package ar import ( "math/big" "github.com/ethereum/eth-go/ethutil" ) type Entry struct { op OpsFunc i, j *big.Int } type Tape struct { tape []Entry block Block } func NewTape(block Block) *Tape { return &Tape{nil, block} } func (self *Tape) gen(w, h int64, gen NumberGenerator) { self.tape = nil for v := int64(0); v < h; v++ { op := ops[gen.rand64(lenops).Int64()] r := gen.rand64(100).Uint64() var j *big.Int if r < 20 && v > 20 { j = self.tape[len(self.tape)-1].i } else { j = gen.rand64(w) } i := gen.rand64(w) self.tape = append(self.tape, Entry{op, i, j}) } } func (self *Tape) runTape(w, h int64, gen NumberGenerator) *big.Int { var mem []*big.Int for i := int64(0); i < w; i++ { mem = append(mem, gen.rand(ethutil.BigPow(2, 64))) } set := func(i, j int) Entry { entry := self.tape[i*100+j] mem[entry.i.Uint64()] = entry.op(entry.i, entry.j) return entry } dir := true for i := 0; i < int(h)/100; i++ { var entry Entry if dir { for j := 0; j < 100; j++ { entry = set(i, j) } } else { for j := 99; i >= 0; j-- { entry = set(i, j) } } t := mem[entry.i.Uint64()] if big.NewInt(2).Cmp(new(big.Int).Mod(t, big.NewInt(37))) < 0 { dir = !dir } } return Sha3(mem) } func (self *Tape) Verify(header, nonce []byte) bool { n := ethutil.BigD(nonce) var w int64 = 10000 var h int64 = 150000 gen := Rnd(Sha3([]interface{}{header, new(big.Int).Div(n, big.NewInt(1000))})) self.gen(w, h, gen) gen = Rnd(Sha3([]interface{}{header, new(big.Int).Mod(n, big.NewInt(1000))})) hash := self.runTape(w, h, gen) it := self.block.Trie().Iterator() next := it.Next(string(new(big.Int).Mod(hash, ethutil.BigPow(2, 160)).Bytes())) req := ethutil.BigPow(2, 256) req.Div(req, self.block.Diff()) return Sha3([]interface{}{hash, next}).Cmp(req) < 0 } func (self *Tape) Run(header []byte) []byte { nonce := big.NewInt(0) var w int64 = 10000 var h int64 = 150000 req := ethutil.BigPow(2, 256) req.Div(req, self.block.Diff()) for { if new(big.Int).Mod(nonce, b(1000)).Cmp(b(0)) == 0 { gen := Rnd(Sha3([]interface{}{header, new(big.Int).Div(nonce, big.NewInt(1000))})) self.gen(w, h, gen) } gen := Rnd(Sha3([]interface{}{header, new(big.Int).Mod(nonce, big.NewInt(1000))})) hash := self.runTape(w, h, gen) it := self.block.Trie().Iterator() next := it.Next(string(new(big.Int).Mod(hash, ethutil.BigPow(2, 160)).Bytes())) if Sha3([]interface{}{hash, next}).Cmp(req) < 0 { return nonce.Bytes() } else { nonce.Add(nonce, ethutil.Big1) } } }