path: root/pow/ezp/pow.go

package ezp

import (
    "math/big"
    "math/rand"
    "time"

    "github.com/ethereum/go-ethereum/crypto"
    "github.com/ethereum/go-ethereum/crypto/sha3"
    "github.com/ethereum/go-ethereum/ethutil"
    "github.com/ethereum/go-ethereum/logger"
    "github.com/ethereum/go-ethereum/pow"
)

var powlogger = logger.NewLogger("POW")

type EasyPow struct {
    hash     *big.Int
    HashRate int64
    turbo    bool
}

func New() *EasyPow {
    return &EasyPow{turbo: false}
}

func (pow *EasyPow) GetHashrate() int64 {
    return pow.HashRate
}

func (pow *EasyPow) Turbo(on bool) {
    pow.turbo = on
}

func (pow *EasyPow) Search(block pow.Block, stop <-chan struct{}) []byte {
    r := rand.New(rand.NewSource(time.Now().UnixNano()))
    hash := block.HashNoNonce()
    diff := block.Difficulty()
    i := int64(0)
    start := time.Now().UnixNano()
    t := time.Now()

    for {
        select {
        case <-stop:
            powlogger.Infoln("Breaking from mining")
            pow.HashRate = 0
            return nil
        default:
            i++

            if time.Since(t) > (1 * time.Second) {
                elapsed := time.Now().UnixNano() - start
                hashes := ((float64(1e9) / float64(elapsed)) * float64(i)) / 1000
                pow.HashRate = int64(hashes)
                //powlogger.Infoln("Hashing @", pow.HashRate, "khash")

                t = time.Now()
            }

            sha := crypto.Sha3(big.NewInt(r.Int63()).Bytes())
            if verify(hash, diff, sha) {
                return sha
            }
        }

        if !pow.turbo {
            time.Sleep(20 * time.Microsecond)
        }
    }

    return nil
}

func (pow *EasyPow) Verify(block pow.Block) bool {
    return Verify(block)
}

func verify(hash []byte, diff *big.Int, nonce []byte) bool {
    sha := sha3.NewKeccak256()

    d := append(hash, nonce...)
    sha.Write(d)

    verification := new(big.Int).Div(ethutil.BigPow(2, 256), diff)
    res := ethutil.U256(ethutil.BigD(sha.Sum(nil)))

    return res.Cmp(verification) <= 0
}

func Verify(block pow.Block) bool {
    return verify(block.HashNoNonce(), block.Difficulty(), block.N())
}