| ////////////////////////////////////////////////////////////////////////////// |
| // |
| // (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_DETAIL_SIMPLE_SEQ_FIT_IMPL_HPP |
| #define BOOST_INTERPROCESS_MEM_ALGO_DETAIL_SIMPLE_SEQ_FIT_IMPL_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/containers/allocation_type.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/multi_segment_services.hpp> |
| #include <boost/type_traits/alignment_of.hpp> |
| #include <boost/type_traits/type_with_alignment.hpp> |
| #include <boost/interprocess/detail/min_max.hpp> |
| #include <boost/interprocess/sync/scoped_lock.hpp> |
| #include <algorithm> |
| #include <utility> |
| #include <cstring> |
| |
| #include <boost/assert.hpp> |
| #include <new> |
| |
| /*!\file |
| Describes sequential fit algorithm 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 { |
| |
| namespace detail { |
| |
| /*!This class implements the simple sequential fit algorithm with a simply |
| linked list of free buffers. |
| This class is intended as a base class for single segment and multi-segment |
| implementations.*/ |
| template<class MutexFamily, class VoidPointer> |
| class simple_seq_fit_impl |
| { |
| //Non-copyable |
| simple_seq_fit_impl(); |
| simple_seq_fit_impl(const simple_seq_fit_impl &); |
| simple_seq_fit_impl &operator=(const simple_seq_fit_impl &); |
| |
| 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; |
| |
| private: |
| struct block_ctrl; |
| typedef typename boost:: |
| pointer_to_other<void_pointer, block_ctrl>::type block_ctrl_ptr; |
| |
| /*!Block control structure*/ |
| struct block_ctrl |
| { |
| /*!Offset pointer to the next block.*/ |
| block_ctrl_ptr m_next; |
| /*!This block's memory size (including block_ctrl |
| header) in BasicSize units*/ |
| std::size_t m_size; |
| |
| std::size_t get_user_bytes() const |
| { return this->m_size*Alignment - BlockCtrlBytes; } |
| |
| std::size_t get_total_bytes() const |
| { return this->m_size*Alignment; } |
| |
| static block_ctrl *get_block_from_addr(void *addr) |
| { |
| return reinterpret_cast<block_ctrl*> |
| (reinterpret_cast<char*>(addr) - BlockCtrlBytes); |
| } |
| |
| void *get_addr() const |
| { |
| return reinterpret_cast<block_ctrl*> |
| (reinterpret_cast<const char*>(this) + BlockCtrlBytes); |
| } |
| |
| }; |
| |
| /*!Shared interprocess_mutex to protect memory allocate/deallocate*/ |
| typedef typename MutexFamily::mutex_type interprocess_mutex; |
| |
| /*!This struct includes needed data and derives from |
| interprocess_mutex to allow EBO when using null interprocess_mutex*/ |
| struct header_t : public interprocess_mutex |
| { |
| /*!Pointer to the first free block*/ |
| block_ctrl m_root; |
| /*!Allocated bytes for internal checking*/ |
| std::size_t m_allocated; |
| /*!The size of the memory segment*/ |
| std::size_t m_size; |
| } m_header; |
| |
| public: |
| /*!Constructor. "size" is the total size of the managed memory segment, |
| "extra_hdr_bytes" indicates the extra bytes beginning in the sizeof(simple_seq_fit_impl) |
| offset that the allocator should not use at all.*/ |
| simple_seq_fit_impl (std::size_t size, std::size_t extra_hdr_bytes); |
| /*!Destructor.*/ |
| ~simple_seq_fit_impl(); |
| /*!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); |
| |
| /*!Deallocates previously allocated bytes*/ |
| void deallocate (void *addr); |
| |
| /*!Returns the size of the memory segment*/ |
| std::size_t get_size() const; |
| |
| /*!Increases managed memory in extra_size bytes more*/ |
| void grow(std::size_t extra_size); |
| |
| /*!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(); |
| |
| //!Initializes to zero all the memory that's not in use. |
| //!This function is normally used for security reasons. |
| void clear_free_memory(); |
| |
| std::pair<void *, bool> |
| 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 = 0, std::size_t backwards_multiple = 1); |
