utilities.hpp

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//////////////////////////////////////////////////////////////////////////////
//
// (C) Copyright Ion Gaztanaga 2005-2008.
// (C) Copyright Gennaro Prota 2003 - 2004.
//
// 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_DETAIL_UTILITIES_HPP
#define BOOST_INTERPROCESS_DETAIL_UTILITIES_HPP

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

#include <boost/interprocess/detail/config_begin.hpp>
#include <boost/interprocess/detail/workaround.hpp>

#include <boost/interprocess/interprocess_fwd.hpp>
#include <boost/interprocess/detail/move.hpp>
#include <boost/type_traits/has_trivial_destructor.hpp>
#include <boost/interprocess/detail/min_max.hpp>
#include <boost/interprocess/detail/type_traits.hpp>
#include <boost/interprocess/detail/iterators.hpp>
#include <boost/interprocess/detail/version_type.hpp>
#ifndef BOOST_INTERPROCESS_PERFECT_FORWARDING
#include <boost/interprocess/detail/preprocessor.hpp>
#endif
#include <utility>
#include <algorithm>

namespace boost {
namespace interprocess { 
namespace detail {

template<class SmartPtr>
struct smart_ptr_type
{
   typedef typename SmartPtr::value_type value_type;
   typedef value_type *pointer;
   static pointer get (const SmartPtr &smartptr)
   {  return smartptr.get();}
};

template<class T>
struct smart_ptr_type<T*>
{
   typedef T value_type;
   typedef value_type *pointer;
   static pointer get (pointer ptr)
   {  return ptr;}
};

//!Overload for smart pointers to avoid ADL problems with get_pointer
template<class Ptr>
inline typename smart_ptr_type<Ptr>::pointer
get_pointer(const Ptr &ptr)
{  return smart_ptr_type<Ptr>::get(ptr);   }

//!To avoid ADL problems with swap
template <class T>
inline void do_swap(T& x, T& y)
{
   using std::swap;
   swap(x, y);
}

//!A deleter for scoped_ptr that deallocates the memory
//!allocated for an object using a STL allocator.
template <class Allocator>
struct scoped_ptr_dealloc_functor
{
   typedef typename Allocator::pointer pointer;
   typedef detail::integral_constant<unsigned,
      boost::interprocess::detail::
         version<Allocator>::value>                   alloc_version;
   typedef detail::integral_constant<unsigned, 1>     allocator_v1;
   typedef detail::integral_constant<unsigned, 2>     allocator_v2;

   private:
   void priv_deallocate(const typename Allocator::pointer &p, allocator_v1)
   {  m_alloc.deallocate(p, 1); }

   void priv_deallocate(const typename Allocator::pointer &p, allocator_v2)
   {  m_alloc.deallocate_one(p); }

   public:
   Allocator& m_alloc;

   scoped_ptr_dealloc_functor(Allocator& a)
      : m_alloc(a) {}

   void operator()(pointer ptr)
   {  if (ptr) priv_deallocate(ptr, alloc_version());  }
};

//!A deleter for scoped_ptr that deallocates the memory
//!allocated for an object using a STL allocator.
template <class Allocator>
struct scoped_deallocator
{
   typedef typename Allocator::pointer pointer;
   typedef detail::integral_constant<unsigned,
      boost::interprocess::detail::
         version<Allocator>::value>                   alloc_version;
   typedef detail::integral_constant<unsigned, 1>     allocator_v1;
   typedef detail::integral_constant<unsigned, 2>     allocator_v2;

   private:
   void priv_deallocate(allocator_v1)
   {  m_alloc.deallocate(m_ptr, 1); }

   void priv_deallocate(allocator_v2)
   {  m_alloc.deallocate_one(m_ptr); }

   scoped_deallocator(const scoped_deallocator &);
   scoped_deallocator& operator=(const scoped_deallocator &);

   public:
   pointer     m_ptr;
   Allocator&  m_alloc;

   scoped_deallocator(pointer p, Allocator& a)
      : m_ptr(p), m_alloc(a) {}

   ~scoped_deallocator()
   {  if (m_ptr)priv_deallocate(alloc_version());  }

   #ifdef BOOST_INTERPROCESS_RVALUE_REFERENCE
   scoped_deallocator(scoped_deallocator &&o)
      :  m_ptr(o.m_ptr), m_alloc(o.m_alloc)
   {
   #else
   scoped_deallocator(moved_object<scoped_deallocator> mo)
      :  m_ptr(mo.get().m_ptr), m_alloc(mo.get().m_alloc)
   {
      scoped_deallocator &o = mo.get();
   #endif
      o.release();
   }

   pointer get() const
   {  return m_ptr;  }

   void release()
   {  m_ptr = 0; }
};

