d456b8be9b
Reads stored block timestamps and cumulative difficulties, calls difficulty.NextDifficulty() with config.BlockTarget. Returns uint64. Adds getBlockMeta() for lightweight metadata-only lookups. Co-Authored-By: Charon <charon@lethean.io>
48 lines
1.2 KiB
Go
48 lines
1.2 KiB
Go
// Copyright (c) 2017-2026 Lethean (https://lt.hn)
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//
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// Licensed under the European Union Public Licence (EUPL) version 1.2.
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// SPDX-License-Identifier: EUPL-1.2
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package chain
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import (
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"math/big"
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"forge.lthn.ai/core/go-blockchain/config"
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"forge.lthn.ai/core/go-blockchain/difficulty"
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)
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// NextDifficulty computes the expected difficulty for the block at the given
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// height, using the LWMA algorithm over stored block history.
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func (c *Chain) NextDifficulty(height uint64) (uint64, error) {
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if height == 0 {
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return 1, nil
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}
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// Determine how far back to look.
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lookback := height
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if lookback > difficulty.BlocksCount {
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lookback = difficulty.BlocksCount
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}
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startHeight := height - lookback
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count := int(lookback)
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timestamps := make([]uint64, count)
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cumulDiffs := make([]*big.Int, count)
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for i := 0; i < count; i++ {
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meta, err := c.getBlockMeta(startHeight + uint64(i))
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if err != nil {
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// Fewer blocks than expected — use what we have.
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timestamps = timestamps[:i]
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cumulDiffs = cumulDiffs[:i]
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break
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}
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timestamps[i] = meta.Timestamp
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cumulDiffs[i] = new(big.Int).SetUint64(meta.CumulativeDiff)
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}
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result := difficulty.NextDifficulty(timestamps, cumulDiffs, config.BlockTarget)
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return result.Uint64(), nil
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}
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