/*

    Copyright (C) 2005 Apple Inc. All rights reserved.

    This library is free software; you can redistribute it and/or

    modify it under the terms of the GNU Library General Public

    License as published by the Free Software Foundation; either

    version 2 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,

    but WITHOUT ANY WARRANTY; without even the implied warranty of

    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public License

    along with this library; see the file COPYING.LIB.  If not, write to

    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,

    Boston, MA 02110-1301, USA.

*/

#include "config.h"

#include "HashTable.h"

namespace WTF {

#if DUMP_HASHTABLE_STATS

int HashTableStats::numAccesses;

int HashTableStats::numCollisions;

int HashTableStats::collisionGraph[4096];

int HashTableStats::maxCollisions;

int HashTableStats::numRehashes;

int HashTableStats::numRemoves;

int HashTableStats::numReinserts;

static HashTableStats logger;

static Mutex& hashTableStatsMutex()

{

    AtomicallyInitializedStatic(Mutex&, mutex = *new Mutex);

    return mutex;

}

HashTableStats::~HashTableStats()

{

    // Don't lock hashTableStatsMutex here because it can cause deadlocks at shutdown 

    // if any thread was killed while holding the mutex.

    printf("\nWTF::HashTable statistics\n\n");

    printf("%d accesses\n", numAccesses);

    printf("%d total collisions, average %.2f probes per access\n", numCollisions, 1.0 * (numAccesses + numCollisions) / numAccesses);

    printf("longest collision chain: %d\n", maxCollisions);

    for (int i = 1; i <= maxCollisions; i++) {

        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);

    }

    printf("%d rehashes\n", numRehashes);

    printf("%d reinserts\n", numReinserts);

}

void HashTableStats::recordCollisionAtCount(int count)

{

    MutexLocker lock(hashTableStatsMutex());

    if (count > maxCollisions)

        maxCollisions = count;

    numCollisions++;

    collisionGraph[count]++;

}

#endif

} // namespace WTF