| |
| /*!Returns the size of the buffer previously allocated pointed by ptr*/ |
| std::size_t size(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); |
| |
| /*!Allocates bytes, if there is no more memory, it executes functor |
| f(std::size_t) to allocate a new segment to manage. The functor returns |
| std::pair<void*, std::size_t> indicating the base address and size of |
| the new segment. If the new segment can't be allocated, allocate |
| it will return 0.*/ |
| void* multi_allocate(std::size_t nbytes); |
| |
| private: |
| /*!Real allocation algorithm with min allocation option*/ |
| std::pair<void *, bool> priv_allocate(boost::interprocess::allocation_type command |
| ,std::size_t min_size |
| ,std::size_t preferred_size |
| ,std::size_t &received_size |
| ,void *reuse_ptr = 0); |
| /*!Returns next block if it's free. |
| Returns 0 if next block is not free.*/ |
| block_ctrl *priv_next_block_if_free(block_ctrl *ptr); |
| |
| /*!Returns previous block's if it's free. |
| Returns 0 if previous block is not free.*/ |
| std::pair<block_ctrl*, block_ctrl*>priv_prev_block_if_free(block_ctrl *ptr); |
| |
| /*!Real expand function implementation*/ |
| bool priv_expand(void *ptr |
| ,std::size_t min_size, 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); |
| |
| /*!Real shrink function implementation*/ |
| bool priv_shrink(void *ptr |
| ,std::size_t max_size, std::size_t preferred_size |
| ,std::size_t &received_size); |
| |
| //!Real private aligned allocation function |
| void* priv_allocate_aligned (std::size_t nbytes, std::size_t alignment); |
| |
| /*!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* prev |
| ,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); |
| |
| enum { Alignment = boost::alignment_of<boost::detail::max_align>::value }; |
| enum { BlockCtrlBytes = detail::ct_rounded_size<sizeof(block_ctrl), Alignment>::value }; |
| enum { BlockCtrlSize = BlockCtrlBytes/Alignment }; |
| enum { MinBlockSize = BlockCtrlSize + Alignment }; |
| |
| public: |
| enum { PayloadPerAllocation = BlockCtrlBytes }; |
| }; |
| |
| template<class MutexFamily, class VoidPointer> |
| inline simple_seq_fit_impl<MutexFamily, VoidPointer>:: |
| simple_seq_fit_impl(std::size_t size, std::size_t extra_hdr_bytes) |
| { |
| //Initialize sizes and counters |
| m_header.m_allocated = 0; |
| m_header.m_size = size; |
| |
| //Initialize pointers |
| std::size_t block1_off = detail::get_rounded_size(sizeof(*this)+extra_hdr_bytes, Alignment); |
| m_header.m_root.m_next = reinterpret_cast<block_ctrl*> |
| (reinterpret_cast<char*>(this) + block1_off); |
| m_header.m_root.m_next->m_size = (size - block1_off)/Alignment; |
| m_header.m_root.m_next->m_next = &m_header.m_root; |
| } |
| |
| template<class MutexFamily, class VoidPointer> |
| inline simple_seq_fit_impl<MutexFamily, VoidPointer>::~simple_seq_fit_impl() |
| { |
| //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> |
| inline void simple_seq_fit_impl<MutexFamily, VoidPointer>::grow(std::size_t extra_size) |
| { |
| //Old highest address block's end offset |
| std::size_t old_end = m_header.m_size/Alignment*Alignment; |
| |
| //Update managed buffer's size |
| m_header.m_size += extra_size; |
| |
| //We need at least MinBlockSize blocks to create a new block |
| if((m_header.m_size - old_end) < MinBlockSize){ |
| return; |
| } |
| |
| //We'll create a new free block with extra_size bytes |
| block_ctrl *new_block = reinterpret_cast<block_ctrl*> |
| (reinterpret_cast<char*>(this) + old_end); |
| |
| new_block->m_next = 0; |
| new_block->m_size = (m_header.m_size - old_end)/Alignment; |
| m_header.m_allocated += new_block->m_size*Alignment; |
| this->priv_deallocate(reinterpret_cast<char*>(new_block) + BlockCtrlBytes); |
| } |
| |
| template<class MutexFamily, class VoidPointer> |
