT == 32) ? 32 : 64;
 static const std::size_t ctrl_bits = 2;
 static const std::size_t align_bits = 12;
 static const std::size_t align = std::size_t(1) << align_bits;
 static const std::size_t max_segment_size_bits = size_t_bits - 2;
 static const std::size_t max_segment_size = std::size_t(1) << max_segment_size_bits;

static const std::size_t begin_bits = max_segment_size_bits - align_bits;
 static const std::size_t pow_size_bits_helper = static_log2<max_segment_size_bits>::value;
 static const std::size_t pow_size_bits =
 (max_segment_size_bits == (std::size_t(1) << pow_size_bits_helper)) ?
 pow_size_bits_helper : pow_size_bits_helper + 1;
 static const std::size_t frc_size_bits =
 size_t_bits - ctrl_bits - begin_bits - pow_size_bits;

BOOST_STATIC_ASSERT(((size_t_bits - pow_size_bits - frc_size_bits) >= ctrl_bits ));

static const std::size_t relative_size_bits =
      size_t_bits - max_segment_size_bits - ctrl_bits;

static const std::size_t is_pointee_outside  = 0;
   static const std::size_t is_in_stack         = 1;
   static const std::size_t is_relative         = 2;
   static const std::size_t is_segmented        = 3;
   static const std::size_t is_max_mode         = 4;

intersegment_base()
   {
      this->set_mode(is_pointee_outside);
      this->set_null();
   }

struct relative_addressing
   {
      std::size_t ctrl     :  2;
      std::size_t pow      :  pow_size_bits;
      std::size_t frc      :  frc_size_bits;
      std::size_t beg      :  begin_bits;
      std::ptrdiff_t off   :  sizeof(std::ptrdiff_t)*CHAR_BIT - 2;
      std::ptrdiff_t bits  :  2;
   };

struct direct_addressing
   {
      std::size_t ctrl     :  2;
      std::size_t dummy    :  sizeof(std::size_t)*CHAR_BIT - 2;
      void * addr;
   };

struct segmented_addressing
   {
      std::size_t ctrl     :  2;
      std::size_t segment  :  sizeof(std::size_t)*CHAR_BIT - 2;
      std::size_t off      :  sizeof(std::size_t)*CHAR_BIT - 2;
      std::size_t bits     :  2;
   };

union members_t{
      relative_addressing  relative;
      direct_addressing    direct;
      segmented_addressing segmented;
   } members;

BOOST_STATIC_ASSERT(sizeof(members_t) == 2*sizeof(std::size_t));

void *relative_calculate_begin_addr() const
 {
 const std::size_t mask = ~(align - 1);
 std::size_t beg = this->members.relative.beg;
 return reinterpret_cast<void*>((((std::size_t)this) & mask) - (beg << align_bits));
 }

void relative_set_begin_from_base(void *addr)
 {
 BOOST_ASSERT(addr < static_cast<void*>(this));
 std::size_t off = reinterpret_cast<char*>(this) - reinterpret_cast<char*>(addr);
 members.relative.beg = off >> align_bits;
 }

//!Obtains the address pointed by the
 //!object
 std::size_t relative_size() const
 {
 std::size_t pow = members.relative.pow;
 std::size_t size = (std::size_t(1u) << pow);
 BOOST_ASSERT(pow >= frc_size_bits);
 size |= members.relative.frc << (pow - frc_size_bits);
 return size;
 }

static std::size_t calculate_size(std::size_t orig_size, std::size_t &pow, std::size_t &frc)
 {
 if(orig_size < align)
 orig_size = align;
 orig_size = ipcdetail::get_rounded_size_po2(orig_size, align);
 pow = ipcdetail::floor_log2(orig_size);
 std::size_t low_size = (std::size_t(1) << pow);
 std::size_t diff = orig_size - low_size;
 BOOST_ASSERT(pow >= frc_size_bits);
 std::size_t rounded = ipcdetail::get_rounded_size_po2
 (diff, (std::size_t)(1u << (pow - frc_size_bits)));
 if(rounded == low_size){
 ++pow;
 frc = 0;
 rounded = 0;
 }
 else{
 frc = rounded >> (pow - frc_size_bits);
 }
 BOOST_ASSERT(((frc << (pow - frc_size_bits)) & (align-1))==0);
 return low_size + rounded;
 }

std::size_t get_mode()const
   {  return members.direct.ctrl;   }

void set_mode(std::size_t mode)
 {
 BOOST_ASSERT(mode < is_max_mode);
 members.direct.ctrl = mode;
 }

