bloom_filter Class Reference

bloom_filter class More...

#include <bloom_filter.h>

List of all members.

Public Member Functions
	bloom_filter (uint64_t size, uint16_t hash_count, uint64_t max_elem, double max_fp)
	base constructor
	bloom_filter (string indexfilename)
	construct from file - not add to master or fold up.
	bloom_filter (uint8_t *data, uint64_t size, int id, int bf_elem_ct, uint16_t hamming)
	construct bloom filter from buffer
	~bloom_filter ()
	destructor
bool	insert_sha1 (uint32_t *sha1)
	insert SHA1 hash
bool	query_sha1 (uint32_t *sha1)
	query SHA1 hash
uint64_t	elem_count ()
	return element count
double	est_fp_rate ()
	return estimate of false positive rate
double	bits_per_elem ()
	return bits per element
string	name () const
	name associated with bloom filter
void	set_name (string name)
	change name associated with bloom filter
void	fold (uint32_t times)
	fold a large bloom filter onto itself
int	add (bloom_filter *other)
	add another same-sized bloom filter to this one
int	write_out (string filename)
	write bloom filter to .idx file
int	bloom_id ()
	id associated with bloom filter (used for grouping)

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Detailed Description

bloom_filter: a Bloom filter class.

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Constructor & Destructor Documentation

bloom_filter::bloom_filter	(	uint64_t	size,
		uint16_t	hash_count,
		uint64_t	max_elem,
		double	max_fp
	)

Create new empty bloom filter

Parameters:

size	of bloom filter
hash_count	number of hashes for each insertion or query
max_elem	max element size (0 ok)
max_fp	max false positive rate (0 ok)

bloom_filter::bloom_filter

(

string

indexfilename

)

Read bloom filter from a file

Parameters:

indexfilename

file to read

bloom_filter::bloom_filter	(	uint8_t *	data,
		uint64_t	size,
		int	id,
		int	bf_elem_ct,
		uint16_t	hamming
	)

Creates bloom filter from existing buffer of bloom filter data. Experimental: sized for sdbf 256-byte bloom filters at the moment

Parameters:

data	buffer of bloom filter data
size	of bloom filter data
id	identifier for clustering bloom filters
bf_elem_ct	# of elements in filter
hamming	weight of filter

bloom_filter::~bloom_filter

(

)

Destroys bloom filter and frees buffer

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Member Function Documentation

int bloom_filter::add

(

bloom_filter *

other

)

Adds another bloom filter to this one

Parameters:

other

bloom filter

Returns:

0 if successful 1 if not the same size

double bloom_filter::bits_per_elem

(

)

Returns bits per element in bloom filter

Returns:

estimate

uint64_t bloom_filter::elem_count

(

)

Returns number of elements present in bloom filter

Returns:

number of elements

double bloom_filter::est_fp_rate

(

)

Returns estimated false positive rate (not implemented)

Returns:

estimate

void bloom_filter::fold

(

uint32_t

times

)

Folds bloom filter by half N times by or'ing the second half of the bloom filter onto the first half.

Parameters:

times

amount of times to fold filter

bool bloom_filter::insert_sha1

(

uint32_t *

sha1

)

Inserts hash data into this bloom filter

Parameters:

sha1	buffer of sha1 hash values

Returns:

exists or not exists

string bloom_filter::name

(

)

const

Returns name associated with bloom filter

Returns:

name

bool bloom_filter::query_sha1

(

uint32_t *

sha1

)

Queries this bloom filter with hash data

Parameters:

sha1	buffer of sha1 hash values

Returns:

exists or not exists

void bloom_filter::set_name

(

string

name

)

Changes name associated with bloom filter

Parameters:

name

new name

int32_t bloom_filter::write_out

(

string

filename

)

Writes bloom filter out to a file.

Parameters:

filename

file to be written

Returns:

status -1 if compression fails, -2 if cannot open file

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

• sdbf/bloom_filter.h
• sdbf/bloom_filter.cc