boost/interprocess/mem_algo/rbtree_best_fit.hpp
////////////////////////////////////////////////////////////////////////////// // // (C) Copyright Ion Gaztanaga 2005-2012. Distributed under the Boost // Software License, Version 1.0. (See accompanying file // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) // // See http://www.boost.org/libs/interprocess for documentation. // ////////////////////////////////////////////////////////////////////////////// #ifndef BOOST_INTERPROCESS_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 // intrusive #include <boost/intrusive/pointer_traits.hpp> #include <boost/intrusive/set.hpp> // other boost #include <boost/assert.hpp> #include <boost/static_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 { //!This block's memory size (including block_ctrl //!header) in Alignment units size_type m_prev_size; 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, public TreeHook { block_ctrl() { this->m_size = 0; this->m_allocated = 0, this->m_prev_allocated = 0; } friend bool operator<(const block_ctrl &a, const block_ctrl &b) { return a.m_size < b.m_size; } friend bool operator==(const block_ctrl &a, const block_ctrl &b) { return a.m_size == b.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 void* allocate (size_type nbytes); #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED) //Experimental. Dont' use //!Multiple element allocation, same size 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 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 void deallocate_many(multiallocation_chain &chain); #endif //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED //!Deallocates previously allocated bytes void deallocate (void *addr); //!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(); 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); //!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_STATIC_ASSERT((Alignment >= 4)); //Due to rbtree size optimizations, Alignment must have at least pointer alignment BOOST_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 MinBlockUnits = BlockCtrlUnits; static const size_type UsableByPreviousChunk = sizeof(size_type); //Make sure the maximum alignment is power of two BOOST_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; BOOST_ASSERT(first_big_block->m_size >= BlockCtrlUnits); //The "end" node is just a node of size 0 with the "end" bit set block_ctrl *end_block = static_cast<block_ctrl*> (new (reinterpret_cast<char*>(addr) + first_big_block->m_size*Alignment)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 = (reinterpret_cast<char*>(first_big_block) - reinterpret_cast<char*>(end_block))/Alignment; #else first_big_block->m_prev_size = end_block->m_size = (reinterpret_cast<char*>(end_block) - reinterpret_cast<char*>(first_big_block))/Alignment; #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(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() { size_type block1_off = priv_first_block_offset_from_this(this, m_header.m_extra_hdr_bytes); return reinterpret_cast<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() { 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/Alignment*Alignment - block1_off/Alignment*Alignment - EndCtrlBlockBytes; block_ctrl *end_block = reinterpret_cast<block_ctrl*> (reinterpret_cast<char*>(this) + block1_off + original_first_block_size); 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 MinBlockUnits blocks to create a new block if((m_header.m_size - old_border_offset) < MinBlockUnits){ 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 = reinterpret_cast<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 = (reinterpret_cast<char*>(first_block) - reinterpret_cast<char*>(new_end_block))/Alignment; #else new_end_block->m_size = (reinterpret_cast<char*>(new_end_block) - reinterpret_cast<char*>(first_block))/Alignment; #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 = (reinterpret_cast<char*>(new_end_block) - reinterpret_cast<char*>(new_block))/Alignment; 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 = first_block->m_prev_size = (reinterpret_cast<char*>(first_block) - reinterpret_cast<char*>(new_end_block))/Alignment; #else new_end_block->m_size = first_block->m_prev_size = (reinterpret_cast<char*>(new_end_block) - reinterpret_cast<char*>(first_block))/Alignment; #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; 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) + MinBlockUnits + 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; algo_impl_t::assert_alignment(&*ib); 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 = reinterpret_cast<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; BOOST_ASSERT(new_block->m_size >= BlockCtrlUnits); priv_mark_as_allocated_block(new_block); prev_block->m_size = (reinterpret_cast<char*>(new_block) - reinterpret_cast<char*>(prev_block))/Alignment; 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((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 = prev_block->m_size + reuse->m_size; 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((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*> (reinterpret_cast<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)); const bool size_invariants_broken = (next_block->m_size - rem_units ) < BlockCtrlUnits || (old_next_block_it != m_header.m_imultiset.begin() && (--imultiset_iterator(old_next_block_it))->m_size > rem_units); if(size_invariants_broken){ m_header.m_imultiset.erase(old_next_block_it); } //This is the remaining block block_ctrl *rem_block = ::new(reinterpret_cast<block_ctrl*> (reinterpret_cast<char*>(block) + intended_units*Alignment), boost_container_new_t())block_ctrl; rem_block->m_size = rem_units; algo_impl_t::assert_alignment(rem_block); BOOST_ASSERT(rem_block->m_size >= BlockCtrlUnits); priv_mark_as_free_block(rem_block); //Now the second part of the fixup if(size_invariants_broken) m_header.m_imultiset.insert(m_header.m_imultiset.begin(), *rem_block); else m_header.m_imultiset.replace_node(old_next_block_it, *rem_block); //Write the new length block->m_size = intended_user_units + AllocatedCtrlUnits; 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; 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 reinterpret_cast<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 = reinterpret_cast<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 = reinterpret_cast<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 reinterpret_cast<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 = reinterpret_cast<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; reinterpret_cast<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; BOOST_ASSERT(block->m_size >= BlockCtrlUnits); //This is the remaining block block_ctrl *rem_block = ::new(reinterpret_cast<block_ctrl*> (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; BOOST_ASSERT(rem_block->m_size >= BlockCtrlUnits); priv_mark_as_free_block(rem_block); imultiset_iterator it_hint; if(it_old == m_header.m_imultiset.begin() || (--imultiset_iterator(it_old))->m_size <= rem_block->m_size){ //option a: slow but secure //m_header.m_imultiset.insert(m_header.m_imultiset.erase(it_old), *rem_block); //option b: Construct an empty node and swap //Imultiset::init_node(*rem_block); //block->swap_nodes(*rem_block); //option c: replace the node directly m_header.m_imultiset.replace_node(Imultiset::s_iterator_to(*it_old), *rem_block); } else{ //Now we have to update the data in the tree m_header.m_imultiset.erase(it_old); m_header.m_imultiset.insert(m_header.m_imultiset.begin(), *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 = (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 += block->m_size; BOOST_ASSERT(block_to_insert->m_size >= BlockCtrlUnits); } //Merge if the next is free if(merge_with_next){ block_to_insert->m_size += next_block->m_size; BOOST_ASSERT(block_to_insert->m_size >= BlockCtrlUnits); const imultiset_iterator next_it = Imultiset::s_iterator_to(*next_block); if(merge_with_prev){ m_header.m_imultiset.erase(next_it); } else{ m_header.m_imultiset.replace_node(next_it, *block_to_insert); } } //Now try to shortcut erasure + insertion (O(log(N))) with //a O(1) operation if merging does not alter tree positions const imultiset_iterator block_to_check_it = Imultiset::s_iterator_to(*block_to_insert); imultiset_const_iterator next_to_check_it(block_to_check_it), end_it(m_header.m_imultiset.end()); if(++next_to_check_it != end_it && block_to_insert->m_size > next_to_check_it->m_size){ //Block is bigger than next, so move it m_header.m_imultiset.erase(block_to_check_it); m_header.m_imultiset.insert(end_it, *block_to_insert); } else{ //Block size increment didn't violate tree invariants so there is nothing to fix } } else{ m_header.m_imultiset.insert(m_header.m_imultiset.begin(), *block_to_insert); } priv_mark_as_free_block(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