Bitcoin ABC 0.26.3
P2P Digital Currency

Data structure that represents a partial merkle tree. More...
#include <merkleblock.h>
Public Member Functions  
SERIALIZE_METHODS (CPartialMerkleTree, obj)  
CPartialMerkleTree (const std::vector< uint256 > &vTxid, const std::vector< bool > &vMatch)  
Construct a partial merkle tree from a list of transaction ids, and a mask that selects a subset of them.  
CPartialMerkleTree ()  
uint256  ExtractMatches (std::vector< uint256 > &vMatch, std::vector< size_t > &vnIndex) 
Extract the matching txid's represented by this partial merkle tree and their respective indices within the partial tree.  
uint32_t  GetNumTransactions () const 
Get number of transactions the merkle proof is indicating for crossreference with local blockchain knowledge.  
Protected Member Functions  
size_t  CalcTreeWidth (int height) const 
Helper function to efficiently calculate the number of nodes at given height in the merkle tree.  
uint256  CalcHash (int height, size_t pos, const std::vector< uint256 > &vTxid) 
Calculate the hash of a node in the merkle tree (at leaf level: the txid's themselves)  
void  TraverseAndBuild (int height, size_t pos, const std::vector< uint256 > &vTxid, const std::vector< bool > &vMatch) 
Recursive function that traverses tree nodes, storing the data as bits and hashes.  
uint256  TraverseAndExtract (int height, size_t pos, size_t &nBitsUsed, size_t &nHashUsed, std::vector< uint256 > &vMatch, std::vector< size_t > &vnIndex) 
Recursive function that traverses tree nodes, consuming the bits and hashes produced by TraverseAndBuild.  
Protected Attributes  
uint32_t  nTransactions 
the total number of transactions in the block  
std::vector< bool >  vBits 
nodeisparentofmatchedtxid bits  
std::vector< uint256 >  vHash 
txids and internal hashes  
bool  fBad 
flag set when encountering invalid data  
Data structure that represents a partial merkle tree.
It represents a subset of the txid's of a known block, in a way that allows recovery of the list of txid's and the merkle root, in an authenticated way.
The encoding works as follows: we traverse the tree in depthfirst order, storing a bit for each traversed node, signifying whether the node is the parent of at least one matched leaf txid (or a matched txid itself). In case we are at the leaf level, or this bit is 0, its merkle node hash is stored, and its children are not explored further. Otherwise, no hash is stored, but we recurse into both (or the only) child branch. During decoding, the same depthfirst traversal is performed, consuming bits and hashes as they written during encoding.
The serialization is fixed and provides a hard guarantee about the encoded size:
SIZE <= 10 + ceil(32.25*N)
Where N represents the number of leaf nodes of the partial tree. N itself is bounded by:
N <= total_transactions N <= 1 + matched_transactions*tree_height
The serialization format:
Definition at line 56 of file merkleblock.h.
CPartialMerkleTree::CPartialMerkleTree  (  const std::vector< uint256 > &  vTxid, 
const std::vector< bool > &  vMatch  
) 
Construct a partial merkle tree from a list of transaction ids, and a mask that selects a subset of them.
Definition at line 161 of file merkleblock.cpp.
CPartialMerkleTree::CPartialMerkleTree  (  ) 
Definition at line 178 of file merkleblock.cpp.

protected 
Calculate the hash of a node in the merkle tree (at leaf level: the txid's themselves)
Definition at line 63 of file merkleblock.cpp.
Helper function to efficiently calculate the number of nodes at given height in the merkle tree.
Definition at line 74 of file merkleblock.h.
uint256 CPartialMerkleTree::ExtractMatches  (  std::vector< uint256 > &  vMatch, 
std::vector< size_t > &  vnIndex  
) 
Extract the matching txid's represented by this partial merkle tree and their respective indices within the partial tree.
Returns the merkle root, or 0 in case of failure.
Definition at line 180 of file merkleblock.cpp.

inline 
Get number of transactions the merkle proof is indicating for crossreference with local blockchain knowledge.
Definition at line 132 of file merkleblock.h.

inline 

protected 
Recursive function that traverses tree nodes, storing the data as bits and hashes.
Definition at line 88 of file merkleblock.cpp.

protected 
Recursive function that traverses tree nodes, consuming the bits and hashes produced by TraverseAndBuild.
It returns the hash of the respective node and its respective index.
Definition at line 112 of file merkleblock.cpp.

protected 
flag set when encountering invalid data
Definition at line 68 of file merkleblock.h.

protected 
the total number of transactions in the block
Definition at line 59 of file merkleblock.h.

protected 
nodeisparentofmatchedtxid bits
Definition at line 62 of file merkleblock.h.

protected 
txids and internal hashes
Definition at line 65 of file merkleblock.h.