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 //////////////////////////////////////////////////////////////////////////////
 //
 // (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_DETAIL_MEM_ALGO_COMMON_HPP
 #define BOOST_INTERPROCESS_DETAIL_MEM_ALGO_COMMON_HPP
 
 #ifndef BOOST_CONFIG_HPP
 #  include <boost/config.hpp>
 #endif
 0018 ">#
 #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/containers/allocation_type.hpp>
 // interprocess/detail
 #include <boost/interprocess/detail/math_functions.hpp>
 #include <boost/interprocess/detail/min_max.hpp>
 #include <boost/interprocess/detail/type_traits.hpp>
 #include <boost/interprocess/detail/utilities.hpp>
 // container/detail
 #include <boost/container/detail/multiallocation_chain.hpp>
 #include <boost/container/detail/placement_new.hpp>
 // move
 #include <boost/move/utility_core.hpp>
 // move/detail
 #include <boost/move/detail/force_ptr.hpp>
 // other boost
 #include <boost/assert.hpp>
 
 //!\file
 //!Implements common operations for memory algorithms.
 
 namespace boost {
 namespace interprocess {
 namespace ipcdetail {
 
 template<class VoidPointer>
 class basic_multiallocation_chain
    : public boost::container::dtl::
       basic_multiallocation_chain<VoidPointer>
 {
    BOOST_MOVABLE_BUT_NOT_COPYABLE(basic_multiallocation_chain)
    typedef boost::container::dtl::
       basic_multiallocation_chain<VoidPointer> base_t;
    public:
 
    basic_multiallocation_chain()
       :  base_t()
    {}
 
    basic_multiallocation_chain(BOOST_RV_REF(basic_multiallocation_chain) other)
       :  base_t(::boost::move(static_cast<base_t&>(other)))
    {}
 
    basic_multiallocation_chain& operator=(BOOST_RV_REF(basic_multiallocation_chain) other)
    {
       this->base_t::operator=(::boost::move(static_cast<base_t&>(other)));
       return *this;
    }
 
    void *pop_front()
    {
       return boost::interprocess::ipcdetail::to_raw_pointer(this->base_t::pop_front());
    }
 };
 
 //!This class implements several allocation functions shared by different algorithms
 //!(aligned allocation, multiple allocation...).
 template<class MemoryAlgorithm>
 class memory_algorithm_common
 {
    public:
    typedef typename MemoryAlgorithm::void_pointer              void_pointer;
    typedef typename MemoryAlgorithm::block_ctrl                block_ctrl;
    typedef typename MemoryAlgorithm::multiallocation_chain     multiallocation_chain;
    typedef memory_algorithm_common<MemoryAlgorithm>            this_type;
    typedef typename MemoryAlgorithm::size_type                 size_type;
 
    static const size_type Alignment              = MemoryAlgorithm::Alignment;
    static const size_type AllocatedCtrlBytes     = MemoryAlgorithm::AllocatedCtrlBytes;
    static const size_type AllocatedCtrlUnits     = MemoryAlgorithm::AllocatedCtrlUnits;
    static const size_type BlockCtrlBytes         = MemoryAlgorithm::BlockCtrlBytes;
    static const size_type BlockCtrlUnits         = MemoryAlgorithm::BlockCtrlUnits;
    static const size_type UsableByPreviousChunk  = MemoryAlgorithm::UsableByPreviousChunk;
 
    static void assert_alignment(const void *ptr)
    {  assert_alignment((std::size_t)ptr); }
 
    static void assert_alignment(size_type uint_ptr)
    {
       (void)uint_ptr;
       BOOST_ASSERT(uint_ptr % Alignment == 0);
    }
 
    static bool check_alignment(const void *ptr)
    {  return (((std::size_t)ptr) % Alignment == 0);   }
 
    static size_type ceil_units(size_type size)
    {  return get_rounded_size(size, Alignment)/Alignment; }
 
    static size_type floor_units(size_type size)
    {  return size/Alignment;  }
 
    static size_type user_buffer_ceil_units(size_type size)
    {
       if(size <= UsableByPreviousChunk)
          return 0;
       return ceil_units(size - UsableByPreviousChunk);
    }
 
    static size_type multiple_of_units(size_type size)
    {  return get_rounded_size(size, Alignment);  }
 
    static void allocate_many
       (MemoryAlgorithm *memory_algo, size_type elem_bytes, size_type n_elements, multiallocation_chain &chain)
    {
       return this_type::priv_allocate_many(memory_algo, &elem_bytes, n_elements, 0, chain);
    }
 
