| ////////////////////////////////////////////////////////////////////////////// |
| // |
| // (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_DETAIL_MEM_ALGO_COMMON_HPP |
| #define BOOST_INTERPROCESS_DETAIL_MEM_ALGO_COMMON_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/interprocess/interprocess_fwd.hpp> |
| #include <boost/interprocess/containers/allocation_type.hpp> |
| #include <boost/interprocess/detail/utilities.hpp> |
| #include <boost/interprocess/detail/type_traits.hpp> |
| #include <boost/interprocess/detail/math_functions.hpp> |
| #include <boost/interprocess/detail/utilities.hpp> |
| #include <boost/interprocess/detail/move.hpp> |
| #include <boost/interprocess/detail/min_max.hpp> |
| #include <boost/assert.hpp> |
| #include <boost/static_assert.hpp> |
| #include <algorithm> |
| #include <utility> |
| #include <iterator> |
| #include <boost/assert.hpp> |
| |
| //!\file |
| //!Implements common operations for memory algorithms. |
| |
| namespace boost { |
| namespace interprocess { |
| namespace detail { |
| |
| //!This class implements several allocation functions shared by different algorithms |
| //!(aligned allocation, multiple allocation...). |
| template<class MemoryAlgorithm> |
| class memory_algorithm_common |
| { |
| public: |
| typedef typename MemoryAlgorithm::void_pointer void_pointer; |
| typedef typename MemoryAlgorithm::block_ctrl block_ctrl; |
| typedef typename MemoryAlgorithm::multiallocation_chain multiallocation_chain; |
| typedef memory_algorithm_common<MemoryAlgorithm> this_type; |
| |
| static const std::size_t Alignment = MemoryAlgorithm::Alignment; |
| static const std::size_t MinBlockUnits = MemoryAlgorithm::MinBlockUnits; |
| static const std::size_t AllocatedCtrlBytes = MemoryAlgorithm::AllocatedCtrlBytes; |
| static const std::size_t AllocatedCtrlUnits = MemoryAlgorithm::AllocatedCtrlUnits; |
| static const std::size_t BlockCtrlBytes = MemoryAlgorithm::BlockCtrlBytes; |
| static const std::size_t BlockCtrlUnits = MemoryAlgorithm::BlockCtrlUnits; |
| static const std::size_t UsableByPreviousChunk = MemoryAlgorithm::UsableByPreviousChunk; |
| |
| static void assert_alignment(const void *ptr) |
| { assert_alignment((std::size_t)ptr); } |
| |
| static void assert_alignment(std::size_t uint_ptr) |
| { |
| (void)uint_ptr; |
| BOOST_ASSERT(uint_ptr % Alignment == 0); |
| } |
| |
| static bool check_alignment(const void *ptr) |
| { return (((std::size_t)ptr) % Alignment == 0); } |
| |
| static std::size_t ceil_units(std::size_t size) |
| { return detail::get_rounded_size(size, Alignment)/Alignment; } |
| |
| static std::size_t floor_units(std::size_t size) |
| { return size/Alignment; } |
| |
| static std::size_t multiple_of_units(std::size_t size) |
| { return detail::get_rounded_size(size, Alignment); } |
| |
| static multiallocation_chain allocate_many |
| (MemoryAlgorithm *memory_algo, std::size_t elem_bytes, std::size_t n_elements) |
| { |
| return this_type::priv_allocate_many(memory_algo, &elem_bytes, n_elements, 0); |
| } |
| |
| static void deallocate_many(MemoryAlgorithm *memory_algo, multiallocation_chain chain) |
| { |
| return this_type::priv_deallocate_many(memory_algo, boost::interprocess::move(chain)); |
| } |
| |
| static bool calculate_lcm_and_needs_backwards_lcmed |
| (std::size_t backwards_multiple, std::size_t received_size, std::size_t size_to_achieve, |
| std::size_t &lcm_out, std::size_t &needs_backwards_lcmed_out) |
| { |
| // Now calculate lcm |
| std::size_t max = backwards_multiple; |
