Struct tari_mmr::pruned_hashset::PrunedHashSet

pub struct PrunedHashSet { /* fields omitted */ }

This is a specialised struct that represents a pruned hash set for Merkle Mountain Ranges.

The basic idea is that when adding a new hash, only the peaks to the left of the new node hierarchy are ever needed. This means that if we don't care about the data earlier than a given leaf node index, n_0, (i.e. we still have the hashes, but can't recalculate them from source), we only need to store the local peaks for the MMR at that time and we can forget about the rest. There will never be a request for a hash other than those at the peaks for the MMR with n_0 leaf nodes.

The awesome thing is that this struct can be dropped into MerkleMountainRange as a backend and it. just. works.

Trait Implementations

impl ArrayLike for PrunedHashSet

type Error = MerkleMountainRangeError

type Value = Hash

fn len(&self) -> Result<usize, Self::Error>

Returns the number of hashes stored in the backend

fn is_empty(&self) -> Result<bool, Self::Error>

Returns if empty

fn push(&mut self, item: Self::Value) -> Result<usize, Self::Error>

Store a new item and return the index of the stored item

fn get(&self, index: usize) -> Result<Option<Self::Value>, Self::Error>

Return the item at the given index

fn get_or_panic(&self, index: usize) -> Self::Value

Return the item at the given index. Use this if you know that the index is valid. Requesting a hash for an invalid index may cause the a panic

fn clear(&mut self) -> Result<(), Self::Error>

Remove all stored items from the the backend.

impl Debug for PrunedHashSet

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

Formats the value using the given formatter.

impl<'_, D, B> TryFrom<&'_ MerkleMountainRange<D, B>> for PrunedHashSet where
    D: Digest,
    B: ArrayLike<Value = Hash>, 

type Error = MerkleMountainRangeError

The type returned in the event of a conversion error.

fn try_from(base_mmr: &MerkleMountainRange<D, B>) -> Result<Self, Self::Error>

Performs the conversion.