mirror of
https://github.com/dashpay/dash.git
synced 2024-12-29 05:49:11 +01:00
95 lines
3.2 KiB
C++
95 lines
3.2 KiB
C++
// Copyright (c) 2009-2010 Satoshi Nakamoto
|
|
// Copyright (c) 2009-2016 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 "pow.h"
|
|
|
|
#include "arith_uint256.h"
|
|
#include "chain.h"
|
|
#include "primitives/block.h"
|
|
#include "uint256.h"
|
|
|
|
unsigned int GetNextWorkRequired(const CBlockIndex* pindexLast, const CBlockHeader *pblock, const Consensus::Params& params)
|
|
{
|
|
unsigned int nProofOfWorkLimit = UintToArith256(params.powLimit).GetCompact();
|
|
|
|
// Genesis block
|
|
if (pindexLast == NULL)
|
|
return nProofOfWorkLimit;
|
|
|
|
// 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 CalculateNextWorkRequired(pindexLast, pindexFirst->GetBlockTime(), params);
|
|
}
|
|
|
|
unsigned int CalculateNextWorkRequired(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.nPowTargetTimespan/4)
|
|
nActualTimespan = params.nPowTargetTimespan/4;
|
|
if (nActualTimespan > params.nPowTargetTimespan*4)
|
|
nActualTimespan = params.nPowTargetTimespan*4;
|
|
|
|
// Retarget
|
|
const arith_uint256 bnPowLimit = UintToArith256(params.powLimit);
|
|
arith_uint256 bnNew;
|
|
bnNew.SetCompact(pindexLast->nBits);
|
|
bnNew *= nActualTimespan;
|
|
bnNew /= params.nPowTargetTimespan;
|
|
|
|
if (bnNew > bnPowLimit)
|
|
bnNew = bnPowLimit;
|
|
|
|
return bnNew.GetCompact();
|
|
}
|
|
|
|
bool CheckProofOfWork(uint256 hash, unsigned int nBits, 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))
|
|
return false;
|
|
|
|
// Check proof of work matches claimed amount
|
|
if (UintToArith256(hash) > bnTarget)
|
|
return false;
|
|
|
|
return true;
|
|
}
|