| std::size_t min = Alignment; |
| std::size_t needs_backwards; |
| std::size_t needs_backwards_lcmed; |
| std::size_t lcm; |
| std::size_t current_forward; |
| //Swap if necessary |
| if(max < min){ |
| std::size_t tmp = min; |
| min = max; |
| max = tmp; |
| } |
| //Check if it's power of two |
| if((backwards_multiple & (backwards_multiple-1)) == 0){ |
| if(0 != (size_to_achieve & ((backwards_multiple-1)))){ |
| return false; |
| } |
| |
| lcm = max; |
| //If we want to use minbytes data to get a buffer between maxbytes |
| //and minbytes if maxbytes can't be achieved, calculate the |
| //biggest of all possibilities |
| current_forward = detail::get_truncated_size_po2(received_size, backwards_multiple); |
| needs_backwards = size_to_achieve - current_forward; |
| BOOST_ASSERT((needs_backwards % backwards_multiple) == 0); |
| needs_backwards_lcmed = detail::get_rounded_size_po2(needs_backwards, lcm); |
| lcm_out = lcm; |
| needs_backwards_lcmed_out = needs_backwards_lcmed; |
| return true; |
| } |
| //Check if it's multiple of alignment |
| else if((backwards_multiple & (Alignment - 1u)) == 0){ |
| lcm = backwards_multiple; |
| current_forward = detail::get_truncated_size(received_size, backwards_multiple); |
| //No need to round needs_backwards because backwards_multiple == lcm |
| needs_backwards_lcmed = needs_backwards = size_to_achieve - current_forward; |
| BOOST_ASSERT((needs_backwards_lcmed & (Alignment - 1u)) == 0); |
| lcm_out = lcm; |
| needs_backwards_lcmed_out = needs_backwards_lcmed; |
| return true; |
| } |
| //Check if it's multiple of the half of the alignmment |
| else if((backwards_multiple & ((Alignment/2u) - 1u)) == 0){ |
| lcm = backwards_multiple*2u; |
| current_forward = detail::get_truncated_size(received_size, backwards_multiple); |
| needs_backwards_lcmed = needs_backwards = size_to_achieve - current_forward; |
| if(0 != (needs_backwards_lcmed & (Alignment-1))) |
| //while(0 != (needs_backwards_lcmed & (Alignment-1))) |
| needs_backwards_lcmed += backwards_multiple; |
| BOOST_ASSERT((needs_backwards_lcmed % lcm) == 0); |
| lcm_out = lcm; |
| needs_backwards_lcmed_out = needs_backwards_lcmed; |
| return true; |
| } |
| //Check if it's multiple of the half of the alignmment |
| else if((backwards_multiple & ((Alignment/4u) - 1u)) == 0){ |
| std::size_t remainder; |
| lcm = backwards_multiple*4u; |
| current_forward = detail::get_truncated_size(received_size, backwards_multiple); |
| needs_backwards_lcmed = needs_backwards = size_to_achieve - current_forward; |
| //while(0 != (needs_backwards_lcmed & (Alignment-1))) |
| //needs_backwards_lcmed += backwards_multiple; |
| if(0 != (remainder = ((needs_backwards_lcmed & (Alignment-1))>>(Alignment/8u)))){ |
| if(backwards_multiple & Alignment/2u){ |
| needs_backwards_lcmed += (remainder)*backwards_multiple; |
| } |
| else{ |
| needs_backwards_lcmed += (4-remainder)*backwards_multiple; |
| } |
| } |
| BOOST_ASSERT((needs_backwards_lcmed % lcm) == 0); |
| lcm_out = lcm; |
| needs_backwards_lcmed_out = needs_backwards_lcmed; |
| return true; |
| } |
| else{ |
| lcm = detail::lcm(max, min); |
| } |
| //If we want to use minbytes data to get a buffer between maxbytes |
| //and minbytes if maxbytes can't be achieved, calculate the |
| //biggest of all possibilities |
| current_forward = detail::get_truncated_size(received_size, backwards_multiple); |
| needs_backwards = size_to_achieve - current_forward; |
| BOOST_ASSERT((needs_backwards % backwards_multiple) == 0); |
