boost/interprocess/mem_algo/rbtree_best_fit.hpp
////////////////////////////////////////////////////////////////////////////// // // (C) Copyright Ion Gaztanaga 2005-2009. 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 #if (defined _MSC_VER) && (_MSC_VER >= 1200) # pragma once #endif #include <boost/interprocess/detail/config_begin.hpp> #include <boost/interprocess/detail/workaround.hpp> #include <boost/pointer_to_other.hpp> #include <boost/interprocess/interprocess_fwd.hpp> #include <boost/interprocess/mem_algo/detail/mem_algo_common.hpp> #include <boost/interprocess/containers/allocation_type.hpp> #include <boost/interprocess/containers/container/detail/multiallocation_chain.hpp> #include <boost/interprocess/offset_ptr.hpp> #include <boost/interprocess/sync/interprocess_mutex.hpp> #include <boost/interprocess/exceptions.hpp> #include <boost/interprocess/detail/utilities.hpp> #include <boost/interprocess/detail/min_max.hpp> #include <boost/interprocess/detail/math_functions.hpp> #include <boost/interprocess/detail/type_traits.hpp> #include <boost/interprocess/sync/scoped_lock.hpp> #include <boost/assert.hpp> #include <boost/static_assert.hpp> #include <algorithm> #include <utility> #include <climits> #include <cstring> #include <iterator> #include <cassert> #include <new> #include <boost/intrusive/set.hpp> //!\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 { /// @cond //Non-copyable rbtree_best_fit(); rbtree_best_fit(const rbtree_best_fit &); rbtree_best_fit &operator=(const rbtree_best_fit &); /// @endcond public: //!Shared interprocess_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 boost::container::containers_detail:: basic_multiallocation_chain<VoidPointer> multiallocation_chain; /// @cond private: struct block_ctrl; typedef typename boost:: pointer_to_other<void_pointer, block_ctrl>::type block_ctrl_ptr; typedef typename boost:: pointer_to_other<void_pointer, char>::type char_ptr; 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 std::size_t m_prev_size : sizeof(std::size_t)*CHAR_BIT; std::size_t m_size : sizeof(std::size_t)*CHAR_BIT - 2; std::size_t m_prev_allocated : 1; std::size_t 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()(std::size_t size, const block_ctrl &block) const { return size < block.m_size; } bool operator()(const block_ctrl &block, std::size_t size) const { return block.m_size < size; } }; //!Shared interprocess_mutex to protect memory allocate/deallocate typedef typename MutexFamily::mutex_type interprocess_mutex; typedef typename bi::make_multiset <block_ctrl, bi::base_hook<TreeHook> >::type Imultiset; typedef typename Imultiset::iterator imultiset_iterator; //!This struct includes needed data and derives from //!interprocess_mutex to allow EBO when using null interprocess_mutex struct header_t : public interprocess_mutex { Imultiset m_imultiset; //!The extra size required by the segment std::size_t m_extra_hdr_bytes; //!Allocated bytes for internal checking std::size_t m_allocated; //!The size of the memory segment std::size_t m_size; } m_header; friend class detail::memory_algorithm_common<rbtree_best_fit>; typedef detail::memory_algorithm_common<rbtree_best_fit> algo_impl_t; public: /// @endcond //!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 (std::size_t size, std::size_t extra_hdr_bytes); //!Destructor. ~rbtree_best_fit(); //!Obtains the minimum size needed by the algorithm static std::size_t get_min_size (std::size_t extra_hdr_bytes); //Functions for single segment management //!Allocates bytes, returns 0 if there is not more memory void* allocate (std::size_t nbytes); /// @cond //Experimental. Dont' use //!Multiple element allocation, same size multiallocation_chain allocate_many(std::size_t elem_bytes, std::size_t num_elements) { //----------------------- boost::interprocess::scoped_lock<interprocess_mutex> guard(m_header); //----------------------- return algo_impl_t::allocate_many(this, elem_bytes, num_elements); } //!Multiple element allocation, different size multiallocation_chain allocate_many(const std::size_t *elem_sizes, std::size_t n_elements, std::size_t sizeof_element) { //----------------------- boost::interprocess::scoped_lock<interprocess_mutex> guard(m_header); //----------------------- return