ACE/apps/JAWS2/JAWS/Hash_Bucket_T.h

   1 /* -*- c++ -*- */
   2 // Hey Emacs!  This is a C++ file!
   3 #ifndef JAWS_HASH_BUCKET_T_H
   4 #define JAWS_HASH_BUCKET_T_H
   5
   6 #include "ace/Containers.h"
   7
   8 #define JAWS_HASH_BUCKET_ITEM JAWS_Hash_Bucket_Item<EXT_ID, INT_ID>
   9 #define JAWS_HASH_BUCKET_DLCSTACK JAWS_Hash_Bucket_DLCStack<EXT_ID, INT_ID>
  10 #define JAWS_HASH_BUCKET_DLCSTACK_ITERATOR \
  11         JAWS_Hash_Bucket_DLCStack_Iterator<EXT_ID, INT_ID>
  12
  13
  14 // Why Hash_Bucket?
  15 //
  16 // This is an attempt to simplify the creation of high-performance
  17 // hash tables with respect to concurrent access by multiple threads.
  18 // To this end, we attempt to raise the amount of concurrency through
  19 // the use or readers/writer locks rather than through mutual
  20 // exclusion.
  21
  22 template <class EXT_ID, class INT_ID>
  23 class JAWS_Hash_Bucket_Item
  24 {
  25 public:
  26   JAWS_Hash_Bucket_Item (const EXT_ID &ext_id, const INT_ID &int_id,
  27                          JAWS_Hash_Bucket_Item<EXT_ID, INT_ID> *next = 0,
  28                          JAWS_Hash_Bucket_Item<EXT_ID, INT_ID> *prev = 0);
  29   JAWS_Hash_Bucket_Item (JAWS_Hash_Bucket_Item<EXT_ID, INT_ID> *next = 0,
  30                          JAWS_Hash_Bucket_Item<EXT_ID, INT_ID> *prev = 0);
  31
  32   ~JAWS_Hash_Bucket_Item (void);
  33   // Destructor.
  34
  35   EXT_ID ext_id_;
  36   // Key used to look up an entry.
  37
  38   INT_ID int_id_;
  39   // The contents of the entry itself.
  40
  41   JAWS_Hash_Bucket_Item<EXT_ID, INT_ID> *next_;
  42   // Pointer to the next item in the bucket of overflow nodes.
  43
  44   JAWS_Hash_Bucket_Item<EXT_ID, INT_ID> *prev_;
  45   // Pointer to the prev item in the bucket of overflow nodes.
  46
  47 };
  48
  49
  50 template <class EXT_ID, class INT_ID> class JAWS_Hash_Bucket_DLCStack_Iterator;
  51
  52 template <class EXT_ID, class INT_ID, class EQ_FUNC>
  53 class JAWS_Hash_Bucket_Manager;
  54
  55 template <class EXT_ID, class INT_ID>
  56 class JAWS_Hash_Bucket_DLCStack
  57 // Create a doubly linked circular stack to be managed by the
  58 // Hash_Bucket_Manager
  59 {
  60   friend class JAWS_Hash_Bucket_DLCStack_Iterator<EXT_ID, INT_ID>;
  61
  62 public:
  63
  64   JAWS_Hash_Bucket_DLCStack (ACE_Allocator *alloc = 0);
  65   ~JAWS_Hash_Bucket_DLCStack (void);
  66
  67   int is_empty (void) const;
  68   // Returns 1 if the container is empty, otherwise returns 0.
  69
  70   JAWS_Hash_Bucket_Item<EXT_ID, INT_ID> *push (const EXT_ID &ext_id,
  71                                               const INT_ID &int_id);
  72   // Adds <new_item> to the head of the list.
  73   // Returns the new item that was inserted.
  74
  75   JAWS_Hash_Bucket_Item<EXT_ID, INT_ID> *pop (void);
  76   // Removes and returns the first <item> in the list.  Returns
  77   // internal node's address on success, 0 if the queue was empty.
  78   // This method will *not* free the internal node.
  79
  80   void reset (void);
  81   // Reset the <JAWS_Hash_Bucket_DLCStack> to be empty.
  82   // Notice that since no one is interested in the items within,
  83   // This operation will delete all items.
  84
  85   int remove (JAWS_Hash_Bucket_Item<EXT_ID, INT_ID> *item);
  86   // If item is still part of the CStack, it is removed.
  87   // In anycase, if there is no error, item is freed.
  88   // Returns 0 if ok, -1 on error.
  89
  90   ACE_Allocator *allocator_;
  91
  92 private:
  93
  94   JAWS_Hash_Bucket_Item<EXT_ID, INT_ID> *head_;
  95   JAWS_Hash_Bucket_Item<EXT_ID, INT_ID> *tail_;
  96
  97 };
  98
  99
 100 template <class EXT_ID, class INT_ID>
 101 class JAWS_Hash_Bucket_DLCStack_Iterator
 102 {
 103 public:
 104
 105   JAWS_Hash_Bucket_DLCStack_Iterator (const JAWS_HASH_BUCKET_DLCSTACK &dlcstack);
 106
 107   int first (void);
 108   // Moves to first element in the set, clears done flag.  Returns 0
 109   // if empty, 1 otherwise.
