boost/interprocess/indexes/unordered_map_index.hpp
//////////////////////////////////////////////////////////////////////////////
//
// (C) Copyright Ion Gaztanaga 2005-2012. 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_UNORDERED_MAP_INDEX_HPP
#define BOOST_INTERPROCESS_UNORDERED_MAP_INDEX_HPP
#include <boost/interprocess/detail/config_begin.hpp>
#include <boost/interprocess/detail/workaround.hpp>
#include <functional>
#include <utility>
#include <boost/unordered_map.hpp>
#include <boost/interprocess/detail/utilities.hpp>
#include <boost/interprocess/allocators/private_adaptive_pool.hpp>
//!\file
//!Describes index adaptor of boost::unordered_map container, to use it
//!as name/shared memory index
namespace boost {
namespace interprocess {
///@cond
//!Helper class to define typedefs from
//!IndexTraits
template <class MapConfig>
struct unordered_map_index_aux
{
typedef typename MapConfig::key_type key_type;
typedef typename MapConfig::mapped_type mapped_type;
typedef std::equal_to<key_type> key_equal;
typedef std::pair<const key_type, mapped_type> value_type;
typedef private_adaptive_pool
<value_type,
typename MapConfig::
segment_manager_base> allocator_type;
struct hasher
: std::unary_function<key_type, std::size_t>
{
std::size_t operator()(const key_type &val) const
{
typedef typename key_type::char_type char_type;
const char_type *beg = ipcdetail::to_raw_pointer(val.mp_str),
*end = beg + val.m_len;
return boost::hash_range(beg, end);
}
};
typedef unordered_map<key_type, mapped_type, hasher,
key_equal, allocator_type> index_t;
};
///@endcond
//!Index type based in unordered_map. Just derives from unordered_map and
//!defines the interface needed by managed memory segments
template <class MapConfig>
class unordered_map_index
//Derive class from unordered_map specialization
: public unordered_map_index_aux<MapConfig>::index_t
{
/// @cond
typedef unordered_map_index_aux<MapConfig> index_aux;
typedef typename index_aux::index_t base_type;
typedef typename
MapConfig::segment_manager_base segment_manager_base;
/// @endcond
public:
//!Constructor. Takes a pointer to the
//!segment manager. Can throw
unordered_map_index(segment_manager_base *segment_mngr)
: base_type(0,
typename index_aux::hasher(),
typename index_aux::key_equal(),
segment_mngr){}
//!This reserves memory to optimize the insertion of n
//!elements in the index
void reserve(typename segment_manager_base::size_type n)
{ base_type::rehash(n); }
//!This tries to free previously allocate
//!unused memory.
void shrink_to_fit()
{ base_type::rehash(base_type::size()); }
};
/// @cond
//!Trait class to detect if an index is a node
//!index. This allows more efficient operations
//!when deallocating named objects.
template<class MapConfig>
struct is_node_index
<boost::interprocess::unordered_map_index<MapConfig> >
{
static const bool value = true;
};
/// @endcond
}} //namespace boost { namespace interprocess {
#include <boost/interprocess/detail/config_end.hpp>
#endif //#ifndef BOOST_INTERPROCESS_UNORDERED_MAP_INDEX_HPP