| inline void simple_seq_fit_impl<MutexFamily, VoidPointer>::priv_add_segment(void *addr, std::size_t size) |
| { |
| //Check size |
| BOOST_ASSERT(!(size < MinBlockSize)); |
| if(size < MinBlockSize) |
| return; |
| //Construct big block using the new segment |
| block_ctrl *new_block = static_cast<block_ctrl *>(addr); |
| new_block->m_size = size/Alignment; |
| new_block->m_next = 0; |
| //Simulate this block was previously allocated |
| m_header.m_allocated += new_block->m_size*Alignment; |
| //Return block and insert it in the free block list |
| this->priv_deallocate(reinterpret_cast<char*>(new_block) + BlockCtrlBytes); |
| } |
| |
| template<class MutexFamily, class VoidPointer> |
| inline std::size_t simple_seq_fit_impl<MutexFamily, VoidPointer>::get_size() const |
| { return m_header.m_size; } |
| |
| template<class MutexFamily, class VoidPointer> |
| inline std::size_t simple_seq_fit_impl<MutexFamily, VoidPointer>:: |
| get_min_size (std::size_t extra_hdr_bytes) |
| { |
| return detail::get_rounded_size(sizeof(simple_seq_fit_impl)+extra_hdr_bytes |
| ,Alignment) |
| + MinBlockSize; |
| } |
| |
| template<class MutexFamily, class VoidPointer> |
| inline bool simple_seq_fit_impl<MutexFamily, VoidPointer>:: |
| all_memory_deallocated() |
| { |
| //----------------------- |
| boost::interprocess::scoped_lock<interprocess_mutex> guard(m_header); |
| //----------------------- |
| return m_header.m_allocated == 0 && |
| detail::get_pointer(m_header.m_root.m_next->m_next) == &m_header.m_root; |
| } |
| |
| template<class MutexFamily, class VoidPointer> |
| inline void simple_seq_fit_impl<MutexFamily, VoidPointer>::clear_free_memory() |
| { |
| //----------------------- |
| boost::interprocess::scoped_lock<interprocess_mutex> guard(m_header); |
| //----------------------- |
| block_ctrl *block = detail::get_pointer(m_header.m_root.m_next); |
| |
| //Iterate through all free portions |
| do{ |
| //Just clear user the memory part reserved for the user |
| std::memset( reinterpret_cast<char*>(block) + BlockCtrlBytes |
| , 0 |
| , block->m_size*Alignment - BlockCtrlBytes); |
| block = detail::get_pointer(block->m_next); |
| } |
| while(block != &m_header.m_root); |
| } |
| |
| template<class MutexFamily, class VoidPointer> |
| inline bool simple_seq_fit_impl<MutexFamily, VoidPointer>:: |
| check_sanity() |
| { |
| //----------------------- |
| boost::interprocess::scoped_lock<interprocess_mutex> guard(m_header); |
| //----------------------- |
| block_ctrl *block = detail::get_pointer(m_header.m_root.m_next); |
| |
| std::size_t free_memory = 0; |
| |
| //Iterate through all blocks obtaining their size |
| do{ |
| //Free blocks's next must be always valid |
| block_ctrl *next = detail::get_pointer(block->m_next); |
| if(!next){ |
| return false; |
| } |
| free_memory += block->m_size*Alignment; |
| block = next; |
| } |
| while(block != &m_header.m_root); |
| |
| //Check allocated bytes are less than size |
| if(m_header.m_allocated > m_header.m_size){ |
| return false; |
| } |
| |
| //Check free bytes are less than size |
| if(free_memory > m_header.m_size){ |
| return false; |
| } |
| return true; |
| } |
| |
| template<class MutexFamily, class VoidPointer> |
| inline void* simple_seq_fit_impl<MutexFamily, VoidPointer>:: |
| allocate(std::size_t nbytes) |
| { |
| //----------------------- |
| boost::interprocess::scoped_lock<interprocess_mutex> guard(m_header); |
| //----------------------- |
| std::size_t ignore; |
| return priv_allocate(boost::interprocess::allocate_new, nbytes, nbytes, ignore).first; |
| } |
| |
| template<class MutexFamily, class VoidPointer> |
| inline void* simple_seq_fit_impl<MutexFamily, VoidPointer>:: |
| allocate_aligned(std::size_t nbytes, std::size_t alignment) |
| { |
| //----------------------- |
| boost::interprocess::scoped_lock<interprocess_mutex> guard(m_header); |
| //----------------------- |
