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MOVEONLY: non-consensus: from pow to chain:

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- GetBlockProof
- GetBlockProofEquivalentTime
This commit is contained in:
Jorge Timón 2015-11-30 00:46:49 +01:00
parent 3cd836c1d8
commit e86756193e
4 changed files with 36 additions and 37 deletions
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32
src/chain.cpp
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@ -110,3 +110,35 @@ void CBlockIndex::BuildSkip()
if (pprev)
pskip = pprev->GetAncestor(GetSkipHeight(nHeight));
}
arith_uint256 GetBlockProof(const CBlockIndex& block)
{
arith_uint256 bnTarget;
bool fNegative;
bool fOverflow;
bnTarget.SetCompact(block.nBits, &fNegative, &fOverflow);
if (fNegative || fOverflow || bnTarget == 0)
return 0;
// We need to compute 2**256 / (bnTarget+1), but we can't represent 2**256
// as it's too large for a arith_uint256. However, as 2**256 is at least as large
// as bnTarget+1, it is equal to ((2**256 - bnTarget - 1) / (bnTarget+1)) + 1,
// or ~bnTarget / (nTarget+1) + 1.
return (~bnTarget / (bnTarget + 1)) + 1;
}
int64_t GetBlockProofEquivalentTime(const CBlockIndex& to, const CBlockIndex& from, const CBlockIndex& tip, const Consensus::Params& params)
{
arith_uint256 r;
int sign = 1;
if (to.nChainWork > from.nChainWork) {
r = to.nChainWork - from.nChainWork;
} else {
r = from.nChainWork - to.nChainWork;
sign = -1;
}
r = r * arith_uint256(params.nPowTargetSpacing) / GetBlockProof(tip);
if (r.bits() > 63) {
return sign * std::numeric_limits<int64_t>::max();
}
return sign * r.GetLow64();
}

4
src/chain.h
View file

@ -282,6 +282,10 @@ public:
const CBlockIndex* GetAncestor(int height) const;
};
arith_uint256 GetBlockProof(const CBlockIndex& block);
/** Return the time it would take to redo the work difference between from and to, assuming the current hashrate corresponds to the difficulty at tip, in seconds. */
int64_t GetBlockProofEquivalentTime(const CBlockIndex& to, const CBlockIndex& from, const CBlockIndex& tip, const Consensus::Params&);
/** Used to marshal pointers into hashes for db storage. */
class CDiskBlockIndex : public CBlockIndex
{

32
src/pow.cpp
View file

@ -102,35 +102,3 @@ bool CheckProofOfWork(uint256 hash, unsigned int nBits, const Consensus::Params&
return true;
}
arith_uint256 GetBlockProof(const CBlockIndex& block)
{
arith_uint256 bnTarget;
bool fNegative;
bool fOverflow;
bnTarget.SetCompact(block.nBits, &fNegative, &fOverflow);
if (fNegative || fOverflow || bnTarget == 0)
return 0;
// We need to compute 2**256 / (bnTarget+1), but we can't represent 2**256
// as it's too large for a arith_uint256. However, as 2**256 is at least as large
// as bnTarget+1, it is equal to ((2**256 - bnTarget - 1) / (bnTarget+1)) + 1,
// or ~bnTarget / (nTarget+1) + 1.
return (~bnTarget / (bnTarget + 1)) + 1;
}
int64_t GetBlockProofEquivalentTime(const CBlockIndex& to, const CBlockIndex& from, const CBlockIndex& tip, const Consensus::Params& params)
{
arith_uint256 r;
int sign = 1;
if (to.nChainWork > from.nChainWork) {
r = to.nChainWork - from.nChainWork;
} else {
r = from.nChainWork - to.nChainWork;
sign = -1;
}
r = r * arith_uint256(params.nPowTargetSpacing) / GetBlockProof(tip);
if (r.bits() > 63) {
return sign * std::numeric_limits<int64_t>::max();
}
return sign * r.GetLow64();
}

5
src/pow.h
View file

@ -13,16 +13,11 @@
class CBlockHeader;
class CBlockIndex;
class uint256;
class arith_uint256;
unsigned int GetNextWorkRequired(const CBlockIndex* pindexLast, const CBlockHeader *pblock, const Consensus::Params&);
unsigned int CalculateNextWorkRequired(const CBlockIndex* pindexLast, int64_t nFirstBlockTime, const Consensus::Params&);
/** Check whether a block hash satisfies the proof-of-work requirement specified by nBits */
bool CheckProofOfWork(uint256 hash, unsigned int nBits, const Consensus::Params&);
arith_uint256 GetBlockProof(const CBlockIndex& block);
/** Return the time it would take to redo the work difference between from and to, assuming the current hashrate corresponds to the difficulty at tip, in seconds. */
int64_t GetBlockProofEquivalentTime(const CBlockIndex& to, const CBlockIndex& from, const CBlockIndex& tip, const Consensus::Params&);
#endif // BITCOIN_POW_H