Struct MerkleCap 

pub struct MerkleCap<F, Digest> { /* private fields */ }

The Merkle cap of height h of a Merkle tree is the h-th layer (from the root) of the tree. It can be used in place of the root to verify Merkle paths, which are h elements shorter.

A cap of height 0 contains a single element (the root), while a cap of height h contains 2^h elements. The Digest type is the full digest (e.g. [W; DIGEST_ELEMS]).

The root count is always a power of two.

A cap is one full layer of a binary tree, so a layer at depth h holds 2^h digests.

The height is recovered as log_2 of the root count, which exists only for a power of two.

Every path that builds a cap enforces this, including the one that reads it off the wire.

Implementations

impl<F, Digest> MerkleCap<F, Digest>

pub fn new(cap: Vec<Digest>) -> Self

Wrap one full layer of digests as a cap.

Panics

Panics when the number of digests is not a power of two.

pub const fn num_roots(&self) -> usize

Returns the number of digests in the cap.

pub const fn height(&self) -> usize

Returns the height of the cap (log2 of the number of elements). A cap with 1 element has height 0, a cap with 2 elements has height 1, etc.

pub fn roots(&self) -> &[Digest]

Returns a reference to the underlying slice of digests.

pub fn into_roots(self) -> Vec<Digest>

Flattens the cap into a single vector of digest words.

Trait Implementations

impl<F, Digest> AsRef<[Digest]> for MerkleCap<F, Digest>

fn as_ref(&self) -> &[Digest]

Converts this type into a shared reference of the (usually inferred) input type.

impl<F, Digest> Borrow<[Digest]> for MerkleCap<F, Digest>

fn borrow(&self) -> &[Digest]

Immutably borrows from an owned value.

impl<F: Clone, Digest: Clone> Clone for MerkleCap<F, Digest>

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<F: Debug, Digest: Debug> Debug for MerkleCap<F, Digest>

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

Formats the value using the given formatter.

impl<'de, F, Digest: Deserialize<'de>> Deserialize<'de> for MerkleCap<F, Digest>

fn deserialize<D: Deserializer<'de>>(deserializer: D) -> Result<Self, D::Error>

Errors

Returns an error when the root count is not a power of two.

Such a count has no base-two logarithm, so the cap would have no height.

Untrusted bytes are the only route by which such a cap could reach a verifier.

impl<F: Eq, Digest: Eq> Eq for MerkleCap<F, Digest>

impl<F, W, const N: usize> From<Hash<F, W, N>> for MerkleCap<F, [W; N]>

fn from(hash: Hash<F, W, N>) -> Self

Converts to this type from the input type.

impl<F, Digest> From<Vec<Digest>> for MerkleCap<F, Digest>

fn from(cap: Vec<Digest>) -> Self

Converts to this type from the input type.

impl<F, Digest> Index<usize> for MerkleCap<F, Digest>

type Output = Digest

The returned type after indexing.

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

Performs the indexing (container[index]) operation.

impl<F, Digest> IntoIterator for MerkleCap<F, Digest>

type Item = Digest

The type of the elements being iterated over.

type IntoIter = IntoIter<Digest>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<F: PartialEq, Digest: PartialEq> PartialEq for MerkleCap<F, Digest>

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

Equality operator ==.

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

Inequality operator !=.

impl<F, Digest> Serialize for MerkleCap<F, Digest>

where Digest: Serialize,

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

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl<F: PartialEq, Digest: PartialEq> StructuralPartialEq for MerkleCap<F, Digest>