MapMPHF< Key, Value, Adaptator > Class Template Reference

hash table implementation More...

#include <MapMPHF.hpp>

Inheritance diagram for MapMPHF< Key, Value, Adaptator >:

Public Types
typedef BooPHF< Key, Adaptator >	Hash

Public Member Functions
	MapMPHF ()
void	build (tools::collections::Iterable< Key > &keys, int nbThreads=1, tools::dp::IteratorListener *progress=0)
size_t	save (tools::storage::impl::Group &group, const std::string &name)
void	load (tools::storage::impl::Group &group, const std::string &name)
Value &	operator[] (const Key &key)
Value &	at (typename Hash::Code code)
Hash::Code	getCode (const Key &key)
size_t	size () const
Public Member Functions inherited from SmartPointer
void	use ()
void	forget ()
Public Member Functions inherited from ISmartPointer
virtual	~ISmartPointer ()

Additional Inherited Members
Protected Member Functions inherited from SmartPointer
	SmartPointer ()
virtual	~SmartPointer ()

Detailed Description

template<class Key, class Value, class Adaptator = AdaptatorDefault<Key>>
class gatb::core::tools::collections::impl::MapMPHF< Key, Value, Adaptator >

hash table implementation

This hash table implementation uses a minimal perfect hash function (MPHF) for identifying the keys with a unique number in [0..N-1] where N is the number of items.

Using BooPHF, the memory usage is about 3-4 bits per key.

The values can be stored in a simple vector. The keys are not stored in memory, only the mphf is needed.

Note that such an implementation can't afford to add items into the map (it's static).

Member Typedef Documentation

typedef BooPHF<Key, Adaptator> Hash

Hash type.

Constructor & Destructor Documentation

MapMPHF ( )

inline

Default constructor.

Member Function Documentation

Value& at ( typename Hash::Code  code )

inline

Get the value for a given index

Parameters

[in]

code

: the key

Returns

the value associated to the key.

void build ( tools::collections::Iterable< Key > &  keys, int  nbThreads = 1, tools::dp::IteratorListener *  progress = 0  )

inline

Build the hash function from a set of items.

Parameters

[in]	keys	: iterable over the keys of the hash table
[in]	progress	: listener called during the building of the MPHF

Hash::Code getCode ( const Key &  key )

inline

Get the hash code of the given key.

void load ( tools::storage::impl::Group &  group, const std::string &  name  )

inline

Load hash function from a Group

Parameters

[in]	group	: group where to load the MPHF from
[in]	name	: name of the MPHF

Value& operator[] ( const Key &  key )

inline

Get the value for a given key

Parameters

[in]

key

: the key

Returns

the value associated to the key.

size_t save ( tools::storage::impl::Group &  group, const std::string &  name  )

inline

Save the hash function into a Group object.

Parameters

[out]	group	: group where to save the MPHF
[in]	name	: name of the saved MPHF

Returns

the number of bytes of the saved data.

size_t size ( ) const

inline

Get the number of keys.

Returns

keys number.

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

• /builds/workspace/publish-doc-api-gitlab/gatb-core/src/gatb/tools/collections/impl/MapMPHF.hpp