func (dag *Dagger) Eval(N *big.Int) *big.Int {
pow := ethutil.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))
}
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 Sha3Bin(data []byte) []byte {
d := sha3.NewKeccak256()
d.Reset()
d.Write(data)
return d.Sum(nil)
}
func (pow *EasyPow) Verify(hash []byte, diff *big.Int, nonce []byte) bool {
sha := sha3.NewKeccak256()
d := append(hash, nonce...)
sha.Write(d)
v := ethutil.BigPow(2, 256)
ret := new(big.Int).Div(v, diff)
res := new(big.Int)
res.SetBytes(sha.Sum(nil))
return res.Cmp(ret) == -1
}