boost/container/detail/node_pool_impl.hpp
//////////////////////////////////////////////////////////////////////////////
//
// (C) Copyright Ion Gaztanaga 2005-2013. 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/container for documentation.
//
//////////////////////////////////////////////////////////////////////////////
#ifndef BOOST_CONTAINER_DETAIL_NODE_POOL_IMPL_HPP
#define BOOST_CONTAINER_DETAIL_NODE_POOL_IMPL_HPP
#ifndef BOOST_CONFIG_HPP
# include <boost/config.hpp>
#endif
#if defined(BOOST_HAS_PRAGMA_ONCE)
# pragma once
#endif
#include <boost/container/detail/config_begin.hpp>
#include <boost/container/detail/workaround.hpp>
#include <boost/container/container_fwd.hpp>
#include <boost/container/detail/math_functions.hpp>
#include <boost/container/detail/mpl.hpp>
#include <boost/container/detail/pool_common.hpp>
#include <boost/move/detail/to_raw_pointer.hpp>
#include <boost/container/detail/type_traits.hpp>
#include <boost/intrusive/pointer_traits.hpp>
#include <boost/intrusive/set.hpp>
#include <boost/intrusive/slist.hpp>
#include <boost/core/no_exceptions_support.hpp>
#include <boost/assert.hpp>
#include <cstddef>
namespace boost {
namespace container {
namespace container_detail {
template<class SegmentManagerBase>
class private_node_pool_impl
{
//Non-copyable
private_node_pool_impl();
private_node_pool_impl(const private_node_pool_impl &);
private_node_pool_impl &operator=(const private_node_pool_impl &);
//A node object will hold node_t when it's not allocated
public:
typedef typename SegmentManagerBase::void_pointer void_pointer;
typedef typename node_slist<void_pointer>::slist_hook_t slist_hook_t;
typedef typename node_slist<void_pointer>::node_t node_t;
typedef typename node_slist<void_pointer>::node_slist_t free_nodes_t;
typedef typename SegmentManagerBase::multiallocation_chain multiallocation_chain;
typedef typename SegmentManagerBase::size_type size_type;
private:
typedef typename bi::make_slist
< node_t, bi::base_hook<slist_hook_t>
, bi::linear<true>
, bi::constant_time_size<false> >::type blockslist_t;
static size_type get_rounded_size(size_type orig_size, size_type round_to)
{ return ((orig_size-1)/round_to+1)*round_to; }
public:
//!Segment manager typedef
typedef SegmentManagerBase segment_manager_base_type;
//!Constructor from a segment manager. Never throws
private_node_pool_impl(segment_manager_base_type *segment_mngr_base, size_type node_size, size_type nodes_per_block)
: m_nodes_per_block(nodes_per_block)
, m_real_node_size(lcm(node_size, size_type(alignment_of<node_t>::value)))
//General purpose allocator
, mp_segment_mngr_base(segment_mngr_base)
, m_blocklist()
, m_freelist()
//Debug node count
, m_allocated(0)
{}
//!Destructor. Deallocates all allocated blocks. Never throws
~private_node_pool_impl()
{ this->purge_blocks(); }
size_type get_real_num_node() const
{ return m_nodes_per_block; }
//!Returns the segment manager. Never throws
segment_manager_base_type* get_segment_manager_base()const
{ return boost::movelib::to_raw_pointer(mp_segment_mngr_base); }
void *allocate_node()
{ return this->priv_alloc_node(); }
//!Deallocates an array pointed by ptr. Never throws
void deallocate_node(void *ptr)
{ this->priv_dealloc_node(ptr); }
//!Allocates a singly linked list of n nodes ending in null pointer.