| return priv_allocate_aligned(nbytes, alignment); |
| } |
| |
| template<class MutexFamily, class VoidPointer> |
| inline std::pair<void *, bool> simple_seq_fit_impl<MutexFamily, VoidPointer>:: |
| allocation_command (boost::interprocess::allocation_type command, std::size_t min_size, |
| std::size_t preferred_size,std::size_t &received_size, |
| void *reuse_ptr, std::size_t backwards_multiple) |
| { |
| //----------------------- |
| boost::interprocess::scoped_lock<interprocess_mutex> guard(m_header); |
| //----------------------- |
| (void)backwards_multiple; |
| command &= ~boost::interprocess::expand_bwd; |
| if(!command) |
| return std::pair<void *, bool>(0, false); |
| return priv_allocate(command, min_size, preferred_size, received_size, reuse_ptr); |
| } |
| |
| template<class MutexFamily, class VoidPointer> |
| inline std::size_t simple_seq_fit_impl<MutexFamily, VoidPointer>:: |
| size(void *ptr) const |
| { |
| //We need no synchronization since this block is not going |
| //to be modified |
| //Obtain the real size of the block |
| block_ctrl *block = reinterpret_cast<block_ctrl*> |
| (reinterpret_cast<char*>(ptr) - BlockCtrlBytes); |
| return block->m_size*Alignment - BlockCtrlBytes; |
| } |
| |
| template<class MutexFamily, class VoidPointer> |
| inline void* simple_seq_fit_impl<MutexFamily, VoidPointer>:: |
| multi_allocate(std::size_t nbytes) |
| { |
| //----------------------- |
| boost::interprocess::scoped_lock<interprocess_mutex> guard(m_header); |
| //----------------------- |
| //Multisegment pointer. Let's try first the normal allocation |
| //since it's faster. |
| std::size_t ignore; |
| void *addr = this->priv_allocate(boost::interprocess::allocate_new, nbytes, nbytes, ignore).first; |
| if(!addr){ |
| //If this fails we will try the allocation through the segment |
| //creator. |
| std::size_t group, id; |
| //Obtain the segment group of this segment |
| void_pointer::get_group_and_id(this, group, id); |
| if(group == 0){ |
| //Ooops, group 0 is not valid. |
| return 0; |
| } |
| //Now obtain the polymorphic functor that creates |
| //new segments and try to allocate again. |
| boost::interprocess::multi_segment_services *p_services = |
| static_cast<boost::interprocess::multi_segment_services*> |
| (void_pointer::find_group_data(group)); |
| BOOST_ASSERT(p_services); |
| std::pair<void *, std::size_t> ret = |
| p_services->create_new_segment(MinBlockSize > nbytes ? MinBlockSize : nbytes); |
| if(ret.first){ |
| priv_add_segment(ret.first, ret.second); |
| addr = this->priv_allocate(boost::interprocess::allocate_new, nbytes, nbytes, ignore).first; |
| } |
| } |
| return addr; |
| } |
| |
| template<class MutexFamily, class VoidPointer> |
| void* simple_seq_fit_impl<MutexFamily, VoidPointer>:: |
| 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) |
| { |
| typedef std::pair<block_ctrl *, block_ctrl *> prev_block_t; |
| block_ctrl *reuse = block_ctrl::get_block_from_addr(reuse_ptr); |
| received_size = 0; |
| |
| if(this->size(reuse_ptr) > min_size){ |
| received_size = this->size(reuse_ptr); |
| return 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(command & boost::interprocess::expand_bwd){ |
| std::size_t extra_forward = !received_size ? 0 : received_size + BlockCtrlBytes; |
| prev_block_t prev_pair = priv_prev_block_if_free(reuse); |
| block_ctrl *prev = prev_pair.second; |
| if(!prev){ |
| return 0; |
| } |
| |
| std::size_t needs_backwards = |
| detail::get_rounded_size(preferred_size - extra_forward, Alignment); |
| |
| if(!only_preferred_backwards){ |
| needs_backwards = |
| max_value(detail::get_rounded_size(min_size - extra_forward, Alignment) |
| ,min_value(prev->get_user_bytes(), needs_backwards)); |
| } |
| |
| //Check if previous block has enough size |
| if((prev->get_user_bytes()) >= needs_backwards){ |
| //Now take all next space. This will succeed |
