/****************************************************************************
**
**
** Implementation of QGCache and QGCacheIterator classes
**
** Created : 950208
**
** Copyright (C) 1992-2000 Trolltech AS. All rights reserved.
**
** This file is part of the tools module of the Qt GUI Toolkit.
**
** This file may be distributed under the terms of the Q Public License
** as defined by Trolltech AS of Norway and appearing in the file
** LICENSE.QPL included in the packaging of this file.
**
** This file may be distributed and/or modified under the terms of the
** GNU General Public License version 2 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.
**
** Licensees holding valid Qt Enterprise Edition or Qt Professional Edition
** licenses may use this file in accordance with the Qt Commercial License
** Agreement provided with the Software.
**
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
**
** See http://www.trolltech.com/pricing.html or email sales@trolltech.com for
** information about Qt Commercial License Agreements.
** See http://www.trolltech.com/qpl/ for QPL licensing information.
** See http://www.trolltech.com/gpl/ for GPL licensing information.
**
** Contact info@trolltech.com if any conditions of this licensing are
** not clear to you.
**
**********************************************************************/
#include "qgcache.h"
#include "qinternallist.h"
#include "qdict.h"
#include "qstring.h"
// NOT REVISED
/*!
\class QGCache qgcache.h
\brief The QGCache class is an internal class for implementing QCache template classes.
QGCache is a strictly internal class that acts as a base class for the
\link collection.html collection classes\endlink QCache and QIntCache.
*/
/*****************************************************************************
QGCacheItem class (internal cache item)
*****************************************************************************/
struct QCacheItem
{
QCacheItem( void *k, QCollection::Item d, int c, short p )
: priority(p), skipPriority(p), cost(c), key(k), data(d), node(0) {}
short priority;
short skipPriority;
int cost;
void *key;
QCollection::Item data;
QLNode *node;
};
/*****************************************************************************
QCList class (internal list of cache items)
*****************************************************************************/
class QCList : private QInternalList<QCacheItem>
{
friend class QGCacheIterator;
friend class QCListIt;
public:
QCList() {}
~QCList();
void insert( QCacheItem * ); // insert according to priority
void insert( int, QCacheItem * );
void take( QCacheItem * );
void reference( QCacheItem * );
void setAutoDelete( bool del ) { QCollection::setAutoDelete(del); }
bool removeFirst() { return QInternalList<QCacheItem>::removeFirst(); }
bool removeLast() { return QInternalList<QCacheItem>::removeLast(); }
QCacheItem *first() { return QInternalList<QCacheItem>::first(); }
QCacheItem *last() { return QInternalList<QCacheItem>::last(); }
QCacheItem *prev() { return QInternalList<QCacheItem>::prev(); }
QCacheItem *next() { return QInternalList<QCacheItem>::next(); }
#if defined(DEBUG)
int inserts; // variables for statistics
int insertCosts;
int insertMisses;
int finds;
int hits;
int hitCosts;
int dumps;
int dumpCosts;
#endif
};
QCList::~QCList()
{
#if defined(DEBUG)
ASSERT( count() == 0 );
#endif
}
void QCList::insert( QCacheItem *ci )
{
QCacheItem *item = first();
while( item && item->skipPriority > ci->priority ) {
item->skipPriority--;
item = next();
}
if ( item )
QInternalList<QCacheItem>::insert( at(), ci );
else
append( ci );
#if defined(DEBUG)
ASSERT( ci->node == 0 );
#endif
ci->node = currentNode();
}
inline void QCList::insert( int i, QCacheItem *ci )
{
QInternalList<QCacheItem>::insert( i, ci );
#if defined(DEBUG)
ASSERT( ci->node == 0 );
#endif
ci->node = currentNode();
}
void QCList::take( QCacheItem *ci )
{
if ( ci ) {
#if defined(DEBUG)
ASSERT( ci->node != 0 );
#endif
takeNode( ci->node );
ci->node = 0;
}
}
inline void QCList::reference( QCacheItem *ci )
{
#if defined(DEBUG)
ASSERT( ci != 0 && ci->node != 0 );
#endif
ci->skipPriority = ci->priority;
relinkNode( ci->node ); // relink as first item
}
class QCListIt: public QInternalListIterator<QCacheItem>
{
public:
QCListIt( const QCList *p ): QInternalListIterator<QCacheItem>( *p ) {}
QCListIt( const QCListIt *p ): QInternalListIterator<QCacheItem>( *p ) {}
};
/*****************************************************************************
QCDict class (internal dictionary of cache items)
*****************************************************************************/
//
// Since we need to decide if the dictionary should use an int or const
// char * key (the "bool trivial" argument in the constructor below)
// we cannot use the macro/template dict, but inherit directly from QGDict.