//!Returns true if object represents
 //!null pointer
 bool is_null() const
 {
 return (this->get_mode() < is_relative) &&
 !members.direct.dummy &&
 !members.direct.addr;
 }

//!Sets the object to represent
   //!the null pointer
   void set_null()
   {
      if(this->get_mode() >= is_relative){
         this->set_mode(is_pointee_outside);
      }
      members.direct.dummy = 0;
      members.direct.addr  = 0;
   }

static std::size_t round_size(std::size_t orig_size)
   {
      std::size_t pow, frc;
      return calculate_size(orig_size, pow, frc);
   }
};

//!Configures intersegment_ptr with the capability to address:
//!2^(sizeof(std::size_t)*CHAR_BIT/2) segment groups
//!2^(sizeof(std::size_t)*CHAR_BIT/2) segments per group.
//!2^(sizeof(std::size_t)*CHAR_BIT/2)-1 bytes maximum per segment.
//!The mapping is implemented through flat_maps synchronized with mutexes.
template <class Mutex>
struct flat_map_intersegment
 : public intersegment_base
{
 typedef flat_map_intersegment<Mutex> self_t;

void set_from_pointer(const volatile void *ptr)
 { this->set_from_pointer(const_cast<const void *>(ptr)); }

//!Obtains the address pointed
 //!by the object
 void *to_raw_pointer() const
 {
 if(is_null()){
 return 0;
 }
 switch(this->get_mode()){
 case is_relative:
 return const_cast<char*>(reinterpret_cast<const char*>(this)) + members.relative.off;
 break;
 case is_segmented:
 {
 segment_info_t segment_info;
 std::size_t offset;
 void *this_base;
 get_segment_info_and_offset(this, segment_info, offset, this_base);
 char *base = static_cast<char*>(segment_info.group->address_of(this->members.segmented.segment));
 return base + this->members.segmented.off;
 }
 break;
 case is_in_stack:
 case is_pointee_outside:
 return members.direct.addr;
 break;
 default:
 return 0;
 break;
 }
 }

//!Calculates the distance between two basic_intersegment_ptr-s.
 //!This only works with two basic_intersegment_ptr pointing
 //!to the same segment. Otherwise undefined
 std::ptrdiff_t diff(const self_t &other) const
 { return static_cast<char*>(this->to_raw_pointer()) - static_cast<char*>(other.to_raw_pointer()); }

//!Returns true if both point to
   //!the same object
   bool equal(const self_t &y) const
   {  return this->to_raw_pointer() == y.to_raw_pointer();  }

//!Returns true if *this is less than other.
 //!This only works with two basic_intersegment_ptr pointing
 //!to the same segment group. Otherwise undefined. Never throws
 bool less(const self_t &y) const
 { return this->to_raw_pointer() < y.to_raw_pointer(); }

void swap(self_t &other)
   {
      void *ptr_this  = this->to_raw_pointer();
      void *ptr_other = other.to_raw_pointer();
      other.set_from_pointer(ptr_this);
      this->set_from_pointer(ptr_other);
   }

//!Sets the object internals to represent the
   //!address pointed by ptr
   void set_from_pointer(const void *ptr)
   {
      if(!ptr){
         this->set_null();
         return;
      }

std::size_t mode = this->get_mode();
 if(mode == is_in_stack){
 members.direct.addr = const_cast<void*>(ptr);
 return;
 }
 if(mode == is_relative){
 char *beg_addr = static_cast<char*>(this->relative_calculate_begin_addr());
 std::size_t seg_size = this->relative_size();
 if(ptr >= beg_addr && ptr < (beg_addr + seg_size)){
 members.relative.off = static_cast<const char*>(ptr) - reinterpret_cast<const char*>(this);
 return;
 }
 }
 std::size_t ptr_offset;
 std::size_t this_offset;
 segment_info_t ptr_info;
 segment_info_t this_info;
 void *ptr_base;
 void *this_base;
 get_segment_info_and_offset(this, this_info, this_offset, this_base);