    static void deallocate_many(MemoryAlgorithm *memory_algo, multiallocation_chain &chain)
    {
       return this_type::priv_deallocate_many(memory_algo, chain);
    }
 
    static bool calculate_lcm_and_needs_backwards_lcmed
       (size_type backwards_multiple, size_type received_size, size_type size_to_achieve,
       size_type &lcm_out, size_type &needs_backwards_lcmed_out)
    {
       // Now calculate lcm_val
       size_type max = backwards_multiple;
       size_type min = Alignment;
       size_type needs_backwards;
       size_type needs_backwards_lcmed;
       size_type lcm_val;
       size_type current_forward;
       //Swap if necessary
       if(max < min){
          size_type tmp = min;
          min = max;
          max = tmp;
       }
       //Check if it's power of two
       if((backwards_multiple & (backwards_multiple-1)) == 0){
          if(0 != (size_to_achieve & ((backwards_multiple-1)))){
             return false;
          }
 
          lcm_val = max;
          //If we want to use minbytes data to get a buffer between maxbytes
          //and minbytes if maxbytes can't be achieved, calculate the
          //biggest of all possibilities
          current_forward = get_truncated_size_po2(received_size, backwards_multiple);
          needs_backwards = size_to_achieve - current_forward;
          BOOST_ASSERT((needs_backwards % backwards_multiple) == 0);
          needs_backwards_lcmed = get_rounded_size_po2(needs_backwards, lcm_val);
          lcm_out = lcm_val;
          needs_backwards_lcmed_out = needs_backwards_lcmed;
          return true;
       }
       //Check if it's multiple of alignment
       else if((backwards_multiple & (Alignment - 1u)) == 0){
          lcm_val = backwards_multiple;
          current_forward = get_truncated_size(received_size, backwards_multiple);
          //No need to round needs_backwards because backwards_multiple == lcm_val
          needs_backwards_lcmed = needs_backwards = size_to_achieve - current_forward;
          BOOST_ASSERT((needs_backwards_lcmed & (Alignment - 1u)) == 0);
          lcm_out = lcm_val;
          needs_backwards_lcmed_out = needs_backwards_lcmed;
          return true;
       }
       //Check if it's multiple of the half of the alignmment
       else if((backwards_multiple & ((Alignment/2u) - 1u)) == 0){
          lcm_val = backwards_multiple*2u;
          current_forward = get_truncated_size(received_size, backwards_multiple);
          needs_backwards_lcmed = needs_backwards = size_to_achieve - current_forward;
          if(0 != (needs_backwards_lcmed & (Alignment-1)))
          //while(0 != (needs_backwards_lcmed & (Alignment-1)))
             needs_backwards_lcmed += backwards_multiple;
          BOOST_ASSERT((needs_backwards_lcmed % lcm_val) == 0);
          lcm_out = lcm_val;
          needs_backwards_lcmed_out = needs_backwards_lcmed;
          return true;
       }
       //Check if it's multiple of the quarter of the alignmment
       else if((backwards_multiple & ((Alignment/4u) - 1u)) == 0){
          size_type remainder;
          lcm_val = backwards_multiple*4u;
          current_forward = get_truncated_size(received_size, backwards_multiple);
          needs_backwards_lcmed = needs_backwards = size_to_achieve - current_forward;
          //while(0 != (needs_backwards_lcmed & (Alignment-1)))
             //needs_backwards_lcmed += backwards_multiple;
          if(0 != (remainder = ((needs_backwards_lcmed & (Alignment-1))>>(Alignment/8u)))){
             if(backwards_multiple & Alignment/2u){
                needs_backwards_lcmed += (remainder)*backwards_multiple;
             }
             else{
                needs_backwards_lcmed += (4-remainder)*backwards_multiple;
             }
          }
          BOOST_ASSERT((needs_backwards_lcmed % lcm_val) == 0);
          lcm_out = lcm_val;
          needs_backwards_lcmed_out = needs_backwards_lcmed;
          return true;
       }
       else{
          lcm_val = lcm(max, min);
       }
       //If we want to use minbytes data to get a buffer between maxbytes
       //and minbytes if maxbytes can't be achieved, calculate the
       //biggest of all possibilities
       current_forward = get_truncated_size(received_size, backwards_multiple);
       needs_backwards = size_to_achieve - current_forward;
       BOOST_ASSERT((needs_backwards % backwards_multiple) == 0);
       needs_backwards_lcmed = get_rounded_size(needs_backwards, lcm_val);
       lcm_out = lcm_val;
       needs_backwards_lcmed_out = needs_backwards_lcmed;
       return true;
    }
 
