// Deprecated for Bitcoin Gold
unsigned int BitcoinGetNextWorkRequired(const CBlockIndex* pindexLast, const CBlockHeader *pblock, const Consensus::Params& params)
{
assert(pindexLast != nullptr);
unsigned int nProofOfWorkLimit = UintToArith256(params.PowLimit(false)).GetCompact();
// Only change once per difficulty adjustment interval
if ((pindexLast->nHeight+1) % params.DifficultyAdjustmentInterval() != 0)
{
if (params.fPowAllowMinDifficultyBlocks)
{
// Special difficulty rule for testnet:
// If the new block's timestamp is more than 2* 10 minutes
// then allow mining of a min-difficulty block.
if (pblock->GetBlockTime() > pindexLast->GetBlockTime() + params.nPowTargetSpacing*2)
return nProofOfWorkLimit;
else
{
// Return the last non-special-min-difficulty-rules-block
const CBlockIndex* pindex = pindexLast;
while (pindex->pprev && pindex->nHeight % params.DifficultyAdjustmentInterval() != 0 && pindex->nBits == nProofOfWorkLimit)
pindex = pindex->pprev;
return pindex->nBits;
}
}
return pindexLast->nBits;
}
// Go back by what we want to be 14 days worth of blocks
int nHeightFirst = pindexLast->nHeight - (params.DifficultyAdjustmentInterval()-1);
assert(nHeightFirst >= 0);
const CBlockIndex* pindexFirst = pindexLast->GetAncestor(nHeightFirst);
assert(pindexFirst);
return BitcoinCalculateNextWorkRequired(pindexLast, pindexFirst->GetBlockTime(), params);
}
unsigned int GetNextWorkRequired(const CBlockIndex* pindexLast, const CBlockHeader *pblock, const Consensus::Params& params)
{
assert(pindexLast != nullptr);
int nHeight = pindexLast->nHeight + 1;
bool postfork = nHeight >= params.BTGHeight;
unsigned int nProofOfWorkLimit = UintToArith256(params.PowLimit(postfork)).GetCompact();
if (postfork == false) {
return BitcoinGetNextWorkRequired(pindexLast, pblock, params);
}
else if (nHeight < params.BTGHeight + params.BTGPremineWindow) {
return nProofOfWorkLimit;
}
else if (nHeight < params.BTGHeight + params.BTGPremineWindow + params.nPowAveragingWindow){
return UintToArith256(params.powLimitStart).GetCompact();
}
const CBlockIndex* pindexFirst = pindexLast;
arith_uint256 bnTot {0};
for (int i = 0; pindexFirst && i < params.nPowAveragingWindow; i++) {
arith_uint256 bnTmp;
bnTmp.SetCompact(pindexFirst->nBits);
bnTot += bnTmp;
pindexFirst = pindexFirst->pprev;
}
if (pindexFirst == NULL)
return nProofOfWorkLimit;
arith_uint256 bnAvg {bnTot / params.nPowAveragingWindow};
return CalculateNextWorkRequired(bnAvg, pindexLast->GetMedianTimePast(), pindexFirst->GetMedianTimePast(), params);
}
bool CheckProofOfWork(uint256 hash, unsigned int nBits, bool postfork, const Consensus::Params& params)
{
bool fNegative;
bool fOverflow;
arith_uint256 bnTarget;
bnTarget.SetCompact(nBits, &fNegative, &fOverflow);
// Check range
if (fNegative || bnTarget == 0 || fOverflow || bnTarget > UintToArith256(params.PowLimit(postfork)))
return false;
// Check proof of work matches claimed amount
if (UintToArith256(hash) > bnTarget)
return false;
return true;
}
unsigned int CalculateNextWorkRequired(arith_uint256 bnAvg, int64_t nLastBlockTime, int64_t nFirstBlockTime, const Consensus::Params& params)
{
// Limit adjustment
int64_t nActualTimespan = nLastBlockTime - nFirstBlockTime;
if (nActualTimespan < params.MinActualTimespan())
nActualTimespan = params.MinActualTimespan();
if (nActualTimespan > params.MaxActualTimespan())
nActualTimespan = params.MaxActualTimespan();
// Retarget
const arith_uint256 bnPowLimit = UintToArith256(params.PowLimit(true));
arith_uint256 bnNew {bnAvg};
bnNew /= params.AveragingWindowTimespan();
bnNew *= nActualTimespan;
if (bnNew > bnPowLimit)
bnNew = bnPowLimit;
return bnNew.GetCompact();
}
// Depricated for Bitcoin Gold
unsigned int BitcoinCalculateNextWorkRequired(const CBlockIndex* pindexLast, int64_t nFirstBlockTime, const Consensus::Params& params)
{
if (params.fPowNoRetargeting)
return pindexLast->nBits;
// Limit adjustment step
int64_t nActualTimespan = pindexLast->GetBlockTime() - nFirstBlockTime;
if (nActualTimespan < params.nPowTargetTimespanLegacy/4)
nActualTimespan = params.nPowTargetTimespanLegacy/4;
if (nActualTimespan > params.nPowTargetTimespanLegacy*4)
nActualTimespan = params.nPowTargetTimespanLegacy*4;
// Retarget
const arith_uint256 bnPowLimit = UintToArith256(params.PowLimit(false));
arith_uint256 bnNew;
bnNew.SetCompact(pindexLast->nBits);
bnNew *= nActualTimespan;
bnNew /= params.nPowTargetTimespanLegacy;
if (bnNew > bnPowLimit)
bnNew = bnPowLimit;
return bnNew.GetCompact();
}