| needs_backwards_lcmed = detail::get_rounded_size(needs_backwards, lcm); |
| lcm_out = lcm; |
| needs_backwards_lcmed_out = needs_backwards_lcmed; |
| return true; |
| } |
| |
| static multiallocation_chain allocate_many |
| ( MemoryAlgorithm *memory_algo |
| , const std::size_t *elem_sizes |
| , std::size_t n_elements |
| , std::size_t sizeof_element) |
| { |
| return this_type::priv_allocate_many(memory_algo, elem_sizes, n_elements, sizeof_element); |
| } |
| |
| static void* allocate_aligned |
| (MemoryAlgorithm *memory_algo, 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 real_size; |
| if(alignment <= Alignment){ |
| return memory_algo->priv_allocate |
| (boost::interprocess::allocate_new, nbytes, nbytes, real_size).first; |
| } |
| |
| if(nbytes > UsableByPreviousChunk) |
| nbytes -= UsableByPreviousChunk; |
| |
| //We can find a aligned portion if we allocate a block that has alignment |
| //nbytes + alignment bytes or more. |
| std::size_t minimum_allocation = max_value |
| (nbytes + alignment, std::size_t(MinBlockUnits*Alignment)); |
| //Since we will split that block, we must request a bit more memory |
| //if the alignment is near the beginning of the buffer, because otherwise, |
| //there is no space for a new block before the alignment. |
| // |
| // ____ Aligned here |
| // | |
| // ----------------------------------------------------- |
| // | MBU | |
| // ----------------------------------------------------- |
| std::size_t request = |
| minimum_allocation + (2*MinBlockUnits*Alignment - AllocatedCtrlBytes |
| //prevsize - UsableByPreviousChunk |
| ); |
| |
| //Now allocate the buffer |
| void *buffer = memory_algo->priv_allocate |
| (boost::interprocess::allocate_new, request, request, real_size).first; |
| if(!buffer){ |
| return 0; |
| } |
| else if ((((std::size_t)(buffer)) % alignment) == 0){ |
| //If we are lucky and the buffer is aligned, just split it and |
| //return the high part |
| block_ctrl *first = memory_algo->priv_get_block(buffer); |
| std::size_t old_size = first->m_size; |
| const std::size_t first_min_units = |
| max_value(ceil_units(nbytes) + AllocatedCtrlUnits, std::size_t(MinBlockUnits)); |
| //We can create a new block in the end of the segment |
| if(old_size >= (first_min_units + MinBlockUnits)){ |
| block_ctrl *second = reinterpret_cast<block_ctrl *> |
| (reinterpret_cast<char*>(first) + Alignment*first_min_units); |
| first->m_size = first_min_units; |
| second->m_size = old_size - first->m_size; |
| BOOST_ASSERT(second->m_size >= MinBlockUnits); |
| memory_algo->priv_mark_new_allocated_block(first); |
| //memory_algo->priv_tail_size(first, first->m_size); |
| memory_algo->priv_mark_new_allocated_block(second); |
| memory_algo->priv_deallocate(memory_algo->priv_get_user_buffer(second)); |
| } |
| return buffer; |
| } |
| |
| //Buffer not aligned, find the aligned part. |
| // |
| // ____ Aligned here |
| // | |
| // ----------------------------------------------------- |
| // | MBU +more | ACB | |
| // ----------------------------------------------------- |
| char *pos = reinterpret_cast<char*> |
| (reinterpret_cast<std::size_t>(static_cast<char*>(buffer) + |
| //This is the minimum size of (2) |
| (MinBlockUnits*Alignment - AllocatedCtrlBytes) + |
| //This is the next MBU for the aligned memory |
| AllocatedCtrlBytes + |
| //This is the alignment trick |
| alignment - 1) & -alignment); |
| |
| //Now obtain the address of the blocks |
| block_ctrl *first = memory_algo->priv_get_block(buffer); |
| block_ctrl *second = memory_algo->priv_get_block(pos); |
