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// Copyright 2014 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package dagger
import (
"hash"
"math/big"
"math/rand"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/crypto/sha3"
"github.com/ethereum/go-ethereum/logger"
)
var powlogger = logger.NewLogger("POW")
type Dagger struct {
hash *big.Int
xn *big.Int
}
var Found bool
func (dag *Dagger) Find(obj *big.Int, resChan chan int64) {
r := rand.New(rand.NewSource(time.Now().UnixNano()))
for i := 0; i < 1000; i++ {
rnd := r.Int63()
res := dag.Eval(big.NewInt(rnd))
powlogger.Infof("rnd %v\nres %v\nobj %v\n", rnd, res, obj)
if res.Cmp(obj) < 0 {
// Post back result on the channel
resChan <- rnd
// Notify other threads we've found a valid nonce
Found = true
}
// Break out if found
if Found {
break
}
}
resChan <- 0
}
func (dag *Dagger) Search(hash, diff *big.Int) (uint64, []byte) {
// TODO fix multi threading. Somehow it results in the wrong nonce
amountOfRoutines := 1
dag.hash = hash
obj := common.BigPow(2, 256)
obj = obj.Div(obj, diff)
Found = false
resChan := make(chan int64, 3)
var res int64
for k := 0; k < amountOfRoutines; k++ {
go dag.Find(obj, resChan)
// Wait for each go routine to finish
}
for k := 0; k < amountOfRoutines; k++ {
// Get the result from the channel. 0 = quit
if r := <-resChan; r != 0 {
res = r
}
}
return uint64(res), nil
}
func (dag *Dagger) Verify(hash, diff, nonce *big.Int) bool {
dag.hash = hash
obj := common.BigPow(2, 256)
obj = obj.Div(obj, diff)
return dag.Eval(nonce).Cmp(obj) < 0
}
func DaggerVerify(hash, diff, nonce *big.Int) bool {
dagger := &Dagger{}
dagger.hash = hash
obj := common.BigPow(2, 256)
obj = obj.Div(obj, diff)
return dagger.Eval(nonce).Cmp(obj) < 0
}
func (dag *Dagger) Node(L uint64, i uint64) *big.Int {
if L == i {
return dag.hash
}
var m *big.Int
if L == 9 {
m = big.NewInt(16)
} else {
m = big.NewInt(3)
}
sha := sha3.NewKeccak256()
sha.Reset()
d := sha3.NewKeccak256()
b := new(big.Int)
ret := new(big.Int)
for k := 0; k < int(m.Uint64()); k++ {
d.Reset()
d.Write(dag.hash.Bytes())
d.Write(dag.xn.Bytes())
d.Write(big.NewInt(int64(L)).Bytes())
d.Write(big.NewInt(int64(i)).Bytes())
d.Write(big.NewInt(int64(k)).Bytes())
b.SetBytes(Sum(d))
pk := b.Uint64() & ((1 << ((L - 1) * 3)) - 1)
sha.Write(dag.Node(L-1, pk).Bytes())
}
ret.SetBytes(Sum(sha))
return ret
}
func Sum(sha hash.Hash) []byte {
//in := make([]byte, 32)
return sha.Sum(nil)
}
func (dag *Dagger) Eval(N *big.Int) *big.Int {
pow := common.BigPow(2, 26)
dag.xn = pow.Div(N, pow)
sha := sha3.NewKeccak256()
sha.Reset()
ret := new(big.Int)
for k := 0; k < 4; k++ {
d := sha3.NewKeccak256()
b := new(big.Int)
d.Reset()
d.Write(dag.hash.Bytes())
d.Write(dag.xn.Bytes())
d.Write(N.Bytes())
d.Write(big.NewInt(int64(k)).Bytes())
b.SetBytes(Sum(d))
pk := (b.Uint64() & 0x1ffffff)
sha.Write(dag.Node(9, pk).Bytes())
}
return ret.SetBytes(Sum(sha))
}
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