    static void allocate_many
       ( MemoryAlgorithm *memory_algo
       , const size_type *elem_sizes
       , size_type n_elements
       , size_type sizeof_element
       , multiallocation_chain &chain)
    {
       this_type::priv_allocate_many(memory_algo, elem_sizes, n_elements, sizeof_element, chain);
    }
 
    static void* allocate_aligned
       (MemoryAlgorithm * const memory_algo, const size_type nbytes, const size_type alignment)
    {
 
       //Ensure power of 2
       const bool alignment_ok = (alignment & (alignment - 1u)) == 0;
       if (!alignment_ok){
          //Alignment is not power of two
          BOOST_ASSERT(alignment_ok);
          return 0;
       }
 
       if(alignment <= Alignment){
          size_type real_size = nbytes;
          void *ignore_reuse = 0;
          return memory_algo->priv_allocate
             (boost::interprocess::allocate_new, nbytes, real_size, ignore_reuse);
       }
 
       //To fulfill user's request we need at least min_user_units
       size_type needed_units = user_buffer_ceil_units(nbytes);
       //However, there is a minimum allocation unit count (BlockCtrlUnits) to be able to deallocate the buffer,
       //The allocation will give us a part of it (AllocatedCtrlUnits) so (BlockCtrlUnits - AllocatedCtrlUnits)
       //is the minimum ammount of blocks we need to allocate.
       needed_units += max_value(needed_units, BlockCtrlUnits - AllocatedCtrlUnits);
       //If we need to align, we need to at least move enough to create a new block at the beginning
       //that can be marked as free, so we need BlockCtrlUnits units for that
       needed_units += BlockCtrlUnits;
       //Finally, we need to add extra space to be sure we will find an aligned address
       needed_units += (alignment - Alignment)/Alignment;
 
       //Transform units to bytes
       const size_type request = needed_units*Alignment + UsableByPreviousChunk;
 
       //Now allocate the buffer
       size_type real_size = request;
       void *ignore_reuse = 0;
       void *const buffer = memory_algo->priv_allocate(boost::interprocess::allocate_new, request, real_size, ignore_reuse);
       if(!buffer){
          return 0;
       }
       else if ((((std::size_t)(buffer)) & (alignment-1)) == 0){
          //If we are lucky and the buffer is aligned, just split it and
          //return the high part
          block_ctrl *const first  = memory_algo->priv_get_block(buffer);
          const size_type orig_first_units = first->m_size;
          const size_type first_min_units =
             max_value(user_buffer_ceil_units(nbytes) + AllocatedCtrlUnits, size_type(BlockCtrlUnits));
          //We can create a new block in the end of the segment
          if(orig_first_units >= (first_min_units + BlockCtrlUnits)){
             block_ctrl *second =  move_detail::force_ptr<block_ctrl*>
                (reinterpret_cast<char*>(first) + Alignment*first_min_units);
             //Update first size
             first->m_size  = first_min_units & block_ctrl::size_mask;
             memory_algo->priv_mark_new_allocated_block(first);
 
             //Deallocate the remaining memory
             second->m_size = (orig_first_units - first_min_units) & block_ctrl::size_mask;
             memory_algo->priv_mark_new_allocated_block(second);
             memory_algo->priv_deallocate(memory_algo->priv_get_user_buffer(second));
          }
          return buffer;
       }
 
       //Now obtain the address of the allocated block
       block_ctrl* const first = memory_algo->priv_get_block(buffer);
       //The block must be marked as allocated
       BOOST_ASSERT(memory_algo->priv_is_allocated_block(first));
       //Assert allocated block has at least the desired size
       BOOST_ASSERT(first->m_size >= (needed_units + AllocatedCtrlUnits));
       //Assert allocated block can be splitted in the two blocks
       BOOST_ASSERT(first->m_size >= 2 * BlockCtrlUnits);
 
