Struct PageId 

pub struct PageId { /* private fields */ }

A unique ID for a page.

Ordering

Page IDs are ordered “depth-first” such that:

• An ID is always less than its child IDs.
• An ID’s child IDs are ordered ascending by child index.
• An ID’s child IDs are always less than any sibling IDs to the right of the ID.

This property lets us refer to sub-trees cleanly with simple ordering statements.

Implementations

impl PageId

pub fn decode(bytes: [u8; 32]) -> Result<Self, InvalidPageIdBytes>

Decode a page ID from its disambiguated representation.

This can fall out of bounds.

pub fn child_index_at_level(&self, depth: usize) -> ChildPageIndex

Get the child index of the page at the given depth.

This panics if the depth of the page is not at least depth + 1.

pub fn encode(&self) -> [u8; 32]

Encode this page ID to its disambiguated (fixed-width) representation.

pub fn length_dependent_encoding(&self) -> &[u8]

Get a length-dependent representation of the page id.

pub fn depth(&self) -> usize

Get the depth of the page ID. The depth of the ROOT_PAGE_ID is 0.

pub fn child_page_id( &self, child_index: ChildPageIndex, ) -> Result<Self, ChildPageIdError>

Construct the Child PageId given the previous PageId and the child index.

Child index must be a 6 bit integer, two most significant bits must be zero. Passed PageId must be a valid PageId and be located in a layer below 42 otherwise PageIdOverflow will be returned.

pub fn parent_page_id(&self) -> Self

Extract the Parent PageId given a PageId.

If the provided PageId is the one pointing to the root, then itself is returned.

pub fn is_descendant_of(&self, other: &PageId) -> bool

Whether this page is a descendant of the other.

pub fn max_descendant(&self) -> PageId

Get the maximum descendant of this page.

pub fn min_key_path(&self) -> KeyPath

Get the minimum key-path which could land in this page.

pub fn max_key_path(&self) -> KeyPath

Get the maximum key-path which could land in this page.

Trait Implementations

impl Clone for PageId

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for PageId

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

Formats the value using the given formatter.

impl Hash for PageId

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 PageId

fn cmp(&self, other: &PageId) -> 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 PageId

fn eq(&self, other: &PageId) -> 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 PageId

fn partial_cmp(&self, other: &PageId) -> 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 Eq for PageId

impl StructuralPartialEq for PageId