d2cf49327f
* consensus/misc, params: add EIP-4844 blobfee conversions * consensus/misc: pull in fakeExponential test cases * consensus/misc: reuse bigints * consensus/misc: nit renames, additional larger testcase --------- Co-authored-by: Roberto Bayardo <bayardo@alum.mit.edu> Co-authored-by: Martin Holst Swende <martin@swende.se>
55 lines
1.8 KiB
Go
55 lines
1.8 KiB
Go
// Copyright 2023 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package misc
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import (
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"math/big"
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"github.com/ethereum/go-ethereum/params"
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)
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var (
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minDataGasPrice = big.NewInt(params.BlobTxMinDataGasprice)
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dataGaspriceUpdateFraction = big.NewInt(params.BlobTxDataGaspriceUpdateFraction)
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)
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// CalcBlobFee calculates the blobfee from the header's excess data gas field.
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func CalcBlobFee(excessDataGas *big.Int) *big.Int {
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// If this block does not yet have EIP-4844 enabled, return the starting fee
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if excessDataGas == nil {
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return big.NewInt(params.BlobTxMinDataGasprice)
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}
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return fakeExponential(minDataGasPrice, excessDataGas, dataGaspriceUpdateFraction)
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}
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// fakeExponential approximates factor * e ** (numerator / denominator) using
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// Taylor expansion.
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func fakeExponential(factor, numerator, denominator *big.Int) *big.Int {
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var (
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output = new(big.Int)
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accum = new(big.Int).Mul(factor, denominator)
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)
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for i := 1; accum.Sign() > 0; i++ {
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output.Add(output, accum)
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accum.Mul(accum, numerator)
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accum.Div(accum, denominator)
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accum.Div(accum, big.NewInt(int64(i)))
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}
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return output.Div(output, denominator)
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}
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