       //Buffer is not overaligned, so find the aligned part
 
       // BCB: BlockControlBytes
       // ACB: AllocatedControlBytes (<= BlockControlBytes)
       //
       //  __________> Block control ("first")
       // |           _________> Block control ("second")
       // |          |      ___> usr_buf, overaligned
       // |          |     |
       //  -----------------------------------------------------
       // | BCB+more | ACB |
       //  -----------------------------------------------------
       char *const usr_buf = reinterpret_cast<char*>
          (reinterpret_cast<std::size_t>(static_cast<char*>(buffer)
             + BlockCtrlBytes                 //Minimum to create a free block at the beginning
             + alignment - 1) & -alignment);  //This is the alignment trick
 
       //Assert the user buffer is inside the allocated range
       BOOST_ASSERT(usr_buf <= (reinterpret_cast<char*>(first) + first->m_size*Alignment));
       //Assert all user data is inside the allocated range
       BOOST_ASSERT((usr_buf + nbytes) <= (reinterpret_cast<char*>(first) + first->m_size*Alignment + UsableByPreviousChunk));
 
       //Set the new size of the secone block
       const size_type orig_first_units = first->m_size;
 
       block_ctrl* const second = memory_algo->priv_get_block(usr_buf);
 
       //Update first block size until second block starts and deallocate it
       const size_type final_first_units =
          size_type(reinterpret_cast<char*>(second) - reinterpret_cast<char*>(first))/Alignment & block_ctrl::size_mask;
 
       //Now check if we can create a new buffer in the end
       //
       //  _______________________> "first" (free block)
       // |           ____________> "second" block
       // |          |      ______> user data aligned here (usr_buf)
       // |          |     |            ____> optional "third" (free block)
       //  ----------|-----|-----------|------------------------------
       // | BCB+more | ACB | user_data | BCB |
       //  -----------------------------------------------------
       //This size will be the minimum size to be able to create a
       //new block in the end.
       const size_type orig_second_units = orig_first_units - final_first_units;
       const size_type second_min_units = max_value( size_type(BlockCtrlUnits)
                                                   , user_buffer_ceil_units(nbytes) + AllocatedCtrlUnits );
 
       //Check if we can create a new free block (of size BlockCtrlUnits) at the end of the segment
       if(orig_second_units >= (second_min_units + BlockCtrlUnits)){
          //Now obtain the address of the end block
          block_ctrl *const third = ::new (reinterpret_cast<char*>(second) + Alignment*second_min_units, boost_container_new_t()) block_ctrl;
          second->m_size = second_min_units & block_ctrl::size_mask;
          third->m_size  = (orig_second_units - second->m_size) & block_ctrl::size_mask;
          BOOST_ASSERT(third->m_size >= BlockCtrlUnits);
          memory_algo->priv_mark_new_allocated_block(second);
          memory_algo->priv_mark_new_allocated_block(third);
          //We can deallocate third block because the previous "second" is properly set
          memory_algo->priv_deallocate(memory_algo->priv_get_user_buffer(third));
       }
       else{
          second->m_size = orig_second_units & block_ctrl::size_mask;
          BOOST_ASSERT(second->m_size >= BlockCtrlUnits);
          memory_algo->priv_mark_new_allocated_block(second);
       }
 
       //We can deallocate first block because the next "second" is properly set
       first->m_size = final_first_units & block_ctrl::size_mask;
       //Now mark second's previous allocated flag as allocated
       memory_algo->priv_mark_new_allocated_block(first);
       memory_algo->priv_deallocate(memory_algo->priv_get_user_buffer(first));
 
       //Make sure all user data fits
       BOOST_ASSERT((reinterpret_cast<char*>(usr_buf) + nbytes) <= (reinterpret_cast<char*>(second) + second->m_size*Alignment + UsableByPreviousChunk));
       //Make sure user data is properly aligned
       BOOST_ASSERT(0 == ((std::size_t)usr_buf & (alignment-1u)));
       return usr_buf;
    }
 
    static bool try_shrink
       (MemoryAlgorithm *memory_algo, void *ptr
       ,const size_type max_size, size_type &received_size)
    {
       size_type const preferred_size = received_size;
       (void)memory_algo;
       //Obtain the real block
       block_ctrl *block = memory_algo->priv_get_block(ptr);
       size_type old_block_units = (size_type)block->m_size;
 
       //The block must be marked as allocated
       BOOST_ASSERT(memory_algo->priv_is_allocated_block(block));
 
       //Check if alignment and block size are right
       assert_alignment(ptr);
 
       //Put this to a safe value
       received_size = (old_block_units - AllocatedCtrlUnits)*Alignment + UsableByPreviousChunk;
 
