Struct smtree::index::TreeIndex

pub struct TreeIndex { /* fields omitted */ }

The index of a tree node includes the height (the root with height 0), and the path from the root to the node.

The path is a bit array, and each bit indicates which direction the child node goes.

The i-th bit being 0 indicates that the node at height i+1 in the path is the left child of the node at height i, and 1 indicates the right child.

Implementations

impl TreeIndex

pub fn new(height: usize, pos: [u8; 32]) -> TreeIndex

The constructor.

Panics if the input height exceeds MAX_HEIGHT,

pub fn from_u32(height: usize, pos: u32) -> TreeIndex

Construct TreeIndex from a u32 leaf position.

Panics if:

• height exceeds MAX_HEIGHT.
• pos is not a valid leaf position in the tree of the specified height.

pub fn from_u64(height: usize, pos: u64) -> TreeIndex

Construct TreeIndex from a u64 leaf position.

Panics if:

• height exceeds MAX_HEIGHT.
• pos is not a valid leaf position in the tree of the specified height.

pub fn zero(height: usize) -> TreeIndex

Returns a tree index of the left-most node (all bits in the path being 0) at the given height.

Panics if the input height exceeds MAX_HEIGHT.

pub fn get_height(&self) -> usize

Returns the height of a tree index.

pub fn set_height(&mut self, height: usize)

Set the height of a tree index.

Panics if the input height exceeds MAX_HEIGHT.

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

Returns the path of a tree index.

pub fn get_bit(&self, i: usize) -> u8

Get the i-th bit in the path.

Panics if queried bit index is out of the range [0, height-1].

pub fn get_last_bit(self) -> u8

Returns the last bit in the path of the tree index.

Panics if the tree index has height 0 thus the bit doesn’t exist.

pub fn get_prefix(&self, height: usize) -> TreeIndex

Returns a tree index with the input height and the path being a prefix of the self path.

Panics if the input height exceeds the height of the index.

pub fn randomize(&mut self)

Randomly samples a path.

pub fn get_lch_index(&self) -> TreeIndex

Returns the tree index of the left child of a node.

Panics if the height of the child node exceeds MAX_HEIGHT.

pub fn get_rch_index(&self) -> TreeIndex

Returns the tree index of the right child of a node.

Panics if the height of the child node exceeds MAX_HEIGHT.

pub fn get_child_index_by_dir(&self, dir: ChildDir) -> TreeIndex

Returns the tree index of the child in the input direction of a node.

Panics if the height of the child node exceeds MAX_HEIGHT.

pub fn get_sibling_index(&self) -> TreeIndex

Returns the tree index of the sibling of a node.

Panics if the queried node is the root, which means that the sibling doesn’t exist.

pub fn get_parent_index(&self) -> TreeIndex

Returns the tree index of the parent of a node.

Panics if the queried node is the root, which means that the parent doesn’t exist.

pub fn get_left_index(&self) -> Option<TreeIndex>

Returns the index on the left of self.

pub fn get_right_index(&self) -> Option<TreeIndex>

Returns the index on the right of self.

pub fn serialize(list: &[TreeIndex]) -> Vec<u8>

Encode a list of tree indexes in the format: height || path || ... || path.

If the input list is empty, return empty vector.

pub fn deserialize_as_a_unit(
    bytes: &[u8],
    num: usize,
    begin: &mut usize
) -> Result<Vec<TreeIndex>, DecodingError>

Decode input bytes (height || path || ... || path) as a list of tree indexes.

Note that bytes is the input bytes, num is the target number of tree indexes, begin is the beginning position of bytes.

If the decoded height exceeds MAX_HEIGHT, return DecodingError::ExceedMaxHeight.

If the bytes are not enough for decoding, return DecodingError::BytesNotEnough.

Trait Implementations

impl Clone for TreeIndex

fn clone(&self) -> TreeIndex

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for TreeIndex

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

Formats the value using the given formatter.

impl Default for TreeIndex

fn default() -> TreeIndex

Returns the “default value” for a type.

impl Hash for TreeIndex

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, 

Feeds a slice of this type into the given Hasher.

impl Ord for TreeIndex

If two indexes have the same height, the right-side one is greater.

If two indexes have different heights, the one with smaller height is greater, i.o.w., the higher the node in the SMT, the greater its index is.

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

This method returns an Ordering between self and other.

#[must_use]

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

Compares and returns the maximum of two values.

#[must_use]

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

Compares and returns the minimum of two values.

#[must_use]

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

Restrict a value to a certain interval.

impl PartialEq<TreeIndex> for TreeIndex

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

This method tests for self and other values to be equal, and is used by ==.

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

This method tests for !=.

impl PartialOrd<TreeIndex> for TreeIndex

If two indexes have the same height, the right-side one is greater.

If two indexes have different heights, the one with smaller height is greater, i.o.w., the higher the node in the SMT, the greater its index is.

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

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

#[must_use]

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

This method tests less than (for self and other) and is used by the < operator.

#[must_use]

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

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

#[must_use]

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

This method tests greater than (for self and other) and is used by the > operator.

#[must_use]

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

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

impl Copy for TreeIndex

impl Eq for TreeIndex

impl StructuralEq for TreeIndex

impl StructuralPartialEq for TreeIndex