//
class QCDict : public QGDict
{
public:
QCDict( uint size, uint kt, bool caseSensitive, bool copyKeys )
: QGDict( size, (KeyType)kt, caseSensitive, copyKeys ) {}
QCacheItem *find_string(const QString &key) const
{ return (QCacheItem*)((QCDict*)this)->look_string(key, 0, 0); }
QCacheItem *find_ascii(const char *key) const
{ return (QCacheItem*)((QCDict*)this)->look_ascii(key, 0, 0); }
QCacheItem *find_int(long key) const
{ return (QCacheItem*)((QCDict*)this)->look_int(key, 0, 0); }
QCacheItem *take_string(const QString &key)
{ return (QCacheItem*)QGDict::take_string(key); }
QCacheItem *take_ascii(const char *key)
{ return (QCacheItem*)QGDict::take_ascii(key); }
QCacheItem *take_int(long key)
{ return (QCacheItem*)QGDict::take_int(key); }
bool insert_string( const QString &key, const QCacheItem *ci )
{ return QGDict::look_string(key,(Item)ci,1)!=0;}
bool insert_ascii( const char *key, const QCacheItem *ci )
{ return QGDict::look_ascii(key,(Item)ci,1)!=0;}
bool insert_int( long key, const QCacheItem *ci )
{ return QGDict::look_int(key,(Item)ci,1)!=0;}
bool remove_string( QCacheItem *item )
{ return QGDict::remove_string(*((QString*)(item->key)),item); }
bool remove_ascii( QCacheItem *item )
{ return QGDict::remove_ascii((const char *)item->key,item); }
bool remove_int( QCacheItem *item )
{ return QGDict::remove_int((intptr_t)item->key,item);}
void statistics() { QGDict::statistics(); }
};
/*****************************************************************************
QGDict member functions
*****************************************************************************/
/*!
\internal
Constructs a cache.
*/
QGCache::QGCache( int maxCost, uint size, KeyType kt, bool caseSensitive,
bool copyKeys )
{
keytype = kt;
lruList = new QCList;
CHECK_PTR( lruList );
lruList->setAutoDelete( TRUE );
copyk = ((keytype == AsciiKey) && copyKeys);
dict = new QCDict( size, kt, caseSensitive, FALSE );
CHECK_PTR( dict );
mCost = maxCost;
tCost = 0;
#if defined(DEBUG)
lruList->inserts = 0;
lruList->insertCosts = 0;
lruList->insertMisses = 0;
lruList->finds = 0;
lruList->hits = 0;
lruList->hitCosts = 0;
lruList->dumps = 0;
lruList->dumpCosts = 0;
#endif
}
/*!
\internal
Cannot copy a cache.
*/
QGCache::QGCache( const QGCache & )
: QCollection()
{
#if defined(CHECK_NULL)
qFatal( "QGCache::QGCache(QGCache &): Cannot copy a cache" );
#endif
}
/*!
\internal
Removes all items from the cache and destroys it.
*/
QGCache::~QGCache()
{
clear(); // delete everything first
delete dict;
delete lruList;
}
/*!
\internal
Cannot assign a cache.
*/
QGCache &QGCache::operator=( const QGCache & )
{
#if defined(CHECK_NULL)
qFatal( "QGCache::operator=: Cannot copy a cache" );
#endif
return *this; // satisfy the compiler
}
/*!
\fn uint QGCache::count() const
\internal
Returns the number of items in the cache.
*/
/*!
\fn uint QGCache::size() const
\internal
Returns the size of the hash array.
*/
/*!