| BOOST_ASSERT(pos <= (reinterpret_cast<char*>(first) + first->m_size*Alignment)); |
| BOOST_ASSERT(first->m_size >= 2*MinBlockUnits); |
| BOOST_ASSERT((pos + MinBlockUnits*Alignment - AllocatedCtrlBytes + nbytes*Alignment/Alignment) <= |
| (reinterpret_cast<char*>(first) + first->m_size*Alignment)); |
| //Set the new size of the first block |
| std::size_t old_size = first->m_size; |
| first->m_size = (reinterpret_cast<char*>(second) - reinterpret_cast<char*>(first))/Alignment; |
| memory_algo->priv_mark_new_allocated_block(first); |
| |
| //Now check if we can create a new buffer in the end |
| // |
| // __"second" block |
| // | __Aligned here |
| // | | __"third" block |
| // -----------|-----|-----|------------------------------ |
| // | MBU +more | ACB | (3) | BCU | |
| // ----------------------------------------------------- |
| //This size will be the minimum size to be able to create a |
| //new block in the end. |
| const std::size_t second_min_units = max_value(std::size_t(MinBlockUnits), |
| ceil_units(nbytes) + AllocatedCtrlUnits ); |
| |
| //Check if we can create a new block (of size MinBlockUnits) in the end of the segment |
| if((old_size - first->m_size) >= (second_min_units + MinBlockUnits)){ |
| //Now obtain the address of the end block |
| block_ctrl *third = new (reinterpret_cast<char*>(second) + Alignment*second_min_units)block_ctrl; |
| second->m_size = second_min_units; |
| third->m_size = old_size - first->m_size - second->m_size; |
| BOOST_ASSERT(third->m_size >= MinBlockUnits); |
| memory_algo->priv_mark_new_allocated_block(second); |
| memory_algo->priv_mark_new_allocated_block(third); |
| memory_algo->priv_deallocate(memory_algo->priv_get_user_buffer(third)); |
| } |
| else{ |
| second->m_size = old_size - first->m_size; |
| BOOST_ASSERT(second->m_size >= MinBlockUnits); |
| memory_algo->priv_mark_new_allocated_block(second); |
| } |
| |
| memory_algo->priv_deallocate(memory_algo->priv_get_user_buffer(first)); |
| return memory_algo->priv_get_user_buffer(second); |
| } |
| |
| static bool try_shrink |
| (MemoryAlgorithm *memory_algo, void *ptr |
| ,const std::size_t max_size, const std::size_t preferred_size |
| ,std::size_t &received_size) |
| { |
| (void)memory_algo; |
| //Obtain the real block |
| block_ctrl *block = memory_algo->priv_get_block(ptr); |
| std::size_t old_block_units = block->m_size; |
| |
| //The block must be marked as allocated |
| BOOST_ASSERT(memory_algo->priv_is_allocated_block(block)); |
| |
| //Check if alignment and block size are right |
| assert_alignment(ptr); |
| |
| //Put this to a safe value |
| received_size = (old_block_units - AllocatedCtrlUnits)*Alignment + UsableByPreviousChunk; |
| |
| //Now translate it to Alignment units |
| const std::size_t max_user_units = floor_units(max_size - UsableByPreviousChunk); |
| const std::size_t preferred_user_units = ceil_units(preferred_size - UsableByPreviousChunk); |
| |
| //Check if rounded max and preferred are possible correct |
| if(max_user_units < preferred_user_units) |
| return false; |
| |
| //Check if the block is smaller than the requested minimum |
| std::size_t old_user_units = old_block_units - AllocatedCtrlUnits; |
| |
| if(old_user_units < preferred_user_units) |
| return false; |
| |
| //If the block is smaller than the requested minimum |
| if(old_user_units == preferred_user_units) |
| return true; |
| |
| std::size_t shrunk_user_units = |
| ((BlockCtrlUnits - AllocatedCtrlUnits) > preferred_user_units) |
| ? (BlockCtrlUnits - AllocatedCtrlUnits) |
