EIC code displayed by LXR master/​include/​boost/​interprocess/​mem_algo/​rbtree_best_fit.hpp	Source navigation Diff markup Identifier search General search
	Version: master test Revert   Change

File indexing completed on 2025-09-17 08:34:10

 //////////////////////////////////////////////////////////////////////////////
 //
 // (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_MEM_ALGO_RBTREE_BEST_FIT_HPP
 #define BOOST_INTERPROCESS_MEM_ALGO_RBTREE_BEST_FIT_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/containers/allocation_type.hpp>
 #include <boost/interprocess/exceptions.hpp>
 #include <boost/interprocess/interprocess_fwd.hpp>
 #include <boost/interprocess/mem_algo/detail/mem_algo_common.hpp>
 #include <boost/interprocess/offset_ptr.hpp>
 #include <boost/interprocess/sync/scoped_lock.hpp>
 // interprocess/detail
 #include <boost/interprocess/detail/min_max.hpp>
 #include <boost/interprocess/detail/math_functions.hpp>
 #include <boost/interprocess/detail/type_traits.hpp>
 #include <boost/interprocess/detail/utilities.hpp>
 // container
 #include <boost/container/detail/multiallocation_chain.hpp>
 // container/detail
 #include <boost/container/detail/placement_new.hpp>
 // move/detail
 #include <boost/move/detail/type_traits.hpp> //make_unsigned, alignment_of
 #include <boost/move/detail/force_ptr.hpp> //make_unsigned, alignment_of
 // intrusive
 #include <boost/intrusive/pointer_traits.hpp>
 #include <boost/intrusive/set.hpp>
 // other boost
 #include <boost/assert.hpp>
 // std
 #include <climits>
 #include <cstring>
 
 //#define BOOST_INTERPROCESS_RBTREE_BEST_FIT_ABI_V1_HPP
 //to maintain ABI compatible with the original version
 //ABI had to be updated to fix compatibility issues when
 //sharing shared memory between 32 adn 64 bit processes.
 
 //!\file
 //!Describes a best-fit algorithm based in an intrusive red-black tree used to allocate
 //!objects in shared memory. This class is intended as a base class for single segment
 //!and multi-segment implementations.
 
 namespace boost {
 namespace interprocess {
 
 //!This class implements an algorithm that stores the free nodes in a red-black tree
 //!to have logarithmic search/insert times.
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment>
 class rbtree_best_fit
 {
    #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
    //Non-copyable
    rbtree_best_fit();
    rbtree_best_fit(const rbtree_best_fit &);
    rbtree_best_fit &operator=(const rbtree_best_fit &);
 
    private:
    struct block_ctrl;
    typedef typename boost::intrusive::
       pointer_traits<VoidPointer>::template
          rebind_pointer<block_ctrl>::type                   block_ctrl_ptr;
 
    typedef typename boost::intrusive::
       pointer_traits<VoidPointer>::template
          rebind_pointer<char>::type                         char_ptr;
 
    #endif   //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
 
    public:
    //!Shared mutex family used for the rest of the Interprocess framework
    typedef MutexFamily        mutex_family;
    //!Pointer type to be used with the rest of the Interprocess framework
    typedef VoidPointer        void_pointer;
    typedef ipcdetail::basic_multiallocation_chain<VoidPointer>  multiallocation_chain;
 
    typedef typename boost::intrusive::pointer_traits<char_ptr>::difference_type difference_type;
    typedef typename boost::container::dtl::make_unsigned<difference_type>::type     size_type;
 
    #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
 
    private:
 
    typedef typename bi::make_set_base_hook
       < bi::void_pointer<VoidPointer>
       , bi::optimize_size<true>
       , bi::link_mode<bi::normal_link> >::type           TreeHook;
 
    struct SizeHolder
    {
       static const size_type size_mask = size_type(-1) >> 2;
       //!Previous block's memory size (including block_ctrl
       //!header) in Alignment units. This field (UsableByPreviousChunk bytes)
       //!is OVERWRITTEN by the previous block if allocated (m_prev_allocated)
       size_type m_prev_size;
       //!This block's memory size (including block_ctrl
       //!header) in Alignment units
       size_type m_size      :  sizeof(size_type)*CHAR_BIT - 2;
       size_type m_prev_allocated :  1;
       size_type m_allocated :  1;
    };
 
    //!Block control structure
    struct block_ctrl
       :  public SizeHolder
       //This tree hook is overwritten when this block is used
       , public TreeHook
    {
       block_ctrl()
       {
          this->SizeHolder::m_size = 0;
          this->SizeHolder::m_allocated = 0;
          this->SizeHolder::m_prev_allocated = 0;
       }
 
       friend bool operator<(const block_ctrl &a, const block_ctrl &b)
       {  return a.SizeHolder::m_size < b.SizeHolder::m_size;  }
 
       friend bool operator==(const block_ctrl &a, const block_ctrl &b)
       {  return a.SizeHolder::m_size == b.SizeHolder::m_size;  }
    };
 
    struct size_block_ctrl_compare
    {
       bool operator()(size_type size, const block_ctrl &block) const
       {  return size < block.m_size;  }
 
       bool operator()(const block_ctrl &block, size_type size) const
       {  return block.m_size < size;  }
    };
 
    //!Shared mutex to protect memory allocate/deallocate
    typedef typename MutexFamily::mutex_type                       mutex_type;
    typedef typename bi::make_multiset
       <block_ctrl, bi::base_hook<TreeHook> >::type                Imultiset;
 
    typedef typename Imultiset::iterator                           imultiset_iterator;
    typedef typename Imultiset::const_iterator                     imultiset_const_iterator;
 
    //!This struct includes needed data and derives from
    //!mutex_type to allow EBO when using null mutex_type
    struct header_t : public mutex_type
    {
       Imultiset            m_imultiset;
 
       //!The extra size required by the segment
       size_type            m_extra_hdr_bytes;
       //!Allocated bytes for internal checking
       size_type            m_allocated;
       //!The size of the memory segment
       size_type            m_size;
    }  m_header;
 
    friend class ipcdetail::memory_algorithm_common<rbtree_best_fit>;
 
    typedef ipcdetail::memory_algorithm_common<rbtree_best_fit> algo_impl_t;
 
    public:
    #endif   //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
 
    //!Constructor. "size" is the total size of the managed memory segment,
    //!"extra_hdr_bytes" indicates the extra bytes beginning in the sizeof(rbtree_best_fit)
    //!offset that the allocator should not use at all.
    rbtree_best_fit           (size_type size, size_type extra_hdr_bytes);
 
    //!Destructor.
    ~rbtree_best_fit();
 
    //!Obtains the minimum size needed by the algorithm
    static size_type get_min_size (size_type extra_hdr_bytes);
 
    //Functions for single segment management
 
    //!Allocates bytes, returns 0 if there is not more memory.
    //!Returned memory is aligned to Alignment bytes.
    void* allocate             (size_type nbytes);
 