\fn int QGCache::maxCost() const
\internal
Returns the maximum cache cost.
*/
/*!
\fn int QGCache::totalCost() const
\internal
Returns the total cache cost.
*/
/*!
\internal
Sets the maximum cache cost.
*/
void QGCache::setMaxCost( int maxCost )
{
if ( maxCost < tCost ) {
if ( !makeRoomFor(tCost - maxCost) ) // remove excess cost
return;
}
mCost = maxCost;
}
/*!
\internal
Inserts an item into the cache.
\warning If this function returns FALSE, you must delete \a data
yourself. Additionally, be very careful about using \a data after
calling this function, as any other insertions into the cache, from
anywhere in the application, or within Qt itself, could cause the
data to be discarded from the cache, and the pointer to become
invalid.
*/
bool QGCache::insert_string( const QString &key, QCollection::Item data,
int cost, int priority)
{
if ( tCost + cost > mCost ) {
if ( !makeRoomFor(tCost + cost - mCost, priority) ) {
#if defined(DEBUG)
lruList->insertMisses++;
#endif
return FALSE;
}
}
#if defined(DEBUG)
ASSERT( keytype == StringKey );
lruList->inserts++;
lruList->insertCosts += cost;
#endif
if ( priority < -32768 )
priority = -32768;
else if ( priority > 32767 )
priority = 32677;
QCacheItem *ci = new QCacheItem( new QString(key), newItem(data),
cost, (short)priority );
CHECK_PTR( ci );
lruList->insert( 0, ci );
dict->insert_string( key, ci );
tCost += cost;
return TRUE;
}
/*! \internal */
bool QGCache::insert_other( const char *key, QCollection::Item data,
int cost, int priority)
{
if ( tCost + cost > mCost ) {
if ( !makeRoomFor(tCost + cost - mCost, priority) ) {
#if defined(DEBUG)
lruList->insertMisses++;
#endif
return FALSE;
}
}
#if defined(DEBUG)
ASSERT( keytype != StringKey );
lruList->inserts++;
lruList->insertCosts += cost;
#endif
if ( keytype == AsciiKey && copyk )
key = qstrdup( key );
if ( priority < -32768 )
priority = -32768;
else if ( priority > 32767 )
priority = 32677;
QCacheItem *ci = new QCacheItem( (void*)key, newItem(data), cost,
(short)priority );
CHECK_PTR( ci );
lruList->insert( 0, ci );
if ( keytype == AsciiKey )
dict->insert_ascii( key, ci );
else
dict->insert_int( (intptr_t)key, ci );
tCost += cost;
return TRUE;
}
/*!
\internal
Removes an item from the cache.
*/
bool QGCache::remove_string( const QString &key )
{
Item d = take_string( key );
if ( d )
deleteItem( d );
return d != 0;
}
/*! \internal */
bool QGCache::remove_other( const char *key )
{
Item d = take_other( key );
if ( d )
deleteItem( d );
return d != 0;
}
/*!
\internal
Takes an item out of the cache (no delete).
*/
QCollection::Item QGCache::take_string( const QString &key )
{
QCacheItem *ci = dict->take_string( key ); // take from dict
Item d;
if ( ci ) {
d = ci->data;
tCost -= ci->cost;
lruList->take( ci ); // take from list
delete (QString*)ci->key;
delete ci;
} else {
d = 0;
}
return d;
}
/*!
\internal
Takes an item out of the cache (no delete).
*/
QCollection::Item QGCache::take_other( const char *key )
{
QCacheItem *ci;
if ( keytype == AsciiKey )
ci = dict->take_ascii( key );
else
ci = dict->take_int( (intptr_t)key );
Item d;
if ( ci ) {
d = ci->data;
tCost -= ci->cost;
lruList->take( ci ); // take from list
if ( copyk )
delete [] (char *)ci->key;
delete ci;
} else {
d = 0;
}
return d;
}
/*!
\internal
Clears the cache.