if(!this_info.group){
 this->set_mode(is_in_stack);
 this->members.direct.addr = const_cast<void*>(ptr);
 }
 else{
 get_segment_info_and_offset(ptr, ptr_info, ptr_offset, ptr_base);

if(ptr_info.group != this_info.group){
 this->set_mode(is_pointee_outside);
 this->members.direct.addr = const_cast<void*>(ptr);
 }
 else if(ptr_info.id == this_info.id){
 this->set_mode(is_relative);
 members.relative.off = (static_cast<const char*>(ptr) - reinterpret_cast<const char*>(this));
 this->relative_set_begin_from_base(this_base);
 std::size_t pow, frc;
 std::size_t s = calculate_size(this_info.size, pow, frc);
 (void)s;
 BOOST_ASSERT(this_info.size == s);
 this->members.relative.pow = pow;
 this->members.relative.frc = frc;
 }
 else{
 this->set_mode(is_segmented);
 this->members.segmented.segment = ptr_info.id;
 this->members.segmented.off = ptr_offset;
 }
 }
 }

//!Sets the object internals to represent the address pointed
   //!by another flat_map_intersegment
   void set_from_other(const self_t &other)
   {
      this->set_from_pointer(other.to_raw_pointer());
   }

//!Increments internal
 //!offset
 void inc_offset(std::ptrdiff_t bytes)
 {
 this->set_from_pointer(static_cast<char*>(this->to_raw_pointer()) + bytes);
 }

//!Decrements internal
 //!offset
 void dec_offset(std::ptrdiff_t bytes)
 {
 this->set_from_pointer(static_cast<char*>(this->to_raw_pointer()) - bytes);
 }

//////////////////////////////////////
   //////////////////////////////////////
   //////////////////////////////////////

flat_map_intersegment()
      :  intersegment_base()
   {}

~flat_map_intersegment()
   {}

private:

class segment_group_t
 {
 struct segment_data
 {
 void *addr;
 std::size_t size;
 };
 vector<segment_data> m_segments;
 multi_segment_services &m_ms_services;

public:
      segment_group_t(multi_segment_services &ms_services)
         :  m_ms_services(ms_services)
      {}

void push_back(void *addr, std::size_t size)
      {
         segment_data d = { addr, size };
         m_segments.push_back(d);
      }

void pop_back()
      {
         BOOST_ASSERT(!m_segments.empty());
         m_segments.erase(--m_segments.end());
      }

void *address_of(std::size_t segment_id)
 {
 BOOST_ASSERT(segment_id < (std::size_t)m_segments.size());
 return m_segments[segment_id].addr;
 }

void clear_segments()
      {  m_segments.clear();  }

std::size_t get_size() const
      {  return m_segments.size();  }

multi_segment_services &get_multi_segment_services() const
      {  return m_ms_services;   }

friend bool operator< (const segment_group_t&l, const segment_group_t &r)
 { return &l.m_ms_services < &r.m_ms_services; }
 };

struct segment_info_t
   {
      std::size_t size;
      std::size_t id;
      segment_group_t *group;
      segment_info_t()
         :  size(0), id(0), group(0)
      {}
   };

typedef set<segment_group_t> segment_groups_t;

typedef boost::interprocess::flat_map
 <const void *
 ,segment_info_t
 ,std::less<const void *> > ptr_to_segment_info_t;

struct mappings_t : Mutex
   {
      //!Mutex to preserve integrity in multi-threaded
      //!enviroments
      typedef Mutex        mutex_type;
      //!Maps base addresses and segment information
      //!(size and segment group and id)*

ptr_to_segment_info_t      m_ptr_to_segment_info;

~mappings_t()
      {
         //Check that all mappings have been erased
         BOOST_ASSERT(m_ptr_to_segment_info.empty());
      }
   };

//Static members
   static mappings_t       s_map;
   static segment_groups_t s_groups;
   public:

typedef segment_group_t*      segment_group_id;