    //!Deallocates previously allocated bytes
    void   deallocate(void* addr);
 
    #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
 
    //Experimental. Dont' use
 
    //!Multiple element allocation, same size
    //!Experimental. Dont' use
    void allocate_many(size_type elem_bytes, size_type num_elements, multiallocation_chain &chain)
    {
       //-----------------------
       boost::interprocess::scoped_lock<mutex_type> guard(m_header);
       //-----------------------
       algo_impl_t::allocate_many(this, elem_bytes, num_elements, chain);
    }
 
    //!Multiple element allocation, different size
    //!Experimental. Dont' use
    void allocate_many(const size_type *elem_sizes, size_type n_elements, size_type sizeof_element, multiallocation_chain &chain)
    {
       //-----------------------
       boost::interprocess::scoped_lock<mutex_type> guard(m_header);
       //-----------------------
       algo_impl_t::allocate_many(this, elem_sizes, n_elements, sizeof_element, chain);
    }
 
    //!Multiple element allocation, different size
    //!Experimental. Dont' use
    void deallocate_many(multiallocation_chain &chain);
 
    template<class T>
    T* allocation_command(boost::interprocess::allocation_type command, size_type limit_size,
       size_type& prefer_in_recvd_out_size, T*& reuse);
 
    void* raw_allocation_command(boost::interprocess::allocation_type command, size_type limit_object,
       size_type& prefer_in_recvd_out_size,
       void*& reuse_ptr, size_type sizeof_object = 1);
 
    #endif   //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
 
    //!Returns the size of the memory segment
    size_type get_size()  const;
 
    //!Returns the number of free bytes of the segment
    size_type get_free_memory()  const;
 
    //!Initializes to zero all the memory that's not in use.
    //!This function is normally used for security reasons.
    void zero_free_memory();
 
    //!Increases managed memory in
    //!extra_size bytes more
    void grow(size_type extra_size);
 
    //!Decreases managed memory as much as possible
    void shrink_to_fit();
 
    //!Returns true if all allocated memory has been deallocated
    bool all_memory_deallocated();
 
    //!Makes an internal sanity check
    //!and returns true if success
    bool check_sanity();
 
    //!Returns the size of the buffer previously allocated pointed by ptr
    size_type size(const void *ptr) const;
 
    //!Allocates aligned bytes, returns 0 if there is not more memory.
    //!Alignment must be power of 2
    void* allocate_aligned     (size_type nbytes, size_type alignment);
 
    #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
    private:
    static size_type priv_first_block_offset_from_this(const void *this_ptr, size_type extra_hdr_bytes);
 
    block_ctrl *priv_first_block();
 
    block_ctrl *priv_end_block();
 
    void* priv_allocation_command(boost::interprocess::allocation_type command,   size_type limit_size,
                         size_type &prefer_in_recvd_out_size, void *&reuse_ptr, size_type sizeof_object);
 
 
    //!Real allocation algorithm with min allocation option
    void * priv_allocate( boost::interprocess::allocation_type command
                        , size_type limit_size, size_type &prefer_in_recvd_out_size
                        , void *&reuse_ptr, size_type backwards_multiple = 1);
 
    //!Obtains the block control structure of the user buffer
    static block_ctrl *priv_get_block(const void *ptr);
 
    //!Obtains the pointer returned to the user from the block control
    static void *priv_get_user_buffer(const block_ctrl *block);
 
    //!Returns the number of total units that a user buffer
    //!of "userbytes" bytes really occupies (including header)
    static size_type priv_get_total_units(size_type userbytes);
 
    //!Real expand function implementation
    bool priv_expand(void *ptr, const size_type min_size, size_type &prefer_in_recvd_out_size);
 
    //!Real expand to both sides implementation
    void* priv_expand_both_sides(boost::interprocess::allocation_type command
                                ,size_type min_size
                                ,size_type &prefer_in_recvd_out_size
                                ,void *reuse_ptr
                                ,bool only_preferred_backwards
                                ,size_type backwards_multiple);
 
    //!Returns true if the previous block is allocated
    bool priv_is_prev_allocated(block_ctrl *ptr);
 
    //!Get a pointer of the "end" block from the first block of the segment
    static block_ctrl * priv_end_block(block_ctrl *first_segment_block);
 
    //!Get a pointer of the "first" block from the end block of the segment
    static block_ctrl * priv_first_block(block_ctrl *end_segment_block);
 
    //!Get poitner of the previous block (previous block must be free)
    static block_ctrl * priv_prev_block(block_ctrl *ptr);
 
    //!Get the size in the tail of the previous block
    static block_ctrl * priv_next_block(block_ctrl *ptr);
 
    //!Check if this block is free (not allocated)
    bool priv_is_allocated_block(block_ctrl *ptr);
 
    //!Marks the block as allocated
    void priv_mark_as_allocated_block(block_ctrl *ptr);
 
    //!Marks the block as allocated
    void priv_mark_new_allocated_block(block_ctrl *ptr)
    {  return priv_mark_as_allocated_block(ptr); }
 
    //!Marks the block as allocated
    void priv_mark_as_free_block(block_ctrl *ptr);
 
    //!Checks if block has enough memory and splits/unlinks the block
    //!returning the address to the users
    void* priv_check_and_allocate(size_type units
                                 ,block_ctrl* block
                                 ,size_type &received_size);
    //!Real deallocation algorithm
    void priv_deallocate(void *addr);
 
    //!Makes a new memory portion available for allocation
    void priv_add_segment(void *addr, size_type size);
 
    public:
 
    static const size_type Alignment = !MemAlignment
       ? size_type(::boost::container::dtl::alignment_of
                   < ::boost::container::dtl::max_align_t>::value)
       : size_type(MemAlignment)
       ;
 
    private:
    //Due to embedded bits in size, Alignment must be at least 4
    BOOST_INTERPROCESS_STATIC_ASSERT((Alignment >= 4));
    //Due to rbtree size optimizations, Alignment must have at least pointer alignment
    BOOST_INTERPROCESS_STATIC_ASSERT((Alignment >= ::boost::container::dtl::alignment_of<void_pointer>::value));
    static const size_type AlignmentMask = (Alignment - 1);
    static const size_type BlockCtrlBytes = ipcdetail::ct_rounded_size<sizeof(block_ctrl), Alignment>::value;
    static const size_type BlockCtrlUnits = BlockCtrlBytes/Alignment;
    static const size_type AllocatedCtrlBytes  = ipcdetail::ct_rounded_size<sizeof(SizeHolder), Alignment>::value;
    static const size_type AllocatedCtrlUnits  = AllocatedCtrlBytes/Alignment;
    static const size_type EndCtrlBlockBytes   = ipcdetail::ct_rounded_size<sizeof(SizeHolder), Alignment>::value;
    static const size_type EndCtrlBlockUnits   = EndCtrlBlockBytes/Alignment;
    static const size_type UsableByPreviousChunk   = sizeof(size_type);
 
