83 lines
2.5 KiB
C++
83 lines
2.5 KiB
C++
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// Copyright (c) 2009-2010 Satoshi Nakamoto
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// Copyright (c) 2009-2020 The Bitcoin Core developers
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// Copyright (c) 2014-2020 The DigiByte Core developers
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// Distributed under the MIT software license, see the accompanying
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// file COPYING or http://www.opensource.org/licenses/mit-license.php.
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#include <pow.h>
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#include <logging.h>
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#include <arith_uint256.h>
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#include <chain.h>
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#include <primitives/block.h>
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#include <uint256.h>
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#include <chainparams.h>
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inline unsigned int PowLimit(const Consensus::Params& params)
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{
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return UintToArith256(params.powLimit).GetCompact();
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}
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unsigned int InitialDifficulty(const Consensus::Params& params)
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{
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return PowLimit(params);
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}
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unsigned int GetNextWorkRequired(const CBlockIndex* pindexLast, const CBlockHeader *pblock, const Consensus::Params& params)
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{
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// Vexta is SHA256D-only. Use one global averaging window.
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if (pindexLast == nullptr) {
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return InitialDifficulty(params);
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}
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const CBlockIndex* pindexFirst = pindexLast;
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for (int i = 0; pindexFirst && i < params.difficultyAveragingWindow; i++) {
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pindexFirst = pindexFirst->pprev;
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}
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if (pindexFirst == nullptr) {
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return InitialDifficulty(params);
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}
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if (params.fPowNoRetargeting || params.fEasyPow) {
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return pindexLast->nBits;
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}
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int64_t nActualTimespan = pindexLast->GetMedianTimePast() - pindexFirst->GetMedianTimePast();
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nActualTimespan = params.difficultyTargetTimespan + (nActualTimespan - params.difficultyTargetTimespan) / 4;
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if (nActualTimespan < params.difficultyMinActualTimespan)
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nActualTimespan = params.difficultyMinActualTimespan;
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if (nActualTimespan > params.difficultyMaxActualTimespan)
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nActualTimespan = params.difficultyMaxActualTimespan;
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arith_uint256 bnNew;
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bnNew.SetCompact(pindexLast->nBits);
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bnNew *= nActualTimespan;
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bnNew /= params.difficultyTargetTimespan;
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if (bnNew > UintToArith256(params.powLimit)) {
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bnNew = UintToArith256(params.powLimit);
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}
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return bnNew.GetCompact();
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}
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bool CheckProofOfWork(uint256 hash, unsigned int nBits, const Consensus::Params& params)
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{
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bool fNegative;
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bool fOverflow;
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arith_uint256 bnTarget;
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bnTarget.SetCompact(nBits, &fNegative, &fOverflow);
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// Check range
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if (fNegative || bnTarget == 0 || fOverflow || bnTarget > UintToArith256(params.powLimit))
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return false;
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// Check proof of work matches claimed amount
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if (UintToArith256(hash) > bnTarget)
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return false;
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return true;
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}
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