* core/evm, contracts: avoid copying memory for input in calls + make ecrecover not modify input buffer * core/vm: optimize mstore a bit * core/vm: change Get -> GetCopy in vm memory access
		
			
				
	
	
		
			503 lines
		
	
	
		
			16 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
			
		
		
	
	
			503 lines
		
	
	
		
			16 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
// Copyright 2014 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 vm
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import (
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	"crypto/sha256"
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	"encoding/binary"
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	"errors"
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	"math/big"
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	"github.com/ethereum/go-ethereum/common"
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	"github.com/ethereum/go-ethereum/common/math"
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	"github.com/ethereum/go-ethereum/crypto"
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	"github.com/ethereum/go-ethereum/crypto/blake2b"
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	"github.com/ethereum/go-ethereum/crypto/bn256"
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	"github.com/ethereum/go-ethereum/params"
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	"golang.org/x/crypto/ripemd160"
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)
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// PrecompiledContract is the basic interface for native Go contracts. The implementation
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// requires a deterministic gas count based on the input size of the Run method of the
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// contract.
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type PrecompiledContract interface {
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	RequiredGas(input []byte) uint64  // RequiredPrice calculates the contract gas use
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	Run(input []byte) ([]byte, error) // Run runs the precompiled contract
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}
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// PrecompiledContractsHomestead contains the default set of pre-compiled Ethereum
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// contracts used in the Frontier and Homestead releases.
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var PrecompiledContractsHomestead = map[common.Address]PrecompiledContract{
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	common.BytesToAddress([]byte{1}): &ecrecover{},
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	common.BytesToAddress([]byte{2}): &sha256hash{},
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	common.BytesToAddress([]byte{3}): &ripemd160hash{},
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	common.BytesToAddress([]byte{4}): &dataCopy{},
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}
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// PrecompiledContractsByzantium contains the default set of pre-compiled Ethereum
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// contracts used in the Byzantium release.
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var PrecompiledContractsByzantium = map[common.Address]PrecompiledContract{
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	common.BytesToAddress([]byte{1}): &ecrecover{},
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	common.BytesToAddress([]byte{2}): &sha256hash{},
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	common.BytesToAddress([]byte{3}): &ripemd160hash{},
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	common.BytesToAddress([]byte{4}): &dataCopy{},
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	common.BytesToAddress([]byte{5}): &bigModExp{},
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	common.BytesToAddress([]byte{6}): &bn256AddByzantium{},
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	common.BytesToAddress([]byte{7}): &bn256ScalarMulByzantium{},
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	common.BytesToAddress([]byte{8}): &bn256PairingByzantium{},
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}
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// PrecompiledContractsIstanbul contains the default set of pre-compiled Ethereum
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// contracts used in the Istanbul release.
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var PrecompiledContractsIstanbul = map[common.Address]PrecompiledContract{
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	common.BytesToAddress([]byte{1}): &ecrecover{},
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	common.BytesToAddress([]byte{2}): &sha256hash{},
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	common.BytesToAddress([]byte{3}): &ripemd160hash{},
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	common.BytesToAddress([]byte{4}): &dataCopy{},
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	common.BytesToAddress([]byte{5}): &bigModExp{},
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	common.BytesToAddress([]byte{6}): &bn256AddIstanbul{},
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	common.BytesToAddress([]byte{7}): &bn256ScalarMulIstanbul{},
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	common.BytesToAddress([]byte{8}): &bn256PairingIstanbul{},
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	common.BytesToAddress([]byte{9}): &blake2F{},
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}
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// RunPrecompiledContract runs and evaluates the output of a precompiled contract.
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func RunPrecompiledContract(p PrecompiledContract, input []byte, contract *Contract) (ret []byte, err error) {
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	gas := p.RequiredGas(input)
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	if contract.UseGas(gas) {
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		return p.Run(input)
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	}
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	return nil, ErrOutOfGas
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}
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// ECRECOVER implemented as a native contract.
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type ecrecover struct{}
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func (c *ecrecover) RequiredGas(input []byte) uint64 {
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	return params.EcrecoverGas
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}
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func (c *ecrecover) Run(input []byte) ([]byte, error) {
