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authorTimothy Pearson <kb9vqf@pearsoncomputing.net>2011-11-08 12:31:36 -0600
committerTimothy Pearson <kb9vqf@pearsoncomputing.net>2011-11-08 12:31:36 -0600
commitd796c9dd933ab96ec83b9a634feedd5d32e1ba3f (patch)
tree6e3dcca4f77e20ec8966c666aac7c35bd4704053 /src/tools/qmutexpool.cpp
downloadtqt3-d796c9dd933ab96ec83b9a634feedd5d32e1ba3f.tar.gz
tqt3-d796c9dd933ab96ec83b9a634feedd5d32e1ba3f.zip
Test conversion to TQt3 from Qt3 8c6fc1f8e35fd264dd01c582ca5e7549b32ab731
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+/****************************************************************************
+**
+** ...
+**
+** Copyright (C) 2005-2008 Trolltech ASA. All rights reserved.
+**
+** This file is part of the tools module of the TQt GUI Toolkit.
+**
+** This file may be used under the terms of the GNU General
+** Public License versions 2.0 or 3.0 as published by the Free
+** Software Foundation and appearing in the files LICENSE.GPL2
+** and LICENSE.GPL3 included in the packaging of this file.
+** Alternatively you may (at your option) use any later version
+** of the GNU General Public License if such license has been
+** publicly approved by Trolltech ASA (or its successors, if any)
+** and the KDE Free TQt Foundation.
+**
+** Please review the following information to ensure GNU General
+** Public Licensing retquirements will be met:
+** http://trolltech.com/products/qt/licenses/licensing/opensource/.
+** If you are unsure which license is appropriate for your use, please
+** review the following information:
+** http://trolltech.com/products/qt/licenses/licensing/licensingoverview
+** or contact the sales department at sales@trolltech.com.
+**
+** This file may be used under the terms of the Q Public License as
+** defined by Trolltech ASA and appearing in the file LICENSE.TQPL
+** included in the packaging of this file. Licensees holding valid TQt
+** Commercial licenses may use this file in accordance with the TQt
+** Commercial License Agreement provided with the Software.
+**
+** This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+** INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE. Trolltech reserves all rights not granted
+** herein.
+**
+**********************************************************************/
+
+#include "qmutexpool_p.h"
+
+#ifdef QT_THREAD_SUPPORT
+
+#include <qthread.h>
+
+Q_EXPORT TQMutexPool *qt_global_mutexpool = 0;
+
+
+/*!
+ \class TQMutexPool qmutexpool_p.h
+ \brief The TQMutexPool class provides a pool of TQMutex objects.
+
+ \internal
+
+ \ingroup thread
+
+ TQMutexPool is a convenience class that provides access to a fixed
+ number of TQMutex objects.
+
+ Typical use of a TQMutexPool is in situations where it is not
+ possible or feasible to use one TQMutex for every protected object.
+ The mutex pool will return a mutex based on the address of the
+ object that needs protection.
+
+ For example, consider this simple class:
+
+ \code
+ class Number {
+ public:
+ Number( double n ) : num ( n ) { }
+
+ void setNumber( double n ) { num = n; }
+ double number() const { return num; }
+
+ private:
+ double num;
+ };
+ \endcode
+
+ Adding a TQMutex member to the Number class does not make sense,
+ because it is so small. However, in order to ensure that access to
+ each Number is protected, you need to use a mutex. In this case, a
+ TQMutexPool would be ideal.
+
+ Code to calculate the square of a number would then look something
+ like this:
+
+ \code
+ void calcSquare( Number *num )
+ {
+ TQMutexLocker locker( mutexpool.get( num ) );
+ num.setNumber( num.number() * num.number() );
+ }
+ \endcode
+
+ This function will safely calculate the square of a number, since
+ it uses a mutex from a TQMutexPool. The mutex is locked and
+ unlocked automatically by the TQMutexLocker class. See the
+ TQMutexLocker documentation for more details.
+*/
+
+/*!
+ Constructs a TQMutexPool, reserving space for \a size TQMutexes. If
+ \a recursive is TRUE, all TQMutexes in the pool will be recursive
+ mutexes; otherwise they will all be non-recursive (the default).
+
+ The TQMutexes are created when needed, and deleted when the
+ TQMutexPool is destructed.
+*/
+TQMutexPool::TQMutexPool( bool recursive, int size )
+ : mutex( FALSE ), count( size ), recurs( recursive )
+{
+ mutexes = new TQMutex*[count];
+ for ( int index = 0; index < count; ++index ) {
+ mutexes[index] = 0;
+ }
+}
+
+/*!
+ Destructs a TQMutexPool. All TQMutexes that were created by the pool
+ are deleted.
+*/
+TQMutexPool::~TQMutexPool()
+{
+ TQMutexLocker locker( &mutex );
+ for ( int index = 0; index < count; ++index ) {
+ delete mutexes[index];
+ mutexes[index] = 0;
+ }
+ delete [] mutexes;
+ mutexes = 0;
+}
+
+/*!
+ Returns a TQMutex from the pool. TQMutexPool uses the value \a
+ address to determine which mutex is retured from the pool.
+*/
+TQMutex *TQMutexPool::get( void *address )
+{
+ int index = (int) ( (unsigned long) address % count );
+
+ if ( ! mutexes[index] ) {
+ // mutex not created, create one
+
+ TQMutexLocker locker( &mutex );
+ // we need to check once again that the mutex hasn't been created, since
+ // 2 threads could be trying to create a mutex as the same index...
+ if ( ! mutexes[index] ) {
+ mutexes[index] = new TQMutex( recurs );
+ }
+ }
+
+ return mutexes[index];
+}
+
+#endif