wtf/HashTable.cpp

   1 /*
   2     This file is part of the KDE libraries
   3
   4     Copyright (C) 2005 Apple Computer
   5
   6     This library is free software; you can redistribute it and/or
   7     modify it under the terms of the GNU Library General Public
   8     License as published by the Free Software Foundation; either
   9     version 2 of the License, or (at your option) any later version.
  10
  11     This library is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14     Library General Public License for more details.
  15
  16     You should have received a copy of the GNU Library General Public License
  17     along with this library; see the file COPYING.LIB.  If not, write to
  18     the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  19     Boston, MA 02110-1301, USA.
  20 */
  21
  22 #include "config.h"
  23 #include "HashTable.h"
  24
  25 namespace WTF {
  26
  27 #if DUMP_HASHTABLE_STATS
  28
  29 int HashTableStats::numAccesses;
  30 int HashTableStats::numCollisions;
  31 int HashTableStats::collisionGraph[4096];
  32 int HashTableStats::maxCollisions;
  33 int HashTableStats::numRehashes;
  34 int HashTableStats::numRemoves;
  35 int HashTableStats::numReinserts;
  36
  37 static HashTableStats logger;
  38
  39 HashTableStats::~HashTableStats()
  40 {
  41     printf("\nkhtml::HashTable statistics\n\n");
  42     printf("%d accesses\n", numAccesses);
  43     printf("%d total collisions, average %.2f probes per access\n", numCollisions, 1.0 * (numAccesses + numCollisions) / numAccesses);
  44     printf("longest collision chain: %d\n", maxCollisions);
  45     for (int i = 1; i <= maxCollisions; i++) {
  46         printf("  %d lookups with exactly %d collisions (%.2f%% , %.2f%% with this many or more)\n", collisionGraph[i], i, 100.0 * (collisionGraph[i] - collisionGraph[i+1]) / numAccesses, 100.0 * collisionGraph[i] / numAccesses);
  47     }
  48     printf("%d rehashes\n", numRehashes);
  49     printf("%d reinserts\n", numReinserts);
  50 }
  51
  52 void HashTableStats::recordCollisionAtCount(int count)
  53 {
  54     if (count > maxCollisions)
  55         maxCollisions = count;
  56     numCollisions++;
  57     collisionGraph[count]++;
  58 }
  59
  60 #endif
  61
  62 } // namespace WTF