src/hashtable.h

   1 /* Copyright (C) 2007-2011 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* entries;
  36
  37     public:
  38         HashTable(int used_space = MT_SIZE) :
  39             hits(0),
  40             collisions(0),
  41             misses(0),
  42             SIZE(used_space / sizeof(Entry)),
  43             entries(new Entry[SIZE])
  44             {}
  45         ~HashTable() {
  46             delete [] entries;
  47             entries = NULL;
  48         };
  49         T lookup(Hash h, bool* is_empty);
  50         void save(Hash h, T v) {
  51             entries[h & (SIZE - 1)].hash = h;
  52             entries[h & (SIZE - 1)].value = v;
  53         };
  54         void clear();
  55
  56         // Used to print stats
  57         int size() const {
  58             return SIZE;
  59         };
  60
  61         T value_at(int i) const {
  62             return entries[i].value;
  63         };
  64         Hash hash_at(int i) const {
  65             return entries[i].hash;
  66         };
  67
  68         int get_usage() const;
  69         long nb_lookups() const {
  70             return hits + misses;
  71         };
  72         long nb_hits() const {
  73             return hits;
  74         };
  75         long nb_collisions() const {
  76             return collisions;
  77         };
  78         long nb_misses() const {
  79             return misses;
  80         };
  81 };
  82
  83 #endif /* !HASH_TABLE_H */