 110
 111   int last (void);
 112   // Moves to last element in the set, clears done flag.  Returns 0 if
 113   // empty, 1 otherwise.
 114
 115   int advance (void);
 116   // Move forward by one element of set.  Returns 0 if empty or we end
 117   // up being the first element in the set, 1 otherwise.  If advance
 118   // takes us to the first element, done is set to true.
 119
 120   int revert (void);
 121   // Move backward by one element of set.  Returns 0 if empty or we
 122   // end up being the last element in the set, 1 otherwise.  If revert
 123   // takes us to the last element, done is set to true.
 124
 125   int next (JAWS_HASH_BUCKET_ITEM *&item);
 126   int next (JAWS_HASH_BUCKET_ITEM *&item) const;
 127   // Pass back the next item.  Returns 0 if done is true, 1 otherwise.
 128
 129   int prev (JAWS_HASH_BUCKET_ITEM *&item);
 130   int prev (JAWS_HASH_BUCKET_ITEM *&item) const;
 131   // Pass back the previous item.  Returns 0 if done is true, 1
 132   // otherwise.
 133
 134   int done (void) const;
 135   // Returns 1 if done_ flag is set, 0 otherwise.  done_ flag is set
 136   // if next takes us to first element or prev takes us to last
 137   // element.
 138
 139 private:
 140   const JAWS_HASH_BUCKET_DLCSTACK &dlcstack_;
 141   JAWS_HASH_BUCKET_ITEM *next_;
 142   JAWS_HASH_BUCKET_ITEM *prev_;
 143   int done_;
 144 };
 145
 146
 147 template <class EXT_ID, class INT_ID, class EQ_FUNC>
 148 class JAWS_Hash_Bucket_Manager
 149 {
 150 public:
 151   JAWS_Hash_Bucket_Manager (ACE_Allocator *alloc = 0);
 152   int open (ACE_Allocator *alloc = 0);
 153
 154   ~JAWS_Hash_Bucket_Manager (void);
 155   int close (void);
 156
 157   int find (const EXT_ID &ext_id) const;
 158   int find (const EXT_ID &ext_id, INT_ID &int_id) const;
 159   // Locate <ext_id> and pass out parameter via <int_id>.  If found,
 160   // return 0, returns -1 if not found.
 161
 162   int bind (const EXT_ID &ext_id, const INT_ID &int_id);
 163   int trybind (const EXT_ID &ext_id, INT_ID &int_id);
 164   // Associate <ext_id> with <int_id> if and only if <ext_id> is not
 165   // in the map.  If <ext_id> is already in the map then the <int_id>
 166   // parameter is assigned the existing value in the map.  Returns 0
 167   // if a new entry is bound successfully, returns 1 if an attempt is
 168   // made to bind an existing entry, and returns -1 if failures occur.
 169
 170   int rebind (const EXT_ID &ext_id, const INT_ID &int_id,
 171               EXT_ID &old_ext_id, INT_ID &old_int_id);
 172   // Associate <ext_id> with <int_id>.  If <ext_id> is not in the map
 173   // then behaves just like <bind>.  Otherwise, store the old values
 174   // of <ext_id> and <int_id> into the "out" parameters and rebind the
 175   // new parameters.  This is very useful if you need to have an
 176   // atomic way of updating <JAWS_Hash_Map_Entrys> and you also need full
 177   // control over memory allocation.  Returns 0 if a new entry is
 178   // bound successfully, returns 1 if an existing entry was rebound,
 179   // and returns -1 if failures occur.
 180
 181   int unbind (const EXT_ID &ext_id);
 182   int unbind (const EXT_ID &ext_id, INT_ID &int_id);
 183   // Break any association of <ext_id>.  Returns the value of <int_id>
 184   // in case the caller needs to deallocate memory.  Return value is 0
 185   // if unbind succeeds, -1 otherwise.
 186
 187 protected:
 188
 189   JAWS_Hash_Bucket_Item<EXT_ID, INT_ID> *find_i (const EXT_ID &ext_id) const;
 190   // Returns the item associated with ext_id if found in list.
 191   // Returns NULL if not found.
 192
 193 private:
 194
 195   JAWS_Hash_Bucket_DLCStack<EXT_ID, INT_ID> dlcstack_;
 196
 197 };
 198
 199
 200 #if defined (ACE_TEMPLATES_REQUIRE_SOURCE)
 201 #include "JAWS/Hash_Bucket_T.cpp"
 202 #endif /* ACE_TEMPLATES_REQUIRE_SOURCE */
 203
 204 #endif /* JAWS_HASH_BUCKET_T_H */