src/hashtable.h

   1 /* Copyright (C) 2007-2012 Vincent Ollivier
   2  *
   3  * Purple Haze is free software: you can redistribute it and/or modify
   4  * it under the terms of the GNU General Public License as published by
   5  * the Free Software Foundation, either version 3 of the License, or
   6  * (at your option) any later version.
   7  *
   8  * Purple Haze is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  15  */
  16
  17 #ifndef HASH_TABLE_H
  18 #define HASH_TABLE_H
  19
  20 #include "common.h"
  21 #include "zobrist.h"
  22
  23 template <class T>
  24 class HashTable
  25 {
  26     protected:
  27         long hits;
  28         long collisions;
  29         long misses;
  30         const int SIZE;
  31         struct Entry {
  32             Hash hash;
  33             T value;
  34
  35             Entry() : hash(0), value() {}
  36         };
  37         Entry* entries;
  38
  39     public:
  40         HashTable(int used_space = MT_SIZE) :
  41             hits(0),
  42             collisions(0),
  43             misses(0),
  44             SIZE(used_space / sizeof(Entry)),
  45             entries(new Entry[SIZE])
  46             {}
  47         ~HashTable() {
  48             delete [] entries;
  49             entries = NULL;
  50         };
  51         T lookup(Hash h, bool* is_empty);
  52         void save(Hash h, T v) {
  53             entries[h & (SIZE - 1)].hash = h;
  54             entries[h & (SIZE - 1)].value = v;
  55         };
  56         void clear();
  57
  58         // Used to print stats
  59         int size() const {
  60             return SIZE;
  61         };
  62
  63         T value_at(int i) const {
  64             return entries[i].value;
  65         };
  66         Hash hash_at(int i) const {
  67             return entries[i].hash;
  68         };
  69
  70         int usage() const;
  71         long nb_lookups() const {
  72             return hits + misses;
  73         };
  74         long nb_hits() const {
  75             return hits;
  76         };
  77         long nb_collisions() const {
  78             return collisions;
  79         };
  80         long nb_misses() const {
  81             return misses;
  82         };
  83 };
  84
  85 #endif /* !HASH_TABLE_H */