algo_impl_t::allocate_many(this, elem_sizes, n_elements, sizeof_element); } //!Multiple element allocation, different size void deallocate_many(multiallocation_chain chain); /// @endcond //!Deallocates previously allocated bytes void deallocate (void *addr); //!Returns the size of the memory segment std::size_t get_size() const; //!Returns the number of free bytes of the segment std::size_t 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(std::size_t 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> std::pair<T *, bool> allocation_command (boost::interprocess::allocation_type command, std::size_t limit_size, std::size_t preferred_size,std::size_t &received_size, T *reuse_ptr = 0); std::pair<void *, bool> raw_allocation_command (boost::interprocess::allocation_type command, std::size_t limit_object, std::size_t preferred_object,std::size_t &received_object, void *reuse_ptr = 0, std::size_t sizeof_object = 1); //!Returns the size of the buffer previously allocated pointed by ptr std::size_t 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 (std::size_t nbytes, std::size_t alignment); /// @cond private: static std::size_t priv_first_block_offset(const void *this_ptr, std::size_t extra_hdr_bytes); std::pair<void*, bool> priv_allocation_command(boost::interprocess::allocation_type command, std::size_t limit_size, std::size_t preferred_size,std::size_t &received_size, void *reuse_ptr, std::size_t sizeof_object); //!Real allocation algorithm with min allocation option std::pair<void *, bool> priv_allocate(boost::interprocess::allocation_type command ,std::size_t limit_size ,std::size_t preferred_size ,std::size_t &received_size ,void *reuse_ptr = 0 ,std::size_t 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 std::size_t priv_get_total_units(std::size_t userbytes); //!Real expand function implementation bool priv_expand(void *ptr ,const std::size_t min_size, const std::size_t preferred_size ,std::size_t &received_size); //!Real expand to both sides implementation void* priv_expand_both_sides(boost::interprocess::allocation_type command ,std::size_t min_size ,std::size_t preferred_size ,std::size_t &received_size ,void *reuse_ptr ,bool only_preferred_backwards ,std::size_t backwards_multiple); //!Get poitner of the previous block (previous block must be free) block_ctrl * priv_prev_block(block_ctrl *ptr); //!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 block_ctrl * priv_end_block(block_ctrl *first_segment_block); //!Get the size in the tail of the previous block 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_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(std::size_t units ,block_ctrl* block ,std::size_t &received_size); //!Real deallocation algorithm void priv_deallocate(void *addr); //!Makes a new memory portion available for allocation void priv_add_segment(void *addr, std::size_t size); void priv_mark_new_allocated_block(block_ctrl *block); public: static const std::size_t Alignment = !MemAlignment ? detail::alignment_of<detail::max_align>::value : 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 >= detail::alignment_of<void_pointer>::value)); static const std::size_t AlignmentMask = (Alignment - 1); static const std::size_t BlockCtrlBytes = detail::ct_rounded_size<sizeof(block_ctrl), Alignment>::value; static const std::size_t BlockCtrlUnits = BlockCtrlBytes/Alignment; static const std::size_t AllocatedCtrlBytes = detail::ct_rounded_size<sizeof(SizeHolder), Alignment>::value; static const std::size_t AllocatedCtrlUnits = AllocatedCtrlBytes/Alignment; static const std::size_t EndCtrlBlockBytes = detail::ct_rounded_size<sizeof(SizeHolder), Alignment>::value; static const std::size_t EndCtrlBlockUnits = EndCtrlBlockBytes/Alignment; static const std::size_t MinBlockUnits = BlockCtrlUnits; static const std::size_t UsableByPreviousChunk = sizeof(std::size_t); //Make sure the maximum alignment is power of two BOOST_STATIC_ASSERT((0 == (Alignment & (Alignment - std::size_t(1u))))); /// @endcond public: static const std::size_t PayloadPerAllocation = AllocatedCtrlBytes - UsableByPreviousChunk; }; /// @cond template<class MutexFamily, class VoidPointer, std::size_t MemAlignment> inline std::size_t rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment> ::priv_first_block_offset(const void *this_ptr, std::size_t extra_hdr_bytes) { std::size_t uint_this = (std::size_t)this_ptr; std::size_t main_hdr_end = uint_this + sizeof(rbtree_best_fit) + extra_hdr_bytes; std::size_t aligned_main_hdr_end = detail::get_rounded_size(main_hdr_end, Alignment); std::size_t 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> inline rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>:: rbtree_best_fit(std::size_t size, std::size_t extra_hdr_bytes) { //Initialize the header m_header.m_allocated = 0; m_header.m_size = 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 assert(get_min_size(extra_hdr_bytes) <= size); std::size_t block1_off = priv_first_block_offset(this, extra_hdr_bytes); priv_add_segment(reinterpret_cast<char*>(this) + block1_off, 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! // assert(m_header.m_allocated == 0); // 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(std::size_t extra_size) { //Get the address of the first block std::size_t block1_off = priv_first_block_offset(this, m_header.m_extra_hdr_bytes); block_ctrl *first_block = reinterpret_cast<block_ctrl *> (reinterpret_cast<char*>(this) + block1_off); block_ctrl *old_end_block = priv_end_block(first_block); assert(priv_is_allocated_block(old_end_block)); std::size_t old_border_offset = (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 // assert((m_header.m_size - old_end) >= MinBlockUnits); if((m_header.m_size - old_border_offset) < MinBlockUnits){ return; } //Now create a new block between the old end and the new end std::size_t 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); new_end_block->m_size = (reinterpret_cast<char*>(first_block) - reinterpret_cast<char*>(new_end_block))/Alignment; first_block->m_prev_size = new_end_block->m_size; assert(first_block == priv_next_block(new_end_block)); priv_mark_new_allocated_block(new_end_block); assert(new_end_block == priv_end_block(first_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; assert(new_block->m_size >= BlockCtrlUnits); priv_mark_new_allocated_block(new_block); assert(priv_next_block(new_block) == new_end_block); m_header.m_allocated += 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 std::size_t block1_off = priv_first_block_offset(this, m_header.m_extra_hdr_bytes); block_ctrl *first_block = reinterpret_cast<block_ctrl*> (reinterpret_cast<char*>(this) + block1_off); algo_impl_t::assert_alignment(first_block); block_ctrl *old_end_block = priv_end_block(first_block); algo_impl_t::assert_alignment(old_end_block); assert(priv_is_allocated_block(old_end_block)); algo_impl_t::assert_alignment(old_end_block); std::size_t old_end_block_size = old_end_block->m_size; void *unique_buffer = 0; block_ctrl *last_block; if(priv_next_block(first_block) == old_end_block){ std::size_t ignore; unique_buffer = priv_allocate(boost::interprocess::allocate_new, 0, 0, ignore).first; if(!unique_buffer) return; algo_impl_t::assert_alignment(unique_buffer); block_ctrl *unique_block = priv_get_block(unique_buffer); assert(priv_is_allocated_block(unique_block)); algo_impl_t::assert_alignment(unique_block); last_block = priv_next_block(unique_block); assert(!priv_is_allocated_block(last_block)); algo_impl_t::assert_alignment(last_block); } else{ if(priv_is_prev_allocated(old_end_block)) return; last_block = priv_prev_block(old_end_block); } std::size_t 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)); std::size_t shrunk_border_offset = (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); new_end_block->m_size = old_end_block_size + last_block_size; priv_mark_as_allocated_block(new_end_block); //Although the first block might be allocated, we'll //store the offset to the end block since in the previous //offset can't be overwritten by a previous block first_block->m_prev_size = new_end_block->m_size; assert(priv_end_block(first_block) == new_end_block); //Update managed buffer's size m_header.m_size = shrunk_border_offset; if(unique_buffer) priv_deallocate(unique_buffer); } template<class MutexFamily, class VoidPointer, std::size_t MemAlignment> void rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>:: priv_add_segment(void *addr, std::size_t size) { //Check alignment algo_impl_t::check_alignment(addr); //Check size assert(size >= (BlockCtrlBytes + EndCtrlBlockBytes)); //Initialize the first big block and the "end" node block_ctrl *first_big_block = new(addr)block_ctrl; first_big_block->m_size = size/Alignment - EndCtrlBlockUnits; 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); first_big_block->m_prev_size = end_block->m_size = (reinterpret_cast<char*>(first_big_block) - reinterpret_cast<char*>(end_block))/Alignment; priv_mark_as_allocated_block(end_block); assert(priv_next_block(first_big_block) == end_block); assert(priv_next_block(end_block) == first_big_block); assert(priv_end_block(first_big_block) == end_block); assert(priv_prev_block(end_block) == first_big_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 assert(static_cast<void*>(static_cast<SizeHolder*>(first_big_block)) < static_cast<void*>(static_cast<TreeHook*>(first_big_block))); //Check that the alignment is power of two (we use some optimizations based on this) //assert((Alignment % 2) == 0); //Insert it in the intrusive containers m_header.m_imultiset.insert(*first_big_block); } template<class MutexFamily, class VoidPointer, std::size_t MemAlignment> inline void rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>:: priv_mark_new_allocated_block(block_ctrl *new_block) { priv_mark_as_allocated_block(new_block); } template<class MutexFamily, class VoidPointer, std::size_t MemAlignment> inline std::size_t rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::get_size() const { return m_header.m_size; } template<class MutexFamily, class VoidPointer, std::size_t MemAlignment> inline std::size_t rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::get_free_memory() const { return m_header.m_size - m_header.m_allocated - priv_first_block_offset(this, m_header.m_extra_hdr_bytes); } template<class MutexFamily, class VoidPointer, std::size_t MemAlignment> inline std::size_t rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>:: get_min_size (std::size_t 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<interprocess_mutex> guard(m_header); //----------------------- std::size_t block1_off = priv_first_block_offset(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<interprocess_mutex> guard(m_header); //----------------------- imultiset_iterator ib(m_header.m_imultiset.begin()), ie(m_header.m_imultiset.end()); std::size_t free_memory = 0; //Iterate through all blocks obtaining their size for(; ib != ie; ++ib){ free_memory += 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; } std::size_t block1_off = priv_first_block_offset(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(std::size_t nbytes) { //----------------------- boost::interprocess::scoped_lock<interprocess_mutex> guard(m_header); //----------------------- std::size_t ignore; void * ret = priv_allocate(boost::interprocess::allocate_new, nbytes, nbytes, ignore).first; return ret; } template<class MutexFamily, class VoidPointer, std::size_t MemAlignment> inline void* rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>:: allocate_aligned(std::size_t nbytes, std::size_t alignment) { //----------------------- boost::interprocess::scoped_lock<interprocess_mutex> 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 std::pair<T*, bool> rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>:: allocation_command (boost::interprocess::allocation_type command, std::size_t limit_size, std::size_t preferred_size,std::size_t &received_size, T *reuse_ptr) { std::pair<void*, bool> ret = priv_allocation_command (command, limit_size, preferred_size, received_size, static_cast<void*>(reuse_ptr), sizeof(T)); BOOST_ASSERT(0 == ((std::size_t)ret.first % detail::alignment_of<T>::value)); return std::pair<T *, bool>(static_cast<T*>(ret.first), ret.second); } template<class MutexFamily, class VoidPointer, std::size_t MemAlignment> inline std::pair<void*, bool> rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>:: raw_allocation_command (boost::interprocess::allocation_type command, std::size_t limit_objects, std::size_t preferred_objects,std::size_t &received_objects, void *reuse_ptr, std::size_t sizeof_object) { if(!sizeof_object) return