    //Make sure the maximum alignment is power of two
    BOOST_INTERPROCESS_STATIC_ASSERT((0 == (Alignment & (Alignment - size_type(1u)))));
    #endif   //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
    public:
    static const size_type PayloadPerAllocation = AllocatedCtrlBytes - UsableByPreviousChunk;
 };
 
 #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment>
 inline typename rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::size_type
        rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>
    ::priv_first_block_offset_from_this(const void *this_ptr, size_type extra_hdr_bytes)
 {
    size_type uint_this      = (std::size_t)this_ptr;
    size_type main_hdr_end   = uint_this + sizeof(rbtree_best_fit) + extra_hdr_bytes;
    size_type aligned_main_hdr_end = ipcdetail::get_rounded_size(main_hdr_end, Alignment);
    size_type block1_off = aligned_main_hdr_end -  uint_this;
    algo_impl_t::assert_alignment(aligned_main_hdr_end);
    algo_impl_t::assert_alignment(uint_this + block1_off);
    return block1_off;
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment>
 void rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::
    priv_add_segment(void *addr, size_type segment_size)
 {
    //Check alignment
    algo_impl_t::check_alignment(addr);
    //Check size
    BOOST_ASSERT(segment_size >= (BlockCtrlBytes + EndCtrlBlockBytes));
 
    //Initialize the first big block and the "end" node
    block_ctrl *first_big_block = ::new(addr, boost_container_new_t()) block_ctrl;
    first_big_block->m_size = (segment_size/Alignment - EndCtrlBlockUnits) & block_ctrl::size_mask;
    BOOST_ASSERT(first_big_block->m_size >= BlockCtrlUnits);
 
    //The "end" node is just a node of size 0 with the "end" bit set
    SizeHolder *end_block =
       ::new(reinterpret_cast<char*>(addr) + first_big_block->m_size*Alignment, boost_container_new_t()) SizeHolder;
 
    //This will overwrite the prev part of the "end" node
    priv_mark_as_free_block (first_big_block);
    #ifdef BOOST_INTERPROCESS_RBTREE_BEST_FIT_ABI_V1_HPP
    first_big_block->m_prev_size = end_block->m_size =
       size_type(reinterpret_cast<char*>(first_big_block) - reinterpret_cast<char*>(end_block))/Alignment) & block_ctrl::size_mask;
    #else
    first_big_block->m_prev_size = end_block->m_size =
       size_type(reinterpret_cast<char*>(end_block) - reinterpret_cast<char*>(first_big_block))/Alignment & block_ctrl::size_mask;
    #endif
    end_block->m_allocated = 1;
    first_big_block->m_prev_allocated = 1;
 
    BOOST_ASSERT(priv_next_block(first_big_block) == end_block);
    BOOST_ASSERT(priv_prev_block((block_ctrl*)end_block) == first_big_block);
    BOOST_ASSERT(priv_first_block() == first_big_block);
    BOOST_ASSERT(priv_end_block() == end_block);
 
    //Some check to validate the algorithm, since it makes some assumptions
    //to optimize the space wasted in bookkeeping:
 
    //Check that the sizes of the header are placed before the rbtree
    BOOST_ASSERT(static_cast<void*>(static_cast<SizeHolder*>(first_big_block))
           < static_cast<void*>(static_cast<TreeHook*>(first_big_block)));
    //Insert it in the intrusive containers
    m_header.m_imultiset.insert(*first_big_block);
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment>
 inline typename rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::block_ctrl *
        rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>
    ::priv_first_block()
 {
    const size_type block1_off = priv_first_block_offset_from_this(this, m_header.m_extra_hdr_bytes);
    return move_detail::force_ptr<block_ctrl*>(reinterpret_cast<char*>(this) + block1_off);
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment>
 inline typename rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::block_ctrl *
        rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>
    ::priv_end_block()
 {
    const size_type block1_off = priv_first_block_offset_from_this(this, m_header.m_extra_hdr_bytes);
    const size_type original_first_block_size = (m_header.m_size - block1_off)/Alignment - EndCtrlBlockUnits;
    block_ctrl *end_block = move_detail::force_ptr<block_ctrl*>
       (reinterpret_cast<char*>(this) + block1_off + original_first_block_size*Alignment);
    return end_block;
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment>
 inline rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::
    rbtree_best_fit(size_type segment_size, size_type extra_hdr_bytes)
 {
    //Initialize the header
    m_header.m_allocated       = 0;
    m_header.m_size            = segment_size;
    m_header.m_extra_hdr_bytes = extra_hdr_bytes;
 
    //Now write calculate the offset of the first big block that will
    //cover the whole segment
    BOOST_ASSERT(get_min_size(extra_hdr_bytes) <= segment_size);
    size_type block1_off  = priv_first_block_offset_from_this(this, extra_hdr_bytes);
    priv_add_segment(reinterpret_cast<char*>(this) + block1_off, segment_size - block1_off);
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment>
 inline rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::~rbtree_best_fit()
 {
    //There is a memory leak!
 //   BOOST_ASSERT(m_header.m_allocated == 0);
 //   BOOST_ASSERT(m_header.m_root.m_next->m_next == block_ctrl_ptr(&m_header.m_root));
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment>
 void rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::grow(size_type extra_size)
 {
    //Get the address of the first block
    block_ctrl *first_block = priv_first_block();
    block_ctrl *old_end_block = priv_end_block();
    size_type old_border_offset = (size_type)(reinterpret_cast<char*>(old_end_block) -
                                     reinterpret_cast<char*>(this)) + EndCtrlBlockBytes;
 
    //Update managed buffer's size
    m_header.m_size += extra_size;
 
    //We need at least BlockCtrlBytes blocks to create a new block
    if((m_header.m_size - old_border_offset) < BlockCtrlBytes){
       return;
    }
 
    //Now create a new block between the old end and the new end
    size_type align_offset = (m_header.m_size - old_border_offset)/Alignment;
    block_ctrl *new_end_block = move_detail::force_ptr<block_ctrl*>
       (reinterpret_cast<char*>(old_end_block) + align_offset*Alignment);
 
    //the last and first block are special:
    //new_end_block->m_size & first_block->m_prev_size store the absolute value
    //between them
    new_end_block->m_allocated = 1;
    #ifdef BOOST_INTERPROCESS_RBTREE_BEST_FIT_ABI_V1_HPP
    new_end_block->m_size      = size_type(reinterpret_cast<char*>(first_block) -
                                           reinterpret_cast<char*>(new_end_block))/Alignment & block_ctrl::size_mask;
    #else
    new_end_block->m_size      = size_type(reinterpret_cast<char*>(new_end_block) -
                                           reinterpret_cast<char*>(first_block))/Alignment & block_ctrl::size_mask;
    #endif
    first_block->m_prev_size = new_end_block->m_size;
    first_block->m_prev_allocated = 1;
    BOOST_ASSERT(new_end_block == priv_end_block());
 
