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|
package ar
import (
"math/big"
"github.com/ethereum/go-ethereum/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)
}
}
}
|
