fix: bugfix in PartialMmr apply delta

src/merkle/mmr/inorder.rs

@@ -16,15 +16,17 @@ pub struct InOrderIndex {
 }
 
 impl InOrderIndex {
-    /// Constructor for a new [InOrderIndex].
+    // CONSTRUCTORS
+    // --------------------------------------------------------------------------------------------
+
+    /// Returns a new [InOrderIndex] instantiated from the provided value.
     pub fn new(idx: NonZeroUsize) -> InOrderIndex {
         InOrderIndex { idx: idx.get() }
     }
 
-    /// Constructs an index from a leaf position.
-    ///
-    /// Panics:
+    /// Return a new [InOrderIndex] instantiated from the specified leaf position.
     ///
+    /// # Panics:
     /// If `leaf` is higher than or equal to `usize::MAX / 2`.
     pub fn from_leaf_pos(leaf: usize) -> InOrderIndex {
         // Convert the position from 0-indexed to 1-indexed, since the bit manipulation in this
@@ -33,6 +35,9 @@ impl InOrderIndex {
         InOrderIndex { idx: pos * 2 - 1 }
     }
 
+    // PUBLIC ACCESSORS
+    // --------------------------------------------------------------------------------------------
+
     /// True if the index is pointing at a leaf.
     ///
     /// Every odd number represents a leaf.
@@ -40,6 +45,11 @@ impl InOrderIndex {
         self.idx & 1 == 1
     }
 
+    /// Returns true if this note is a left child of its parent.
+    pub fn is_left_child(&self) -> bool {
+        self.parent().left_child() == *self
+    }
+
     /// Returns the level of the index.
     ///
     /// Starts at level zero for leaves and increases by one for each parent.
@@ -49,8 +59,7 @@ impl InOrderIndex {
 
     /// Returns the index of the left child.
     ///
-    /// Panics:
-    ///
+    /// # Panics:
     /// If the index corresponds to a leaf.
     pub fn left_child(&self) -> InOrderIndex {
         // The left child is itself a parent, with an index that splits its left/right subtrees. To
@@ -62,8 +71,7 @@ impl InOrderIndex {
 
     /// Returns the index of the right child.
     ///
-    /// Panics:
-    ///
+    /// # Panics:
     /// If the index corresponds to a leaf.
     pub fn right_child(&self) -> InOrderIndex {
         // To compute the index of the parent of the right subtree it is sufficient to add the size
@@ -97,6 +105,11 @@ impl InOrderIndex {
             parent.right_child()
         }
     }
+
+    /// Returns the inner value of this [InOrderIndex].
+    pub fn inner(&self) -> u64 {
+        self.idx as u64
+    }
 }
 
 // CONVERSIONS FROM IN-ORDER INDEX