q3gcache.cpp

奇趣公司比较新的qt/emd版本

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#include "q3gcache.h"
#include "q3ptrlist.h"
#include "q3dict.h"
#include "qstring.h"

/*!
  \class Q3GCache
  \reentrant
  \brief The Q3GCache class is an internal class for implementing Q3Cache
  template classes.

  \internal

  Q3GCache is a strictly internal class that acts as a base class for the
  \link collection.html collection classes\endlink Q3Cache and QIntCache.
*/


/*****************************************************************************
  Q3GCacheItem class (internal cache item)
 *****************************************************************************/

struct Q3CacheItem
{
    Q3CacheItem(void *k, Q3PtrCollection::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;
    Q3PtrCollection::Item data;
    Q3LNode     *node;
};


/*****************************************************************************
  Q3CList class (internal list of cache items)
 *****************************************************************************/

class Q3CList : private Q3PtrList<Q3CacheItem>
{
friend class Q3GCacheIterator;
friend class Q3CListIt;
public:
    Q3CList()	{}
   ~Q3CList();

    void	insert(Q3CacheItem *);		// insert according to priority
    void	insert(int, Q3CacheItem *);
    void	take(Q3CacheItem *);
    void	reference(Q3CacheItem *);

    void	setAutoDelete(bool del) { Q3PtrCollection::setAutoDelete(del); }

    bool	removeFirst()	{ return Q3PtrList<Q3CacheItem>::removeFirst(); }
    bool	removeLast()	{ return Q3PtrList<Q3CacheItem>::removeLast(); }

    Q3CacheItem *first()		{ return Q3PtrList<Q3CacheItem>::first(); }
    Q3CacheItem *last()		{ return Q3PtrList<Q3CacheItem>::last(); }
    Q3CacheItem *prev()		{ return Q3PtrList<Q3CacheItem>::prev(); }
    Q3CacheItem *next()		{ return Q3PtrList<Q3CacheItem>::next(); }

#if defined(QT_DEBUG)
    int		inserts;			// variables for statistics
    int		insertCosts;
    int		insertMisses;
    int		finds;
    int		hits;
    int		hitCosts;
    int		dumps;
    int		dumpCosts;
#endif
};


Q3CList::~Q3CList()
{
#if defined(QT_DEBUG)
    Q_ASSERT(count() == 0);
#endif
}


void Q3CList::insert(Q3CacheItem *ci)
{
    Q3CacheItem *item = first();
    while(item && item->skipPriority > ci->priority) {
	item->skipPriority--;
	item = next();
    }
    if (item)
	Q3PtrList<Q3CacheItem>::insert(at(), ci);
    else
	append(ci);
#if defined(QT_DEBUG)
    Q_ASSERT(ci->node == 0);
#endif
    ci->node = currentNode();
}

inline void Q3CList::insert(int i, Q3CacheItem *ci)
{
    Q3PtrList<Q3CacheItem>::insert(i, ci);
#if defined(QT_DEBUG)
    Q_ASSERT(ci->node == 0);
#endif
    ci->node = currentNode();
}


void Q3CList::take(Q3CacheItem *ci)
{
    if (ci) {
#if defined(QT_DEBUG)
	Q_ASSERT(ci->node != 0);
#endif
	takeNode(ci->node);
	ci->node = 0;
    }
}


inline void Q3CList::reference(Q3CacheItem *ci)
{
#if defined(QT_DEBUG)
    Q_ASSERT(ci != 0 && ci->node != 0);
#endif
    ci->skipPriority = ci->priority;
    relinkNode(ci->node);			// relink as first item
}


class Q3CListIt: public Q3PtrListIterator<Q3CacheItem>
{
public:
    Q3CListIt(const Q3CList *p): Q3PtrListIterator<Q3CacheItem>(*p) {}
    Q3CListIt(const Q3CListIt *p): Q3PtrListIterator<Q3CacheItem>(*p) {}
};


/*****************************************************************************
  Q3CDict 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 Q3GDict.
//

class Q3CDict : public Q3GDict
{
public:
    Q3CDict(uint size, uint kt, bool caseSensitive, bool copyKeys)
	: Q3GDict(size, (KeyType)kt, caseSensitive, copyKeys) {}
    ~Q3CDict();

    void clear() { Q3GDict::clear(); }

    Q3CacheItem *find_string(const QString &key) const
	{ return (Q3CacheItem*)((Q3CDict*)this)->look_string(key, 0, 0); }
    Q3CacheItem *find_ascii(const char *key) const
	{ return (Q3CacheItem*)((Q3CDict*)this)->look_ascii(key, 0, 0); }
    Q3CacheItem *find_int(long key) const
	{ return (Q3CacheItem*)((Q3CDict*)this)->look_int(key, 0, 0); }