    //The old end block is the new block
    block_ctrl *new_block = old_end_block;
    new_block->m_size = size_type(reinterpret_cast<char*>(new_end_block) -
                                  reinterpret_cast<char*>(new_block))/Alignment & block_ctrl::size_mask;
    BOOST_ASSERT(new_block->m_size >= BlockCtrlUnits);
    priv_mark_as_allocated_block(new_block);
    BOOST_ASSERT(priv_next_block(new_block) == new_end_block);
 
    m_header.m_allocated += (size_type)new_block->m_size*Alignment;
 
    //Now deallocate the newly created block
    this->priv_deallocate(priv_get_user_buffer(new_block));
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment>
 void rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::shrink_to_fit()
 {
    //Get the address of the first block
    block_ctrl *first_block = priv_first_block();
    algo_impl_t::assert_alignment(first_block);
 
    //block_ctrl *old_end_block = priv_end_block(first_block);
    block_ctrl *old_end_block = priv_end_block();
    algo_impl_t::assert_alignment(old_end_block);
    size_type old_end_block_size = old_end_block->m_size;
 
    void *unique_buffer = 0;
    block_ctrl *last_block;
    //Check if no memory is allocated between the first and last block
    if(priv_next_block(first_block) == old_end_block){
       //If so check if we can allocate memory
       size_type ignore_recvd = 0;
       void *ignore_reuse = 0;
       unique_buffer = priv_allocate(boost::interprocess::allocate_new, 0, ignore_recvd, ignore_reuse);
       //If not, return, we can't shrink
       if(!unique_buffer)
          return;
       //If we can, mark the position just after the new allocation as the new end
       algo_impl_t::assert_alignment(unique_buffer);
       block_ctrl *unique_block = priv_get_block(unique_buffer);
       BOOST_ASSERT(priv_is_allocated_block(unique_block));
       algo_impl_t::assert_alignment(unique_block);
       last_block = priv_next_block(unique_block);
       BOOST_ASSERT(!priv_is_allocated_block(last_block));
       algo_impl_t::assert_alignment(last_block);
    }
    else{
       //If memory is allocated, check if the last block is allocated
       if(priv_is_prev_allocated(old_end_block))
          return;
       //If not, mark last block after the free block
       last_block = priv_prev_block(old_end_block);
    }
 
    size_type last_block_size = last_block->m_size;
 
    //Erase block from the free tree, since we will erase it
    m_header.m_imultiset.erase(Imultiset::s_iterator_to(*last_block));
 
    size_type shrunk_border_offset = (size_type)(reinterpret_cast<char*>(last_block) -
                                        reinterpret_cast<char*>(this)) + EndCtrlBlockBytes;
 
    block_ctrl *new_end_block = last_block;
    algo_impl_t::assert_alignment(new_end_block);
 
    //Write new end block attributes
    #ifdef BOOST_INTERPROCESS_RBTREE_BEST_FIT_ABI_V1_HPP
    new_end_block->m_size = 
       size_type(reinterpret_cast<char*>(first_block) - reinterpret_cast<char*>(new_end_block))/Alignment & block_ctrl::size_mask;
    first_block->m_prev_size = new_end_block->m_size;
    #else
    new_end_block->m_size =
       size_type(reinterpret_cast<char*>(new_end_block) - reinterpret_cast<char*>(first_block))/Alignment & block_ctrl::size_mask;
    first_block->m_prev_size = new_end_block->m_size;
    #endif
 
    new_end_block->m_allocated = 1;
    (void)last_block_size;
    (void)old_end_block_size;
    BOOST_ASSERT(new_end_block->m_size == (old_end_block_size - last_block_size));
 
    //Update managed buffer's size
    m_header.m_size = shrunk_border_offset & block_ctrl::size_mask;
    BOOST_ASSERT(priv_end_block() == new_end_block);
    if(unique_buffer)
       priv_deallocate(unique_buffer);
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment>
 inline typename rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::size_type
 rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::get_size()  const
 {  return m_header.m_size;  }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment>
 typename rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::size_type
 rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::get_free_memory()  const
 {
    return m_header.m_size - m_header.m_allocated -
       priv_first_block_offset_from_this(this, m_header.m_extra_hdr_bytes);
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment>
 typename rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::size_type
 rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::
    get_min_size (size_type extra_hdr_bytes)
 {
    return (algo_impl_t::ceil_units(sizeof(rbtree_best_fit)) +
            algo_impl_t::ceil_units(extra_hdr_bytes) +
            BlockCtrlUnits + EndCtrlBlockUnits)*Alignment;
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment>
 inline bool rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::
     all_memory_deallocated()
 {
    //-----------------------
    boost::interprocess::scoped_lock<mutex_type> guard(m_header);
    //-----------------------
    size_type block1_off  =
       priv_first_block_offset_from_this(this, m_header.m_extra_hdr_bytes);
 
    return m_header.m_allocated == 0 &&
       m_header.m_imultiset.begin() != m_header.m_imultiset.end() &&
        (++m_header.m_imultiset.begin()) == m_header.m_imultiset.end()
        && m_header.m_imultiset.begin()->m_size ==
          (m_header.m_size - block1_off - EndCtrlBlockBytes)/Alignment;
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment>
 bool rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::
     check_sanity()
 {
    //-----------------------
    boost::interprocess::scoped_lock<mutex_type> guard(m_header);
    //-----------------------
    imultiset_iterator ib(m_header.m_imultiset.begin()), ie(m_header.m_imultiset.end());
 
    size_type free_memory = 0;
 
    //Iterate through all blocks obtaining their size
    for(; ib != ie; ++ib){
       free_memory += (size_type)ib->m_size*Alignment;
       if(!algo_impl_t::check_alignment(&*ib))
          return false;
    }
 
    //Check allocated bytes are less than size
    if(m_header.m_allocated > m_header.m_size){
       return false;
    }
 
    size_type block1_off  =
       priv_first_block_offset_from_this(this, m_header.m_extra_hdr_bytes);
 