}  //namespace detail {

template <class Allocator>
struct is_movable<boost::interprocess::detail::scoped_deallocator<Allocator> >
{
   static const bool value = true;
};

namespace detail {

//!A deleter for scoped_ptr that deallocates the memory
//!allocated for an array of objects using a STL allocator.
template <class Allocator>
struct scoped_array_deallocator
{
   typedef typename Allocator::pointer    pointer;
   typedef typename Allocator::size_type  size_type;

   scoped_array_deallocator(pointer p, Allocator& a, size_type length)
      : m_ptr(p), m_alloc(a), m_length(length) {}

   ~scoped_array_deallocator()
   {  if (m_ptr) m_alloc.deallocate(m_ptr, m_length);  }

   void release()
   {  m_ptr = 0; }

   private:
   pointer     m_ptr;
   Allocator&  m_alloc;
   size_type   m_length;
};

template <class Allocator>
struct null_scoped_array_deallocator
{
   typedef typename Allocator::pointer    pointer;
   typedef typename Allocator::size_type  size_type;

   null_scoped_array_deallocator(pointer, Allocator&, size_type)
   {}

   void release()
   {}
};

//!A deleter for scoped_ptr that destroys
//!an object using a STL allocator.
template <class Allocator>
struct scoped_destructor_n
{
   typedef typename Allocator::pointer    pointer;
   typedef typename Allocator::value_type value_type;
   typedef typename Allocator::size_type  size_type;

   pointer     m_p;
   size_type   m_n;

   scoped_destructor_n(pointer p, size_type n)
      : m_p(p), m_n(n)
   {}

   void release()
   {  m_p = 0; }

   void increment_size(size_type inc)
   {  m_n += inc;   }
   
   ~scoped_destructor_n()
   {
      if(!m_p) return;
      value_type *raw_ptr = detail::get_pointer(m_p);
      for(std::size_t i = 0; i < m_n; ++i, ++raw_ptr)
         raw_ptr->~value_type();
   }
};

//!A deleter for scoped_ptr that destroys
//!an object using a STL allocator.
template <class Allocator>
struct null_scoped_destructor_n
{
   typedef typename Allocator::pointer pointer;
   typedef typename Allocator::size_type size_type;

   null_scoped_destructor_n(pointer, size_type)
   {}

   void increment_size(size_type)
   {}

   void release()
   {}
};

template <class A>
class allocator_destroyer
{
   typedef typename A::value_type value_type;
   typedef detail::integral_constant<unsigned,
      boost::interprocess::detail::
         version<A>::value>                           alloc_version;
   typedef detail::integral_constant<unsigned, 1>     allocator_v1;
   typedef detail::integral_constant<unsigned, 2>     allocator_v2;

   private:
   A & a_;

   private:
   void priv_deallocate(const typename A::pointer &p, allocator_v1)
   {  a_.deallocate(p, 1); }

   void priv_deallocate(const typename A::pointer &p, allocator_v2)
   {  a_.deallocate_one(p); }

   public:
   allocator_destroyer(A &a)
      :  a_(a)
   {}

   void operator()(const typename A::pointer &p)
   {  
      detail::get_pointer(p)->~value_type();
      priv_deallocate(p, alloc_version());
   }
};

template <class A>
class allocator_destroyer_and_chain_builder
{
   typedef typename A::value_type value_type;
   typedef typename A::multiallocation_iterator multiallocation_iterator;
   typedef typename A::multiallocation_chain    multiallocation_chain;