std::pair<void *, bool>(static_cast<void*>(0), 0); if(command & boost::interprocess::try_shrink_in_place){ bool success = algo_impl_t::try_shrink ( this, reuse_ptr, limit_objects*sizeof_object , preferred_objects*sizeof_object, received_objects); received_objects /= sizeof_object; return std::pair<void *, bool> ((success ? reuse_ptr : 0), true); } return priv_allocation_command (command, limit_objects, preferred_objects, received_objects, reuse_ptr, sizeof_object); } template<class MutexFamily, class VoidPointer, std::size_t MemAlignment> inline std::pair<void*, bool> rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>:: priv_allocation_command (boost::interprocess::allocation_type command, std::size_t limit_size, std::size_t preferred_size,std::size_t &received_size, void *reuse_ptr, std::size_t sizeof_object) { std::pair<void*, bool> ret; std::size_t max_count = m_header.m_size/sizeof_object; if(limit_size > max_count || preferred_size > max_count){ ret.first = 0; return ret; } std::size_t l_size = limit_size*sizeof_object; std::size_t p_size = preferred_size*sizeof_object; std::size_t r_size; { //----------------------- boost::interprocess::scoped_lock<interprocess_mutex> guard(m_header); //----------------------- ret = priv_allocate(command, l_size, p_size, r_size, reuse_ptr, sizeof_object); } received_size = r_size/sizeof_object; return ret; } template<class MutexFamily, class VoidPointer, std::size_t MemAlignment> inline std::size_t 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 (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<interprocess_mutex> guard(m_header); //----------------------- imultiset_iterator ib(m_header.m_imultiset.begin()), ie(m_header.m_imultiset.end()); //Iterate through all blocks obtaining their size for(; ib != ie; ++ib){ //Just clear user the memory part reserved for the user std::memset( reinterpret_cast<char*>(&*ib) + BlockCtrlBytes , 0 , ib->m_size*Alignment - BlockCtrlBytes); } } 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 ,std::size_t min_size ,std::size_t preferred_size ,std::size_t &received_size ,void *reuse_ptr ,bool only_preferred_backwards ,std::size_t backwards_multiple) { algo_impl_t::assert_alignment(reuse_ptr); if(command & boost::interprocess::expand_fwd){ if(priv_expand(reuse_ptr, min_size, preferred_size, received_size)) return reuse_ptr; } else{ received_size = this->size(reuse_ptr); if(received_size >= preferred_size || received_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 //assert(reuse->m_size == priv_tail_size(reuse)); 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); assert(!priv_is_allocated_block(prev_block)); //Some sanity checks assert(prev_block->m_size == reuse->m_prev_size); algo_impl_t::assert_alignment(prev_block); std::size_t needs_backwards_aligned; std::size_t lcm; if(!algo_impl_t::calculate_lcm_and_needs_backwards_lcmed ( backwards_multiple , received_size , only_preferred_backwards ? preferred_size : min_size , lcm, needs_backwards_aligned)){ return 0; } //Check if previous block has enough size if(std::size_t(prev_block->m_size*Alignment) >= needs_backwards_aligned){ //Now take all next space. This will succeed if(command & boost::interprocess::expand_fwd){ std::size_t received_size2; if(!priv_expand(reuse_ptr, received_size, received_size, received_size2)){ assert(0); } assert(received_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 + (received_size - UsableByPreviousChunk))/Alignment; assert(new_block->m_size >= BlockCtrlUnits); priv_mark_new_allocated_block(new_block); prev_block->m_size = (reinterpret_cast<char*>(new_block) - reinterpret_cast<char*>(prev_block))/Alignment; 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); } } received_size = needs_backwards_aligned + received_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); 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) received_size = received_size + prev_block->m_size*Alignment; m_header.m_allocated += prev_block->m_size*Alignment; //Now update sizes prev_block->m_size = prev_block->m_size + reuse->m_size; assert(prev_block->m_size >= BlockCtrlUnits); priv_mark_new_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); 