Class: Bloom

utils.Bloom

new Bloom(size, n, tweak, update)

Bloom Filter

Parameters:
Name Type Description
size Number

Filter size in bits.
n Number

Number of hash functions.
tweak Number

Seed value.
update Number | String

Update type.
Properties:
Name Type Description
filter Buffer
size Number
n Number
tweak Number
update Number

Update flag (see Bloom.flags).
Source:

Members

(static) flags :Number

Bloom filter update flags.

Type:
  • Number
Properties:
Name Type Description
NONE Number

Never update the filter with outpoints.
ALL Number

Always update the filter with outpoints.
PUBKEY_ONLY Number

Only update the filter with outpoints if it is "asymmetric" in terms of addresses (pubkey/multisig).
Default Value:
  • {"NONE":0,"ALL":1,"PUBKEY_ONLY":2}
Source:

(static, constant) flagsByVal :RevMap

Bloom filter update flags by value.

Type:
Source:

(static, constant) MAX_BLOOM_FILTER_SIZE :Number

Max bloom filter size.

Type:
  • Number
Default Value:
  • 36000
Source:

(static, constant) MAX_HASH_FUNCS :Number

Max number of hash functions.

Type:
  • Number
Default Value:
  • 50
Source:

Methods

(static) fromOptions(size, n, tweak, update) → {Bloom}

Instantiate bloom filter from options.

Parameters:
Name Type Description
size Number

Filter size in bits.
n Number

Number of hash functions.
tweak Number

Seed value.
update Number | String

Update type.
Source:
Returns:
Type
Bloom

(static) fromRate(items, rate, update) → {Boolean}

Create a filter from a false positive rate.

Parameters:
Name Type Description
items Number

Expected number of items.
rate Number

False positive rate (0.0-1.0).
update Number | String
Source:
Returns:
Type
Boolean
Example
Bloom.fromRate(800000, 0.0001, 'none');

(static) fromRaw(data, encnullable) → {Bloom}

Instantiate bloom filter from serialized data.

Parameters:
Name Type Attributes Description
data Buffer
enc String <nullable>
Source:
Returns:
Type
Bloom

(static) fromReader(br) → {Bloom}

Instantiate bloom filter from buffer reader.

Parameters:
Name Type Description
br BufferReader
Source:
Returns:
Type
Bloom

add(val, encnullable)

Add data to the filter.

Parameters:
Name Type Attributes Description
val Buffer | String
enc String <nullable>

Can be any of the Buffer object's encodings.
Source:

added(val, encnullable) → {Boolean}

Test whether data is present in the filter and potentially add data.

Parameters:
Name Type Attributes Description
val Buffer | String
enc String <nullable>

Can be any of the Buffer object's encodings.
Source:
Returns:

Whether data was added.

Type
Boolean

(private) fromOptions(size, n, tweak, update) → {Bloom}

Inject properties from options.

Parameters:
Name Type Description
size Number

Filter size in bits.
n Number

Number of hash functions.
tweak Number

Seed value.
update Number | String

Update type.
Source:
Returns:
Type
Bloom

(private) fromRaw(data)

Inject properties from serialized data.

Parameters:
Name Type Description
data Buffer
Source:

(private) fromReader(br)

Inject properties from buffer reader.

Parameters:
Name Type Description
br BufferReader
Source:

getSize() → {Number}

Get serialization size.

Source:
Returns:
Type
Number

hash(val, n) → {Number}

Perform the mumur3 hash on data.

Parameters:
Name Type Description
val Buffer
n Number
Source:
Returns:
Type
Number

isWithinConstraints() → {Boolean}

Ensure the filter is within the size limits.

Source:
Returns:
Type
Boolean

reset()

Reset the filter.

Source:

test(val, encnullable) → {Boolean}

Test whether data is present in the filter.

Parameters:
Name Type Attributes Description
val Buffer | String
enc String <nullable>

Can be any of the Buffer object's encodings.
Source:
Returns:
Type
Boolean

toRaw() → {Buffer}

Serialize bloom filter.

Source:
Returns:
Type
Buffer

toWriter(bw)

Write filter to buffer writer.

Parameters:
Name Type Description
bw BufferWriter
Source: