FX::FXLRUCache< dictbase, type > Class Template Reference

#include <FXLRUCache.h>

Inheritance diagram for FX::FXLRUCache< dictbase, type >:

List of all members.

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Detailed Description

template<class dictbase, class type>
class FX::FXLRUCache< dictbase, type >

A generic Least Recently Used (LRU) Cache (Qt compatible).

To maximise performance in modern systems which tend to have plenty of free RAM, caching can be used to speed up cases where possibly the same processing may need to be repeated. When I wrote this class, I had the Tornado kernel namespace nodes in mind, but it's generically applicable to any similar situation.

Some effort is made to replicate the Qt API for QCache, sufficiently that with suitable typedef-ing of the template parameters you can make a compatible QCache or QIntCache. However anything that FX::QDictBase can be configured with can also make a FXLRUCache.

One interesting feature of FXLRUCache is that it can handle value objects. This was done primarily with FX::FXRefingObject in mind but its use exists outside of that. To enable FXLRUCache as a value-based container, use the following form:

typedef FXLRUCache<QDict<Foo>, Foo> FooValueCache;

Leaving out the second template parameter causes FXLRUCache to use the dictionary's type which of course is always a pointer. If value-based semantics are enabled, auto-deletion becomes always enabled.

If dynamic mode is enabled, maxCost() is shifted right by FXProcess::memoryFull(). By default dynamic mode is enabled.

Definition at line 79 of file FXLRUCache.h.

Public Types
typedef dictbase::KeyType	KeyType
typedef dictbase::ItemType	FundamentalDictType
Public Member Functions
	FXLRUCache (FXuint maxCost=100, FXuint size=13, bool autodel=false)
void	setAutoDelete (bool a)
bool	dynamic () const throw ()
void	setDynamic (bool v) const throw ()
FXuint	maxCost () const throw ()
void	setMaxCost (FXuint newmax)
FXuint	totalCost () const throw ()
void	cacheStats (float *hitrate, float *churn) const throw ()
void	statistics () const
bool	insert (KeyTypeAsParam k, TypeAsParam d, FXint itemcost=1)
bool	remove (KeyTypeAsParam k)
TypeAsReturn	take (KeyTypeAsParam k)
TypeAsReturn	find (KeyTypeAsParam k, bool tofront=true) const
TypeAsReturn	operator[] (KeyTypeAsParam k) const
Protected Types
typedef FundamentalDictType *	DictType
typedef Generic::select< Generic::sameType< type, Generic::NullType >::value, DictType, type >::value	Type
typedef Generic::TraitsBasic< Type >	TypeTraits
typedef Generic::TraitsBasic< KeyType >::asROParam	KeyTypeAsParam
typedef TypeTraits::asROParam	TypeAsParam
typedef Generic::leastIndir< Type >::value *	TypeAsReturn
typedef FXLRUCacheImpl::getPtr< Type, TypeAsParam, TypeTraits::isValue >	CacheItemBase
Protected Member Functions
virtual void	purgeLFU ()
virtual void	deleteItem (DictType d)
Protected Attributes
FXuint	topmax
FXuint	maximum
FXuint	cost
bool	amDynamic
std::list< CacheItem >	cache
FX::FXLRUCache::stats_t	stats
Friends
class	FXLRUCacheIterator
Classes
struct	CacheItem
struct	stats_t

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The documentation for this class was generated from the following file:

• FXLRUCache.h

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(C) 2002-2009 Niall Douglas. Some parts (C) to assorted authors.