//!Returns the segment and offset
 //!of an address
 static void get_segment_info_and_offset(const void *ptr, segment_info_t &segment, std::size_t &offset, void *&base)
 {
 //------------------------------------------------------------------
 boost::interprocess::scoped_lock<typename mappings_t::mutex_type> lock(s_map);
 //------------------------------------------------------------------
 base = 0;
 if(s_map.m_ptr_to_segment_info.empty()){
 segment = segment_info_t();
 offset = reinterpret_cast<const char*>(ptr) - static_cast<const char*>(0);
 return;
 }
 //Find the first base address greater than ptr
 typename ptr_to_segment_info_t::iterator it
 = s_map.m_ptr_to_segment_info.upper_bound(ptr);
 if(it == s_map.m_ptr_to_segment_info.begin()){
 segment = segment_info_t();
 offset = reinterpret_cast<const char*>(ptr) - static_cast<const char *>(0);
 }
 //Go to the previous one
 --it;
 char * segment_base = const_cast<char*>(reinterpret_cast<const char*>(it->first));
 std::size_t segment_size = it->second.size;

if(segment_base <= reinterpret_cast<const char*>(ptr) &&
 (segment_base + segment_size) >= reinterpret_cast<const char*>(ptr)){
 segment = it->second;
 offset = reinterpret_cast<const char*>(ptr) - segment_base;
 base = segment_base;
 }
 else{
 segment = segment_info_t();
 offset = reinterpret_cast<const char*>(ptr) - static_cast<const char*>(0);
 }
 }

//!Associates a segment defined by group/id with a base address and size.
 //!Returns false if the group is not found or there is an error
 static void insert_mapping(segment_group_id group_id, void *ptr, std::size_t size)
 {
 //------------------------------------------------------------------
 boost::interprocess::scoped_lock<typename mappings_t::mutex_type> lock(s_map);
 //------------------------------------------------------------------

typedef typename ptr_to_segment_info_t::value_type value_type;
 typedef typename ptr_to_segment_info_t::iterator iterator;
 typedef std::pair<iterator, bool> it_b_t;

segment_info_t info;
      info.group = group_id;
      info.size  = size;
      info.id    = group_id->get_size();

it_b_t ret = s_map.m_ptr_to_segment_info.insert(value_type(ptr, info));
      BOOST_ASSERT(ret.second);

value_eraser<ptr_to_segment_info_t> v_eraser(s_map.m_ptr_to_segment_info, ret.first);
 group_id->push_back(ptr, size);
 v_eraser.release();
 }

static bool erase_last_mapping(segment_group_id group_id)
 {
 //------------------------------------------------------------------
 boost::interprocess::scoped_lock<typename mappings_t::mutex_type> lock(s_map);
 //------------------------------------------------------------------
 if(!group_id->get_size()){
 return false;
 }
 else{
 void *addr = group_id->address_of(group_id->get_size()-1);
 group_id->pop_back();
 std::size_t erased = s_map.m_ptr_to_segment_info.erase(addr);
 (void)erased;
 BOOST_ASSERT(erased);
 return true;
 }
 }

static segment_group_id new_segment_group(multi_segment_services *services)
 {
 { //------------------------------------------------------------------
 boost::interprocess::scoped_lock<typename mappings_t::mutex_type> lock(s_map);
 //------------------------------------------------------------------
 typedef typename segment_groups_t::iterator iterator;
 std::pair<iterator, bool> ret =
 s_groups.insert(segment_group_t(*services));
 BOOST_ASSERT(ret.second);
 return &*ret.first;
 }
 }

static bool delete_group(segment_group_id id)
 {
 { //------------------------------------------------------------------
 boost::interprocess::scoped_lock<typename mappings_t::mutex_type> lock(s_map);
 //------------------------------------------------------------------
 bool success = 1u == s_groups.erase(segment_group_t(*id));
 if(success){
 typedef typename ptr_to_segment_info_t::iterator ptr_to_segment_info_it;
 ptr_to_segment_info_it it(s_map.m_ptr_to_segment_info.begin());
 while(it != s_map.m_ptr_to_segment_info.end()){
 if(it->second.group == id){
 it = s_map.m_ptr_to_segment_info.erase(it);
 }
 else{
 ++it;
 }
 }
 }
 return success;
 }
 }
};

