1/// The representation of a single Merkle path.
 2use super::super::MerklePath;
 3use super::{full::high_bitmask, leaf_to_corresponding_tree};
 4
 5#[derive(Debug, Clone, PartialEq)]
 6#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 7pub struct MmrProof {
 8    /// The state of the MMR when the MmrProof was created.
 9    pub forest: usize,
10
11    /// The position of the leaf value on this MmrProof.
12    pub position: usize,
13
14    /// The Merkle opening, starting from the value's sibling up to and excluding the root of the
15    /// responsible tree.
16    pub merkle_path: MerklePath,
17}
18
19impl MmrProof {
20    /// Converts the leaf global position into a local position that can be used to verify the
21    /// merkle_path.
22    pub fn relative_pos(&self) -> usize {
23        let tree_bit = leaf_to_corresponding_tree(self.position, self.forest)
24            .expect("position must be part of the forest");
25        let forest_before = self.forest & high_bitmask(tree_bit + 1);
26        self.position - forest_before
27    }
28
29    pub fn peak_index(&self) -> usize {
30        let root = leaf_to_corresponding_tree(self.position, self.forest)
31            .expect("position must be part of the forest");
32        (self.forest.count_ones() - root - 1) as usize
33    }
34}