    //Check free bytes are less than size
    if(free_memory > (m_header.m_size - block1_off)){
       return false;
    }
    return true;
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment>
 inline void* rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::
    allocate(size_type nbytes)
 {
    //-----------------------
    boost::interprocess::scoped_lock<mutex_type> guard(m_header);
    //-----------------------
    size_type ignore_recvd = nbytes;
    void *ignore_reuse = 0;
    return priv_allocate(boost::interprocess::allocate_new, nbytes, ignore_recvd, ignore_reuse);
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment>
 inline void* rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::
    allocate_aligned(size_type nbytes, size_type alignment)
 {
    //-----------------------
    boost::interprocess::scoped_lock<mutex_type> guard(m_header);
    //-----------------------
    return algo_impl_t::allocate_aligned(this, nbytes, alignment);
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment>
 template<class T>
 inline T* rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::
    allocation_command  (boost::interprocess::allocation_type command,   size_type limit_size,
                         size_type &prefer_in_recvd_out_size, T *&reuse)
 {
    void* raw_reuse = reuse;
    void* const ret = priv_allocation_command(command, limit_size, prefer_in_recvd_out_size, raw_reuse, sizeof(T));
    reuse = static_cast<T*>(raw_reuse);
    BOOST_ASSERT(0 == ((std::size_t)ret % ::boost::container::dtl::alignment_of<T>::value));
    return static_cast<T*>(ret);
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment>
 inline void* rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::
    raw_allocation_command  (boost::interprocess::allocation_type command,   size_type limit_objects,
                         size_type &prefer_in_recvd_out_objects, void *&reuse_ptr, size_type sizeof_object)
 {
    size_type const preferred_objects = prefer_in_recvd_out_objects;
    if(!sizeof_object)
       return reuse_ptr = 0, static_cast<void*>(0);
    if(command & boost::interprocess::try_shrink_in_place){
       if(!reuse_ptr)  return static_cast<void*>(0);
       const bool success = algo_impl_t::try_shrink
          ( this, reuse_ptr, limit_objects*sizeof_object
          , prefer_in_recvd_out_objects = preferred_objects*sizeof_object);
       prefer_in_recvd_out_objects /= sizeof_object;
       return success ? reuse_ptr : 0;
    }
    else{
       return priv_allocation_command
          (command, limit_objects, prefer_in_recvd_out_objects, reuse_ptr, sizeof_object);
    }
 }
 
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment>
 inline void* rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::
    priv_allocation_command (boost::interprocess::allocation_type command,   size_type limit_size,
                        size_type &prefer_in_recvd_out_size,
                        void *&reuse_ptr, size_type sizeof_object)
 {
    void* ret;
    size_type const preferred_size = prefer_in_recvd_out_size;
    size_type const max_count = m_header.m_size/sizeof_object;
    if(limit_size > max_count || preferred_size > max_count){
       return reuse_ptr = 0, static_cast<void*>(0);
    }
    size_type l_size = limit_size*sizeof_object;
    size_type p_size = preferred_size*sizeof_object;
    size_type r_size;
    {
       //-----------------------
       boost::interprocess::scoped_lock<mutex_type> guard(m_header);
       //-----------------------
       ret = priv_allocate(command, l_size, r_size = p_size, reuse_ptr, sizeof_object);
    }
    prefer_in_recvd_out_size = r_size/sizeof_object;
    return ret;
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment>
 typename rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::size_type
 rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::
    size(const void *ptr) const
 {
    //We need no synchronization since this block's size is not going
    //to be modified by anyone else
    //Obtain the real size of the block
    return ((size_type)priv_get_block(ptr)->m_size - AllocatedCtrlUnits)*Alignment + UsableByPreviousChunk;
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment>
 inline void rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::zero_free_memory()
 {
    //-----------------------
    boost::interprocess::scoped_lock<mutex_type> guard(m_header);
    //-----------------------
    imultiset_iterator ib(m_header.m_imultiset.begin()), ie(m_header.m_imultiset.end());
 
    //Iterate through all blocks obtaining their size
    while(ib != ie){
       //Just clear user the memory part reserved for the user
       volatile char *ptr = reinterpret_cast<char*>(&*ib) + BlockCtrlBytes;
       size_type s = (size_type)ib->m_size*Alignment - BlockCtrlBytes;
       while(s--){
          *ptr++ = 0;
       }
 
       //This surprisingly is optimized out by Visual C++ 7.1 in release mode!
       //std::memset( reinterpret_cast<char*>(&*ib) + BlockCtrlBytes
       //           , 0
       //           , ib->m_size*Alignment - BlockCtrlBytes);
       ++ib;
    }
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment>
 void* rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::
    priv_expand_both_sides(boost::interprocess::allocation_type command
                          ,size_type min_size
                          ,size_type &prefer_in_recvd_out_size
                          ,void *reuse_ptr
                          ,bool only_preferred_backwards
                          ,size_type backwards_multiple)
 {
    size_type const preferred_size = prefer_in_recvd_out_size;
    algo_impl_t::assert_alignment(reuse_ptr);
    if(command & boost::interprocess::expand_fwd){
       if(priv_expand(reuse_ptr, min_size, prefer_in_recvd_out_size = preferred_size))
          return reuse_ptr;
    }
    else{
       prefer_in_recvd_out_size = this->size(reuse_ptr);
       if(prefer_in_recvd_out_size >= preferred_size || prefer_in_recvd_out_size >= min_size)
          return reuse_ptr;
    }
 
    if(backwards_multiple){
       BOOST_ASSERT(0 == (min_size       % backwards_multiple));
       BOOST_ASSERT(0 == (preferred_size % backwards_multiple));
    }
 
    if(command & boost::interprocess::expand_bwd){
       //Obtain the real size of the block
       block_ctrl *reuse = priv_get_block(reuse_ptr);
 
       //Sanity check
       algo_impl_t::assert_alignment(reuse);
 
       block_ctrl *prev_block;
 
       //If the previous block is not free, there is nothing to do
       if(priv_is_prev_allocated(reuse)){
          return 0;
       }
 
       prev_block = priv_prev_block(reuse);
       BOOST_ASSERT(!priv_is_allocated_block(prev_block));
 
       //Some sanity checks
       BOOST_ASSERT(prev_block->m_size == reuse->m_prev_size);
       algo_impl_t::assert_alignment(prev_block);
 
       size_type needs_backwards_aligned;
       size_type lcm;
       if(!algo_impl_t::calculate_lcm_and_needs_backwards_lcmed
          ( backwards_multiple
          , prefer_in_recvd_out_size
          , only_preferred_backwards ? preferred_size : min_size
          , lcm, needs_backwards_aligned)){
          return 0;
       }
 
       //Check if previous block has enough size
       if(size_type(prev_block->m_size*Alignment) >= needs_backwards_aligned){
          //Now take all next space. This will succeed
          if(command & boost::interprocess::expand_fwd){
             size_type received_size2;
             if(!priv_expand(reuse_ptr, prefer_in_recvd_out_size, received_size2 = prefer_in_recvd_out_size)){
                BOOST_ASSERT(0);
             }
             BOOST_ASSERT(prefer_in_recvd_out_size == received_size2);
          }
          //We need a minimum size to split the previous one
          if(prev_block->m_size >= (needs_backwards_aligned/Alignment + BlockCtrlUnits)){
             block_ctrl *new_block = move_detail::force_ptr<block_ctrl*>
                (reinterpret_cast<char*>(reuse) - needs_backwards_aligned);
 