    Q3CacheItem *take_string(const QString &key)
	{ return (Q3CacheItem*)Q3GDict::take_string(key); }
    Q3CacheItem *take_ascii(const char *key)
	{ return (Q3CacheItem*)Q3GDict::take_ascii(key); }
    Q3CacheItem *take_int(long key)
	{ return (Q3CacheItem*)Q3GDict::take_int(key); }

    bool  insert_string(const QString &key, const Q3CacheItem *ci)
	{ return Q3GDict::look_string(key,(Item)ci,1)!=0;}
    bool  insert_ascii(const char *key, const Q3CacheItem *ci)
	{ return Q3GDict::look_ascii(key,(Item)ci,1)!=0;}
    bool  insert_int(long key, const Q3CacheItem *ci)
	{ return Q3GDict::look_int(key,(Item)ci,1)!=0;}

    bool  remove_string(Q3CacheItem *item)
	{ return Q3GDict::remove_string(*((QString*)(item->key)),item); }
    bool  remove_ascii(Q3CacheItem *item)
	{ return Q3GDict::remove_ascii((const char *)item->key,item); }
    bool  remove_int(Q3CacheItem *item)
	{ return Q3GDict::remove_int((long)item->key,item);}

    void  statistics()			{ Q3GDict::statistics(); }

private:
    void deleteItem(void *item)
	{ if (del_item) { Q3CacheItem *d = (Q3CacheItem*)item; delete d; } }
};

inline Q3CDict::~Q3CDict()
{
    clear();
}

/*****************************************************************************
  Q3GDict member functions
 *****************************************************************************/

/*!
  Constructs a cache.
  The maximum cost of the cache is given by \a maxCost and the size by \a
  size. The key type is \a kt which may be \c StringKey, \c AsciiKey,
  \c IntKey or \c PtrKey. The case-sensitivity of lookups is set with
  \a caseSensitive. Keys are copied if \a copyKeys is true.
*/

Q3GCache::Q3GCache(int maxCost, uint size, KeyType kt, bool caseSensitive,
		  bool copyKeys)
{
    keytype = kt;
    lruList = new Q3CList;
    Q_CHECK_PTR(lruList);
    lruList->setAutoDelete(true);
    copyk   = ((keytype == AsciiKey) && copyKeys);
    dict    = new Q3CDict(size, kt, caseSensitive, false);
    Q_CHECK_PTR(dict);
    mCost   = maxCost;
    tCost   = 0;
#if defined(QT_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
}

/*!
  Cannot copy a cache.
*/

Q3GCache::Q3GCache(const Q3GCache &)
    : Q3PtrCollection()
{
#if defined(QT_CHECK_NULL)
    qFatal("Q3GCache::Q3GCache(Q3GCache &): Cannot copy a cache");
#endif
}

/*!
  Removes all items from the cache and destroys it.
*/

Q3GCache::~Q3GCache()
{
    clear();
    delete dict;
    delete lruList;
}

/*!
  Cannot assign a cache.
*/

Q3GCache &Q3GCache::operator=(const Q3GCache &)
{
#if defined(QT_CHECK_NULL)
    qFatal("Q3GCache::operator=: Cannot copy a cache");
#endif
    return *this;
}


/*!
  Returns the number of items in the cache.
*/

uint Q3GCache::count() const
{
    return dict->count();
}

/*!
  Returns the size of the hash array.
*/

uint Q3GCache::size() const
{
    return dict->size();
}

/*!
  \fn int Q3GCache::maxCost() const

  Returns the maximum cache cost.
*/

/*!
  \fn int Q3GCache::totalCost() const

  Returns the total cache cost.
*/

/*!
  Sets the maximum cache cost to \a maxCost.
*/

void Q3GCache::setMaxCost(int maxCost)
{
    if (maxCost < tCost) {
	if (!makeRoomFor(tCost - maxCost))	// remove excess cost
	    return;
    }
    mCost = maxCost;
}


/*!
    Inserts an item with data \a data into the cache using key \a key.
    The item has cost \a cost and priority \a priority.

  \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 Q3GCache::insert_string(const QString &key, Q3PtrCollection::Item data,
			     int cost, int priority)
{
    if (tCost + cost > mCost) {
	if (!makeRoomFor(tCost + cost - mCost, priority)) {
#if defined(QT_DEBUG)
	    lruList->insertMisses++;
#endif
	    return false;
	}
    }
#if defined(QT_DEBUG)
    Q_ASSERT(keytype == StringKey);
    lruList->inserts++;
    lruList->insertCosts += cost;
#endif
    if (priority < -32768)
	priority = -32768;
    else if (priority > 32767)
	priority = 32677;
    Q3CacheItem *ci = new Q3CacheItem(new QString(key), newItem(data),
				     cost, (short)priority);
    Q_CHECK_PTR(ci);
    lruList->insert(0, ci);
    dict->insert_string(key, ci);
    tCost += cost;
    return true;
}

bool Q3GCache::insert_other(const char *key, Q3PtrCollection::Item data,
			    int cost, int priority)
{
    if (tCost + cost > mCost) {
	if (!makeRoomFor(tCost + cost - mCost, priority)) {
#if defined(QT_DEBUG)
	    lruList->insertMisses++;
#endif
	    return false;
	}
    }
#if defined(QT_DEBUG)
    Q_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;
    Q3CacheItem *ci = new Q3CacheItem((void*)key, newItem(data), cost,
				     (short)priority);
    Q_CHECK_PTR(ci);
    lruList->insert(0, ci);
    if (keytype == AsciiKey)
	dict->insert_ascii(key, ci);
    else
	dict->insert_int((long)key, ci);
    tCost += cost;
    return true;
}


/*!
  Removes the item with key \a key from the cache. Returns true if the
  item was removed; otherwise returns false.