//!Static map-segment_info associated with
//!flat_map_intersegment<>
template <class Mutex>
typename flat_map_intersegment<Mutex>::mappings_t
 flat_map_intersegment<Mutex>::s_map;

//!Static segment group container associated with
//!flat_map_intersegment<>
template <class Mutex>
typename flat_map_intersegment<Mutex>::segment_groups_t
 flat_map_intersegment<Mutex>::s_groups;

//!A smart pointer that can point to a pointee that resides in another memory
//!memory mapped or shared memory segment.
template <class T>
class intersegment_ptr : public flat_map_intersegment<interprocess_mutex>
{
 typedef flat_map_intersegment<interprocess_mutex> PT;
 typedef intersegment_ptr<T> self_t;
 typedef PT base_t;

void unspecified_bool_type_func() const {}
   typedef void (self_t::*unspecified_bool_type)() const;

public:
 typedef T * pointer;
 typedef typename ipcdetail::add_reference<T>::type reference;
 typedef T value_type;
 typedef std::ptrdiff_t difference_type;
 typedef std::random_access_iterator_tag iterator_category;

public:   //Public Functions

//!Constructor from raw pointer (allows "0" pointer conversion).
   //!Never throws.
   intersegment_ptr(pointer ptr = 0)
   {  base_t::set_from_pointer(ptr);   }

//!Constructor from other pointer.
 //!Never throws.
 template <class U>
 intersegment_ptr(U *ptr){ base_t::set_from_pointer(pointer(ptr)); }

//!Constructor from other intersegment_ptr
   //!Never throws
   intersegment_ptr(const intersegment_ptr& ptr)
   {  base_t::set_from_other(ptr);   }

//!Constructor from other intersegment_ptr. If pointers of pointee types are
 //!convertible, intersegment_ptrs will be convertibles. Never throws.
 template<class T2>
 intersegment_ptr(const intersegment_ptr<T2> &ptr)
 { pointer p(ptr.get()); (void)p; base_t::set_from_other(ptr); }

//!Emulates static_cast operator.
 //!Never throws.
 template<class U>
 intersegment_ptr(const intersegment_ptr &r, ipcdetail::static_cast_tag)
 { base_t::set_from_pointer(static_cast<T*>(r.get())); }

//!Emulates const_cast operator.
 //!Never throws.
 template<class U>
 intersegment_ptr(const intersegment_ptr &r, ipcdetail::const_cast_tag)
 { base_t::set_from_pointer(const_cast<T*>(r.get())); }

//!Emulates dynamic_cast operator.
 //!Never throws.
 template<class U>
 intersegment_ptr(const intersegment_ptr &r, ipcdetail::dynamic_cast_tag)
 { base_t::set_from_pointer(dynamic_cast<T*>(r.get())); }

//!Emulates reinterpret_cast operator.
 //!Never throws.
 template<class U>
 intersegment_ptr(const intersegment_ptr &r, ipcdetail::reinterpret_cast_tag)
 { base_t::set_from_pointer(reinterpret_cast<T*>(r.get())); }

//!Obtains raw pointer from offset.
 //!Never throws.
 pointer get()const
 { return static_cast<pointer>(base_t::to_raw_pointer()); }

//!Pointer-like -> operator. It can return 0 pointer.
   //!Never throws.
   pointer operator->() const
   {  return self_t::get(); }

//!Dereferencing operator, if it is a null intersegment_ptr behavior
   //!is undefined. Never throws.
   reference operator* () const
   {  return *(self_t::get());   }

//!Indexing operator.
   //!Never throws.
   reference operator[](std::ptrdiff_t idx) const
   {  return self_t::get()[idx];  }

//!Assignment from pointer (saves extra conversion).
   //!Never throws.
   intersegment_ptr& operator= (pointer from)
   {  base_t::set_from_pointer(from); return *this;  }

//!Assignment from other intersegment_ptr.
   //!Never throws.
   intersegment_ptr& operator= (const intersegment_ptr &ptr)
   {  base_t::set_from_other(ptr);  return *this;  }