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	const ecRecoverInputLength = 128
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	input = common.RightPadBytes(input, ecRecoverInputLength)
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	// "input" is (hash, v, r, s), each 32 bytes
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	// but for ecrecover we want (r, s, v)
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	r := new(big.Int).SetBytes(input[64:96])
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	s := new(big.Int).SetBytes(input[96:128])
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	v := input[63] - 27
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	// tighter sig s values input homestead only apply to tx sigs
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	if !allZero(input[32:63]) || !crypto.ValidateSignatureValues(v, r, s, false) {
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		return nil, nil
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	}
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	// We must make sure not to modify the 'input', so placing the 'v' along with
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	// the signature needs to be done on a new allocation
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	sig := make([]byte, 65)
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	copy(sig, input[64:128])
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	sig[64] = v
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	// v needs to be at the end for libsecp256k1
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	pubKey, err := crypto.Ecrecover(input[:32], sig)
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	// make sure the public key is a valid one
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	if err != nil {
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		return nil, nil
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	}
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	// the first byte of pubkey is bitcoin heritage
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	return common.LeftPadBytes(crypto.Keccak256(pubKey[1:])[12:], 32), nil
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}
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// SHA256 implemented as a native contract.
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type sha256hash struct{}
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// RequiredGas returns the gas required to execute the pre-compiled contract.
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//
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// This method does not require any overflow checking as the input size gas costs
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// required for anything significant is so high it's impossible to pay for.
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func (c *sha256hash) RequiredGas(input []byte) uint64 {
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	return uint64(len(input)+31)/32*params.Sha256PerWordGas + params.Sha256BaseGas
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}
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func (c *sha256hash) Run(input []byte) ([]byte, error) {
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	h := sha256.Sum256(input)
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	return h[:], nil
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}
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// RIPEMD160 implemented as a native contract.
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type ripemd160hash struct{}
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// RequiredGas returns the gas required to execute the pre-compiled contract.
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//
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// This method does not require any overflow checking as the input size gas costs
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// required for anything significant is so high it's impossible to pay for.
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func (c *ripemd160hash) RequiredGas(input []byte) uint64 {
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	return uint64(len(input)+31)/32*params.Ripemd160PerWordGas + params.Ripemd160BaseGas
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}
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func (c *ripemd160hash) Run(input []byte) ([]byte, error) {
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	ripemd := ripemd160.New()
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	ripemd.Write(input)
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	return common.LeftPadBytes(ripemd.Sum(nil), 32), nil
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}
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// data copy implemented as a native contract.
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type dataCopy struct{}
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// RequiredGas returns the gas required to execute the pre-compiled contract.
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//
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// This method does not require any overflow checking as the input size gas costs
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// required for anything significant is so high it's impossible to pay for.
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func (c *dataCopy) RequiredGas(input []byte) uint64 {
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	return uint64(len(input)+31)/32*params.IdentityPerWordGas + params.IdentityBaseGas
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}
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func (c *dataCopy) Run(in []byte) ([]byte, error) {
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	return in, nil
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}
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// bigModExp implements a native big integer exponential modular operation.
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type bigModExp struct{}
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var (
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	big1      = big.NewInt(1)
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	big4      = big.NewInt(4)
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	big8      = big.NewInt(8)
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	big16     = big.NewInt(16)
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	big32     = big.NewInt(32)
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	big64     = big.NewInt(64)
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	big96     = big.NewInt(96)
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	big480    = big.NewInt(480)