             //Free old previous buffer
             new_block->m_size =
                (AllocatedCtrlUnits + (needs_backwards_aligned + (prefer_in_recvd_out_size - UsableByPreviousChunk))/Alignment) & block_ctrl::size_mask;
             BOOST_ASSERT(new_block->m_size >= BlockCtrlUnits);
             priv_mark_as_allocated_block(new_block);
 
             prev_block->m_size = size_type(reinterpret_cast<char*>(new_block) -
                                            reinterpret_cast<char*>(prev_block))/Alignment & block_ctrl::size_mask;
             BOOST_ASSERT(prev_block->m_size >= BlockCtrlUnits);
             priv_mark_as_free_block(prev_block);
 
             //Update the old previous block in the free blocks tree
             //If the new size fulfills tree invariants do nothing,
             //otherwise erase() + insert()
             {
                imultiset_iterator prev_block_it(Imultiset::s_iterator_to(*prev_block));
                imultiset_iterator was_smaller_it(prev_block_it);
                if(prev_block_it != m_header.m_imultiset.begin() &&
                   (--(was_smaller_it = prev_block_it))->m_size > prev_block->m_size){
                   m_header.m_imultiset.erase(prev_block_it);
                   m_header.m_imultiset.insert(m_header.m_imultiset.begin(), *prev_block);
                }
             }
 
             prefer_in_recvd_out_size = needs_backwards_aligned + prefer_in_recvd_out_size;
             m_header.m_allocated += needs_backwards_aligned;
 
             //Check alignment
             algo_impl_t::assert_alignment(new_block);
 
             //If the backwards expansion has remaining bytes in the
             //first bytes, fill them with a pattern
             void *p = priv_get_user_buffer(new_block);
             void *user_ptr = reinterpret_cast<char*>(p);
             BOOST_ASSERT(size_type(static_cast<char*>(reuse_ptr) - static_cast<char*>(user_ptr)) % backwards_multiple == 0);
             algo_impl_t::assert_alignment(user_ptr);
             return user_ptr;
          }
          //Check if there is no place to create a new block and
          //the whole new block is multiple of the backwards expansion multiple
          else if(prev_block->m_size >= needs_backwards_aligned/Alignment &&
                  0 == ((prev_block->m_size*Alignment) % lcm)) {
             //Erase old previous block, since we will change it
             m_header.m_imultiset.erase(Imultiset::s_iterator_to(*prev_block));
 
             //Just merge the whole previous block
             //prev_block->m_size*Alignment is multiple of lcm (and backwards_multiple)
             prefer_in_recvd_out_size = prefer_in_recvd_out_size + (size_type)prev_block->m_size*Alignment;
 
             m_header.m_allocated += (size_type)prev_block->m_size*Alignment;
             //Now update sizes
             prev_block->m_size = size_type(prev_block->m_size + reuse->m_size) & block_ctrl::size_mask;
             BOOST_ASSERT(prev_block->m_size >= BlockCtrlUnits);
             priv_mark_as_allocated_block(prev_block);
 
             //If the backwards expansion has remaining bytes in the
             //first bytes, fill them with a pattern
             void *user_ptr = priv_get_user_buffer(prev_block);
             BOOST_ASSERT(size_type(static_cast<char*>(reuse_ptr) - static_cast<char*>(user_ptr)) % backwards_multiple == 0);
             algo_impl_t::assert_alignment(user_ptr);
             return user_ptr;
          }
          else{
             //Alignment issues
          }
       }
    }
    return 0;
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment>
 inline void rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::
    deallocate_many(typename rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::multiallocation_chain &chain)
 {
    //-----------------------
    boost::interprocess::scoped_lock<mutex_type> guard(m_header);
    //-----------------------
    algo_impl_t::deallocate_many(this, chain);
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment>
 void * rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::
    priv_allocate(boost::interprocess::allocation_type command
                 ,size_type limit_size
                 ,size_type &prefer_in_recvd_out_size
                 ,void *&reuse_ptr
                ,size_type backwards_multiple)
 {
    size_type const preferred_size = prefer_in_recvd_out_size;
    if(command & boost::interprocess::shrink_in_place){
       if(!reuse_ptr)  return static_cast<void*>(0);
       bool success =
          algo_impl_t::shrink(this, reuse_ptr, limit_size, prefer_in_recvd_out_size = preferred_size);
       return success ? reuse_ptr : 0;
    }
 
    prefer_in_recvd_out_size = 0;
 
    if(limit_size > preferred_size)
       return reuse_ptr = 0, static_cast<void*>(0);
 
    //Number of units to request (including block_ctrl header)
    size_type preferred_units = priv_get_total_units(preferred_size);
 
    //Number of units to request (including block_ctrl header)
    size_type limit_units = priv_get_total_units(limit_size);
 
    //Expand in place
    prefer_in_recvd_out_size = preferred_size;
    if(reuse_ptr && (command & (boost::interprocess::expand_fwd | boost::interprocess::expand_bwd))){
       void *ret = priv_expand_both_sides
          (command, limit_size, prefer_in_recvd_out_size, reuse_ptr, true, backwards_multiple);
       if(ret)
          return ret;
    }
 
    if(command & boost::interprocess::allocate_new){
       size_block_ctrl_compare comp;
       imultiset_iterator it(m_header.m_imultiset.lower_bound(preferred_units, comp));
 
       if(it != m_header.m_imultiset.end()){
          return reuse_ptr = 0, this->priv_check_and_allocate
             (preferred_units, ipcdetail::to_raw_pointer(&*it), prefer_in_recvd_out_size);
       }
 
       if(it != m_header.m_imultiset.begin()&&
               (--it)->m_size >= limit_units){
          return reuse_ptr = 0, this->priv_check_and_allocate
             (it->m_size, ipcdetail::to_raw_pointer(&*it), prefer_in_recvd_out_size);
       }
    }
 
 
    //Now try to expand both sides with min size
    if(reuse_ptr && (command & (boost::interprocess::expand_fwd | boost::interprocess::expand_bwd))){
       return priv_expand_both_sides
          (command, limit_size, prefer_in_recvd_out_size = preferred_size, reuse_ptr, false, backwards_multiple);
    }
    return reuse_ptr = 0, static_cast<void*>(0);
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment>
 inline
 typename rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::block_ctrl *
    rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::priv_get_block(const void *ptr)
 {
    return const_cast<block_ctrl*>
       (move_detail::force_ptr<const block_ctrl*>
          (reinterpret_cast<const char*>(ptr) - AllocatedCtrlBytes));
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment>
 inline
 void *rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::
       priv_get_user_buffer(const typename rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::block_ctrl *block)
 {  return const_cast<char*>(reinterpret_cast<const char*>(block) + AllocatedCtrlBytes);   }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment>
 inline typename rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::size_type
 rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::
    priv_get_total_units(size_type userbytes)
 {
    if(userbytes < UsableByPreviousChunk)
       userbytes = UsableByPreviousChunk;
    size_type units = ipcdetail::get_rounded_size(userbytes - UsableByPreviousChunk, Alignment)/Alignment + AllocatedCtrlUnits;
    if(units < BlockCtrlUnits) units = BlockCtrlUnits;
    return units;
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment>
 bool rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::
    priv_expand (void *ptr, const size_type min_size, size_type &prefer_in_recvd_out_size)
 {
    size_type const preferred_size = prefer_in_recvd_out_size;
    //Obtain the real size of the block
    block_ctrl *block = priv_get_block(ptr);
    size_type old_block_units = block->m_size;
 