*/
void QGCache::clear()
{
QCacheItem *ci;
while ( (ci = lruList->first()) ) {
switch ( keytype ) {
case StringKey:
dict->remove_string( ci );
delete (QString*)ci->key;
break;
case AsciiKey:
dict->remove_ascii( ci );
if ( copyk )
delete [] (char*)ci->key;
break;
case IntKey:
dict->remove_int( ci );
break;
case PtrKey: // unused
break;
}
deleteItem( ci->data ); // delete data
lruList->removeFirst(); // remove from list
}
tCost = 0;
}
/*!
\internal
Finds an item in the cache.
*/
QCollection::Item QGCache::find_string( const QString &key, bool ref ) const
{
QCacheItem *ci = dict->find_string( key );
#if defined(DEBUG)
lruList->finds++;
#endif
if ( ci ) {
#if defined(DEBUG)
lruList->hits++;
lruList->hitCosts += ci->cost;
#endif
if ( ref )
lruList->reference( ci );
return ci->data;
}
return 0;
}
/*!
\internal
Finds an item in the cache.
*/
QCollection::Item QGCache::find_other( const char *key, bool ref ) const
{
QCacheItem *ci = keytype == AsciiKey ? dict->find_ascii(key)
: dict->find_int((intptr_t)key);
#if defined(DEBUG)
lruList->finds++;
#endif
if ( ci ) {
#if defined(DEBUG)
lruList->hits++;
lruList->hitCosts += ci->cost;
#endif
if ( ref )
lruList->reference( ci );
return ci->data;
}
return 0;
}
/*!
\internal
Allocates cache space for one or more items.
*/
bool QGCache::makeRoomFor( int cost, int priority )
{
if ( cost > mCost ) // cannot make room for more
return FALSE; // than maximum cost
if ( priority == -1 )
priority = 32767;
register QCacheItem *ci = lruList->last();
int cntCost = 0;
int dumps = 0; // number of items to dump
while ( cntCost < cost && ci && ci->skipPriority <= priority ) {
cntCost += ci->cost;
ci = lruList->prev();
dumps++;
}
if ( cntCost < cost ) // can enough cost be dumped?
return FALSE; // no
#if defined(DEBUG)
ASSERT( dumps > 0 );
#endif
while ( dumps-- ) {
ci = lruList->last();
#if defined(DEBUG)
lruList->dumps++;
lruList->dumpCosts += ci->cost;
#endif
switch ( keytype ) {
case StringKey:
dict->remove_string( ci );
delete (QString*)ci->key;
break;
case AsciiKey:
dict->remove_ascii( ci );
if ( copyk )
delete [] (char *)ci->key;
break;
case IntKey:
dict->remove_int( ci );
break;
case PtrKey: // unused
break;
}
deleteItem( ci->data ); // delete data
lruList->removeLast(); // remove from list
}
tCost -= cntCost;
return TRUE;
}
/*!
\internal
Outputs debug statistics.
*/
void QGCache::statistics() const
{
#if defined(DEBUG)
QString line;
line.fill( '*', 80 );
qDebug( "%s",line.ascii() );
qDebug( "CACHE STATISTICS:" );
qDebug( "cache contains %d item%s, with a total cost of %d",
count(), count() != 1 ? "s" : "", tCost );
qDebug( "maximum cost is %d, cache is %d%% full.",
mCost, (200*tCost + mCost) / (mCost*2) );
qDebug( "find() has been called %d time%s",
lruList->finds, lruList->finds != 1 ? "s" : "" );
qDebug( "%d of these were hits, items found had a total cost of %d.",
lruList->hits,lruList->hitCosts );
qDebug( "%d item%s %s been inserted with a total cost of %d.",
lruList->inserts,lruList->inserts != 1 ? "s" : "",
lruList->inserts != 1 ? "have" : "has", lruList->insertCosts );
qDebug( "%d item%s %s too large or had too low priority to be inserted.",
lruList->insertMisses, lruList->insertMisses != 1 ? "s" : "",
lruList->insertMisses != 1 ? "were" : "was" );
qDebug( "%d item%s %s been thrown away with a total cost of %d.",
lruList->dumps, lruList->dumps != 1 ? "s" : "",
lruList->dumps != 1 ? "have" : "has", lruList->dumpCosts );
qDebug( "Statistics from internal dictionary class:" );
dict->statistics();
qDebug( "%s",line.ascii() );
#endif
}
int QGCache::hits() const
{
return lruList->hits;
}
int QGCache::misses() const
{
return lruList->finds - lruList->hits;
}
/*****************************************************************************
QGCacheIterator member functions
*****************************************************************************/
/*!