//!Assignment from related intersegment_ptr. If pointers of pointee types
 //!are assignable, intersegment_ptrs will be assignable. Never throws.
 template <class T2>
 intersegment_ptr& operator= (const intersegment_ptr<T2> & ptr)
 {
 pointer p(ptr.get()); (void)p;
 base_t::set_from_other(ptr); return *this;
 }

//!intersegment_ptr + std::ptrdiff_t.
   //!Never throws.
   intersegment_ptr operator+ (std::ptrdiff_t idx) const
   {
      intersegment_ptr result (*this);
      result.inc_offset(idx*sizeof(T));
      return result;
   }

//!intersegment_ptr - std::ptrdiff_t.
   //!Never throws.
   intersegment_ptr operator- (std::ptrdiff_t idx) const
   {
      intersegment_ptr result (*this);
      result.dec_offset(idx*sizeof(T));
      return result;
   }

//!intersegment_ptr += std::ptrdiff_t.
   //!Never throws.
   intersegment_ptr &operator+= (std::ptrdiff_t offset)
   {  base_t::inc_offset(offset*sizeof(T));  return *this;  }

//!intersegment_ptr -= std::ptrdiff_t.
   //!Never throws.
   intersegment_ptr &operator-= (std::ptrdiff_t offset)
   {  base_t::dec_offset(offset*sizeof(T));  return *this;  }

//!++intersegment_ptr.
   //!Never throws.
   intersegment_ptr& operator++ (void)
   {  base_t::inc_offset(sizeof(T));   return *this;  }

//!intersegment_ptr++.
   //!Never throws.
   intersegment_ptr operator++ (int)
   {  intersegment_ptr temp(*this); ++*this; return temp; }

//!--intersegment_ptr.
   //!Never throws.
   intersegment_ptr& operator-- (void)
   {  base_t::dec_offset(sizeof(T));   return *this;  }

//!intersegment_ptr--.
   //!Never throws.
   intersegment_ptr operator-- (int)
   {  intersegment_ptr temp(*this); --*this; return temp; }

//!Safe bool conversion operator.
   //!Never throws.
   operator unspecified_bool_type() const
   {  return base_t::is_null()? 0 : &self_t::unspecified_bool_type_func;   }

//!Not operator. Not needed in theory, but improves portability.
   //!Never throws.
   bool operator! () const
   {  return base_t::is_null();   }

//!Swaps two intersegment_ptr-s. More efficient than standard swap.
   //!Never throws.
   void swap(intersegment_ptr &other)
   {  base_t::swap(other);   }

//!Calculates the distance between two intersegment_ptr-s.
 //!This only works with two basic_intersegment_ptr pointing
 //!to the same segment. Otherwise undefined
 template <class T2>
 std::ptrdiff_t _diff(const intersegment_ptr<T2> &other) const
 { return base_t::diff(other); }

//!Returns true if both point to the
 //!same object
 template <class T2>
 bool _equal(const intersegment_ptr<T2>&other) const
 { return base_t::equal(other); }

//!Compares the equality of two intersegment_ptr-s.
//!Never throws.
template <class T1, class T2> inline
bool operator ==(const intersegment_ptr<T1> &left,
 const intersegment_ptr<T2> &right)
{
 //Make sure both pointers can be compared
 bool e = typename intersegment_ptr<T1>::pointer(0) ==
 typename intersegment_ptr<T2>::pointer(0);
 (void)e;
 return left._equal(right);
}

//!Returns true if *this is less than other.
//!This only works with two basic_intersegment_ptr pointing
//!to the same segment group. Otherwise undefined. Never throws
template <class T1, class T2> inline
bool operator <(const intersegment_ptr<T1> &left,
 const intersegment_ptr<T2> &right)
{
 //Make sure both pointers can be compared
 bool e = typename intersegment_ptr<T1>::pointer(0) <
 typename intersegment_ptr<T2>::pointer(0);
 (void)e;
 return left._less(right);
}

template<class T1, class T2> inline
bool operator!= (const intersegment_ptr<T1> &pt1,
 const intersegment_ptr<T2> &pt2)
{ return !(pt1 ==pt2); }

