Below is the source requested.... Located at https://github.com/bitcoin/bitcoin/blob/master/src/checkpoints.cpp
// Copyright (c) 2009-2015 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#include "checkpoints.h"
#include "chain.h"
#include "chainparams.h"
#include "main.h"
#include "uint256.h"
#include <stdint.h>
#include <boost/foreach.hpp>
namespace Checkpoints {
/**
* How many times slower we expect checking transactions after the last
* checkpoint to be (from checking signatures, which is skipped up to the
* last checkpoint). This number is a compromise, as it can't be accurate
* for every system. When reindexing from a fast disk with a slow CPU, it
* can be up to 20, while when downloading from a slow network with a
* fast multicore CPU, it won't be much higher than 1.
*/
static const double SIGCHECK_VERIFICATION_FACTOR = 5.0;
//! Guess how far we are in the verification process at the given block index
double GuessVerificationProgress(const CCheckpointData& data, CBlockIndex *pindex, bool fSigchecks) {
if (pindex==NULL)
return 0.0;
int64_t nNow = time(NULL);
double fSigcheckVerificationFactor = fSigchecks ? SIGCHECK_VERIFICATION_FACTOR : 1.0;
double fWorkBefore = 0.0; // Amount of work done before pindex
double fWorkAfter = 0.0; // Amount of work left after pindex (estimated)
// Work is defined as: 1.0 per transaction before the last checkpoint, and
// fSigcheckVerificationFactor per transaction after.
if (pindex->nChainTx <= data.nTransactionsLastCheckpoint) {
double nCheapBefore = pindex->nChainTx;
double nCheapAfter = data.nTransactionsLastCheckpoint - pindex->nChainTx;
double nExpensiveAfter = (nNow - data.nTimeLastCheckpoint)/86400.0*data.fTransactionsPerDay;
fWorkBefore = nCheapBefore;
fWorkAfter = nCheapAfter + nExpensiveAfter*fSigcheckVerificationFactor;
} else {
double nCheapBefore = data.nTransactionsLastCheckpoint;
double nExpensiveBefore = pindex->nChainTx - data.nTransactionsLastCheckpoint;
double nExpensiveAfter = (nNow - pindex->GetBlockTime())/86400.0*data.fTransactionsPerDay;
fWorkBefore = nCheapBefore + nExpensiveBefore*fSigcheckVerificationFactor;
fWorkAfter = nExpensiveAfter*fSigcheckVerificationFactor;
}
return fWorkBefore / (fWorkBefore + fWorkAfter);
}
int GetTotalBlocksEstimate(const CCheckpointData& data)
{
const MapCheckpoints& checkpoints = data.mapCheckpoints;
if (checkpoints.empty())
return 0;
return checkpoints.rbegin()->first;
}
CBlockIndex* GetLastCheckpoint(const CCheckpointData& data)
{
const MapCheckpoints& checkpoints = data.mapCheckpoints;
BOOST_REVERSE_FOREACH(const MapCheckpoints::value_type& i, checkpoints)
{
const uint256& hash = i.second;
BlockMap::const_iterator t = mapBlockIndex.find(hash);
if (t != mapBlockIndex.end())
return t->second;
}
return NULL;
}
} // namespace Checkpoints