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<interprocess_mutex> guard(m_header); //----------------------- algo_impl_t::deallocate_many(this, boost::interprocess::move(chain)); } template<class MutexFamily, class VoidPointer, std::size_t MemAlignment> std::pair<void *, bool> rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>:: priv_allocate(boost::interprocess::allocation_type command ,std::size_t limit_size ,std::size_t preferred_size ,std::size_t &received_size ,void *reuse_ptr ,std::size_t backwards_multiple) { //Remove me. Forbid backwards allocation //command &= (~boost::interprocess::expand_bwd); if(command & boost::interprocess::shrink_in_place){ bool success = algo_impl_t::shrink(this, reuse_ptr, limit_size, preferred_size, received_size); return std::pair<void *, bool> ((success ? reuse_ptr : 0), true); } typedef std::pair<void *, bool> return_type; received_size = 0; if(limit_size > preferred_size) return return_type(static_cast<void*>(0), false); //Number of units to request (including block_ctrl header) std::size_t preferred_units = priv_get_total_units(preferred_size); //Number of units to request (including block_ctrl header) std::size_t limit_units = priv_get_total_units(limit_size); //Expand in place if(reuse_ptr && (command & (boost::interprocess::expand_fwd | boost::interprocess::expand_bwd))){ void *ret = priv_expand_both_sides (command, limit_size, preferred_size, received_size, reuse_ptr, true, backwards_multiple); if(ret) return return_type(ret, true); } 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 return_type(this->priv_check_and_allocate (preferred_units, detail::get_pointer(&*it), received_size), false); } if(it != m_header.m_imultiset.begin()&& (--it)->m_size >= limit_units){ return return_type(this->priv_check_and_allocate (it->m_size, detail::get_pointer(&*it), received_size), false); } } //Now try to expand both sides with min size if(reuse_ptr && (command & (boost::interprocess::expand_fwd | boost::interprocess::expand_bwd))){ return return_type(priv_expand_both_sides (command, limit_size, preferred_size, received_size, reuse_ptr, false, backwards_multiple), true); } return return_type(static_cast<void*>(0), false); } 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 std::size_t rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>:: priv_get_total_units(std::size_t userbytes) { if(userbytes < UsableByPreviousChunk) userbytes = UsableByPreviousChunk; std::size_t units = detail::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 std::size_t min_size ,const std::size_t preferred_size ,std::size_t &received_size) { //Obtain the real size of the block block_ctrl *block = priv_get_block(ptr); std::size_t old_block_units = block->m_size; //The block must be marked as allocated and the sizes must be equal assert(priv_is_allocated_block(block)); //assert(old_block_units == priv_tail_size(block)); //Put this to a safe value received_size = (old_block_units - AllocatedCtrlUnits)*Alignment + UsableByPreviousChunk; if(received_size >= preferred_size || received_size >= min_size) return true; //Now translate it to Alignment units const std::size_t min_user_units = algo_impl_t::ceil_units(min_size - UsableByPreviousChunk); const std::size_t preferred_user_units = algo_impl_t::ceil_units(preferred_size - UsableByPreviousChunk); //Some parameter checks assert(min_user_units <= preferred_user_units); block_ctrl *next_block; if(priv_is_allocated_block(next_block = priv_next_block(block))){ return received_size >= min_size ? true : false; } algo_impl_t::assert_alignment(next_block); //Is "block" + "next_block" big enough? const std::size_t merged_units = old_block_units + next_block->m_size; //Now get the expansion size const std::size_t merged_user_units = merged_units - AllocatedCtrlUnits; if(merged_user_units < min_user_units){ received_size = merged_units*Alignment - UsableByPreviousChunk; return false; } //Now get the maximum size the user can allocate std::size_t 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 std::size_t 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 assert(next_block->m_size == priv_next_block(next_block)->m_prev_size); const std::size_t 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))block_ctrl; rem_block->m_size = rem_units; algo_impl_t::assert_alignment(rem_block); 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; 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; assert(block->m_size >= BlockCtrlUnits); m_header.m_allocated += (merged_units - old_block_units)*Alignment; } priv_mark_as_allocated_block(block); received_size = (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) { 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 bool rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::priv_is_prev_allocated (typename rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::block_ctrl *ptr) { if(ptr->m_prev_allocated){ return true; } else{ block_ctrl *prev = priv_prev_block(ptr); (void)prev; assert(!priv_is_allocated_block(prev)); return false; } } 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) { 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; assert(priv_is_allocated_block(end_block)); 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_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; 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; assert(allocated == next_block_prev_allocated); return allocated; } 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) { //assert(!priv_is_allocated_block(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; reinterpret_cast<block_ctrl *> (reinterpret_cast<char*>(block) + block->m_size*Alignment)->m_prev_allocated = 0; //assert(!priv_is_allocated_block(ptr)); priv_next_block(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 (std::size_t nunits ,typename rbtree_best_fit<MutexFamily, VoidPointer, MemAlignment>::block_ctrl* block ,std::size_t &received_size) { std::size_t 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" std::size_t block_old_size = block->m_size; block->m_size = nunits; 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))block_ctrl; algo_impl_t::assert_alignment(rem_block); rem_block->m_size = block_old_size - nunits; 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{ assert(0); return 0; } //We need block_ctrl for deallocation stuff, so //return memory user can overwrite m_header.m_allocated += block->m_size*Alignment; received_size = (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); std::memset(t, 0, sizeof(*t)); 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<interprocess_mutex> 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 assert(priv_is_allocated_block(block)); // assert(block->m_size == priv_tail_size(block)); //Check if alignment and block size are right algo_impl_t::assert_alignment(addr); std::size_t block_old_size = Alignment*block->m_size; 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 *next_block = priv_next_block(block); bool merge_with_prev = !priv_is_prev_allocated(block); 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_ctrl *prev_block = priv_prev_block(block); prev_block->m_size += block->m_size; assert(prev_block->m_size >= BlockCtrlUnits); block_to_insert = prev_block; } //Merge if the next is free if(merge_with_next){ block_to_insert->m_size += next_block->m_size; assert(block_to_insert->m_size >= BlockCtrlUnits); if(merge_with_prev) m_header.m_imultiset.erase(Imultiset::s_iterator_to(*next_block)); } bool only_merge_next = !merge_with_prev && merge_with_next; imultiset_iterator free_block_to_check_it (Imultiset::s_iterator_to(only_merge_next ? *next_block : *block_to_insert)); imultiset_iterator was_bigger_it(free_block_to_check_it); //Now try to shortcut erasure + insertion (O(log(N))) with //a O(1) operation if merging does not alter tree positions if(++was_bigger_it != m_header.m_imultiset.end() && block_to_insert->m_size > was_bigger_it->m_size ){ m_header.m_imultiset.erase(free_block_to_check_it); m_header.m_imultiset.insert(m_header.m_imultiset.begin(), *block_to_insert); } else if(only_merge_next){ m_header.m_imultiset.replace_node(free_block_to_check_it, *block_to_insert); } } else{ m_header.m_imultiset.insert(m_header.m_imultiset.begin(), *block_to_insert); } priv_mark_as_free_block(block_to_insert); } /// @endcond } //namespace interprocess { } //namespace boost { #include <boost/interprocess/detail/config_end.hpp> #endif //#ifndef BOOST_INTERPROCESS_MEM_ALGO_RBTREE_BEST_FIT_HPP