//!intersegment_ptr<T1> <= intersegment_ptr<T2>.
//!Never throws.
template<class T1, class T2> inline
bool operator<= (const intersegment_ptr<T1> &pt1,
 const intersegment_ptr<T2> &pt2)
{ return !(pt1 > pt2); }

//!intersegment_ptr<T1> > intersegment_ptr<T2>.
//!Never throws.
template<class T1, class T2> inline
bool operator> (const intersegment_ptr<T1> &pt1,
 const intersegment_ptr<T2> &pt2)
{ return (pt2 < pt1); }

//!intersegment_ptr<T1> >= intersegment_ptr<T2>.
//!Never throws.
template<class T1, class T2> inline
bool operator>= (const intersegment_ptr<T1> &pt1,
 const intersegment_ptr<T2> &pt2)
{ return !(pt1 < pt2); }

//!operator<<
template<class E, class T, class U> inline
std::basic_ostream<E, T> & operator<<
 (std::basic_ostream<E, T> & os, const intersegment_ptr & p)
{ return os << p.get(); }

//!operator>>
template<class E, class T, class U> inline
std::basic_istream<E, T> & operator>>
 (std::basic_istream<E, T> & os, intersegment_ptr & p)
{ U * tmp; return os >> tmp; p = tmp; }

//!std::ptrdiff_t + intersegment_ptr.
//!The result is another pointer of the same segment
template<class T> inline
intersegment_ptr<T> operator+
 (std::ptrdiff_t diff, const intersegment_ptr<T>& right)
{ return right + diff; }

//!intersegment_ptr - intersegment_ptr.
//!This only works with two intersegment_ptr-s that point to the
//!same segment
template <class T, class T2> inline
std::ptrdiff_t operator- (const intersegment_ptr<T> &pt,
 const intersegment_ptr<T2> &pt2)
{ return pt._diff(pt2)/sizeof(T); }

//! swap specialization
template<class T> inline
void swap (boost::interprocess::intersegment_ptr<T> &pt,
 boost::interprocess::intersegment_ptr<T> &pt2)
{ pt.swap(pt2); }

//!to_raw_pointer() enables boost::mem_fn to recognize intersegment_ptr.
//!Never throws.
template<class T> inline
T * to_raw_pointer(boost::interprocess::intersegment_ptr<T> const & p)
{ return p.get(); }

//!Simulation of static_cast between pointers.
//!Never throws.
template<class T, class U> inline
boost::interprocess::intersegment_ptr<T> static_pointer_cast(const boost::interprocess::intersegment_ptr &r)
{ return boost::interprocess::intersegment_ptr<T>(r, boost::interprocess::ipcdetail::static_cast_tag()); }

//!Simulation of const_cast between pointers.
//!Never throws.
template<class T, class U> inline
boost::interprocess::intersegment_ptr<T> const_pointer_cast(const boost::interprocess::intersegment_ptr &r)
{ return boost::interprocess::intersegment_ptr<T>(r, boost::interprocess::ipcdetail::const_cast_tag()); }

//!Simulation of dynamic_cast between pointers.
//!Never throws.
template<class T, class U> inline
boost::interprocess::intersegment_ptr<T> dynamic_pointer_cast(const boost::interprocess::intersegment_ptr &r)
{ return boost::interprocess::intersegment_ptr<T>(r, boost::interprocess::ipcdetail::dynamic_cast_tag()); }

//!Simulation of reinterpret_cast between pointers.
//!Never throws.
template<class T, class U> inline
boost::interprocess::intersegment_ptr<T> reinterpret_pointer_cast(const boost::interprocess::intersegment_ptr &r)
{ return boost::interprocess::intersegment_ptr<T>(r, boost::interprocess::ipcdetail::reinterpret_cast_tag()); }

//!Trait class to detect if an smart pointer has
//!multi-segment addressing capabilities.
template <class T>
struct is_multisegment_ptr
 <boost::interprocess::intersegment_ptr<T> >
{
 static const bool value = true;
};