void allocate_nodes(const size_type n, multiallocation_chain &chain)
{
//Preallocate all needed blocks to fulfill the request
size_type cur_nodes = m_freelist.size();
if(cur_nodes < n){
this->priv_alloc_block(((n - cur_nodes) - 1)/m_nodes_per_block + 1);
}
//We just iterate the needed nodes to get the last we'll erase
typedef typename free_nodes_t::iterator free_iterator;
free_iterator before_last_new_it = m_freelist.before_begin();
for(size_type j = 0; j != n; ++j){
++before_last_new_it;
}
//Cache the first node of the allocated range before erasing
free_iterator first_node(m_freelist.begin());
free_iterator last_node (before_last_new_it);
//Erase the range. Since we already have the distance, this is O(1)
m_freelist.erase_after( m_freelist.before_begin()
, ++free_iterator(before_last_new_it)
, n);
//Now take the last erased node and just splice it in the end
//of the intrusive list that will be traversed by the multialloc iterator.
chain.incorporate_after(chain.before_begin(), &*first_node, &*last_node, n);
m_allocated += n;
}
void deallocate_nodes(multiallocation_chain &chain)
{
typedef typename multiallocation_chain::iterator iterator;
iterator it(chain.begin()), itend(chain.end());
while(it != itend){
void *pElem = &*it;
++it;
this->priv_dealloc_node(pElem);
}
}
//!Deallocates all the free blocks of memory. Never throws
void deallocate_free_blocks()
{
typedef typename free_nodes_t::iterator nodelist_iterator;
typename blockslist_t::iterator bit(m_blocklist.before_begin()),
it(m_blocklist.begin()),
itend(m_blocklist.end());
free_nodes_t backup_list;
nodelist_iterator backup_list_last = backup_list.before_begin();
//Execute the algorithm and get an iterator to the last value
size_type blocksize = (get_rounded_size)
(m_real_node_size*m_nodes_per_block, (size_type) alignment_of<node_t>::value);
while(it != itend){
//Collect all the nodes from the block pointed by it
//and push them in the list
free_nodes_t free_nodes;
nodelist_iterator last_it = free_nodes.before_begin();
const void *addr = get_block_from_hook(&*it, blocksize);
m_freelist.remove_and_dispose_if
(is_between(addr, blocksize), push_in_list(free_nodes, last_it));
//If the number of nodes is equal to m_nodes_per_block
//this means that the block can be deallocated
if(free_nodes.size() == m_nodes_per_block){
//Unlink the nodes
free_nodes.clear();
it = m_blocklist.erase_after(bit);
mp_segment_mngr_base->deallocate((void*)addr);
}
//Otherwise, insert them in the backup list, since the
//next "remove_if" does not need to check them again.
else{
//Assign the iterator to the last value if necessary
if(backup_list.empty() && !m_freelist.empty()){
backup_list_last = last_it;
}
//Transfer nodes. This is constant time.
backup_list.splice_after
( backup_list.before_begin()
, free_nodes
, free_nodes.before_begin()
, last_it
, free_nodes.size());
bit = it;
++it;
}
}
//We should have removed all the nodes from the free list
BOOST_ASSERT(m_freelist.empty());
//Now pass all the node to the free list again
m_freelist.splice_after
( m_freelist.before_begin()
, backup_list
, backup_list.before_begin()
, backup_list_last
, backup_list.size());
}
size_type num_free_nodes()
{ return m_freelist.size(); }
//!Deallocates all used memory. Precondition: all nodes allocated from this pool should
//!already be deallocated. Otherwise, undefined behaviour. Never throws
void purge_blocks()
{
//check for memory leaks
BOOST_ASSERT(m_allocated==0);
size_type blocksize = (get_rounded_size)
(m_real_node_size*m_nodes_per_block, (size_type)alignment_of<node_t>::value);
//We iterate though the NodeBlock list to free the memory
while(!m_blocklist.empty()){
void *addr = get_block_from_hook(&m_blocklist.front(), blocksize);
m_blocklist.pop_front();
mp_segment_mngr_base->deallocate((void*)addr);
}
//Just clear free node list
m_freelist.clear();
}
void swap(private_node_pool_impl &other)
{
BOOST_ASSERT(m_nodes_per_block == other.m_nodes_per_block);
BOOST_ASSERT(m_real_node_size == other.m_real_node_size);
std::swap(mp_segment_mngr_base, other.mp_segment_mngr_base);
m_blocklist.swap(other.m_blocklist);
m_freelist.swap(other.m_freelist);
std::swap(m_allocated, other.m_allocated);
}
private:
struct push_in_list
{
push_in_list(free_nodes_t &l, typename free_nodes_t::iterator &it)
: slist_(l), last_it_(it)
{}
void operator()(typename free_nodes_t::pointer p) const
{
slist_.push_front(*p);
if(slist_.size() == 1){ //Cache last element
++last_it_ = slist_.begin();
}
}
private:
free_nodes_t &slist_;
typename free_nodes_t::iterator &last_it_;
};
struct is_between
{
typedef typename free_nodes_t::value_type argument_type;
typedef bool result_type;
is_between(const void *addr, std::size_t size)
: beg_(static_cast<const char *>(addr)), end_(beg_+size)
{}
bool operator()(typename free_nodes_t::const_reference v) const
{
return (beg_ <= reinterpret_cast<const char *>(&v) &&
end_ > reinterpret_cast<const char *>(&v));
}
private:
const char * beg_;
const char * end_;
};
//!Allocates one node, using single segregated storage algorithm.
