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-//////////////////////////////////////////////////////////////////////////////
-//
-// (C) Copyright Ion Gaztanaga 2005-2011. 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)
-# pragma once
-#endif
-
-#include <boost/interprocess/detail/config_begin.hpp>
-#include <boost/interprocess/detail/workaround.hpp>
-
-#include <boost/intrusive/pointer_traits.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 <boost/intrusive/pointer_traits.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 ipcdetail {
-
-/*!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;
-
- typedef typename boost::intrusive::pointer_traits<char_ptr>::difference_type difference_type;
- typedef typename boost::make_unsigned<difference_type>::type size_type;
-
-
- private:
- struct block_ctrl;
- typedef typename boost::intrusive::
- pointer_traits<void_pointer>::template
- rebind_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*/
- size_type m_size;
-
- size_type get_user_bytes() const
- { return this->m_size*Alignment - BlockCtrlBytes; }
-
- size_type 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*/
- size_type m_allocated;
- /*!The size of the memory segment*/
- size_type 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 (size_type size, size_type extra_hdr_bytes);
- /*!Destructor.*/
- ~simple_seq_fit_impl();
- /*!Obtains the minimum size needed by the algorithm*/
- static size_type get_min_size (size_type extra_hdr_bytes);
-
- //Functions for single segment management
-
- /*!Allocates bytes, returns 0 if there is not more memory*/
- void* allocate (size_type nbytes);
-
- /*!Deallocates previously allocated bytes*/
- void deallocate (void *addr);
-
- /*!Returns the size of the memory segment*/
- size_type get_size() const;
-
- /*!Increases managed memory in extra_size bytes more*/
- void grow(size_type 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, size_type limit_size,
- size_type preferred_size,size_type &received_size,
- void *reuse_ptr = 0, size_type backwards_multiple = 1);
-
- /*!Returns the size of the buffer previously allocated pointed by ptr*/
- size_type size(void *ptr) const;
-
- /*!Allocates aligned bytes, returns 0 if there is not more memory.
- Alignment must be power of 2*/
- void* allocate_aligned (size_type nbytes, size_type alignment);
-
- /*!Allocates bytes, if there is no more memory, it executes functor
- f(size_type) to allocate a new segment to manage. The functor returns
- std::pair<void*, size_type> 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(size_type nbytes);
-
- private:
- /*!Real allocation algorithm with min allocation option*/
- std::pair<void *, bool> priv_allocate(boost::interprocess::allocation_type command
- ,size_type min_size
- ,size_type preferred_size
- ,size_type &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
- ,size_type min_size, size_type preferred_size
- ,size_type &received_size);
-
- /*!Real expand to both sides implementation*/
- void* priv_expand_both_sides(boost::interprocess::allocation_type command
- ,size_type min_size
- ,size_type preferred_size
- ,size_type &received_size
- ,void *reuse_ptr
- ,bool only_preferred_backwards);
-
- /*!Real shrink function implementation*/
- bool priv_shrink(void *ptr
- ,size_type max_size, size_type preferred_size
- ,size_type &received_size);
-
- //!Real private aligned allocation function
- void* priv_allocate_aligned (size_type nbytes, size_type alignment);
-
- /*!Checks if block has enough memory and splits/unlinks the block
- returning the address to the users*/
- void* priv_check_and_allocate(size_type units
- ,block_ctrl* prev
- ,block_ctrl* block
- ,size_type &received_size);
- /*!Real deallocation algorithm*/
- void priv_deallocate(void *addr);
-
- /*!Makes a new memory portion available for allocation*/
- void priv_add_segment(void *addr, size_type size);
-
- static const std::size_t Alignment = ::boost::alignment_of<boost::ipcdetail::max_align>::value;
- static const std::size_t BlockCtrlBytes = ipcdetail::ct_rounded_size<sizeof(block_ctrl), Alignment>::value;
- static const std::size_t BlockCtrlSize = BlockCtrlBytes/Alignment;
- static const std::size_t MinBlockSize = BlockCtrlSize + Alignment;
-
- public:
- static const std::size_t PayloadPerAllocation = BlockCtrlBytes;
-};
-
-template<class MutexFamily, class VoidPointer>
-inline simple_seq_fit_impl<MutexFamily, VoidPointer>::
- simple_seq_fit_impl(size_type size, size_type extra_hdr_bytes)
-{
- //Initialize sizes and counters
- m_header.m_allocated = 0;
- m_header.m_size = size;
-
- //Initialize pointers
- size_type block1_off = ipcdetail::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(size_type extra_size)
-{
- //Old highest address block's end offset
- size_type 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, size_type 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 typename simple_seq_fit_impl<MutexFamily, VoidPointer>::size_type
-simple_seq_fit_impl<MutexFamily, VoidPointer>::get_size() const
- { return m_header.m_size; }
-
-template<class MutexFamily, class VoidPointer>
-inline typename simple_seq_fit_impl<MutexFamily, VoidPointer>::size_type
-simple_seq_fit_impl<MutexFamily, VoidPointer>::
- get_min_size (size_type extra_hdr_bytes)
-{
- return ipcdetail::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 &&
- ipcdetail::to_raw_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 = ipcdetail::to_raw_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 = ipcdetail::to_raw_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 = ipcdetail::to_raw_pointer(m_header.m_root.m_next);
-
- size_type free_memory = 0;
-
- //Iterate through all blocks obtaining their size
- do{
- //Free blocks's next must be always valid
- block_ctrl *next = ipcdetail::to_raw_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(size_type nbytes)
-{
- //-----------------------
- boost::interprocess::scoped_lock<interprocess_mutex> guard(m_header);
- //-----------------------
- size_type 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(size_type nbytes, size_type 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, size_type min_size,
- size_type preferred_size,size_type &received_size,
- void *reuse_ptr, size_type 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 typename simple_seq_fit_impl<MutexFamily, VoidPointer>::size_type
-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(size_type nbytes)
-{
- //-----------------------
- boost::interprocess::scoped_lock<interprocess_mutex> guard(m_header);
- //-----------------------
- //Multisegment pointer. Let's try first the normal allocation
- //since it's faster.
