container/detail/block_list.hpp

0001 //////////////////////////////////////////////////////////////////////////////
0002 //
0003 // (C) Copyright Ion Gaztanaga 2015-2015. Distributed under the Boost
0004 // Software License, Version 1.0. (See accompanying file
0005 // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0006 //
0007 // See http://www.boost.org/libs/container for documentation.
0008 //
0009 //////////////////////////////////////////////////////////////////////////////
0010
0011 #ifndef BOOST_CONTAINER_DETAIL_BLOCK_LIST_HEADER
0012 #define BOOST_CONTAINER_DETAIL_BLOCK_LIST_HEADER
0013
0014 #ifndef BOOST_CONFIG_HPP
0015 #  include <boost/config.hpp>
0016 #endif
0017
0018 #if defined(BOOST_HAS_PRAGMA_ONCE)
0019 #  pragma once
0020 #endif
0021
0022 #include <boost/container/detail/config_begin.hpp>
0023 #include <boost/container/detail/workaround.hpp>
0024 #include <boost/container/container_fwd.hpp>
0025 #include <boost/container/pmr/memory_resource.hpp>
0026 #include <boost/container/throw_exception.hpp>
0027 #include <boost/intrusive/circular_list_algorithms.hpp>
0028 #include <boost/move/detail/type_traits.hpp>
0029 #include <boost/assert.hpp>
0030 #include <boost/container/detail/placement_new.hpp>
0031
0032 #include <cstddef>
0033
0034 namespace boost {
0035 namespace container {
0036 namespace pmr {
0037
0038 struct list_node
0039 {
0040    list_node *next;
0041    list_node *previous;
0042 };
0043
0044 struct list_node_traits
0045 {
0046    typedef list_node         node;
0047    typedef list_node*        node_ptr;
0048    typedef const list_node*  const_node_ptr;
0049
0050    static node_ptr get_next(const_node_ptr n)
0051    {  return n->next;  }
0052
0053    static node_ptr get_previous(const_node_ptr n)
0054    {  return n->previous;  }
0055
0056    static void set_next(const node_ptr & n, const node_ptr & next)
0057    {  n->next = next;  }
0058
0059    static void set_previous(const node_ptr & n, const node_ptr & previous)
0060    {  n->previous = previous;  }
0061 };
0062
0063 struct block_list_header
0064    : public list_node
0065 {
0066    std::size_t size;
0067 };
0068
0069 typedef bi::circular_list_algorithms<list_node_traits> list_algo;
0070
0071
0072 template<class DerivedFromBlockListHeader = block_list_header>
0073 class block_list_base
0074 {
0075    list_node m_list;
0076
0077    static const std::size_t MaxAlignMinus1 = memory_resource::max_align-1u;
0078
0079    public:
0080
0081    static const std::size_t header_size = std::size_t(sizeof(DerivedFromBlockListHeader) + MaxAlignMinus1) & std::size_t(~MaxAlignMinus1);
0082
0083    explicit block_list_base()
0084    {  list_algo::init_header(&m_list);  }
0085
0086    #if !defined(BOOST_NO_CXX11_DELETED_FUNCTIONS) || defined(BOOST_CONTAINER_DOXYGEN_INVOKED)
0087    block_list_base(const block_list_base&) = delete;
0088    block_list_base operator=(const block_list_base&) = delete;
0089    #else
0090    private:
0091    block_list_base          (const block_list_base&);
0092    block_list_base operator=(const block_list_base&);
0093    public:
0094    #endif
0095
0096    ~block_list_base()
0097    {}
0098
0099    void *allocate(std::size_t size, memory_resource &mr)
0100    {
0101       if((size_t(-1) - header_size) < size)
0102          throw_bad_alloc();
0103       void *p = mr.allocate(size+header_size);
0104       block_list_header &mb  = *::new((void*)p, boost_container_new_t()) DerivedFromBlockListHeader;
0105       mb.size = size+header_size;
0106       list_algo::link_after(&m_list, &mb);
0107       return (char *)p + header_size;
0108    }
0109
0110    void deallocate(void *p, memory_resource &mr) BOOST_NOEXCEPT
0111    {
0112       DerivedFromBlockListHeader *pheader = static_cast<DerivedFromBlockListHeader*>
0113          (static_cast<void*>((char*)p - header_size));
0114       list_algo::unlink(pheader);
0115       const std::size_t size = pheader->size;
0116       static_cast<DerivedFromBlockListHeader*>(pheader)->~DerivedFromBlockListHeader();
0117       mr.deallocate(pheader, size, memory_resource::max_align);
0118    }
0119
0120    void release(memory_resource &mr) BOOST_NOEXCEPT
0121    {
0122       list_node *n = list_algo::node_traits::get_next(&m_list);
0123       while(n != &m_list){
0124          DerivedFromBlockListHeader &d = static_cast<DerivedFromBlockListHeader&>(*n);
0125          n = list_algo::node_traits::get_next(n);
0126          std::size_t size = d.size;
0127          d.~DerivedFromBlockListHeader();
0128          mr.deallocate(reinterpret_cast<char*>(&d), size, memory_resource::max_align);
0129       }
0130       list_algo::init_header(&m_list);
0131    }
0132 };
0133
0134 }  //namespace pmr {
0135 }  //namespace container {
0136 }  //namespace boost {
0137
0138 #include <boost/container/detail/config_end.hpp>
0139
0140 #endif   //BOOST_CONTAINER_DETAIL_BLOCK_LIST_HEADER