Provides an in-memory storage with Least Frequently Used (LFU) replacement policy. More...

#include <ndn-cxx/ims/in-memory-storage-lfu.hpp>

Inheritance diagram for ndn::InMemoryStorageLfu:

Collaboration diagram for ndn::InMemoryStorageLfu:

Public Types
using	Cache = boost::multi_index_container< InMemoryStorageEntry *, boost::multi_index::indexed_by< boost::multi_index::ordered_unique< boost::multi_index::tag< byFullName >, boost::multi_index::const_mem_fun< InMemoryStorageEntry, const Name &, &InMemoryStorageEntry::getFullName >, std::less< Name > > > >

Public Member Functions
	InMemoryStorageLfu (boost::asio::io_context &ioCtx, size_t limit=16)

	InMemoryStorageLfu (size_t limit=16)

InMemoryStorage::const_iterator	begin () const
	Returns begin iterator of the in-memory storage ordering by name with digest. More...

InMemoryStorage::const_iterator	end () const
	Returns end iterator of the in-memory storage ordering by name with digest. More...

void	erase (const Name &prefix, const bool isPrefix=true)
	Deletes in-memory storage entry by prefix by default. More...

shared_ptr< const Data >	find (const Interest &interest)
	Finds the best match Data for an Interest. More...

shared_ptr< const Data >	find (const Name &name)
	Finds the best match Data for a Name with or without implicit digest. More...

size_t	getLimit () const

void	insert (const Data &data, const time::milliseconds &mustBeFreshProcessingWindow=INFINITE_WINDOW)
	Inserts a Data packet. More...

size_t	size () const

Static Public Attributes
static constexpr time::milliseconds	INFINITE_WINDOW = -1_ms

Protected Member Functions
void	afterAccess (InMemoryStorageEntry *entry) override
	Update the entry when the entry is returned by the find() function, increment the frequency according to LFU. More...

void	afterInsert (InMemoryStorageEntry *entry) override
	Update the entry after a entry is successfully inserted, add it to the cleanupIndex. More...

void	beforeErase (InMemoryStorageEntry *entry) override
	Update the entry or other data structures before a entry is successfully erased, erase it from the cleanupIndex. More...

void	eraseImpl (const Name &name)
	Deletes in-memory storage entries by the Name with implicit digest. More...

bool	evictItem () override
	Removes one Data packet from in-memory storage based on LFU, i.e. More...

size_t	getCapacity () const
	Returns current capacity of in-memory storage (in packets). More...

bool	isFull () const
	Returns true if the in-memory storage uses up the current capacity, false otherwise. More...

void	printCache (std::ostream &os) const
	Prints contents of the in-memory storage. More...

void	setCapacity (size_t nMaxPackets)
	Sets current capacity of in-memory storage (in packets). More...

Detailed Description

Provides an in-memory storage with Least Frequently Used (LFU) replacement policy.

Note: The frequency right now is usage count.

Definition at line 39 of file in-memory-storage-lfu.hpp.

Member Typedef Documentation

◆ Cache

using ndn::InMemoryStorage::Cache = boost::multi_index_container< InMemoryStorageEntry*, boost::multi_index::indexed_by< boost::multi_index::ordered_unique< boost::multi_index::tag<byFullName>, boost::multi_index::const_mem_fun<InMemoryStorageEntry, const Name&, &InMemoryStorageEntry::getFullName>, std::less<Name> > > >

inherited

Definition at line 47 of file in-memory-storage.hpp.

Constructor & Destructor Documentation

◆ InMemoryStorageLfu() [1/2]

ndn::InMemoryStorageLfu::InMemoryStorageLfu ( size_t limit = 16 )

explicit

Definition at line 26 of file in-memory-storage-lfu.cpp.