| if(!priv_expand(reuse_ptr, received_size, received_size, received_size)){ |
| BOOST_ASSERT(0); |
| } |
| |
| //We need a minimum size to split the previous one |
| if((prev->get_user_bytes() - needs_backwards) > 2*BlockCtrlBytes){ |
| block_ctrl *new_block = reinterpret_cast<block_ctrl *> |
| (reinterpret_cast<char*>(reuse) - needs_backwards - BlockCtrlBytes); |
| new_block->m_next = 0; |
| new_block->m_size = |
| BlockCtrlSize + (needs_backwards + extra_forward)/Alignment; |
| prev->m_size = |
| (prev->get_total_bytes() - needs_backwards)/Alignment - BlockCtrlSize; |
| received_size = needs_backwards + extra_forward; |
| m_header.m_allocated += needs_backwards + BlockCtrlBytes; |
| return new_block->get_addr(); |
| } |
| else{ |
| //Just merge the whole previous block |
| block_ctrl *prev_2_block = prev_pair.first; |
| //Update received size and allocation |
| received_size = extra_forward + prev->get_user_bytes(); |
| m_header.m_allocated += prev->get_total_bytes(); |
| //Now unlink it from previous block |
| prev_2_block->m_next = prev->m_next; |
| prev->m_size = reuse->m_size + prev->m_size; |
| prev->m_next = 0; |
| return prev->get_addr(); |
| } |
| } |
| } |
| return 0; |
| } |
| |
| template<class MutexFamily, class VoidPointer> |
| std::pair<void *, bool> simple_seq_fit_impl<MutexFamily, VoidPointer>:: |
| 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) |
| { |
| if(command & boost::interprocess::shrink_in_place){ |
| bool success = |
| this->priv_shrink(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(0, false); |
| |
| //Number of units to request (including block_ctrl header) |
| std::size_t nunits = detail::get_rounded_size(preferred_size, Alignment)/Alignment + BlockCtrlSize; |
| |
| //Get the root and the first memory block |
| block_ctrl *prev = &m_header.m_root; |
| block_ctrl *block = detail::get_pointer(prev->m_next); |
| block_ctrl *root = &m_header.m_root; |
| block_ctrl *biggest_block = 0; |
| block_ctrl *prev_biggest_block = 0; |
| std::size_t biggest_size = limit_size; |
| |
| //Expand in place |
| //reuse_ptr, limit_size, preferred_size, received_size |
| // |
| 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); |
| if(ret) |
| return return_type(ret, true); |
| } |
| |
| if(command & boost::interprocess::allocate_new){ |
| received_size = 0; |
| while(block != root){ |
| //Update biggest block pointers |
| if(block->m_size > biggest_size){ |
| prev_biggest_block = prev; |
| biggest_size = block->m_size; |
| biggest_block = block; |
| } |
| void *addr = this->priv_check_and_allocate(nunits, prev, block, received_size); |
| if(addr) return return_type(addr, false); |
| //Bad luck, let's check next block |
| prev = block; |
| block = detail::get_pointer(block->m_next); |
| } |
| |
| //Bad luck finding preferred_size, now if we have any biggest_block |
| //try with this block |
| if(biggest_block){ |
| received_size = biggest_block->m_size*Alignment - BlockCtrlSize; |
| nunits = detail::get_rounded_size(limit_size, Alignment)/Alignment + BlockCtrlSize; |
| void *ret = this->priv_check_and_allocate |
| (nunits, prev_biggest_block, biggest_block, received_size); |
| if(ret) |
| return return_type(ret, 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), true); |
| } |
| return return_type(0, false); |
| } |
| |
| template<class MutexFamily, class VoidPointer> |
| inline typename simple_seq_fit_impl<MutexFamily, VoidPointer>::block_ctrl * |
| simple_seq_fit_impl<MutexFamily, VoidPointer>:: |
| priv_next_block_if_free |
| (typename simple_seq_fit_impl<MutexFamily, VoidPointer>::block_ctrl *ptr) |
| { |
| //Take the address where the next block should go |
| block_ctrl *next_block = reinterpret_cast<block_ctrl*> |
| (reinterpret_cast<char*>(ptr) + ptr->m_size*Alignment); |
| |
| //Check if the adjacent block is in the managed segment |
| std::size_t distance = (reinterpret_cast<char*>(next_block) - reinterpret_cast<char*>(this))/Alignment; |