       //Now translate it to Alignment units
       const size_type max_user_units       = floor_units(max_size - UsableByPreviousChunk);
       const size_type preferred_user_units = ceil_units(preferred_size - UsableByPreviousChunk);
 
       //Check if rounded max and preferred are possible correct
       if(max_user_units < preferred_user_units)
          return false;
 
       //Check if the block is smaller than the requested minimum
       size_type old_user_units = old_block_units - AllocatedCtrlUnits;
 
       if(old_user_units < preferred_user_units)
          return false;
 
       //If the block is smaller than the requested minimum
       if(old_user_units == preferred_user_units)
          return true;
 
       size_type shrunk_user_units =
          ((BlockCtrlUnits - AllocatedCtrlUnits) >= preferred_user_units)
          ? (BlockCtrlUnits - AllocatedCtrlUnits)
          : preferred_user_units;
 
       //Some parameter checks
       if(max_user_units < shrunk_user_units)
          return false;
 
       //We must be able to create at least a new empty block
       if((old_user_units - shrunk_user_units) < BlockCtrlUnits ){
          return false;
       }
 
       //Update new size
       received_size = shrunk_user_units*Alignment + UsableByPreviousChunk;
       return true;
    }
 
    static bool shrink
       (MemoryAlgorithm *memory_algo, void *ptr
       ,const size_type max_size, size_type &received_size)
    {
       size_type const preferred_size = received_size;
       //Obtain the real block
       block_ctrl *block = memory_algo->priv_get_block(ptr);
       size_type old_block_units = (size_type)block->m_size;
 
       if(!try_shrink(memory_algo, ptr, max_size, received_size)){
          return false;
       }
 
       //Check if the old size was just the shrunk size (no splitting)
       if((old_block_units - AllocatedCtrlUnits) == ceil_units(preferred_size - UsableByPreviousChunk))
          return true;
 
       //Now we can just rewrite the size of the old buffer
       block->m_size = ((received_size-UsableByPreviousChunk)/Alignment + AllocatedCtrlUnits) & block_ctrl::size_mask;
       BOOST_ASSERT(block->m_size >= BlockCtrlUnits);
 
       //We create the new block
       block_ctrl *new_block = move_detail::force_ptr<block_ctrl*>
                   (reinterpret_cast<char*>(block) + block->m_size*Alignment);
       //Write control data to simulate this new block was previously allocated
       //and deallocate it
       new_block->m_size = (old_block_units - block->m_size) & block_ctrl::size_mask;
       BOOST_ASSERT(new_block->m_size >= BlockCtrlUnits);
       memory_algo->priv_mark_new_allocated_block(block);
       memory_algo->priv_mark_new_allocated_block(new_block);
       memory_algo->priv_deallocate(memory_algo->priv_get_user_buffer(new_block));
       return true;
    }
 
    private:
    static void priv_allocate_many
       ( MemoryAlgorithm *memory_algo
       , const size_type *elem_sizes
       , size_type n_elements
       , size_type sizeof_element
       , multiallocation_chain &chain)
    {
       //Note: sizeof_element == 0 indicates that we want to
       //allocate n_elements of the same size "*elem_sizes"
 
       //Calculate the total size of all requests
       size_type total_request_units = 0;
       size_type elem_units = 0;
       const size_type ptr_size_units = memory_algo->priv_get_total_units(sizeof(void_pointer));
       if(!sizeof_element){
          elem_units = memory_algo->priv_get_total_units(*elem_sizes);
          elem_units = ptr_size_units > elem_units ? ptr_size_units : elem_units;
          total_request_units = n_elements*elem_units;
       }
       else{
          for(size_type i = 0; i < n_elements; ++i){
             if(multiplication_overflows(elem_sizes[i], sizeof_element)){
                total_request_units = 0;
                break;
             }
             elem_units = memory_algo->priv_get_total_units(elem_sizes[i]*sizeof_element);
             elem_units = ptr_size_units > elem_units ? ptr_size_units : elem_units;
             if(sum_overflows(total_request_units, elem_units)){
                total_request_units = 0;
                break;
             }
             total_request_units += elem_units;
          }
       }
 
