TrainHash Class Reference

This class handles creation of new Hash functions. More...

Inheritance diagram for TrainHash:

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List of all members.

Public Member Functions
	TrainHash (int nrOfS, int d, int nrOfW)
	~TrainHash ()
void	storeHash (FILE *file)
void	initialiseMapping ()
bool	fillMapping (int *w)
void	finalizeHash ()
int	getIndex (int *w)
Protected Member Functions
bool	traverse ()
Protected Attributes
Edge *	edges
VertexSet *	vertexSet
int	nrOfEdges

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Detailed Description

This class handles creation of new Hash functions.

The theory from: ["An Optimal Algorithm for Generating Minimal Perfect Hash Functions", Z.J. Czech, G. Havas and B.S. Majewski]. is used to construct and use the hash function. This class only loads, stores and uses the hash function. The class TrainHash is able to create new hash functions.

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Constructor & Destructor Documentation

TrainHash::TrainHash	(	int	nrOfS,
		int	d,
		int	nrOfW
	)

The constructor initialises the training parameters.

References Hash::depth, edges, Hash::gLength, Hash::gTable, VertexSet::next, nrOfEdges, Hash::nrOfSamples, Hash::random1, Hash::random2, Hash::randomTableLength, VertexSet::setNr, and vertexSet.

TrainHash::~TrainHash

(

)

The destructor deletes all claimed memory.

References edges, and vertexSet.

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Member Function Documentation

bool TrainHash::fillMapping

(

int *

w

)

Given the by initialiseMapping() random generated numbers, the mapping is filled. If the mapping is not a-cyclic (and therefor it is useless), this method will return false. If a succesfull mapping was possible, it will return true.

References Hash::depth, edges, Hash::gLength, Hash::gTable, VertexSet::next, nrOfEdges, Hash::nrOfSamples, Hash::random1, Hash::random2, Hash::randomTableLength, VertexSet::setNr, Edge::vertexID_A, Edge::vertexID_B, and vertexSet.

Referenced by Shout_lm2bin::Shout_lm2bin().

void TrainHash::finalizeHash

(

)

This method may be used when fillMapping() has returned true for all samples. It will fill the gTable table with the hash appropriate hash indices.

References Hash::gLength, Hash::gTable, VertexSet::next, traverse(), and vertexSet.

Referenced by Shout_lm2bin::Shout_lm2bin().

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int TrainHash::getIndex

(

int *

w

)

Todo:

Docs

Reimplemented from Hash.

References Hash::depth, Hash::gLength, Hash::gTable, Hash::nrOfSamples, Hash::random1, Hash::random2, and Hash::randomTableLength.

Referenced by Shout_lm2bin::Shout_lm2bin().

void TrainHash::initialiseMapping

(

)

This method deletes all existing data and will generate new random numbers for a new mapping.

References Hash::depth, Hash::gLength, Hash::gTable, VertexSet::next, nrOfEdges, Hash::random1, Hash::random2, Hash::randomTableLength, VertexSet::setNr, and vertexSet.

Referenced by Shout_lm2bin::Shout_lm2bin().

void TrainHash::storeHash

(

FILE *

file

)

Todo:

Docs

References Hash::depth, WriteFileLittleBigEndian::fwriteEndianSafe(), Hash::gLength, Hash::gTable, Hash::nrOfSamples, Hash::random1, Hash::random2, and Hash::randomTableLength.

Referenced by Shout_lm2bin::Shout_lm2bin().

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bool TrainHash::traverse

(

)

[protected]

This is a helper function for finalizeHash().

References edges, Hash::gTable, VertexSet::next, nrOfEdges, Hash::nrOfSamples, Edge::vertexID_A, Edge::vertexID_B, and vertexSet.

Referenced by finalizeHash().

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Member Data Documentation

Edge* TrainHash::edges [protected]

Referenced by fillMapping(), TrainHash(), traverse(), and ~TrainHash().

int TrainHash::nrOfEdges [protected]

Referenced by fillMapping(), initialiseMapping(), TrainHash(), and traverse().

VertexSet* TrainHash::vertexSet [protected]

Referenced by fillMapping(), finalizeHash(), initialiseMapping(), TrainHash(), traverse(), and ~TrainHash().