| if(distance >= (m_header.m_size/Alignment)){ |
| //"next_block" does not exist so we can't expand "block" |
| return 0; |
| } |
| |
| if(!next_block->m_next) |
| return 0; |
| |
| return next_block; |
| } |
| |
| template<class MutexFamily, class VoidPointer> |
| inline |
| std::pair<typename simple_seq_fit_impl<MutexFamily, VoidPointer>::block_ctrl * |
| ,typename simple_seq_fit_impl<MutexFamily, VoidPointer>::block_ctrl *> |
| simple_seq_fit_impl<MutexFamily, VoidPointer>:: |
| priv_prev_block_if_free |
| (typename simple_seq_fit_impl<MutexFamily, VoidPointer>::block_ctrl *ptr) |
| { |
| typedef std::pair<block_ctrl *, block_ctrl *> prev_pair_t; |
| //Take the address where the previous block should go |
| block_ctrl *root = &m_header.m_root; |
| block_ctrl *prev_2_block = root; |
| block_ctrl *prev_block = detail::get_pointer(root->m_next); |
| while((reinterpret_cast<char*>(prev_block) + prev_block->m_size*Alignment) |
| != (reinterpret_cast<char*>(ptr)) |
| && prev_block != root){ |
| prev_2_block = prev_block; |
| prev_block = detail::get_pointer(prev_block->m_next); |
| } |
| |
| if(prev_block == root || !prev_block->m_next) |
| return prev_pair_t(0, 0); |
| |
| //Check if the previous block is in the managed segment |
| std::size_t distance = (reinterpret_cast<char*>(prev_block) - reinterpret_cast<char*>(this))/Alignment; |
| if(distance >= (m_header.m_size/Alignment)){ |
| //"previous_block" does not exist so we can't expand "block" |
| return prev_pair_t(0, 0); |
| } |
| return prev_pair_t(prev_2_block, prev_block); |
| } |
| |
| |
| template<class MutexFamily, class VoidPointer> |
| inline bool simple_seq_fit_impl<MutexFamily, VoidPointer>:: |
| priv_expand (void *ptr |
| ,std::size_t min_size |
| ,std::size_t preferred_size |
| ,std::size_t &received_size) |
| { |
| //Obtain the real size of the block |
| block_ctrl *block = reinterpret_cast<block_ctrl*> |
| (reinterpret_cast<char*>(ptr) - BlockCtrlBytes); |
| std::size_t old_block_size = block->m_size; |
| |
| //All used blocks' next is marked with 0 so check it |
| BOOST_ASSERT(block->m_next == 0); |
| |
| //Put this to a safe value |
| received_size = old_block_size*Alignment - BlockCtrlBytes; |
| |
| //Now translate it to Alignment units |
| min_size = detail::get_rounded_size(min_size, Alignment)/Alignment; |
| preferred_size = detail::get_rounded_size(preferred_size, Alignment)/Alignment; |
| |
| //Some parameter checks |
| if(min_size > preferred_size) |
| return false; |
| |
| std::size_t data_size = old_block_size - BlockCtrlSize; |
| |
| if(data_size >= min_size) |
| return true; |
| |
| block_ctrl *next_block = priv_next_block_if_free(block); |
| if(!next_block){ |
| return false; |
| } |
| |
| //Is "block" + "next_block" big enough? |
| std::size_t merged_size = old_block_size + next_block->m_size; |
| |
| //Now we can expand this block further than before |
| received_size = merged_size*Alignment - BlockCtrlBytes; |
| |
| if(merged_size < (min_size + BlockCtrlSize)){ |
| return false; |
| } |
| |
| //We can fill expand. Merge both blocks, |
| block->m_next = next_block->m_next; |
| block->m_size = merged_size; |
| |
| //Find the previous free block of next_block |
| block_ctrl *prev = &m_header.m_root; |
| while(detail::get_pointer(prev->m_next) != next_block){ |
| prev = detail::get_pointer(prev->m_next); |
| } |
| |
| //Now insert merged block in the free list |
| //This allows reusing allocation logic in this function |
| m_header.m_allocated -= old_block_size*Alignment; |
| prev->m_next = block; |
| |
| //Now use check and allocate to do the allocation logic |
| preferred_size += BlockCtrlSize; |
| std::size_t nunits = preferred_size < merged_size ? preferred_size : merged_size; |
| |
| //This must success since nunits is less than merged_size! |
| if(!this->priv_check_and_allocate (nunits, prev, block, received_size)){ |