    //The block must be marked as allocated and the sizes must be equal
    BOOST_ASSERT(priv_is_allocated_block(block));
 
    //Put this to a safe value
    prefer_in_recvd_out_size = (old_block_units - AllocatedCtrlUnits)*Alignment + UsableByPreviousChunk;
    if(prefer_in_recvd_out_size >= preferred_size || prefer_in_recvd_out_size >= min_size)
       return true;
 
    //Now translate it to Alignment units
    const size_type min_user_units = algo_impl_t::ceil_units(min_size - UsableByPreviousChunk);
    const size_type preferred_user_units = algo_impl_t::ceil_units(preferred_size - UsableByPreviousChunk);
 
    //Some parameter checks
    BOOST_ASSERT(min_user_units <= preferred_user_units);
 
    block_ctrl *next_block;
 
    if(priv_is_allocated_block(next_block = priv_next_block(block))){
       return prefer_in_recvd_out_size >= min_size;
    }
    algo_impl_t::assert_alignment(next_block);
 
    //Is "block" + "next_block" big enough?
    const size_type merged_units = old_block_units + (size_type)next_block->m_size;
 
    //Now get the expansion size
    const size_type merged_user_units = merged_units - AllocatedCtrlUnits;
 
    if(merged_user_units < min_user_units){
       prefer_in_recvd_out_size = merged_units*Alignment - UsableByPreviousChunk;
       return false;
    }
 
    //Now get the maximum size the user can allocate
    size_type intended_user_units = (merged_user_units < preferred_user_units) ?
       merged_user_units : preferred_user_units;
 
    //These are total units of the merged block (supposing the next block can be split)
    const size_type intended_units = AllocatedCtrlUnits + intended_user_units;
 
    //Check if we can split the next one in two parts
    if((merged_units - intended_units) >=  BlockCtrlUnits){
       //This block is bigger than needed, split it in
       //two blocks, the first one will be merged and
       //the second's size will be the remaining space
       BOOST_ASSERT(next_block->m_size == priv_next_block(next_block)->m_prev_size);
       const size_type rem_units = merged_units - intended_units;
 
       //Check if we we need to update the old next block in the free blocks tree
       //If the new size fulfills tree invariants, we just need to replace the node
       //(the block start has been displaced), otherwise erase() + insert().
       //
       //This fixup must be done in two parts, because the new next block might
       //overwrite the tree hook of the old next block. So we first erase the
       //old if needed and we'll insert the new one after creating the new next
       imultiset_iterator old_next_block_it(Imultiset::s_iterator_to(*next_block));
       m_header.m_imultiset.erase(old_next_block_it);
 
       //This is the remaining block
       block_ctrl *rem_block = 
          ::new(reinterpret_cast<char*>(block) + intended_units*Alignment, boost_container_new_t()) block_ctrl;
       rem_block->m_size = rem_units & block_ctrl::size_mask;
       algo_impl_t::assert_alignment(rem_block);
       BOOST_ASSERT(rem_block->m_size >= BlockCtrlUnits);
       priv_mark_as_free_block(rem_block);
       m_header.m_imultiset.insert(*rem_block);
 
       //Write the new length
       block->m_size = (intended_user_units + AllocatedCtrlUnits) & block_ctrl::size_mask;
       BOOST_ASSERT(block->m_size >= BlockCtrlUnits);
       m_header.m_allocated += (intended_units - old_block_units)*Alignment;
    }
    //There is no free space to create a new node: just merge both blocks
    else{
       //Now we have to update the data in the tree
       m_header.m_imultiset.erase(Imultiset::s_iterator_to(*next_block));
 
       //Write the new length
       block->m_size = merged_units & block_ctrl::size_mask;
       BOOST_ASSERT(block->m_size >= BlockCtrlUnits);
       m_header.m_allocated += (merged_units - old_block_units)*Alignment;
    }
    priv_mark_as_allocated_block(block);
    prefer_in_recvd_out_size = ((size_type)block->m_size - AllocatedCtrlUnits)*Alignment + UsableByPreviousChunk;
    return true;
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment> inline
 typename rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::block_ctrl *
    rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::priv_prev_block
       (typename rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::block_ctrl *ptr)
 {
    BOOST_ASSERT(!ptr->m_prev_allocated);
    return move_detail::force_ptr<block_ctrl*>
       (reinterpret_cast<char*>(ptr) - ptr->m_prev_size*Alignment);
 }
 
 
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment> inline
 typename rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::block_ctrl *
    rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::priv_end_block
       (typename rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::block_ctrl *first_segment_block)
 {
    //The first block's logic is different from the rest of blocks: stores in m_prev_size the absolute
    //distance with the end block
    BOOST_ASSERT(first_segment_block->m_prev_allocated);
    block_ctrl *end_block = move_detail::force_ptr<block_ctrl*>
       (reinterpret_cast<char*>(first_segment_block) + first_segment_block->m_prev_size*Alignment);
    (void)end_block;
    BOOST_ASSERT(end_block->m_allocated == 1);
    BOOST_ASSERT(end_block->m_size == first_segment_block->m_prev_size);
    BOOST_ASSERT(end_block > first_segment_block);
    return end_block;
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment> inline
 typename rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::block_ctrl *
    rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::priv_first_block
       (typename rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::block_ctrl *end_segment_block)
 {
    //The first block's logic is different from the rest of blocks: stores in m_prev_size the absolute
    //distance with the end block
    BOOST_ASSERT(end_segment_block->m_allocated);
    block_ctrl *first_block = move_detail::force_ptr<block_ctrl*>
       (reinterpret_cast<char*>(end_segment_block) - end_segment_block->m_size*Alignment);
    (void)first_block;
    BOOST_ASSERT(first_block->m_prev_allocated == 1);
    BOOST_ASSERT(first_block->m_prev_size == end_segment_block->m_size);
    BOOST_ASSERT(end_segment_block > first_block);
    return first_block;
 }
 
