src/subtitles/mru_cache.h

   1 /************************************************************************/
   2 /* author: xy                                                           */
   3 /* date: 20110918                                                       */
   4 /************************************************************************/
   5 #ifndef __MRU_CACHE_H_256FCF72_8663_41DC_B98A_B822F6007912__
   6 #define __MRU_CACHE_H_256FCF72_8663_41DC_B98A_B822F6007912__
   7
   8 /***
   9  * gather from boost::multi_index MRU example
  10  * http://www.boost.org/doc/libs/1_46_1/libs/multi_index/example/serialization.cpp
  11  */
  12
  13 #if !defined(NDEBUG)
  14 #define BOOST_MULTI_INDEX_ENABLE_INVARIANT_CHECKING
  15 #define BOOST_MULTI_INDEX_ENABLE_SAFE_MODE
  16 #endif
  17
  18 #include <boost/config.hpp> /* keep it first to prevent nasty warns in MSVC */
  19 #include <boost/multi_index_container.hpp>
  20 #include <boost/multi_index/hashed_index.hpp>
  21 #include <boost/multi_index/member.hpp>
  22 #include <boost/multi_index/sequenced_index.hpp>
  23 #include <boost/multi_index/mem_fun.hpp>
  24 #include <boost/bimap/bimap.hpp>
  25
  26 /* An MRU (most recently used) list keeps record of the last n
  27  * inserted items, listing first the newer ones. Care has to be
  28  * taken when a duplicate item is inserted: instead of letting it
  29  * appear twice, the MRU list relocates it to the first position.
  30  */
  31
  32 template <typename Item, typename KeyExtractor>
  33 class mru_list
  34 {
  35 public:
  36   typedef boost::multi_index::multi_index_container<
  37     Item,
  38     boost::multi_index::indexed_by<
  39       boost::multi_index::sequenced<>,
  40       boost::multi_index::hashed_unique<
  41         KeyExtractor
  42       >
  43     >
  44   > item_list;
  45
  46   typedef typename Item item_type;
  47   typedef typename item_list::iterator iterator;
  48   typedef typename item_list::nth_index<1>::type hashed_cache;
  49
  50   mru_list(std::size_t max_num_items_):max_num_items(max_num_items_){}
  51
  52   iterator begin(){return il.begin();}
  53   iterator end(){return il.end();}
  54   void clear() { il.clear();}
  55   const hashed_cache& get_hashed_cache() {return il.get<1>();}
  56
  57 protected:
  58   item_list   il;
  59   std::size_t max_num_items;
  60 };
  61
  62 #endif // end of __MRU_CACHE_H_256FCF72_8663_41DC_B98A_B822F6007912__