//!Never throws
node_t *priv_alloc_node()
{
//If there are no free nodes we allocate a new block
if (m_freelist.empty())
this->priv_alloc_block(1);
//We take the first free node
node_t *n = (node_t*)&m_freelist.front();
m_freelist.pop_front();
++m_allocated;
return n;
}
//!Deallocates one node, using single segregated storage algorithm.
//!Never throws
void priv_dealloc_node(void *pElem)
{
//We put the node at the beginning of the free node list
node_t * to_deallocate = static_cast<node_t*>(pElem);
m_freelist.push_front(*to_deallocate);
BOOST_ASSERT(m_allocated>0);
--m_allocated;
}
//!Allocates several blocks of nodes. Can throw
void priv_alloc_block(size_type num_blocks)
{
BOOST_ASSERT(num_blocks > 0);
size_type blocksize =
(get_rounded_size)(m_real_node_size*m_nodes_per_block, (size_type)alignment_of<node_t>::value);
BOOST_TRY{
for(size_type i = 0; i != num_blocks; ++i){
//We allocate a new NodeBlock and put it as first
//element in the free Node list
char *pNode = reinterpret_cast<char*>
(mp_segment_mngr_base->allocate(blocksize + sizeof(node_t)));
char *pBlock = pNode;
m_blocklist.push_front(get_block_hook(pBlock, blocksize));
//We initialize all Nodes in Node Block to insert
//them in the free Node list
for(size_type j = 0; j < m_nodes_per_block; ++j, pNode += m_real_node_size){
m_freelist.push_front(*new (pNode) node_t);
}
}
}
BOOST_CATCH(...){
//to-do: if possible, an efficient way to deallocate allocated blocks
BOOST_RETHROW
}
BOOST_CATCH_END
}
//!Deprecated, use deallocate_free_blocks
void deallocate_free_chunks()
{ this->deallocate_free_blocks(); }
//!Deprecated, use purge_blocks
void purge_chunks()
{ this->purge_blocks(); }
private:
//!Returns a reference to the block hook placed in the end of the block
static node_t & get_block_hook (void *block, size_type blocksize)
{
return *reinterpret_cast<node_t*>(reinterpret_cast<char*>(block) + blocksize);
}
//!Returns the starting address of the block reference to the block hook placed in the end of the block
void *get_block_from_hook (node_t *hook, size_type blocksize)
{
return (reinterpret_cast<char*>(hook) - blocksize);
}
private:
typedef typename boost::intrusive::pointer_traits
<void_pointer>::template rebind_pointer<segment_manager_base_type>::type segment_mngr_base_ptr_t;
const size_type m_nodes_per_block;
const size_type m_real_node_size;
segment_mngr_base_ptr_t mp_segment_mngr_base; //Segment manager
blockslist_t m_blocklist; //Intrusive container of blocks
free_nodes_t m_freelist; //Intrusive container of free nods
size_type m_allocated; //Used nodes for debugging
};
} //namespace container_detail {
} //namespace container {
} //namespace boost {
#include <boost/container/detail/config_end.hpp>
#endif //#ifndef BOOST_CONTAINER_DETAIL_ADAPTIVE_NODE_POOL_IMPL_HPP