| //Something very ugly is happening here. This is a bug |
| //or there is memory corruption |
| BOOST_ASSERT(0); |
| return false; |
| } |
| return true; |
| } |
| |
| template<class MutexFamily, class VoidPointer> |
| inline bool simple_seq_fit_impl<MutexFamily, VoidPointer>:: |
| priv_shrink (void *ptr |
| ,std::size_t max_size |
| ,std::size_t preferred_size |
| ,std::size_t &received_size) |
| { |
| //Obtain the real size of the block |
| block_ctrl *block = reinterpret_cast<block_ctrl*> |
| (reinterpret_cast<char*>(ptr) - BlockCtrlBytes); |
| std::size_t block_size = block->m_size; |
| |
| //All used blocks' next is marked with 0 so check it |
| BOOST_ASSERT(block->m_next == 0); |
| |
| //Put this to a safe value |
| received_size = block_size*Alignment - BlockCtrlBytes; |
| |
| //Now translate it to Alignment units |
| max_size = max_size/Alignment; |
| preferred_size = detail::get_rounded_size(preferred_size, Alignment)/Alignment; |
| |
| //Some parameter checks |
| if(max_size < preferred_size) |
| return false; |
| |
| std::size_t data_size = block_size - BlockCtrlSize; |
| |
| if(data_size < preferred_size) |
| return false; |
| |
| if(data_size == preferred_size) |
| return true; |
| |
| //We must be able to create at least a new empty block |
| if((data_size - preferred_size) < BlockCtrlSize){ |
| return false; |
| } |
| |
| //Now we can just rewrite the size of the old buffer |
| block->m_size = preferred_size + BlockCtrlSize; |
| |
| //Update new size |
| received_size = preferred_size*Alignment; |
| |
| //We create the new block |
| block = reinterpret_cast<block_ctrl*> |
| (reinterpret_cast<char*>(block) + block->m_size*Alignment); |
| |
| //Write control data to simulate this new block was previously allocated |
| block->m_next = 0; |
| block->m_size = data_size - preferred_size; |
| |
| //Now deallocate the new block to insert it in the free list |
| this->priv_deallocate(reinterpret_cast<char*>(block)+BlockCtrlBytes); |
| return true; |
| } |
| |
| template<class MutexFamily, class VoidPointer> |
| inline void* simple_seq_fit_impl<MutexFamily, VoidPointer>:: |
| priv_allocate_aligned(std::size_t nbytes, std::size_t alignment) |
| { |
| //Ensure power of 2 |
| if ((alignment & (alignment - std::size_t(1u))) != 0){ |
| //Alignment is not power of two |
| BOOST_ASSERT((alignment & (alignment - std::size_t(1u))) != 0); |
| return 0; |
| } |
| |
| std::size_t ignore; |
| if(alignment <= Alignment){ |
| return priv_allocate(boost::interprocess::allocate_new, nbytes, nbytes, ignore).first; |
| } |
| |
| std::size_t request = |
| nbytes + alignment + MinBlockSize*Alignment - BlockCtrlBytes; |
| void *buffer = priv_allocate(boost::interprocess::allocate_new, request, request, ignore).first; |
| if(!buffer) |
| return 0; |
| else if ((((std::size_t)(buffer)) % alignment) == 0) |
| return buffer; |
| |
| char *aligned_portion = reinterpret_cast<char*> |
| (reinterpret_cast<std::size_t>(static_cast<char*>(buffer) + alignment - 1) & -alignment); |
| |
| char *pos = ((aligned_portion - reinterpret_cast<char*>(buffer)) >= (MinBlockSize*Alignment)) ? |
| aligned_portion : (aligned_portion + alignment); |
| |
| block_ctrl *first = reinterpret_cast<block_ctrl*> |
| (reinterpret_cast<char*>(buffer) - BlockCtrlBytes); |
| |
| block_ctrl *second = reinterpret_cast<block_ctrl*>(pos - BlockCtrlBytes); |
| |
| std::size_t old_size = first->m_size; |
| |
| first->m_size = (reinterpret_cast<char*>(second) - reinterpret_cast<char*>(first))/Alignment; |
| second->m_size = old_size - first->m_size; |
| |
| //Write control data to simulate this new block was previously allocated |
| second->m_next = 0; |
| |
| //Now deallocate the new block to insert it in the free list |
| this->priv_deallocate(reinterpret_cast<char*>(first) + BlockCtrlBytes); |
| return reinterpret_cast<char*>(second) + BlockCtrlBytes; |
