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+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Qt Software Information (qt-info@nokia.com)
+**
+** This file is part of the documentation of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the either Technology Preview License Agreement or the
+** Beta Release License Agreement.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain
+** additional rights. These rights are described in the Nokia Qt LGPL
+** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this
+** package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+** If you are unsure which license is appropriate for your use, please
+** contact the sales department at qt-sales@nokia.com.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+/*!
+    \class Q3Cache
+    \brief The Q3Cache class is a template class that provides a cache based on QString keys.
+    \compat
+
+    A cache is a least recently used (LRU) list of cache items. Each
+    cache item has a key and a certain cost. The sum of item costs,
+    totalCost(), never exceeds the maximum cache cost, maxCost(). If
+    inserting a new item would cause the total cost to exceed the
+    maximum cost, the least recently used items in the cache are
+    removed.
+
+    Q3Cache is a template class. Q3Cache\<X\> defines a cache that
+    operates on pointers to X, or X*.
+
+    Apart from insert(), by far the most important function is find()
+    (which also exists as operator[]()). This function looks up an
+    item, returns it, and by default marks it as being the most
+    recently used item.
+
+    There are also methods to remove() or take() an object from the
+    cache. Calling setAutoDelete(TRUE) for a cache tells it to delete
+    items that are removed. The default is to not delete items when
+    they are removed (i.e., remove() and take() are equivalent).
+
+    When inserting an item into the cache, only the pointer is copied,
+    not the item itself. This is called a shallow copy. It is possible
+    to make the cache copy all of the item's data (known as a deep
+    copy) when an item is inserted. insert() calls the virtual
+    function Q3PtrCollection::newItem() for the item to be inserted.
+    Inherit a cache and reimplement newItem() if you want deep copies.
+
+    When removing a cache item, the virtual function
+    Q3PtrCollection::deleteItem() is called. The default
+    implementation deletes the item if auto-deletion is enabled, and
+    does nothing otherwise.
+
+    There is a Q3CacheIterator that can be used to traverse the items
+    in the cache in arbitrary order.
+
+    In Q3Cache, the cache items are accessed via QString keys, which
+    are Unicode strings. If you want to use non-Unicode, plain 8-bit
+    \c char* keys, use the Q3AsciiCache template. A Q3Cache has the
+    same performance as a Q3AsciiCache.
+
+    \sa Q3CacheIterator, Q3AsciiCache, Q3IntCache
+*/
+
+/*!
+  \fn Q3Cache::Q3Cache( const Q3Cache<type> &c )
+
+  \internal
+
+  Do not use. A Q3Cache cannot be copied. Calls qFatal() in debug version.
+*/
+
+
+/*!
+    \fn Q3Cache::Q3Cache( int maxCost, int size, bool caseSensitive )
+
+    Constructs a cache whose contents will never have a total cost
+    greater than \a maxCost and which is expected to contain less than
+    \a size items.
+
+    \a size is actually the size of an internal hash array; it's
+    usually best to make it a prime number and at least 50% bigger
+    than the largest expected number of items in the cache.
+
+    Each inserted item has an associated cost. When inserting a new
+    item, if the total cost of all items in the cache will exceed \a
+    maxCost, the cache will start throwing out the older (least
+    recently used) items until there is enough room for the new item
+    to be inserted.
+
+    If \a caseSensitive is TRUE (the default), the cache keys are case
+    sensitive; if it is FALSE, they are case-insensitive.
+    Case-insensitive comparison considers all Unicode letters.
+*/
+
+/*!
+    \fn Q3Cache::~Q3Cache()
+
+    Removes all items from the cache and destroys it. All iterators
+    that access this cache will be reset.
+*/
+
+/*!
+  \fn Q3Cache<type>& Q3Cache::operator=( const Q3Cache<type> &c )
+
+  \internal
+
+  Do not use. A Q3Cache cannot be copied. Calls qFatal() in debug version.
+*/
+
+/*!
+    \fn int Q3Cache::maxCost() const
+
+    Returns the maximum allowed total cost of the cache.
+
+    \sa setMaxCost() totalCost()
+*/
+
+/*!
+    \fn int Q3Cache::totalCost() const
+
+    Returns the total cost of the items in the cache. This is an
+    integer in the range 0 to maxCost().
+
+    \sa setMaxCost()
+*/
+
+/*!
+    \fn void Q3Cache::setMaxCost( int m )
+
+    Sets the maximum allowed total cost of the cache to \a m. If the
+    current total cost is greater than \a m, some items are deleted
+    immediately.