}  //namespace interprocess {

#if defined(_MSC_VER) && (_MSC_VER < 1400)
//!to_raw_pointer() enables boost::mem_fn to recognize intersegment_ptr.
//!Never throws.
template<class T> inline
T * to_raw_pointer(boost::interprocess::intersegment_ptr<T> const & p)
{ return p.get(); }
#endif

//!has_trivial_constructor<> == true_type specialization
//!for optimizations
template <class T>
struct has_trivial_constructor
 < boost::interprocess::intersegment_ptr<T> >
 : public true_type{};

//!has_trivial_destructor<> == true_type specialization
//!for optimizations
template <class T>
struct has_trivial_destructor
 < boost::interprocess::intersegment_ptr<T> >
 : public true_type{};

}  //namespace boost {

#if 0

//bits
//-> is_segmented
//-> is_relative
//-> is_in_stack
//-> is_pointee_outside

//Data

//segmented:
//
// std::size_t ctrl    : CTRL_BITS;
// std::size_t segment : MAX_SEGMENT_BITS;
// std::size_t offset;

//RELATIVE_SIZE_BITS =  SIZE_T_BITS -
//                      MAX_SEGMENT_BITS -
//                      CTRL_BITS                  10    10
//MAX_SEGMENT_SIZE   = SIZE_T_BITS - ALIGN_BITS    20    52

//SIZE_T_BITS - 1 - ALIGN_BITS                     19    51
//POW_SIZE_BITS = upper_log2
// (SIZE_T_BITS - 1 - ALIGN_BITS)                  5     6
//FRC_SIZE_BITS = SIZE_T_BITS - CTRL_BITS
//  MAX_SEGMENT_SIZE_ALIGNBITS - POW_SIZE_BITS     6     5

//relative:
//
// std::size_t ctrl     : CTRL_BITS;               2     2
// std::size_t size_pow : POW_SIZE_BITS            5     6
// std::size_t size_frc : FRC_SIZE_BITS;           6     5
// std::size_t start    : MAX_SEGMENT_SIZE_ALIGNBITS;19    51
// std::ptrdiff_t distance : SIZE_T_BITS;          32    64

//direct:
//
// std::size_t ctrl     : CTRL_BITS;               2     2
// std::size_t dummy    : SIZE_T_BITS - CTRL_BITS  30    62
// void *addr           : SIZE_T_BITS;             32    64

//32 bits systems:
//Page alignment: 2**12
//

//!Obtains the address pointed by the
//!object
void *to_raw_pointer() const
{
 if(this->is_pointee_outside() || this->is_in_stack()){
 return raw_address();
 }
 else if(this->is_relative()){
 return (const_cast<char*>(reinterpret_cast<const char*>(this))) + this->relative_pointee_offset();
 }
 else{
 group_manager *m = get_segment_group_manager(addr);
 char *base = static_cast<char*>(m->get_id_address(this->segmented_id()));
 return base + this->segmented_offset();
 }
}

void set_from_pointer(const void *ptr)
{
 if(!ptr){
 this->set_pointee_outside();
 this->raw_address(ptr);
 }
 else if(this->is_in_stack()){
 this->raw_address(ptr);
 }
 else if(this->is_relative() &&
 ( (ptr >= this->relative_start())
 &&(ptr < this->relative_start() + this->relative_size()))
 ){
 this->relative_offset(ptr - this);
 }
 else{
 segment_info_t ptr_info = get_id_from_addr(ptr);
 segment_info_t this_info = get_id_from_addr(this);
 if(ptr_info.segment_group != this_info.segment_group){
 if(!ptr_info.segment_group){
 this->set_in_stack();
 }
 else{
 this->set_pointee_outside();
 }
 }
 else if(ptr_info.segment_id == this_info.segment_id){
 set_relative();
 this->relative_size (ptr_info.size);
 this->relative_offset(static_cast<const char*>(ptr) - reinterpret_cast<const char*>(this));
 this->relative_start (ptr_info.base);
 }
 }
}

void set_from_other(const self_t &other)
{  this->set_from_pointer(other.to_raw_pointer()); }

#endif

#include <boost/interprocess/detail/config_end.hpp>

#endif //#ifndef BOOST_INTERPROCESS_INTERSEGMENT_PTR_HPP