       if(total_request_units && !multiplication_overflows(total_request_units, Alignment)){
          size_type low_idx = 0;
          while(low_idx < n_elements){
             size_type total_bytes = total_request_units*Alignment - AllocatedCtrlBytes + UsableByPreviousChunk;
             size_type min_allocation = (!sizeof_element)
                ?  elem_units
                :  memory_algo->priv_get_total_units(elem_sizes[low_idx]*sizeof_element);
             min_allocation = min_allocation*Alignment - AllocatedCtrlBytes + UsableByPreviousChunk;
 
             size_type received_size = total_bytes;
             void *ignore_reuse = 0;
             void *ret = memory_algo->priv_allocate
                (boost::interprocess::allocate_new, min_allocation, received_size, ignore_reuse);
             if(!ret){
                break;
             }
 
             block_ctrl *block = memory_algo->priv_get_block(ret);
             size_type received_units = (size_type)block->m_size;
             char *block_address = reinterpret_cast<char*>(block);
 
             size_type total_used_units = 0;
             while(total_used_units < received_units){
                if(sizeof_element){
                   elem_units = memory_algo->priv_get_total_units(elem_sizes[low_idx]*sizeof_element);
                   elem_units = ptr_size_units > elem_units ? ptr_size_units : elem_units;
                }
                if(total_used_units + elem_units > received_units)
                   break;
                total_request_units -= elem_units;
                //This is the position where the new block must be created
                block_ctrl *new_block = move_detail::force_ptr<block_ctrl*>(block_address);
                assert_alignment(new_block);
 
                //The last block should take all the remaining space
                if((low_idx + 1) == n_elements ||
                   (total_used_units + elem_units +
                   ((!sizeof_element)
                      ? elem_units
                : max_value(memory_algo->priv_get_total_units(elem_sizes[low_idx+1]*sizeof_element), ptr_size_units))
                    > received_units)){
                   //By default, the new block will use the rest of the buffer
                   new_block->m_size = (received_units - total_used_units) & block_ctrl::size_mask;
                   memory_algo->priv_mark_new_allocated_block(new_block);
 
                   //If the remaining units are bigger than needed and we can
                   //split it obtaining a new free memory block do it.
                   if((received_units - total_used_units) >= (elem_units + MemoryAlgorithm::BlockCtrlUnits)){
                      size_type shrunk_request = elem_units*Alignment - AllocatedCtrlBytes + UsableByPreviousChunk;
                      size_type shrunk_received = shrunk_request;
                      bool shrink_ok = shrink
                            (memory_algo
                            ,memory_algo->priv_get_user_buffer(new_block)
                            ,shrunk_request
                            ,shrunk_received);
                      (void)shrink_ok;
                      //Shrink must always succeed with passed parameters
                      BOOST_ASSERT(shrink_ok);
                      //Some sanity checks
                      BOOST_ASSERT(shrunk_request == shrunk_received);
                      BOOST_ASSERT(elem_units == ((shrunk_request-UsableByPreviousChunk)/Alignment + AllocatedCtrlUnits));
                      //"new_block->m_size" must have been reduced to elem_units by "shrink"
                      BOOST_ASSERT(new_block->m_size == elem_units);
                      //Now update the total received units with the reduction
                      received_units = elem_units + total_used_units;
                   }
                }
                else{
                   new_block->m_size = elem_units & block_ctrl::size_mask;
                   memory_algo->priv_mark_new_allocated_block(new_block);
                }
 
                block_address += new_block->m_size*Alignment;
                total_used_units += (size_type)new_block->m_size;
                //Check we have enough room to overwrite the intrusive pointer
                BOOST_ASSERT((new_block->m_size*Alignment - AllocatedCtrlUnits) >= sizeof(void_pointer));
                void_pointer p = ::new(memory_algo->priv_get_user_buffer(new_block), boost_container_new_t())void_pointer(0);
                chain.push_back(p);
                ++low_idx;
             }
             //Sanity check
             BOOST_ASSERT(total_used_units == received_units);
          }
 
          if(low_idx != n_elements){
             priv_deallocate_many(memory_algo, chain);
          }
       }
    }
 
    static void priv_deallocate_many(MemoryAlgorithm *memory_algo, multiallocation_chain &chain)
    {
       while(!chain.empty()){
          memory_algo->priv_deallocate(to_raw_pointer(chain.pop_front()));
       }
    }
 };
 
 }  //namespace ipcdetail {
 }  //namespace interprocess {
 }  //namespace boost {
 
 #include <boost/interprocess/detail/config_end.hpp>
 
 #endif   //#ifndef BOOST_INTERPROCESS_DETAIL_MEM_ALGO_COMMON_HPP

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