268 lines
9.9 KiB
C++
268 lines
9.9 KiB
C++
// 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 "pow.h"
|
|
|
|
#include "chain.h"
|
|
#include "chainparams.h"
|
|
#include "primitives/block.h"
|
|
#include "uint256.h"
|
|
#include "util.h"
|
|
|
|
#include <math.h>
|
|
|
|
unsigned int static KimotoGravityWell(const CBlockIndex* pindexLast) {
|
|
const CBlockIndex *BlockLastSolved = pindexLast;
|
|
const CBlockIndex *BlockReading = pindexLast;
|
|
uint64_t PastBlocksMass = 0;
|
|
int64_t PastRateActualSeconds = 0;
|
|
int64_t PastRateTargetSeconds = 0;
|
|
double PastRateAdjustmentRatio = double(1);
|
|
uint256 PastDifficultyAverage;
|
|
uint256 PastDifficultyAveragePrev;
|
|
double EventHorizonDeviation;
|
|
double EventHorizonDeviationFast;
|
|
double EventHorizonDeviationSlow;
|
|
|
|
uint64_t pastSecondsMin = Params().TargetTimespan() * 0.025;
|
|
uint64_t pastSecondsMax = Params().TargetTimespan() * 7;
|
|
uint64_t PastBlocksMin = pastSecondsMin / Params().TargetSpacing();
|
|
uint64_t PastBlocksMax = pastSecondsMax / Params().TargetSpacing();
|
|
|
|
if (BlockLastSolved == NULL || BlockLastSolved->nHeight == 0 || (uint64_t)BlockLastSolved->nHeight < PastBlocksMin) { return Params().ProofOfWorkLimit().GetCompact(); }
|
|
|
|
for (unsigned int i = 1; BlockReading && BlockReading->nHeight > 0; i++) {
|
|
if (PastBlocksMax > 0 && i > PastBlocksMax) { break; }
|
|
PastBlocksMass++;
|
|
|
|
PastDifficultyAverage.SetCompact(BlockReading->nBits);
|
|
if (i > 1) {
|
|
// handle negative uint256
|
|
if(PastDifficultyAverage >= PastDifficultyAveragePrev)
|
|
PastDifficultyAverage = ((PastDifficultyAverage - PastDifficultyAveragePrev) / i) + PastDifficultyAveragePrev;
|
|
else
|
|
PastDifficultyAverage = PastDifficultyAveragePrev - ((PastDifficultyAveragePrev - PastDifficultyAverage) / i);
|
|
}
|
|
PastDifficultyAveragePrev = PastDifficultyAverage;
|
|
|
|
PastRateActualSeconds = BlockLastSolved->GetBlockTime() - BlockReading->GetBlockTime();
|
|
PastRateTargetSeconds = Params().TargetSpacing() * PastBlocksMass;
|
|
PastRateAdjustmentRatio = double(1);
|
|
if (PastRateActualSeconds < 0) { PastRateActualSeconds = 0; }
|
|
if (PastRateActualSeconds != 0 && PastRateTargetSeconds != 0) {
|
|
PastRateAdjustmentRatio = double(PastRateTargetSeconds) / double(PastRateActualSeconds);
|
|
}
|
|
EventHorizonDeviation = 1 + (0.7084 * pow((double(PastBlocksMass)/double(28.2)), -1.228));
|
|
EventHorizonDeviationFast = EventHorizonDeviation;
|
|
EventHorizonDeviationSlow = 1 / EventHorizonDeviation;
|
|
|
|
if (PastBlocksMass >= PastBlocksMin) {
|
|
if ((PastRateAdjustmentRatio <= EventHorizonDeviationSlow) || (PastRateAdjustmentRatio >= EventHorizonDeviationFast))
|
|
{ assert(BlockReading); break; }
|
|
}
|
|
if (BlockReading->pprev == NULL) { assert(BlockReading); break; }
|
|
BlockReading = BlockReading->pprev;
|
|
}
|
|
|
|
uint256 bnNew(PastDifficultyAverage);
|
|
if (PastRateActualSeconds != 0 && PastRateTargetSeconds != 0) {
|
|
bnNew *= PastRateActualSeconds;
|
|
bnNew /= PastRateTargetSeconds;
|
|
}
|
|
|
|
if (bnNew > Params().ProofOfWorkLimit()) {
|
|