+
+    \sa maxCost() totalCost()
+*/
+
+/*!
+    \fn uint Q3Cache::count() const
+
+    Returns the number of items in the cache.
+
+    \sa totalCost()
+*/
+
+/*!
+    \fn uint Q3Cache::size() const
+
+    Returns the size of the hash array used to implement the cache.
+    This should be a bit bigger than count() is likely to be.
+*/
+
+/*!
+    \fn bool Q3Cache::isEmpty() const
+
+    Returns TRUE if the cache is empty; otherwise returns FALSE.
+*/
+
+/*!
+    \fn bool Q3Cache::insert( const QString &k, const type *d, int c, int p )
+
+    Inserts the item \a d into the cache with key \a k and associated
+    cost, \a c. Returns TRUE if it is successfully inserted; otherwise
+    returns FALSE.
+
+    The cache's size is limited, and if the total cost is too high,
+    Q3Cache will remove old, least recently used items until there is
+    room for this new item.
+
+    The parameter \a p is internal and should be left at the default
+    value (0).
+
+    \warning If this function returns FALSE (which could happen, e.g.
+    if the cost of this item alone exceeds maxCost()) you must delete
+    \a d yourself. Additionally, be very careful about using \a d
+    after calling this function because any other insertions into the
+    cache, from anywhere in the application or within Qt itself, could
+    cause the object to be discarded from the cache and the pointer to
+    become invalid.
+*/
+
+/*!
+    \fn bool Q3Cache::remove( const QString &k )
+
+    Removes the item associated with \a k, and returns TRUE if the
+    item was present in the cache; otherwise returns FALSE.
+
+    The item is deleted if auto-deletion has been enabled, i.e., if
+    you have called setAutoDelete(TRUE).
+
+    If there are two or more items with equal keys, the one that was
+    inserted last is removed.
+
+    All iterators that refer to the removed item are set to point to
+    the next item in the cache's traversal order.
+
+    \sa take(), clear()
+*/
+
+/*!
+    \fn type *Q3Cache::take( const QString &k )
+
+    Takes the item associated with \a k out of the cache without
+    deleting it, and returns a pointer to the item taken out, or 0
+    if the key does not exist in the cache.
+
+    If there are two or more items with equal keys, the one that was
+    inserted last is taken.
+
+    All iterators that refer to the taken item are set to point to the
+    next item in the cache's traversal order.
+
+    \sa remove(), clear()
+*/
+
+/*!
+    \fn void Q3Cache::clear()
+
+    Removes all items from the cache and deletes them if auto-deletion
+    has been enabled.
+
+    All cache iterators that operate this on cache are reset.
+
+    \sa remove() take()
+*/
+
+/*!
+    \fn type *Q3Cache::find( const QString &k, bool ref ) const
+
+    Returns the item associated with key \a k, or 0 if the key does
+    not exist in the cache. If \a ref is TRUE (the default), the item
+    is moved to the front of the least recently used list.
+
+    If there are two or more items with equal keys, the one that was
+    inserted last is returned.
+*/
+
+/*!
+    \fn type *Q3Cache::operator[]( const QString &k ) const
+
+    Returns the item associated with key \a k, or 0 if \a k does not
+    exist in the cache, and moves the item to the front of the least
+    recently used list.
+
+    If there are two or more items with equal keys, the one that was
+    inserted last is returned.
+
+    This is the same as find( k, TRUE ).
+
+    \sa find()
+*/
+
+/*!
+    \fn void Q3Cache::statistics() const
+
+    A debug-only utility function. Prints out cache usage, hit/miss,
+    and distribution information using qDebug(). This function does
+    nothing in the release library.
+*/
+
+/*****************************************************************************
+  Q3CacheIterator documentation
+ *****************************************************************************/
+
+/*!
+    \class Q3CacheIterator qcache.h
+    \brief The Q3CacheIterator class provides an iterator for Q3Cache collections.
+    \compat
+
+    Note that the traversal order is arbitrary; you are not guaranteed
+    any particular order. If new objects are inserted into the cache
+    while the iterator is active, the iterator may or may not see
+    them.
+
+    Multiple iterators are completely independent, even when they
+    operate on the same Q3Cache. Q3Cache updates all iterators that
+    refer an item when that item is removed.
