Struct BaseIndex 

#[repr(transparent)]
pub struct BaseIndex(pub NonZeroU8);

A “base index” as described in Hariguchi’s ART paper; a linearized address for a prefix/octet tuple when considering the hierarchy of possible prefixes for a given 8-bit address.

Note that this only covers up to /7, fringes (/8s) would require a ninth bit, which is encoded structurally in the trie as children (vs prefixes).

Tuple Fields

0: NonZeroU8

Implementations

impl BaseIndex

pub const fn new(val: u8) -> Self

Construct a new index value.

Panics

If val is zero.

pub const fn try_new(val: u8) -> Option<Self>

Construct a new index value. Fails if the value is zero.

pub const fn get(&self) -> u8

Retrieve the value of this index in its u8 representation.

pub const fn from_prefix(octet: u8, prefix_len: u8) -> Self

Maps 8-bit prefixes to numbers. The prefixes range from 0/0 to 255/7. Return values range from 1 to 255.

Panics

If prefix_len >= 8.

pub const fn from_pfx_7(octet: u8) -> Self

Maps octet/7 prefixes to indices in 128..255. Optimization over Self::from_prefix which saves a little bit of math if the prefix length is known to be /7.

pub const fn prefix(self) -> (u8, u8)

Computes the octet and prefix len of this index. Inverse of Self::from_prefix.

pub const fn prefix_bits(&self, depth: usize) -> u8

Compute the bit position of a prefix represented by this index at a given trie depth.

pub const fn range(&self) -> RangeInclusive<u8>

Range of octets covered by this index.

This base index encodes a prefix of up to 8 bits inside a single stride (octet). This function computes the numerical start and end of the value range for that prefix.

pub const fn len(&self) -> u8

Like go’s bits.Len8: compute the number of bits required to represent this index.

pub fn cmp_rank(&self, other: &Self) -> Ordering

Sort indexes in prefix sort order.

pub const fn fmt_prefix(&self) -> impl Debug + use<>

Return a formatter for prefix notation: addr/len.

pub const fn parent(&self) -> Option<BaseIndex>

Return the direct parent of this index (if it’s not the 0/0 index).

Examples

let idx = BaseIndex::from_prefix(0, 4);
assert_eq!(idx.parent(), Some(BaseIndex::from_prefix(0, 3)));

pub const fn children(&self) -> Option<(BaseIndex, BaseIndex)>

Return the two direct children of this index (if it’s not a /7).

Examples

let idx = BaseIndex::from_prefix(0, 0);
assert_eq!(
    idx.children(),
    Some((BaseIndex::from_prefix(0, 1), BaseIndex::from_prefix(128, 1)))
);

Trait Implementations

impl Clone for BaseIndex

fn clone(&self) -> BaseIndex

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for BaseIndex

impl Debug for BaseIndex

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

Formats the value using the given formatter.

impl Display for BaseIndex

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

Formats the value using the given formatter.

impl Eq for BaseIndex

impl From<BaseIndex> for u8

fn from(value: BaseIndex) -> Self

Converts to this type from the input type.

impl From<BaseIndex> for NonZeroU8

fn from(value: BaseIndex) -> Self

Converts to this type from the input type.

impl From<NonZero<u8>> for BaseIndex

fn from(value: NonZeroU8) -> Self

Converts to this type from the input type.

impl Hash for BaseIndex

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 Ord for BaseIndex

fn cmp(&self, other: &BaseIndex) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for BaseIndex

fn eq(&self, other: &BaseIndex) -> 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 PartialOrd for BaseIndex

fn partial_cmp(&self, other: &BaseIndex) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl StructuralPartialEq for BaseIndex

impl TryFrom<u8> for BaseIndex

type Error = ()

The type returned in the event of a conversion error.

fn try_from(value: u8) -> Result<Self, Self::Error>

Performs the conversion.