ACE/apps/JAWS2/JAWS/Cache_List_T.h

   1 /* -*- c++ -*- */
   2 #ifndef JAWS_CACHE_LIST_T_H
   3 #define JAWS_CACHE_LIST_T_H
   4
   5 #include "ace/Malloc.h"
   6 #include "JAWS/Cache_Object.h"
   7
   8 // Forward declarations
   9 template <class EXT_ID, class FACTORY, class HASH_FUNC, class EQ_FUNC>
  10 class JAWS_Cache_Manager;
  11
  12 template <class EXT_ID, class FACTORY, class HASH_FUNC, class EQ_FUNC>
  13 class JAWS_Cache_List_Item;
  14
  15
  16 template <class EXT_ID, class FACT, class H_FN, class E_FN>
  17 class JAWS_Cache_List
  18 // Roll my own heap here.  Eventually, a heap should be its own
  19 // standalone data structure.
  20 //
  21 // This version is not a heap, but a doubly linked list.  We are
  22 // trying to simplify all the heap operations to be O(1).
  23 {
  24 public:
  25   typedef JAWS_Cache_Manager<EXT_ID, FACT, H_FN, E_FN> Cache_Manager;
  26   typedef JAWS_Cache_List_Item<EXT_ID, FACT, H_FN, E_FN> Cache_List_Item;
  27
  28   JAWS_Cache_List (ACE_Allocator *alloc = 0, size_t maxsize = 8192);
  29   // maxsize is the total number of objects the in memory cache is
  30   // willing to manage
  31
  32   ~JAWS_Cache_List ();
  33
  34   int is_empty () const;
  35   int is_full () const;
  36
  37   size_t size () const;
  38   size_t maxsize () const;
  39
  40   int maxsize (Cache_Manager *cm, size_t new_maxsize);
  41   // attempt to grow (or shrink) the heap.  Return 0 on success, -1 on
  42   // error.
  43
  44   int insert (const EXT_ID &ext_id, JAWS_Cache_Object *const &int_id);
  45   // attempt to insert int_id into heap.
  46
  47   int remove (EXT_ID &ext_id, JAWS_Cache_Object *&int_id);
  48   // attempt to remove the top element of heap.
  49
  50   int remove (void *item);
  51   // treat item as a Cache_List_Item, and remove it from the heap
  52
  53   int adjust (void *item);
  54   // treat item as a Cache_List_Item, and alter its heap position
  55
  56 protected:
  57   void insert_i (Cache_List_Item *item);
  58   // insert item into heap.
  59
  60   void remove_i (Cache_List_Item *item);
  61   // remove the element residing at pos, but do not delete it.
  62
  63   void remove_i ();
  64   // remove the element residing at the top of heap, but do not delete it.
  65
  66 private:
  67   ACE_Allocator *allocator_;
  68
  69   size_t maxsize_;
  70   size_t size_;
  71
  72   Cache_List_Item *item_;
  73
  74   Cache_List_Item *head_;
  75   Cache_List_Item *tail_;
  76 };
  77
  78
  79 template <class EXT_ID, class FACT, class H_FN, class E_FN>
  80 class JAWS_Cache_List_Item
  81 {
  82   friend class JAWS_Cache_List<EXT_ID, FACT, H_FN, E_FN>;
  83
  84 public:
  85   typedef JAWS_Cache_List<EXT_ID, FACT, H_FN, E_FN> Cache_List;
  86
  87   JAWS_Cache_List_Item (const EXT_ID &ext_id, JAWS_Cache_Object *const &int_id);
  88   unsigned int priority ();
  89
  90 private:
  91   EXT_ID ext_id_;
  92   JAWS_Cache_Object *int_id_;
  93
  94   JAWS_Cache_List_Item *next_;
  95   JAWS_Cache_List_Item *prev_;
  96 };
  97
  98 #include "JAWS/Cache_List_T.cpp"
  99
 100 #endif /* JAWS_CACHE_LIST_T_H */