◆ InMemoryStorageLfu() [2/2]

ndn::InMemoryStorageLfu::InMemoryStorageLfu	(	boost::asio::io_context &	ioCtx,
		size_t	limit = `16`
	)

explicit

Definition at line 31 of file in-memory-storage-lfu.cpp.

Member Function Documentation

◆ afterAccess()

void ndn::InMemoryStorageLfu::afterAccess ( InMemoryStorageEntry * entry )

overrideprotectedvirtual

Update the entry when the entry is returned by the find() function, increment the frequency according to LFU.

Reimplemented from ndn::InMemoryStorage.

Definition at line 68 of file in-memory-storage-lfu.cpp.

◆ afterInsert()

void ndn::InMemoryStorageLfu::afterInsert ( InMemoryStorageEntry * entry )

overrideprotectedvirtual

Update the entry after a entry is successfully inserted, add it to the cleanupIndex.

Reimplemented from ndn::InMemoryStorage.

Definition at line 37 of file in-memory-storage-lfu.cpp.

◆ beforeErase()

void ndn::InMemoryStorageLfu::beforeErase ( InMemoryStorageEntry * entry )

overrideprotectedvirtual

Update the entry or other data structures before a entry is successfully erased, erase it from the cleanupIndex.

Reimplemented from ndn::InMemoryStorage.

Definition at line 60 of file in-memory-storage-lfu.cpp.

◆ begin()

InMemoryStorage::const_iterator ndn::InMemoryStorage::begin ( ) const

inherited

Returns begin iterator of the in-memory storage ordering by name with digest.

Returns: const_iterator pointing to the beginning of the m_cache

Definition at line 313 of file in-memory-storage.cpp.

◆ end()

InMemoryStorage::const_iterator ndn::InMemoryStorage::end ( ) const

inherited

Returns end iterator of the in-memory storage ordering by name with digest.

Returns: const_iterator pointing to the end of the m_cache

Definition at line 320 of file in-memory-storage.cpp.

◆ erase()

void ndn::InMemoryStorage::erase	(	const Name &	prefix,
		const bool	isPrefix = `true`
	)

inherited

Deletes in-memory storage entry by prefix by default.

Parameters

prefix	Exact name of a prefix of the data to remove
isPrefix	If false, the function will only delete the entry completely matched with the prefix according to canonical ordering. For this case, user should substitute the prefix with full name.

Warning: Please do not use this function directly in any derived class to erase an entry from the cache, use eraseImpl() instead.

Note: It will invoke beforeErase(shared_ptr<InMemoryStorageEntry>).

Definition at line 278 of file in-memory-storage.cpp.

◆ eraseImpl()

void ndn::InMemoryStorage::eraseImpl ( const Name & name )

protectedinherited

Deletes in-memory storage entries by the Name with implicit digest.

This is the function one should use to erase entry in the cache in derived class. It won't invoke beforeErase(shared_ptr<Entry>).

Definition at line 303 of file in-memory-storage.cpp.

◆ evictItem()

bool ndn::InMemoryStorageLfu::evictItem ( )

overrideprotectedvirtual

Removes one Data packet from in-memory storage based on LFU, i.e.

evict the least frequently accessed Data packet

Returns: { whether the Data was removed }

Implements ndn::InMemoryStorage.

Definition at line 47 of file in-memory-storage-lfu.cpp.

◆ find() [1/2]

shared_ptr< const Data > ndn::InMemoryStorage::find ( const Interest & interest )

inherited

Finds the best match Data for an Interest.

Note: It will invoke afterAccess(shared_ptr<InMemoryStorageEntry>). As currently it is impossible to determine whether a Name contains implicit digest or not, therefore this find function is not able to locate a packet according to an interest( including implicit digest) whose name is not the full name of the data matching the implicit digest.

Returns: the best match, if any; otherwise a null shared_ptr

Definition at line 174 of file in-memory-storage.cpp.

◆ find() [2/2]

shared_ptr< const Data > ndn::InMemoryStorage::find ( const Name & name )

inherited

Finds the best match Data for a Name with or without implicit digest.