+
+    Q3CacheIterator provides an operator++(), and an operator+=() to
+    traverse the cache. The current() and currentKey() functions are
+    used to access the current cache item and its key. The atFirst()
+    and atLast() return TRUE if the iterator points to the first or
+    last item in the cache respectively. The isEmpty() function
+    returns TRUE if the cache is empty, and count() returns the number
+    of items in the cache.
+
+    Note that atFirst() and atLast() refer to the iterator's arbitrary
+    ordering, not to the cache's internal least recently used list.
+
+    \sa Q3Cache
+*/
+
+/*!
+    \fn Q3CacheIterator::Q3CacheIterator( const Q3Cache<type> &cache )
+
+    Constructs an iterator for \a cache. The current iterator item is
+    set to point to the first item in the \a cache.
+*/
+
+/*!
+    \fn Q3CacheIterator::Q3CacheIterator (const Q3CacheIterator<type> & ci)
+
+    Constructs an iterator for the same cache as \a ci. The new
+    iterator starts at the same item as ci.current(), but moves
+    independently from there on.
+*/
+
+/*!
+    \fn Q3CacheIterator<type>& Q3CacheIterator::operator=( const Q3CacheIterator<type> &ci )
+
+    Makes this an iterator for the same cache as \a ci. The new
+    iterator starts at the same item as ci.current(), but moves
+    independently thereafter.
+*/
+
+/*!
+    \fn uint Q3CacheIterator::count() const
+
+    Returns the number of items in the cache on which this iterator
+    operates.
+
+    \sa isEmpty()
+*/
+
+/*!
+    \fn bool Q3CacheIterator::isEmpty() const
+
+    Returns TRUE if the cache is empty, i.e. count() == 0; otherwise
+    it returns FALSE.
+    
+    \sa count()
+*/
+
+/*!
+    \fn bool Q3CacheIterator::atFirst() const
+
+    Returns TRUE if the iterator points to the first item in the
+    cache; otherwise returns FALSE. Note that this refers to the
+    iterator's arbitrary ordering, not to the cache's internal least
+    recently used list.
+
+    \sa toFirst(), atLast()
+*/
+
+/*!
+    \fn bool Q3CacheIterator::atLast() const
+
+    Returns TRUE if the iterator points to the last item in the cache;
+    otherwise returns FALSE. Note that this refers to the iterator's
+    arbitrary ordering, not to the cache's internal least recently
+    used list.
+
+    \sa toLast(), atFirst()
+*/
+
+/*!
+    \fn type *Q3CacheIterator::toFirst()
+
+    Sets the iterator to point to the first item in the cache and
+    returns a pointer to the item.
+
+    Sets the iterator to 0 and returns 0 if the cache is empty.
+
+    \sa toLast() isEmpty()
+*/
+
+/*!
+    \fn type *Q3CacheIterator::toLast()
+
+    Sets the iterator to point to the last item in the cache and
+    returns a pointer to the item.
+
+    Sets the iterator to 0 and returns 0 if the cache is empty.
+
+    \sa toFirst() isEmpty()
+*/
+
+/*!
+    \fn Q3CacheIterator::operator type *() const
+
+    Cast operator. Returns a pointer to the current iterator item.
+    Same as current().
+*/
+
+/*!
+    \fn type *Q3CacheIterator::current() const
+
+    Returns a pointer to the current iterator item.
+*/
+
+/*!
+    \fn QString Q3CacheIterator::currentKey() const
+
+    Returns the key for the current iterator item.
+*/
+
+/*!
+    \fn type *Q3CacheIterator::operator()()
+
+    Makes the succeeding item current and returns the original current
+    item.
+
+    If the current iterator item was the last item in the cache or if
+    it was 0, 0 is returned.
+*/
+
+/*!
+    \fn type *Q3CacheIterator::operator+=( uint jump )
+
+    Returns the item \a jump positions after the current item, or 0 if
+    it is beyond the last item. Makes this the current item.
+*/
+
+/*!
+    \fn type *Q3CacheIterator::operator-=( uint jump )
+
+    Returns the item \a jump positions before the current item, or 0
+    if it is before the first item. Makes this the current item.
+*/
+
+/*!
+    \fn type *Q3CacheIterator::operator++()
+
+    Prefix++ makes the iterator point to the item just after current()
+    and makes that the new current item for the iterator. If current()
+    was the last item, operator++() returns 0.
+*/
+
+/*!
+    \fn type *Q3CacheIterator::operator--()
+
+    Prefix-- makes the iterator point to the item just before
+    current() and makes that the new current item for the iterator. If
+    current() was the first item, operator--() returns 0.
+*/
+