   A & a_;
   multiallocation_chain &c_;

   public:
   allocator_destroyer_and_chain_builder(A &a, multiallocation_chain &c)
      :  a_(a), c_(c)
   {}

   void operator()(const typename A::pointer &p)
   {  
      value_type *vp = detail::get_pointer(p);
      vp->~value_type();
      c_.push_back(vp);
   }
};

template <class A>
class allocator_multialloc_chain_node_deallocator
{
   typedef typename A::value_type value_type;
   typedef typename A::multiallocation_iterator multiallocation_iterator;
   typedef typename A::multiallocation_chain    multiallocation_chain;
   typedef allocator_destroyer_and_chain_builder<A> chain_builder;

   A & a_;
   multiallocation_chain c_;

   public:
   allocator_multialloc_chain_node_deallocator(A &a)
      :  a_(a), c_()
   {}

   chain_builder get_chain_builder()
   {  return chain_builder(a_, c_);  }

   ~allocator_multialloc_chain_node_deallocator()
   {
      multiallocation_iterator it(c_.get_it());
      if(it != multiallocation_iterator())
         a_.deallocate_individual(it);
   }
};

template <class A>
class allocator_multialloc_chain_array_deallocator
{
   typedef typename A::value_type value_type;
   typedef typename A::multiallocation_iterator multiallocation_iterator;
   typedef typename A::multiallocation_chain    multiallocation_chain;
   typedef allocator_destroyer_and_chain_builder<A> chain_builder;

   A & a_;
   multiallocation_chain c_;

   public:
   allocator_multialloc_chain_array_deallocator(A &a)
      :  a_(a), c_()
   {}

   chain_builder get_chain_builder()
   {  return chain_builder(a_, c_);  }

   ~allocator_multialloc_chain_array_deallocator()
   {
      multiallocation_iterator it(c_.get_it());
      if(it != multiallocation_iterator())
         a_.deallocate_many(it);
   }
};

//!A class used for exception-safe multi-allocation + construction.
template <class Allocator>
struct multiallocation_destroy_dealloc
{
   typedef typename Allocator::multiallocation_iterator multiallocation_iterator;
   typedef typename Allocator::value_type value_type;

   multiallocation_iterator m_itbeg;
   Allocator&  m_alloc;

   multiallocation_destroy_dealloc(multiallocation_iterator itbeg, Allocator& a)
      : m_itbeg(itbeg), m_alloc(a) {}

   ~multiallocation_destroy_dealloc()
   {
      multiallocation_iterator endit;
      while(m_itbeg != endit){
         detail::get_pointer(&*m_itbeg)->~value_type();
         m_alloc.deallocate(&*m_itbeg, 1);
         ++m_itbeg;
      }
   }

   void next()
   {  ++m_itbeg; }

   void release()
   {  m_itbeg = multiallocation_iterator(); }
};

//Rounds "orig_size" by excess to round_to bytes
inline std::size_t get_rounded_size(std::size_t orig_size, std::size_t round_to)
{
   return ((orig_size-1)/round_to+1)*round_to;
}

//Truncates "orig_size" to a multiple of "multiple" bytes.
inline std::size_t get_truncated_size(std::size_t orig_size, std::size_t multiple)
{
   return orig_size/multiple*multiple;
}

//Rounds "orig_size" by excess to round_to bytes. round_to must be power of two
inline std::size_t get_rounded_size_po2(std::size_t orig_size, std::size_t round_to)
{
   return ((orig_size-1)&(~(round_to-1))) + round_to;
}

//Truncates "orig_size" to a multiple of "multiple" bytes. multiple must be power of two
inline std::size_t get_truncated_size_po2(std::size_t orig_size, std::size_t multiple)
{
   return (orig_size & (~(multiple-1)));
}

template <std::size_t OrigSize, std::size_t RoundTo>
struct ct_rounded_size
{
   enum { value = ((OrigSize-1)/RoundTo+1)*RoundTo };
};

template <std::size_t Value1, std::size_t Value2>
struct ct_min
{
   enum { value = (Value1 < Value2)? Value1 : Value2 };
};

template <std::size_t Value1, std::size_t Value2>
struct ct_max
{
   enum { value = (Value1 > Value2)? Value1 : Value2 };
};

// Gennaro Prota wrote this. Thanks!
template <int p, int n = 4>
struct ct_max_pow2_less
{
   enum { c = 2*n < p };

   static const std::size_t value =
         c ? (ct_max_pow2_less< c*p, 2*c*n>::value) : n;
};

template <>
struct ct_max_pow2_less<0, 0>
{
   static const std::size_t value = 0;
};