\class QGCacheIterator qgcache.h
\brief An internal class for implementing QCacheIterator and QIntCacheIterator.
QGCacheIterator is a strictly internal class that does the heavy work for
QCacheIterator and QIntCacheIterator.
*/
/*!
\internal
Constructs an iterator that operates on the cache \e c.
*/
QGCacheIterator::QGCacheIterator( const QGCache &c )
{
it = new QCListIt( c.lruList );
#if defined(DEBUG)
ASSERT( it != 0 );
#endif
}
/*!
\internal
Constructs an iterator that operates on the same cache as \e ci.
*/
QGCacheIterator::QGCacheIterator( const QGCacheIterator &ci )
{
it = new QCListIt( ci.it );
#if defined(DEBUG)
ASSERT( it != 0 );
#endif
}
/*!
\internal
Destroys the iterator.
*/
QGCacheIterator::~QGCacheIterator()
{
delete it;
}
/*!
\internal
Assigns the iterator \e ci to this cache iterator.
*/
QGCacheIterator &QGCacheIterator::operator=( const QGCacheIterator &ci )
{
*it = *ci.it;
return *this;
}
/*!
\internal
Returns the number of items in the cache.
*/
uint QGCacheIterator::count() const
{
return it->count();
}
/*!
\internal
Returns TRUE if the iterator points to the first item.
*/
bool QGCacheIterator::atFirst() const
{
return it->atFirst();
}
/*!
\internal
Returns TRUE if the iterator points to the last item.
*/
bool QGCacheIterator::atLast() const
{
return it->atLast();
}
/*!
\internal
Sets the list iterator to point to the first item in the cache.
*/
QCollection::Item QGCacheIterator::toFirst()
{
QCacheItem *item = it->toFirst();
return item ? item->data : 0;
}
/*!
\internal
Sets the list iterator to point to the last item in the cache.
*/
QCollection::Item QGCacheIterator::toLast()
{
QCacheItem *item = it->toLast();
return item ? item->data : 0;
}
/*!
\internal
Returns the current item.
*/
QCollection::Item QGCacheIterator::get() const
{
QCacheItem *item = it->current();
return item ? item->data : 0;
}
/*!
\internal
Returns the key of the current item.
*/
QString QGCacheIterator::getKeyString() const
{
QCacheItem *item = it->current();
return item ? *((QString*)item->key) : QString::null;
}
/*!
\internal
Returns the key of the current item, as a \0-terminated C string.
*/
const char *QGCacheIterator::getKeyAscii() const
{
QCacheItem *item = it->current();
return item ? (const char *)item->key : 0;
}
/*!
\internal
Returns the key of the current item, as a long.
*/
intptr_t QGCacheIterator::getKeyInt() const
{
QCacheItem *item = it->current();
return item ? (intptr_t)item->key : 0;
}
/*!
\internal
Moves to the next item (postfix).
*/
QCollection::Item QGCacheIterator::operator()()
{
QCacheItem *item = it->operator()();
return item ? item->data : 0;
}
/*!
\internal
Moves to the next item (prefix).
*/
QCollection::Item QGCacheIterator::operator++()
{
QCacheItem *item = it->operator++();
return item ? item->data : 0;
}
/*!
\internal
Moves \e jumps positions forward.
*/
QCollection::Item QGCacheIterator::operator+=( uint jump )
{
QCacheItem *item = it->operator+=(jump);
return item ? item->data : 0;
}
/*!
\internal
Moves to the previous item (prefix).
*/
QCollection::Item QGCacheIterator::operator--()
{
QCacheItem *item = it->operator--();
return item ? item->data : 0;
}
/*!
\internal
Moves \e jumps positions backward.
*/
QCollection::Item QGCacheIterator::operator-=( uint jump )
{
QCacheItem *item = it->operator-=(jump);
return item ? item->data : 0;
}