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#include "merkletree/merkle_tree_math.h"
#include <stddef.h>
// static
bool MerkleTreeMath::IsPowerOfTwoPlusOne(size_t leaf_count) {
if (leaf_count == 0)
return false;
if (leaf_count == 1)
return true;
// leaf_count is a power of two plus one if and only if
// ((leaf_count -1) & (leaf_count - 2)) has no bits set.
return (((leaf_count - 1) & (leaf_count - 2)) == 0);
}
// Index of the parent node in the parent level of the tree.
size_t MerkleTreeMath::Parent(size_t leaf) {
return leaf >> 1;
}
// True if the node is a right child; false if it is the left (or only) child.
bool MerkleTreeMath::IsRightChild(size_t leaf) {
return leaf & 1;
}
// Index of the node's (left or right) sibling in the same level.
size_t MerkleTreeMath::Sibling(size_t leaf) {
return IsRightChild(leaf) ? (leaf - 1) : (leaf + 1);
}
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