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	big1024   = big.NewInt(1024)
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	big3072   = big.NewInt(3072)
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	big199680 = big.NewInt(199680)
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)
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// RequiredGas returns the gas required to execute the pre-compiled contract.
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func (c *bigModExp) RequiredGas(input []byte) uint64 {
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	var (
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		baseLen = new(big.Int).SetBytes(getData(input, 0, 32))
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		expLen  = new(big.Int).SetBytes(getData(input, 32, 32))
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		modLen  = new(big.Int).SetBytes(getData(input, 64, 32))
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	)
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	if len(input) > 96 {
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		input = input[96:]
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	} else {
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		input = input[:0]
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	}
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	// Retrieve the head 32 bytes of exp for the adjusted exponent length
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	var expHead *big.Int
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	if big.NewInt(int64(len(input))).Cmp(baseLen) <= 0 {
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		expHead = new(big.Int)
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	} else {
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		if expLen.Cmp(big32) > 0 {
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			expHead = new(big.Int).SetBytes(getData(input, baseLen.Uint64(), 32))
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		} else {
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			expHead = new(big.Int).SetBytes(getData(input, baseLen.Uint64(), expLen.Uint64()))
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		}
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	}
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	// Calculate the adjusted exponent length
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	var msb int
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	if bitlen := expHead.BitLen(); bitlen > 0 {
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		msb = bitlen - 1
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	}
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	adjExpLen := new(big.Int)
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	if expLen.Cmp(big32) > 0 {
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		adjExpLen.Sub(expLen, big32)
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		adjExpLen.Mul(big8, adjExpLen)
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	}
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	adjExpLen.Add(adjExpLen, big.NewInt(int64(msb)))
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	// Calculate the gas cost of the operation
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	gas := new(big.Int).Set(math.BigMax(modLen, baseLen))
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	switch {
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	case gas.Cmp(big64) <= 0:
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		gas.Mul(gas, gas)
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	case gas.Cmp(big1024) <= 0:
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		gas = new(big.Int).Add(
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			new(big.Int).Div(new(big.Int).Mul(gas, gas), big4),
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			new(big.Int).Sub(new(big.Int).Mul(big96, gas), big3072),
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		)
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	default:
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		gas = new(big.Int).Add(
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			new(big.Int).Div(new(big.Int).Mul(gas, gas), big16),
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			new(big.Int).Sub(new(big.Int).Mul(big480, gas), big199680),
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		)
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	}
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	gas.Mul(gas, math.BigMax(adjExpLen, big1))
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	gas.Div(gas, new(big.Int).SetUint64(params.ModExpQuadCoeffDiv))
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	if gas.BitLen() > 64 {
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		return math.MaxUint64
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	}
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	return gas.Uint64()
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}
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func (c *bigModExp) Run(input []byte) ([]byte, error) {
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	var (
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		baseLen = new(big.Int).SetBytes(getData(input, 0, 32)).Uint64()
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		expLen  = new(big.Int).SetBytes(getData(input, 32, 32)).Uint64()
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		modLen  = new(big.Int).SetBytes(getData(input, 64, 32)).Uint64()
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	)
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	if len(input) > 96 {
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		input = input[96:]
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	} else {
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		input = input[:0]
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	}
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	// Handle a special case when both the base and mod length is zero
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	if baseLen == 0 && modLen == 0 {
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		return []byte{}, nil
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	}
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	// Retrieve the operands and execute the exponentiation
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	var (
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		base = new(big.Int).SetBytes(getData(input, 0, baseLen))
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		exp  = new(big.Int).SetBytes(getData(input, baseLen, expLen))
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		mod  = new(big.Int).SetBytes(getData(input, baseLen+expLen, modLen))
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	)
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	if mod.BitLen() == 0 {
