333e1eaeea
- Bump copyright headers to 2015 - [devtools] Rewrite fix-copyright-headers.py - [devtools] Use git pretty-format for year parsing Github-Pull: #7205 Rebased-From: fa6ad855e9159b2247da4fa0054f32fa181499ab fa24439ff3d8ab5b9efaf66ef4dae6713b88cb35 fa71669452e57039e4270fd2b33a0e0e1635b813
182 lines
6.4 KiB
C++
182 lines
6.4 KiB
C++
// Copyright (c) 2009-2010 Satoshi Nakamoto
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// Copyright (c) 2009-2015 The Bitcoin Core developers
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// Distributed under the MIT software license, see the accompanying
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// file COPYING or http://www.opensource.org/licenses/mit-license.php.
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#include "merkleblock.h"
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#include "hash.h"
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#include "consensus/consensus.h"
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#include "utilstrencodings.h"
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using namespace std;
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CMerkleBlock::CMerkleBlock(const CBlock& block, CBloomFilter& filter)
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{
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header = block.GetBlockHeader();
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vector<bool> vMatch;
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vector<uint256> vHashes;
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vMatch.reserve(block.vtx.size());
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vHashes.reserve(block.vtx.size());
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for (unsigned int i = 0; i < block.vtx.size(); i++)
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{
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const uint256& hash = block.vtx[i].GetHash();
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if (filter.IsRelevantAndUpdate(block.vtx[i]))
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{
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vMatch.push_back(true);
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vMatchedTxn.push_back(make_pair(i, hash));
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}
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else
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vMatch.push_back(false);
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vHashes.push_back(hash);
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}
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txn = CPartialMerkleTree(vHashes, vMatch);
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}
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CMerkleBlock::CMerkleBlock(const CBlock& block, const std::set<uint256>& txids)
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{
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header = block.GetBlockHeader();
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vector<bool> vMatch;
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vector<uint256> vHashes;
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vMatch.reserve(block.vtx.size());
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vHashes.reserve(block.vtx.size());
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for (unsigned int i = 0; i < block.vtx.size(); i++)
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{
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const uint256& hash = block.vtx[i].GetHash();
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if (txids.count(hash))
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vMatch.push_back(true);
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else
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vMatch.push_back(false);
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vHashes.push_back(hash);
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}
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txn = CPartialMerkleTree(vHashes, vMatch);
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}
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uint256 CPartialMerkleTree::CalcHash(int height, unsigned int pos, const std::vector<uint256> &vTxid) {
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if (height == 0) {
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// hash at height 0 is the txids themself
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return vTxid[pos];
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} else {
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// calculate left hash
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uint256 left = CalcHash(height-1, pos*2, vTxid), right;
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// calculate right hash if not beyond the end of the array - copy left hash otherwise1
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if (pos*2+1 < CalcTreeWidth(height-1))
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right = CalcHash(height-1, pos*2+1, vTxid);
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else
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right = left;
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// combine subhashes
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return Hash(BEGIN(left), END(left), BEGIN(right), END(right));
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}
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}
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void CPartialMerkleTree::TraverseAndBuild(int height, unsigned int pos, const std::vector<uint256> &vTxid, const std::vector<bool> &vMatch) {
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// determine whether this node is the parent of at least one matched txid
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bool fParentOfMatch = false;
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for (unsigned int p = pos << height; p < (pos+1) << height && p < nTransactions; p++)
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fParentOfMatch |= vMatch[p];
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// store as flag bit
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vBits.push_back(fParentOfMatch);
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if (height==0 || !fParentOfMatch) {
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// if at height 0, or nothing interesting below, store hash and stop
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vHash.push_back(CalcHash(height, pos, vTxid));
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} else {
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// otherwise, don't store any hash, but descend into the subtrees
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TraverseAndBuild(height-1, pos*2, vTxid, vMatch);
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if (pos*2+1 < CalcTreeWidth(height-1))
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TraverseAndBuild(height-1, pos*2+1, vTxid, vMatch);
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}
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}
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uint256 CPartialMerkleTree::TraverseAndExtract(int height, unsigned int pos, unsigned int &nBitsUsed, unsigned int &nHashUsed, std::vector<uint256> &vMatch) {
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if (nBitsUsed >= vBits.size()) {
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// overflowed the bits array - failure
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fBad = true;
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return uint256();
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}
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bool fParentOfMatch = vBits[nBitsUsed++];
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if (height==0 || !fParentOfMatch) {
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// if at height 0, or nothing interesting below, use stored hash and do not descend
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if (nHashUsed >= vHash.size()) {
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// overflowed the hash array - failure
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fBad = true;
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return uint256();
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}
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const uint256 &hash = vHash[nHashUsed++];
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if (height==0 && fParentOfMatch) // in case of height 0, we have a matched txid
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vMatch.push_back(hash);
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return hash;
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} else {
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// otherwise, descend into the subtrees to extract matched txids and hashes
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uint256 left = TraverseAndExtract(height-1, pos*2, nBitsUsed, nHashUsed, vMatch), right;
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if (pos*2+1 < CalcTreeWidth(height-1)) {
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right = TraverseAndExtract(height-1, pos*2+1, nBitsUsed, nHashUsed, vMatch);
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if (right == left) {
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// The left and right branches should never be identical, as the transaction
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// hashes covered by them must each be unique.
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fBad = true;
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}
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} else {
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right = left;
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}
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// and combine them before returning
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return Hash(BEGIN(left), END(left), BEGIN(right), END(right));
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}
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}
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CPartialMerkleTree::CPartialMerkleTree(const std::vector<uint256> &vTxid, const std::vector<bool> &vMatch) : nTransactions(vTxid.size()), fBad(false) {
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// reset state
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vBits.clear();
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vHash.clear();
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// calculate height of tree
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int nHeight = 0;
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while (CalcTreeWidth(nHeight) > 1)
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nHeight++;
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// traverse the partial tree
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TraverseAndBuild(nHeight, 0, vTxid, vMatch);
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}
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CPartialMerkleTree::CPartialMerkleTree() : nTransactions(0), fBad(true) {}
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uint256 CPartialMerkleTree::ExtractMatches(std::vector<uint256> &vMatch) {
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vMatch.clear();
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// An empty set will not work
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if (nTransactions == 0)
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return uint256();
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// check for excessively high numbers of transactions
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if (nTransactions > MAX_BLOCK_SIZE / 60) // 60 is the lower bound for the size of a serialized CTransaction
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return uint256();
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// there can never be more hashes provided than one for every txid
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if (vHash.size() > nTransactions)
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return uint256();
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// there must be at least one bit per node in the partial tree, and at least one node per hash
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if (vBits.size() < vHash.size())
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return uint256();
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// calculate height of tree
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int nHeight = 0;
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while (CalcTreeWidth(nHeight) > 1)
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nHeight++;
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// traverse the partial tree
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unsigned int nBitsUsed = 0, nHashUsed = 0;
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uint256 hashMerkleRoot = TraverseAndExtract(nHeight, 0, nBitsUsed, nHashUsed, vMatch);
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// verify that no problems occurred during the tree traversal
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if (fBad)
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return uint256();
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// verify that all bits were consumed (except for the padding caused by serializing it as a byte sequence)
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if ((nBitsUsed+7)/8 != (vBits.size()+7)/8)
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return uint256();
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// verify that all hashes were consumed
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if (nHashUsed != vHash.size())
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return uint256();
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return hashMerkleRoot;
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}
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