Enum CounterSize 

pub enum CounterSize {
    FourBit,
    EightBit,
    SixteenBit,
}

Bit-width of each counter.

Trades memory against overflow headroom:

Variant	Max value	Bytes/counter	Typical use
FourBit	15	0.5	Low load, k ≤ 7
EightBit	255	1.0	Most production loads
SixteenBit	65535	2.0	High skew, λ > 0.8

Variants

FourBit

4-bit counters (max value: 15)

• Memory: 0.5 bytes per counter
• Good for: λ < 0.3, standard distributions
• Overflow risk: <10⁻⁹ for properly sized filters

EightBit

8-bit counters (max value: 255)

• Memory: 1 byte per counter
• Good for: Most production use cases
• Overflow risk: <10⁻¹⁵ for reasonable parameters

SixteenBit

16-bit counters (max value: 65535)

• Memory: 2 bytes per counter
• Good for: High-skew distributions, λ > 0.8
• Overflow risk: Negligible for all practical workloads

Implementations

impl CounterSize

pub const fn max_value(self) -> usize

Get the maximum value this counter size can represent.

pub const fn bits(self) -> usize

Get the number of bits per counter.

pub const fn bytes_per_counter(self) -> usize

Get memory bytes per counter (physical storage).

pub const fn from_max_count(max: u16) -> Self

Map a maximum counter value to the appropriate CounterSize variant.

Values 1-15 → FourBit, 16-255 → EightBit, 256+ → SixteenBit.

pub const fn mask(self) -> u64

Get bit mask for extracting counter value (for packed storage).

Trait Implementations

impl Clone for CounterSize

fn clone(&self) -> CounterSize

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for CounterSize

impl Debug for CounterSize

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for CounterSize

fn default() -> CounterSize

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for CounterSize

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for CounterSize

impl Hash for CounterSize

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for CounterSize

fn eq(&self, other: &CounterSize) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for CounterSize

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for CounterSize