bnNew = Params().ProofOfWorkLimit();
|
|
}
|
|
|
|
return bnNew.GetCompact();
|
|
}
|
|
|
|
unsigned int static DarkGravityWave(const CBlockIndex* pindexLast) {
|
|
/* current difficulty formula, dash - DarkGravity v3, written by Evan Duffield - evan@dashpay.io */
|
|
const CBlockIndex *BlockLastSolved = pindexLast;
|
|
const CBlockIndex *BlockReading = pindexLast;
|
|
int64_t nActualTimespan = 0;
|
|
int64_t LastBlockTime = 0;
|
|
int64_t PastBlocksMin = 24;
|
|
int64_t PastBlocksMax = 24;
|
|
int64_t CountBlocks = 0;
|
|
uint256 PastDifficultyAverage;
|
|
uint256 PastDifficultyAveragePrev;
|
|
|
|
if (BlockLastSolved == NULL || BlockLastSolved->nHeight == 0 || BlockLastSolved->nHeight < PastBlocksMin) {
|
|
return Params().ProofOfWorkLimit().GetCompact();
|
|
}
|
|
|
|
for (unsigned int i = 1; BlockReading && BlockReading->nHeight > 0; i++) {
|
|
if (PastBlocksMax > 0 && i > PastBlocksMax) { break; }
|
|
CountBlocks++;
|
|
|
|
if(CountBlocks <= PastBlocksMin) {
|
|
if (CountBlocks == 1) { PastDifficultyAverage.SetCompact(BlockReading->nBits); }
|
|
else { PastDifficultyAverage = ((PastDifficultyAveragePrev * CountBlocks) + (uint256().SetCompact(BlockReading->nBits))) / (CountBlocks + 1); }
|
|
PastDifficultyAveragePrev = PastDifficultyAverage;
|
|
}
|
|
|
|
if(LastBlockTime > 0){
|
|
int64_t Diff = (LastBlockTime - BlockReading->GetBlockTime());
|
|
nActualTimespan += Diff;
|
|
}
|
|
LastBlockTime = BlockReading->GetBlockTime();
|
|
|
|
if (BlockReading->pprev == NULL) { assert(BlockReading); break; }
|
|
BlockReading = BlockReading->pprev;
|
|
}
|
|
|
|
uint256 bnNew(PastDifficultyAverage);
|
|
|
|
int64_t _nTargetTimespan = CountBlocks * Params().TargetSpacing();
|
|
|
|
if (nActualTimespan < _nTargetTimespan/3)
|
|
nActualTimespan = _nTargetTimespan/3;
|
|
if (nActualTimespan > _nTargetTimespan*3)
|
|
nActualTimespan = _nTargetTimespan*3;
|
|
|
|
// Retarget
|
|
bnNew *= nActualTimespan;
|
|
bnNew /= _nTargetTimespan;
|
|
|
|
if (bnNew > Params().ProofOfWorkLimit()){
|
|
bnNew = Params().ProofOfWorkLimit();
|
|
}
|
|
|
|
return bnNew.GetCompact();
|
|
}
|
|
|
|
unsigned int GetNextWorkRequired(const CBlockIndex* pindexLast, const CBlockHeader *pblock)
|
|
{
|
|
unsigned int retarget = DIFF_DGW;
|
|
|
|
if (Params().NetworkID() != CBaseChainParams::TESTNET) {
|
|
if (pindexLast->nHeight + 1 >= 34140) retarget = DIFF_DGW;
|
|
else if (pindexLast->nHeight + 1 >= 15200) retarget = DIFF_KGW;
|
|
else retarget = DIFF_BTC;
|
|
} else {
|
|
if (pindexLast->nHeight + 1 >= 2000) retarget = DIFF_DGW;
|
|
else retarget = DIFF_BTC;
|
|
}
|
|
|
|
// Default Bitcoin style retargeting
|
|
if (retarget == DIFF_BTC)
|
|
{
|
|
unsigned int nProofOfWorkLimit = Params().ProofOfWorkLimit().GetCompact();
|
|
|
|
// Genesis block
|
|
if (pindexLast == NULL)
|
|
return nProofOfWorkLimit;
|
|
|
|
// Only change once per interval
|
|
if ((pindexLast->nHeight+1) % Params().Interval() != 0)
|
|
{
|
|
if (Params().AllowMinDifficultyBlocks())
|
|
{
|
|
// Special difficulty rule for testnet:
|
|
// If the new block's timestamp is more than 2* 2.5 minutes
|
|
// then allow mining of a min-difficulty block.