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		// Modulo 0 is undefined, return zero
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		return common.LeftPadBytes([]byte{}, int(modLen)), nil
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	}
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	return common.LeftPadBytes(base.Exp(base, exp, mod).Bytes(), int(modLen)), nil
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}
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// newCurvePoint unmarshals a binary blob into a bn256 elliptic curve point,
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// returning it, or an error if the point is invalid.
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func newCurvePoint(blob []byte) (*bn256.G1, error) {
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	p := new(bn256.G1)
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	if _, err := p.Unmarshal(blob); err != nil {
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		return nil, err
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	}
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	return p, nil
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}
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// newTwistPoint unmarshals a binary blob into a bn256 elliptic curve point,
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// returning it, or an error if the point is invalid.
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func newTwistPoint(blob []byte) (*bn256.G2, error) {
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	p := new(bn256.G2)
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	if _, err := p.Unmarshal(blob); err != nil {
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		return nil, err
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	}
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	return p, nil
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}
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// runBn256Add implements the Bn256Add precompile, referenced by both
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// Byzantium and Istanbul operations.
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func runBn256Add(input []byte) ([]byte, error) {
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	x, err := newCurvePoint(getData(input, 0, 64))
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	if err != nil {
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		return nil, err
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	}
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	y, err := newCurvePoint(getData(input, 64, 64))
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	if err != nil {
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		return nil, err
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	}
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	res := new(bn256.G1)
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	res.Add(x, y)
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	return res.Marshal(), nil
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}
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// bn256Add implements a native elliptic curve point addition conforming to
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// Istanbul consensus rules.
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type bn256AddIstanbul struct{}
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// RequiredGas returns the gas required to execute the pre-compiled contract.
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func (c *bn256AddIstanbul) RequiredGas(input []byte) uint64 {
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	return params.Bn256AddGasIstanbul
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}
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func (c *bn256AddIstanbul) Run(input []byte) ([]byte, error) {
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	return runBn256Add(input)
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}
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// bn256AddByzantium implements a native elliptic curve point addition
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// conforming to Byzantium consensus rules.
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type bn256AddByzantium struct{}
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// RequiredGas returns the gas required to execute the pre-compiled contract.
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func (c *bn256AddByzantium) RequiredGas(input []byte) uint64 {
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	return params.Bn256AddGasByzantium
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}
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func (c *bn256AddByzantium) Run(input []byte) ([]byte, error) {
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	return runBn256Add(input)
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}
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// runBn256ScalarMul implements the Bn256ScalarMul precompile, referenced by
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// both Byzantium and Istanbul operations.
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func runBn256ScalarMul(input []byte) ([]byte, error) {
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	p, err := newCurvePoint(getData(input, 0, 64))
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	if err != nil {
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		return nil, err
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	}
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	res := new(bn256.G1)
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	res.ScalarMult(p, new(big.Int).SetBytes(getData(input, 64, 32)))
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	return res.Marshal(), nil
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}
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// bn256ScalarMulIstanbul implements a native elliptic curve scalar
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// multiplication conforming to Istanbul consensus rules.
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type bn256ScalarMulIstanbul struct{}
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// RequiredGas returns the gas required to execute the pre-compiled contract.
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func (c *bn256ScalarMulIstanbul) RequiredGas(input []byte) uint64 {
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	return params.Bn256ScalarMulGasIstanbul
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}
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func (c *bn256ScalarMulIstanbul) Run(input []byte) ([]byte, error) {
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	return runBn256ScalarMul(input)
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}