| : preferred_user_units; |
| |
| //Some parameter checks |
| if(max_user_units < shrunk_user_units) |
| return false; |
| |
| //We must be able to create at least a new empty block |
| if((old_user_units - shrunk_user_units) < BlockCtrlUnits ){ |
| return false; |
| } |
| |
| //Update new size |
| received_size = shrunk_user_units*Alignment + UsableByPreviousChunk; |
| return true; |
| } |
| |
| static bool shrink |
| (MemoryAlgorithm *memory_algo, void *ptr |
| ,const std::size_t max_size, const std::size_t preferred_size |
| ,std::size_t &received_size) |
| { |
| //Obtain the real block |
| block_ctrl *block = memory_algo->priv_get_block(ptr); |
| std::size_t old_block_units = block->m_size; |
| |
| if(!try_shrink |
| (memory_algo, ptr, max_size, preferred_size, received_size)){ |
| return false; |
| } |
| |
| //Check if the old size was just the shrunk size (no splitting) |
| if((old_block_units - AllocatedCtrlUnits) == ceil_units(preferred_size - UsableByPreviousChunk)) |
| return true; |
| |
| //Now we can just rewrite the size of the old buffer |
| block->m_size = (received_size-UsableByPreviousChunk)/Alignment + AllocatedCtrlUnits; |
| BOOST_ASSERT(block->m_size >= BlockCtrlUnits); |
| |
| //We create the new block |
| block_ctrl *new_block = reinterpret_cast<block_ctrl*> |
| (reinterpret_cast<char*>(block) + block->m_size*Alignment); |
| //Write control data to simulate this new block was previously allocated |
| //and deallocate it |
| new_block->m_size = old_block_units - block->m_size; |
| BOOST_ASSERT(new_block->m_size >= BlockCtrlUnits); |
| memory_algo->priv_mark_new_allocated_block(block); |
| memory_algo->priv_mark_new_allocated_block(new_block); |
| memory_algo->priv_deallocate(memory_algo->priv_get_user_buffer(new_block)); |
| return true; |
| } |
| |
| private: |
| static multiallocation_chain priv_allocate_many |
| ( MemoryAlgorithm *memory_algo |
| , const std::size_t *elem_sizes |
| , std::size_t n_elements |
| , std::size_t sizeof_element) |
| { |
| //Note: sizeof_element == 0 indicates that we want to |
| //allocate n_elements of the same size "*elem_sizes" |
| |
| //Calculate the total size of all requests |
| std::size_t total_request_units = 0; |
| std::size_t elem_units = 0; |
| const std::size_t ptr_size_units = memory_algo->priv_get_total_units(sizeof(void_pointer)); |
| if(!sizeof_element){ |
| elem_units = memory_algo->priv_get_total_units(*elem_sizes); |
| elem_units = ptr_size_units > elem_units ? ptr_size_units : elem_units; |
| total_request_units = n_elements*elem_units; |
| } |
| else{ |
| for(std::size_t i = 0; i < n_elements; ++i){ |
| elem_units = memory_algo->priv_get_total_units(elem_sizes[i]*sizeof_element); |
| elem_units = ptr_size_units > elem_units ? ptr_size_units : elem_units; |
| total_request_units += elem_units; |
| } |
| } |
| |
| multiallocation_chain chain; |
| |
| std::size_t low_idx = 0; |
| while(low_idx < n_elements){ |
| std::size_t total_bytes = total_request_units*Alignment - AllocatedCtrlBytes + UsableByPreviousChunk; |
| std::size_t min_allocation = (!sizeof_element) |
| ? elem_units |
| : memory_algo->priv_get_total_units(elem_sizes[low_idx]*sizeof_element); |
| min_allocation = min_allocation*Alignment - AllocatedCtrlBytes + UsableByPreviousChunk; |
| |
| std::size_t received_size; |
| std::pair<void *, bool> ret = memory_algo->priv_allocate |
| (boost::interprocess::allocate_new, min_allocation, total_bytes, received_size, 0); |
| if(!ret.first){ |
| break; |
| } |
| |