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment> inline
 typename rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::block_ctrl *
    rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::priv_next_block
       (typename rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::block_ctrl *ptr)
 {
    return move_detail::force_ptr<block_ctrl*>
       (reinterpret_cast<char*>(ptr) + ptr->m_size*Alignment);
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment> inline
 bool rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::priv_is_allocated_block
       (typename rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::block_ctrl *block)
 {
    bool allocated = block->m_allocated != 0;
    #ifndef NDEBUG
    if(block != priv_end_block()){
       block_ctrl *next_block = move_detail::force_ptr<block_ctrl*>
          (reinterpret_cast<char*>(block) + block->m_size*Alignment);
       bool next_block_prev_allocated = next_block->m_prev_allocated != 0;
       (void)next_block_prev_allocated;
       BOOST_ASSERT(allocated == next_block_prev_allocated);
    }
    #endif
    return allocated;
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment> inline
 bool rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::priv_is_prev_allocated
       (typename rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::block_ctrl *block)
 {
    if(block->m_prev_allocated){
       return true;
    }
    else{
       #ifndef NDEBUG
       if(block != priv_first_block()){
          block_ctrl *prev = priv_prev_block(block);
          (void)prev;
          BOOST_ASSERT(!prev->m_allocated);
          BOOST_ASSERT(prev->m_size == block->m_prev_size);
       }
       #endif
       return false;
    }
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment> inline
 void rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::priv_mark_as_allocated_block
       (typename rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::block_ctrl *block)
 {
    block->m_allocated = 1;
    move_detail::force_ptr<block_ctrl*>
       (reinterpret_cast<char*>(block)+ block->m_size*Alignment)->m_prev_allocated = 1;
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment> inline
 void rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::priv_mark_as_free_block
       (typename rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::block_ctrl *block)
 {
    block->m_allocated = 0;
    block_ctrl *next_block = priv_next_block(block);
    next_block->m_prev_allocated = 0;
    next_block->m_prev_size = block->m_size;
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment> inline
 void* rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::priv_check_and_allocate
    (size_type nunits
    ,typename rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::block_ctrl* block
    ,size_type &received_size)
 {
    size_type upper_nunits = nunits + BlockCtrlUnits;
    imultiset_iterator it_old = Imultiset::s_iterator_to(*block);
    algo_impl_t::assert_alignment(block);
 
    if (block->m_size >= upper_nunits){
       //This block is bigger than needed, split it in
       //two blocks, the first's size will be "units" and
       //the second's size "block->m_size-units"
       size_type block_old_size = block->m_size;
       block->m_size = nunits & block_ctrl::size_mask;
       BOOST_ASSERT(block->m_size >= BlockCtrlUnits);
 
       //This is the remaining block
       block_ctrl *rem_block =
          ::new(reinterpret_cast<char*>(block) + Alignment*nunits, boost_container_new_t()) block_ctrl;
       algo_impl_t::assert_alignment(rem_block);
       rem_block->m_size = (block_old_size - nunits) & block_ctrl::size_mask;
       BOOST_ASSERT(rem_block->m_size >= BlockCtrlUnits);
       priv_mark_as_free_block(rem_block);
 
       //Now we have to update the data in the tree.
       //Use the position of the erased one as a hint
       m_header.m_imultiset.insert(m_header.m_imultiset.erase(it_old), *rem_block);
    }
    else if (block->m_size >= nunits){
       m_header.m_imultiset.erase(it_old);
    }
    else{
       BOOST_ASSERT(0);
       return 0;
    }
    //We need block_ctrl for deallocation stuff, so
    //return memory user can overwrite
    m_header.m_allocated += (size_type)block->m_size*Alignment;
    received_size =  ((size_type)block->m_size - AllocatedCtrlUnits)*Alignment + UsableByPreviousChunk;
 
    //Mark the block as allocated
    priv_mark_as_allocated_block(block);
 
    //Clear the memory occupied by the tree hook, since this won't be
    //cleared with zero_free_memory
    TreeHook *t = static_cast<TreeHook*>(block);
    //Just clear the memory part reserved for the user
    std::size_t tree_hook_offset_in_block = std::size_t((char*)t - (char*)block);
    //volatile char *ptr =
    char *ptr = reinterpret_cast<char*>(block)+tree_hook_offset_in_block;
    const std::size_t s = BlockCtrlBytes - tree_hook_offset_in_block;
    std::memset(ptr, 0, s);
    this->priv_next_block(block)->m_prev_size = 0;
    return priv_get_user_buffer(block);
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment>
 void rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::deallocate(void* addr)
 {
    if(!addr)   return;
    //-----------------------
    boost::interprocess::scoped_lock<mutex_type> guard(m_header);
    //-----------------------
    return this->priv_deallocate(addr);
 }
 
 template<class MutexFamily, class VoidPointer, std::size_t MemAlignment>
 void rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::priv_deallocate(void* addr)
 {
    if(!addr)   return;
 
    block_ctrl *block = priv_get_block(addr);
 
    //The blocks must be marked as allocated and the sizes must be equal
    BOOST_ASSERT(priv_is_allocated_block(block));
 
    //Check if alignment and block size are right
    algo_impl_t::assert_alignment(addr);
 
    size_type block_old_size = Alignment*(size_type)block->m_size;
    BOOST_ASSERT(m_header.m_allocated >= block_old_size);
 
    //Update used memory count
    m_header.m_allocated -= block_old_size;
 
    //The block to insert in the tree
    block_ctrl *block_to_insert = block;
 
    //Get the next block
    block_ctrl *const next_block  = priv_next_block(block);
    const bool merge_with_prev    = !priv_is_prev_allocated(block);
    const bool merge_with_next    = !priv_is_allocated_block(next_block);
 
    //Merge logic. First just update block sizes, then fix free blocks tree
    if(merge_with_prev || merge_with_next){
       //Merge if the previous is free
       if(merge_with_prev){
          //Get the previous block
          block_to_insert = priv_prev_block(block);
          block_to_insert->m_size = size_type(block_to_insert->m_size + block->m_size) & block_ctrl::size_mask;
          BOOST_ASSERT(block_to_insert->m_size >= BlockCtrlUnits);
          m_header.m_imultiset.erase(Imultiset::s_iterator_to(*block_to_insert));
       }
       //Merge if the next is free
       if(merge_with_next){
          block_to_insert->m_size = size_type(block_to_insert->m_size + next_block->m_size) & block_ctrl::size_mask;
          BOOST_ASSERT(block_to_insert->m_size >= BlockCtrlUnits);
          const imultiset_iterator next_it = Imultiset::s_iterator_to(*next_block);
          m_header.m_imultiset.erase(next_it);
       }
    }
    priv_mark_as_free_block(block_to_insert);
    m_header.m_imultiset.insert(*block_to_insert);
 }
 
 #endif   //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
 
 }  //namespace interprocess {
 }  //namespace boost {
 
 #include <boost/interprocess/detail/config_end.hpp>
 
 #endif   //#ifndef BOOST_INTERPROCESS_MEM_ALGO_RBTREE_BEST_FIT_HPP

This page was automatically generated by the 2.3.7 LXR engine. The LXR team