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// bn256ScalarMulByzantium implements a native elliptic curve scalar
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// multiplication conforming to Byzantium consensus rules.
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type bn256ScalarMulByzantium struct{}
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// RequiredGas returns the gas required to execute the pre-compiled contract.
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func (c *bn256ScalarMulByzantium) RequiredGas(input []byte) uint64 {
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	return params.Bn256ScalarMulGasByzantium
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}
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func (c *bn256ScalarMulByzantium) Run(input []byte) ([]byte, error) {
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	return runBn256ScalarMul(input)
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}
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var (
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	// true32Byte is returned if the bn256 pairing check succeeds.
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	true32Byte = []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}
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	// false32Byte is returned if the bn256 pairing check fails.
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	false32Byte = make([]byte, 32)
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	// errBadPairingInput is returned if the bn256 pairing input is invalid.
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	errBadPairingInput = errors.New("bad elliptic curve pairing size")
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)
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// runBn256Pairing implements the Bn256Pairing precompile, referenced by both
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						|
// Byzantium and Istanbul operations.
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func runBn256Pairing(input []byte) ([]byte, error) {
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	// Handle some corner cases cheaply
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						|
	if len(input)%192 > 0 {
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		return nil, errBadPairingInput
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						|
	}
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	// Convert the input into a set of coordinates
 | 
						|
	var (
 | 
						|
		cs []*bn256.G1
 | 
						|
		ts []*bn256.G2
 | 
						|
	)
 | 
						|
	for i := 0; i < len(input); i += 192 {
 | 
						|
		c, err := newCurvePoint(input[i : i+64])
 | 
						|
		if err != nil {
 | 
						|
			return nil, err
 | 
						|
		}
 | 
						|
		t, err := newTwistPoint(input[i+64 : i+192])
 | 
						|
		if err != nil {
 | 
						|
			return nil, err
 | 
						|
		}
 | 
						|
		cs = append(cs, c)
 | 
						|
		ts = append(ts, t)
 | 
						|
	}
 | 
						|
	// Execute the pairing checks and return the results
 | 
						|
	if bn256.PairingCheck(cs, ts) {
 | 
						|
		return true32Byte, nil
 | 
						|
	}
 | 
						|
	return false32Byte, nil
 | 
						|
}
 | 
						|
 | 
						|
// bn256PairingIstanbul implements a pairing pre-compile for the bn256 curve
 | 
						|
// conforming to Istanbul consensus rules.
 | 
						|
type bn256PairingIstanbul struct{}
 | 
						|
 | 
						|
// RequiredGas returns the gas required to execute the pre-compiled contract.
 | 
						|
func (c *bn256PairingIstanbul) RequiredGas(input []byte) uint64 {
 | 
						|
	return params.Bn256PairingBaseGasIstanbul + uint64(len(input)/192)*params.Bn256PairingPerPointGasIstanbul
 | 
						|
}
 | 
						|
 | 
						|
func (c *bn256PairingIstanbul) Run(input []byte) ([]byte, error) {
 | 
						|
	return runBn256Pairing(input)
 | 
						|
}
 | 
						|
 | 
						|
// bn256PairingByzantium implements a pairing pre-compile for the bn256 curve
 | 
						|
// conforming to Byzantium consensus rules.
 | 
						|
type bn256PairingByzantium struct{}
 | 
						|
 | 
						|
// RequiredGas returns the gas required to execute the pre-compiled contract.
 | 
						|
func (c *bn256PairingByzantium) RequiredGas(input []byte) uint64 {
 | 
						|
	return params.Bn256PairingBaseGasByzantium + uint64(len(input)/192)*params.Bn256PairingPerPointGasByzantium
 | 
						|
}
 | 
						|
 | 
						|
func (c *bn256PairingByzantium) Run(input []byte) ([]byte, error) {
 | 
						|
	return runBn256Pairing(input)
 | 
						|
}
 | 
						|
 | 
						|
type blake2F struct{}
 | 
						|
 | 
						|
func (c *blake2F) RequiredGas(input []byte) uint64 {
 | 
						|
	// If the input is malformed, we can't calculate the gas, return 0 and let the
 | 
						|
	// actual call choke and fault.
 | 
						|
	if len(input) != blake2FInputLength {
 | 
						|
		return 0
 | 
						|
	}
 | 
						|
	return uint64(binary.BigEndian.Uint32(input[0:4]))
 | 
						|
}
 | 
						|
 | 
						|
const (
 | 
						|
	blake2FInputLength        = 213
 | 
						|
	blake2FFinalBlockBytes    = byte(1)
 | 
						|
	blake2FNonFinalBlockBytes = byte(0)
 | 
						|
)
 | 
						|
 | 
						|
var (
 | 
						|
	errBlake2FInvalidInputLength = errors.New("invalid input length")
 | 
						|
	errBlake2FInvalidFinalFlag   = errors.New("invalid final flag")
 | 
						|
)
 | 
						|
 | 
						|
func (c *blake2F) Run(input []byte) ([]byte, error) {
 | 
						|
	// Make sure the input is valid (correct lenth and final flag)
 | 
						|
	if len(input) != blake2FInputLength {
 | 
						|
		return nil, errBlake2FInvalidInputLength
 | 
						|
	}
 | 
						|
	if input[212] != blake2FNonFinalBlockBytes && input[212] != blake2FFinalBlockBytes {
 | 
						|
		return nil, errBlake2FInvalidFinalFlag
 | 
						|
	}
 | 
						|
	// Parse the input into the Blake2b call parameters
 | 
						|
	var (
 | 
						|
		rounds = binary.BigEndian.Uint32(input[0:4])
 | 
						|
		final  = (input[212] == blake2FFinalBlockBytes)
 | 
						|
 | 
						|
		h [8]uint64
 | 
						|
		m [16]uint64
 | 
						|
		t [2]uint64
 | 
						|
	)
 | 
						|
	for i := 0; i < 8; i++ {
 | 
						|
		offset := 4 + i*8
 | 
						|
		h[i] = binary.LittleEndian.Uint64(input[offset : offset+8])
 | 
						|
	}
 | 
						|
	for i := 0; i < 16; i++ {
 | 
						|
		offset := 68 + i*8
 | 
						|
		m[i] = binary.LittleEndian.Uint64(input[offset : offset+8])
 | 
						|
	}
 | 
						|
	t[0] = binary.LittleEndian.Uint64(input[196:204])
 | 
						|
	t[1] = binary.LittleEndian.Uint64(input[204:212])
 | 
						|
 | 
						|
	// Execute the compression function, extract and return the result
 | 
						|
	blake2b.F(&h, m, t, final, rounds)
 | 
						|
 | 
						|
	output := make([]byte, 64)
 | 
						|
	for i := 0; i < 8; i++ {
 | 
						|
		offset := i * 8
 | 
						|
		binary.LittleEndian.PutUint64(output[offset:offset+8], h[i])
 | 
						|
	}
 | 
						|
	return output, nil
 | 
						|
}
 |