- size_type 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.
- size_type 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
- ,size_type min_size
- ,size_type preferred_size
- ,size_type &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){
- size_type 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;
- }
-
- size_type needs_backwards =
- ipcdetail::get_rounded_size(preferred_size - extra_forward, Alignment);
-
- if(!only_preferred_backwards){
- needs_backwards =
- max_value(ipcdetail::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
- ,size_type limit_size
- ,size_type preferred_size
- ,size_type &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)
- size_type nunits = ipcdetail::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 = ipcdetail::to_raw_pointer(prev->m_next);
- block_ctrl *root = &m_header.m_root;
- block_ctrl *biggest_block = 0;
- block_ctrl *prev_biggest_block = 0;
- size_type 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 = ipcdetail::to_raw_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 = ipcdetail::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
- size_type 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 = ipcdetail::to_raw_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 = ipcdetail::to_raw_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
- size_type 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
- ,size_type min_size
- ,size_type preferred_size
- ,size_type &received_size)
-{
- //Obtain the real size of the block
- block_ctrl *block = reinterpret_cast<block_ctrl*>
- (reinterpret_cast<char*>(ptr) - BlockCtrlBytes);
- size_type 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 = ipcdetail::get_rounded_size(min_size, Alignment)/Alignment;
- preferred_size = ipcdetail::get_rounded_size(preferred_size, Alignment)/Alignment;
-
- //Some parameter checks
- if(min_size > preferred_size)
- return false;
-
- size_type 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?
- size_type 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(ipcdetail::to_raw_pointer(prev->m_next) != next_block){
- prev = ipcdetail::to_raw_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;
- size_type 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
- ,size_type max_size
- ,size_type preferred_size
- ,size_type &received_size)
-{
- //Obtain the real size of the block
- block_ctrl *block = reinterpret_cast<block_ctrl*>
- (reinterpret_cast<char*>(ptr) - BlockCtrlBytes);
- size_type 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 = ipcdetail::get_rounded_size(preferred_size, Alignment)/Alignment;
-
- //Some parameter checks
- if(max_size < preferred_size)
- return false;
-
- size_type 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(size_type nbytes, size_type alignment)
-{
- //Ensure power of 2
- if ((alignment & (alignment - size_type(1u))) != 0){
- //Alignment is not power of two
- BOOST_ASSERT((alignment & (alignment - size_type(1u))) != 0);
- return 0;
- }
-
- size_type ignore;
- if(alignment <= Alignment){
- return priv_allocate(boost::interprocess::allocate_new, nbytes, nbytes, ignore).first;
- }
-
- size_type 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<size_type>(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);
-
- size_type 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
- (size_type nunits
- ,typename simple_seq_fit_impl<MutexFamily, VoidPointer>::block_ctrl* prev
- ,typename simple_seq_fit_impl<MutexFamily, VoidPointer>::block_ctrl* block
- ,size_type &received_size)
-{
- size_type 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)
- size_type 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 );
-
- size_type 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((ipcdetail::to_raw_pointer(pos) != &m_header.m_root) && (block > pos)){
- prev = pos;
- pos = pos->m_next;
- }
-
- //Try to combine with upper block
- if ((reinterpret_cast<char*>(ipcdetail::to_raw_pointer(block))
- + Alignment*block->m_size) ==
- reinterpret_cast<char*>(ipcdetail::to_raw_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*>(ipcdetail::to_raw_pointer(prev))
- + Alignment*prev->m_size) ==
- reinterpret_cast<char*>(ipcdetail::to_raw_pointer(block))){
- prev->m_size += block->m_size;
- prev->m_next = block->m_next;
- }
- else{
- prev->m_next = block;
- }
-}
-
-} //namespace ipcdetail {
-
-} //namespace interprocess {
-
-} //namespace boost {
-
-#include <boost/interprocess/detail/config_end.hpp>
-
-#endif //#ifndef BOOST_INTERPROCESS_MEM_ALGO_DETAIL_SIMPLE_SEQ_FIT_IMPL_HPP
-