| block_ctrl *block = memory_algo->priv_get_block(ret.first); |
| std::size_t received_units = block->m_size; |
| char *block_address = reinterpret_cast<char*>(block); |
| |
| std::size_t total_used_units = 0; |
| // block_ctrl *prev_block = 0; |
| while(total_used_units < received_units){ |
| if(sizeof_element){ |
| elem_units = memory_algo->priv_get_total_units(elem_sizes[low_idx]*sizeof_element); |
| elem_units = ptr_size_units > elem_units ? ptr_size_units : elem_units; |
| } |
| if(total_used_units + elem_units > received_units) |
| break; |
| total_request_units -= elem_units; |
| //This is the position where the new block must be created |
| block_ctrl *new_block = reinterpret_cast<block_ctrl *>(block_address); |
| assert_alignment(new_block); |
| |
| //The last block should take all the remaining space |
| if((low_idx + 1) == n_elements || |
| (total_used_units + elem_units + |
| ((!sizeof_element) |
| ? elem_units |
| : memory_algo->priv_get_total_units(elem_sizes[low_idx+1]*sizeof_element)) |
| ) > received_units){ |
| //By default, the new block will use the rest of the buffer |
| new_block->m_size = received_units - total_used_units; |
| memory_algo->priv_mark_new_allocated_block(new_block); |
| |
| //If the remaining units are bigger than needed and we can |
| //split it obtaining a new free memory block do it. |
| if((received_units - total_used_units) >= (elem_units + MemoryAlgorithm::BlockCtrlUnits)){ |
| std::size_t shrunk_received; |
| std::size_t shrunk_request = elem_units*Alignment - AllocatedCtrlBytes + UsableByPreviousChunk; |
| bool shrink_ok = shrink |
| (memory_algo |
| ,memory_algo->priv_get_user_buffer(new_block) |
| ,shrunk_request |
| ,shrunk_request |
| ,shrunk_received); |
| (void)shrink_ok; |
| //Shrink must always succeed with passed parameters |
| BOOST_ASSERT(shrink_ok); |
| //Some sanity checks |
| BOOST_ASSERT(shrunk_request == shrunk_received); |
| BOOST_ASSERT(elem_units == ((shrunk_request-UsableByPreviousChunk)/Alignment + AllocatedCtrlUnits)); |
| //"new_block->m_size" must have been reduced to elem_units by "shrink" |
| BOOST_ASSERT(new_block->m_size == elem_units); |
| //Now update the total received units with the reduction |
| received_units = elem_units + total_used_units; |
| } |
| } |
| else{ |
| new_block->m_size = elem_units; |
| memory_algo->priv_mark_new_allocated_block(new_block); |
| } |
| |
| block_address += new_block->m_size*Alignment; |
| total_used_units += new_block->m_size; |
| //Check we have enough room to overwrite the intrusive pointer |
| BOOST_ASSERT((new_block->m_size*Alignment - AllocatedCtrlUnits) >= sizeof(void_pointer)); |
| void_pointer p = new(memory_algo->priv_get_user_buffer(new_block))void_pointer(0); |
| chain.push_back(p); |
| ++low_idx; |
| //prev_block = new_block; |
| } |
| //Sanity check |
| BOOST_ASSERT(total_used_units == received_units); |
| } |
| |
| if(low_idx != n_elements){ |
| priv_deallocate_many(memory_algo, boost::interprocess::move(chain)); |
| } |
| return boost::interprocess::move(chain); |
| } |
| |
| static void priv_deallocate_many(MemoryAlgorithm *memory_algo, multiallocation_chain chain) |
| { |
| while(!chain.empty()){ |
| void *addr = detail::get_pointer(chain.front()); |
| chain.pop_front(); |
| memory_algo->priv_deallocate(addr); |
| } |
| } |
| }; |
| |
| } //namespace detail { |
| } //namespace interprocess { |
| } //namespace boost { |
| |
| #include <boost/interprocess/detail/config_end.hpp> |
| |
| #endif //#ifndef BOOST_INTERPROCESS_DETAIL_MEM_ALGO_COMMON_HPP |