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8a4ece1101
* [NOD-1223] Move all network stuff into a new network package. * [NOD-1223] Delete the unused package testutil. * [NOD-1223] Move infrastructure stuff into a new instrastructure package. * [NOD-1223] Move domain stuff into a new domain package.
62 lines
2.5 KiB
Go
62 lines
2.5 KiB
Go
// Copyright (c) 2013-2017 The btcsuite developers
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// Use of this source code is governed by an ISC
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// license that can be found in the LICENSE file.
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package blockdag
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import (
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"github.com/kaspanet/kaspad/util/bigintpool"
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"github.com/kaspanet/kaspad/util/mstime"
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"github.com/kaspanet/kaspad/util"
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)
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// requiredDifficulty calculates the required difficulty for a
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// block given its bluest parent.
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func (dag *BlockDAG) requiredDifficulty(bluestParent *blockNode, newBlockTime mstime.Time) uint32 {
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// Genesis block.
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if dag.Params.DisableDifficultyAdjustment || bluestParent == nil || bluestParent.blueScore < dag.difficultyAdjustmentWindowSize+1 {
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return dag.powMaxBits
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}
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// Fetch window of dag.difficultyAdjustmentWindowSize + 1 so we can have dag.difficultyAdjustmentWindowSize block intervals
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timestampsWindow := blueBlockWindow(bluestParent, dag.difficultyAdjustmentWindowSize+1)
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windowMinTimestamp, windowMaxTimeStamp := timestampsWindow.minMaxTimestamps()
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// Remove the last block from the window so to calculate the average target of dag.difficultyAdjustmentWindowSize blocks
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targetsWindow := timestampsWindow[:dag.difficultyAdjustmentWindowSize]
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// Calculate new target difficulty as:
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// averageWindowTarget * (windowMinTimestamp / (targetTimePerBlock * windowSize))
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// The result uses integer division which means it will be slightly
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// rounded down.
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newTarget := bigintpool.Acquire(0)
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defer bigintpool.Release(newTarget)
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windowTimeStampDifference := bigintpool.Acquire(windowMaxTimeStamp - windowMinTimestamp)
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defer bigintpool.Release(windowTimeStampDifference)
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targetTimePerBlock := bigintpool.Acquire(dag.Params.TargetTimePerBlock.Milliseconds())
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defer bigintpool.Release(targetTimePerBlock)
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difficultyAdjustmentWindowSize := bigintpool.Acquire(int64(dag.difficultyAdjustmentWindowSize))
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defer bigintpool.Release(difficultyAdjustmentWindowSize)
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targetsWindow.averageTarget(newTarget)
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newTarget.
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Mul(newTarget, windowTimeStampDifference).
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Div(newTarget, targetTimePerBlock).
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Div(newTarget, difficultyAdjustmentWindowSize)
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if newTarget.Cmp(dag.Params.PowMax) > 0 {
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return dag.powMaxBits
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}
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newTargetBits := util.BigToCompact(newTarget)
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return newTargetBits
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}
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// NextRequiredDifficulty calculates the required difficulty for a block that will
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// be built on top of the current tips.
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//
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// This function is safe for concurrent access.
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func (dag *BlockDAG) NextRequiredDifficulty(timestamp mstime.Time) uint32 {
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difficulty := dag.requiredDifficulty(dag.virtual.parents.bluest(), timestamp)
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return difficulty
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}
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