|
|
if (pblock->GetBlockTime() > pindexLast->GetBlockTime() + Params().TargetSpacing()*2)
|
|
return nProofOfWorkLimit;
|
|
else
|
|
{
|
|
// Return the last non-special-min-difficulty-rules-block
|
|
const CBlockIndex* pindex = pindexLast;
|
|
while (pindex->pprev && pindex->nHeight % Params().Interval() != 0 && pindex->nBits == nProofOfWorkLimit)
|
|
pindex = pindex->pprev;
|
|
return pindex->nBits;
|
|
}
|
|
}
|
|
return pindexLast->nBits;
|
|
}
|
|
|
|
// Go back by what we want to be 1 day worth of blocks
|
|
const CBlockIndex* pindexFirst = pindexLast;
|
|
for (int i = 0; pindexFirst && i < Params().Interval()-1; i++)
|
|
pindexFirst = pindexFirst->pprev;
|
|
assert(pindexFirst);
|
|
|
|
// Limit adjustment step
|
|
int64_t nActualTimespan = pindexLast->GetBlockTime() - pindexFirst->GetBlockTime();
|
|
LogPrintf(" nActualTimespan = %d before bounds\n", nActualTimespan);
|
|
if (nActualTimespan < Params().TargetTimespan()/4)
|
|
nActualTimespan = Params().TargetTimespan()/4;
|
|
if (nActualTimespan > Params().TargetTimespan()*4)
|
|
nActualTimespan = Params().TargetTimespan()*4;
|
|
|
|
// Retarget
|
|
uint256 bnNew;
|
|
uint256 bnOld;
|
|
bnNew.SetCompact(pindexLast->nBits);
|
|
bnOld = bnNew;
|
|
bnNew *= nActualTimespan;
|
|
bnNew /= Params().TargetTimespan();
|
|
|
|
if (bnNew > Params().ProofOfWorkLimit())
|
|
bnNew = Params().ProofOfWorkLimit();
|
|
|
|
/// debug print
|
|
LogPrintf("GetNextWorkRequired RETARGET at %d\n", pindexLast->nHeight + 1);
|
|
LogPrintf("Params().TargetTimespan() = %d nActualTimespan = %d\n", Params().TargetTimespan(), nActualTimespan);
|
|
LogPrintf("Before: %08x %s\n", pindexLast->nBits, bnOld.ToString());
|
|
LogPrintf("After: %08x %s\n", bnNew.GetCompact(), bnNew.ToString());
|
|
|
|
return bnNew.GetCompact();
|
|
|
|
}
|
|
|
|
// Retarget using Kimoto Gravity Wave
|
|
else if (retarget == DIFF_KGW)
|
|
{
|
|
return KimotoGravityWell(pindexLast);
|
|
}
|
|
|
|
// Retarget using Dark Gravity Wave 3
|
|
else if (retarget == DIFF_DGW)
|
|
{
|
|
return DarkGravityWave(pindexLast);
|
|
}
|
|
|
|
return DarkGravityWave(pindexLast);
|
|
}
|
|
|
|
bool CheckProofOfWork(uint256 hash, unsigned int nBits)
|
|
{
|
|
bool fNegative;
|
|
bool fOverflow;
|
|
uint256 bnTarget;
|
|
|
|
if (Params().SkipProofOfWorkCheck())
|
|
return true;
|
|
|
|
bnTarget.SetCompact(nBits, &fNegative, &fOverflow);
|
|
|
|
// Check range
|
|
if (fNegative || bnTarget == 0 || fOverflow || bnTarget > Params().ProofOfWorkLimit())
|
|
return error("CheckProofOfWork() : nBits below minimum work");
|
|
|
|
// Check proof of work matches claimed amount
|
|
if (hash > bnTarget)
|
|
return error("CheckProofOfWork() : hash doesn't match nBits");
|
|
|
|
return true;
|
|
}
|
|
|
|
uint256 GetBlockProof(const CBlockIndex& block)
|
|
{
|
|
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 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;
|
|
}
|