| } |
| |
| template<class MutexFamily, class VoidPointer> inline |
| void* simple_seq_fit_impl<MutexFamily, VoidPointer>::priv_check_and_allocate |
| (std::size_t nunits |
| ,typename simple_seq_fit_impl<MutexFamily, VoidPointer>::block_ctrl* prev |
| ,typename simple_seq_fit_impl<MutexFamily, VoidPointer>::block_ctrl* block |
| ,std::size_t &received_size) |
| { |
| std::size_t upper_nunits = nunits + BlockCtrlSize; |
| bool found = false; |
| |
| if (block->m_size > upper_nunits){ |
| //This block is bigger than needed, split it in |
| //two blocks, the first's size will be (block->m_size-units) |
| //the second's size (units) |
| std::size_t total_size = block->m_size; |
| block->m_size = nunits; |
| block_ctrl *new_block = reinterpret_cast<block_ctrl*> |
| (reinterpret_cast<char*>(block) + Alignment*nunits); |
| new_block->m_size = total_size - nunits; |
| new_block->m_next = block->m_next; |
| prev->m_next = new_block; |
| found = true; |
| } |
| else if (block->m_size >= nunits){ |
| //This block has exactly the right size with an extra |
| //unusable extra bytes. |
| prev->m_next = block->m_next; |
| found = true; |
| } |
| |
| if(found){ |
| //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*Alignment - BlockCtrlBytes; |
| //Mark the block as allocated |
| block->m_next = 0; |
| //Check alignment |
| BOOST_ASSERT(((reinterpret_cast<char*>(block) - reinterpret_cast<char*>(this)) |
| % Alignment) == 0 ); |
| return reinterpret_cast<char*>(block) + BlockCtrlBytes; |
| } |
| return 0; |
| } |
| |
| template<class MutexFamily, class VoidPointer> |
| void simple_seq_fit_impl<MutexFamily, VoidPointer>::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> |
| void simple_seq_fit_impl<MutexFamily, VoidPointer>::priv_deallocate(void* addr) |
| { |
| if(!addr) return; |
| |
| //Let's get free block list. List is always sorted |
| //by memory address to allow block merging. |
| //Pointer next always points to the first |
| //(lower address) block |
| block_ctrl_ptr prev = &m_header.m_root; |
| block_ctrl_ptr pos = m_header.m_root.m_next; |
| block_ctrl_ptr block = reinterpret_cast<block_ctrl*> |
| (reinterpret_cast<char*>(addr) - BlockCtrlBytes); |
| |
| //All used blocks' next is marked with 0 so check it |
| BOOST_ASSERT(block->m_next == 0); |
| |
| //Check if alignment and block size are right |
| BOOST_ASSERT((reinterpret_cast<char*>(addr) - reinterpret_cast<char*>(this)) |
| % Alignment == 0 ); |
| |
| std::size_t total_size = Alignment*block->m_size; |
| BOOST_ASSERT(m_header.m_allocated >= total_size); |
| |
| //Update used memory count |
| m_header.m_allocated -= total_size; |
| |
| //Let's find the previous and the next block of the block to deallocate |
| //This ordering comparison must be done with original pointers |
| //types since their mapping to raw pointers can be different |
| //in each process |
| while((detail::get_pointer(pos) != &m_header.m_root) && (block > pos)){ |
| prev = pos; |
| pos = pos->m_next; |
| } |
| |
| //Try to combine with upper block |
| if ((reinterpret_cast<char*>(detail::get_pointer(block)) |
| + Alignment*block->m_size) == |
| reinterpret_cast<char*>(detail::get_pointer(pos))){ |
| |
| block->m_size += pos->m_size; |
| block->m_next = pos->m_next; |
| } |
| else{ |
| block->m_next = pos; |
| } |
| |
| //Try to combine with lower block |
| if ((reinterpret_cast<char*>(detail::get_pointer(prev)) |
| + Alignment*prev->m_size) == |
| reinterpret_cast<char*>(detail::get_pointer(block))){ |
| prev->m_size += block->m_size; |
| prev->m_next = block->m_next; |
| } |
| else{ |
| prev->m_next = block; |
| } |
| } |
| |
| } //namespace detail { |
| |
| } //namespace interprocess { |
| |
| } //namespace boost { |
| |
| #include <boost/interprocess/detail/config_end.hpp> |
| |
| #endif //#ifndef BOOST_INTERPROCESS_MEM_ALGO_DETAIL_SIMPLE_SEQ_FIT_IMPL_HPP |
| |