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// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2014 The Bitcoin developers
// Distributed under the MIT/X11 software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include "chain.h"
using namespace std;
// CChain implementation
CBlockIndex *CChain::SetTip(CBlockIndex *pindex) {
if (pindex == NULL) {
vChain.clear();
return NULL;
}
vChain.resize(pindex->nHeight + 1);
while (pindex && vChain[pindex->nHeight] != pindex) {
vChain[pindex->nHeight] = pindex;
pindex = pindex->pprev;
}
return pindex;
}
CBlockLocator CChain::GetLocator(const CBlockIndex *pindex) const {
int nStep = 1;
std::vector<uint256> vHave;
vHave.reserve(32);
if (!pindex)
pindex = Tip();
while (pindex) {
vHave.push_back(pindex->GetBlockHash());
// Stop when we have added the genesis block.
if (pindex->nHeight == 0)
break;
// Exponentially larger steps back, plus the genesis block.
int nHeight = std::max(pindex->nHeight - nStep, 0);
if (Contains(pindex)) {
// Use O(1) CChain index if possible.
pindex = (*this)[nHeight];
} else {
// Otherwise, use O(log n) skiplist.
pindex = pindex->GetAncestor(nHeight);
}
if (vHave.size() > 10)
nStep *= 2;
}
return CBlockLocator(vHave);
}
const CBlockIndex *CChain::FindFork(const CBlockIndex *pindex) const {
if (pindex->nHeight > Height())
pindex = pindex->GetAncestor(Height());
while (pindex && !Contains(pindex))
pindex = pindex->pprev;
return pindex;
}