If packets with the same name but different digests exist and the Name supplied is the one without implicit digest, a packet will be arbitrarily chosen to return.

Note: It will invoke afterAccess(shared_ptr<InMemoryStorageEntry>).

Returns: the one matched the Name; otherwise a null shared_ptr

Definition at line 155 of file in-memory-storage.cpp.

◆ getCapacity()

size_t ndn::InMemoryStorage::getCapacity ( ) const

inlineprotectedinherited

Returns current capacity of in-memory storage (in packets).

Returns: number of packets that can be stored in application cache

Definition at line 261 of file in-memory-storage.hpp.

◆ getLimit()

size_t ndn::InMemoryStorage::getLimit ( ) const

inlineinherited

Returns: Maximum number of packets that can be allowed to store in in-memory storage.

Definition at line 193 of file in-memory-storage.hpp.

◆ insert()

void ndn::InMemoryStorage::insert	(	const Data &	data,
		const time::milliseconds &	mustBeFreshProcessingWindow = `INFINITE_WINDOW`
	)

inherited

Inserts a Data packet.

Parameters

data	the packet to insert, must be signed and have wire encoding
mustBeFreshProcessingWindow	Beyond this time period, the inserted data can only be used to answer interest without MustBeFresh. The value of mustBeFreshProcessingWindow is an application decision and it may or may not correspond to FreshnessPeriod.

Note: InMemoryStorage does not use the inserted data packet's FreshnessPeriod value. If the packet needs to be marked "stale" after application-defined period of time, the application must supply proper mustBeFreshProcessingWindow value.; Packets are considered duplicate if the name with implicit digest matches. The new Data packet with the identical name, but a different payload will be placed in the in-memory storage.; It will invoke afterInsert(shared_ptr<InMemoryStorageEntry>).

Definition at line 118 of file in-memory-storage.cpp.

◆ isFull()

bool ndn::InMemoryStorage::isFull ( ) const

inlineprotectedinherited

Returns true if the in-memory storage uses up the current capacity, false otherwise.

Definition at line 269 of file in-memory-storage.hpp.

◆ printCache()

void ndn::InMemoryStorage::printCache ( std::ostream & os ) const

protectedinherited

Prints contents of the in-memory storage.

Definition at line 342 of file in-memory-storage.cpp.

◆ setCapacity()

void ndn::InMemoryStorage::setCapacity ( size_t nMaxPackets )

protectedinherited

Sets current capacity of in-memory storage (in packets).

Definition at line 88 of file in-memory-storage.cpp.

◆ size()

size_t ndn::InMemoryStorage::size ( ) const

inlineinherited

Returns: Number of packets stored in in-memory storage.

Definition at line 201 of file in-memory-storage.hpp.

Member Data Documentation

◆ INFINITE_WINDOW

constexpr time::milliseconds ndn::InMemoryStorage::INFINITE_WINDOW = -1_ms

staticconstexprinherited

Definition at line 328 of file in-memory-storage.hpp.

ndn-cxx: NDN C++ library with eXperimental eXtensions 0.9.0-4-g51974f6b documentation

Public Types

Public Member Functions

Static Public Attributes

Protected Member Functions

Detailed Description

Member Typedef Documentation

◆ Cache

Constructor & Destructor Documentation

◆ InMemoryStorageLfu() [1/2]

◆ InMemoryStorageLfu() [2/2]

Member Function Documentation

◆ afterAccess()

◆ afterInsert()

◆ beforeErase()

◆ begin()

◆ end()

◆ erase()

◆ eraseImpl()

◆ evictItem()

◆ find() [1/2]

◆ find() [2/2]

◆ getCapacity()

◆ getLimit()

◆ insert()

◆ isFull()

◆ printCache()

◆ setCapacity()

◆ size()

Member Data Documentation

◆ INFINITE_WINDOW