Golang Int.Add方法代码示例

// schnorrCombineSigs combines a list of partial Schnorr signatures s values
// into a complete signature s for some group public key. This is achieved
// by simply adding the s values of the partial signatures as scalars.
func schnorrCombineSigs(curve *secp256k1.KoblitzCurve, sigss [][]byte) (*big.Int,
	error) {
	combinedSigS := new(big.Int).SetInt64(0)
	for i, sigs := range sigss {
		sigsBI := EncodedBytesToBigInt(copyBytes(sigs))
		if sigsBI.Cmp(bigZero) == 0 {
			str := fmt.Sprintf("sig s %v is zero", i)
			return nil, schnorrError(ErrInputValue, str)
		}
		if sigsBI.Cmp(curve.N) >= 0 {
			str := fmt.Sprintf("sig s %v is out of bounds", i)
			return nil, schnorrError(ErrInputValue, str)
		}

		combinedSigS.Add(combinedSigS, sigsBI)
		combinedSigS.Mod(combinedSigS, curve.N)
	}

	if combinedSigS.Cmp(bigZero) == 0 {
		str := fmt.Sprintf("combined sig s %v is zero", combinedSigS)
		return nil, schnorrError(ErrZeroSigS, str)
	}

	return combinedSigS, nil
}

func bigAdd(IntSlice []big.Int) *big.Int {
	var sum *big.Int = big.NewInt(0)
	for i := 0; i < len(IntSlice); i++ {
		sum.Add(sum, &IntSlice[i])
	}
	return sum
}

/*
FromFactorBigInt returns n such that d | Mn if n <= max and d is odd. In other
cases zero is returned.

It is conjectured that every odd d ∊ N divides infinitely many Mersenne numbers.
The returned n should be the exponent of smallest such Mn.

NOTE: The computation of n from a given d performs roughly in O(n). It is
thus highly recomended to use the 'max' argument to limit the "searched"
exponent upper bound as appropriate. Otherwise the computation can take a long
time as a large factor can be a divisor of a Mn with exponent above the uint32
limits.

The FromFactorBigInt function is a modification of the original Will
Edgington's "reverse method", discussed here:
http://tech.groups.yahoo.com/group/primenumbers/message/15061
*/
func FromFactorBigInt(d *big.Int, max uint32) (n uint32) {
	if d.Bit(0) == 0 {
		return
	}

	var m big.Int
	for n < max {
		m.Add(&m, d)
		i := 0
		for ; m.Bit(i) == 1; i++ {
			if n == math.MaxUint32 {
				return 0
			}

			n++
		}
		m.Rsh(&m, uint(i))
		if m.Sign() == 0 {
			if n > max {
				n = 0
			}
			return
		}
	}
	return 0
}

// CalcGasLimit computes the gas limit of the next block after parent.
// The result may be modified by the caller.
// This is miner strategy, not consensus protocol.
func CalcGasLimit(parent *types.Block) *big.Int {
	// contrib = (parentGasUsed * 3 / 2) / 1024
	contrib := new(big.Int).Mul(parent.GasUsed(), big.NewInt(3))
	contrib = contrib.Div(contrib, big.NewInt(2))
	contrib = contrib.Div(contrib, params.GasLimitBoundDivisor)

	// decay = parentGasLimit / 1024 -1
	decay := new(big.Int).Div(parent.GasLimit(), params.GasLimitBoundDivisor)
	decay.Sub(decay, big.NewInt(1))

	/*
		strategy: gasLimit of block-to-mine is set based on parent's
		gasUsed value.  if parentGasUsed > parentGasLimit * (2/3) then we
		increase it, otherwise lower it (or leave it unchanged if it's right
		at that usage) the amount increased/decreased depends on how far away
		from parentGasLimit * (2/3) parentGasUsed is.
	*/
	gl := new(big.Int).Sub(parent.GasLimit(), decay)
	gl = gl.Add(gl, contrib)
	gl.Set(common.BigMax(gl, params.MinGasLimit))

	// however, if we're now below the target (TargetGasLimit) we increase the
	// limit as much as we can (parentGasLimit / 1024 -1)
	if gl.Cmp(params.TargetGasLimit) < 0 {
		gl.Add(parent.GasLimit(), decay)
		gl.Set(common.BigMin(gl, params.TargetGasLimit))
	}
	return gl
}

func SumOfBigInts(nums []*big.Int) *big.Int {
	var sum *big.Int = big.NewInt(0)
	for _, i := range nums {
		sum.Add(sum, i)
	}
	return sum
}

func (self *BlockProcessor) ApplyTransactions(gp GasPool, statedb *state.StateDB, block *types.Block, txs types.Transactions, transientProcess bool) (types.Receipts, error) {
	var (
		receipts      types.Receipts
		totalUsedGas  = big.NewInt(0)
		err           error
		cumulativeSum = new(big.Int)
		header        = block.Header()
	)

	for i, tx := range txs {
		statedb.StartRecord(tx.Hash(), block.Hash(), i)

		receipt, txGas, err := self.ApplyTransaction(gp, statedb, header, tx, totalUsedGas, transientProcess)
		if err != nil {
			return nil, err
		}

		if err != nil {
			glog.V(logger.Core).Infoln("TX err:", err)
		}
		receipts = append(receipts, receipt)

		cumulativeSum.Add(cumulativeSum, new(big.Int).Mul(txGas, tx.GasPrice()))
	}

	if block.GasUsed().Cmp(totalUsedGas) != 0 {
		return nil, ValidationError(fmt.Sprintf("gas used error (%v / %v)", block.GasUsed(), totalUsedGas))
	}

	if transientProcess {
		go self.eventMux.Post(PendingBlockEvent{block, statedb.Logs()})
	}

	return receipts, err
}

//Verify verifies the proof file server send.
func (sw *Swizzle) Verify(p Proof) (bool, error) {
	proof, ok := p.(*SwizzleProof)
	if !ok {
		return false, errors.New("use SwizzleProof instance for proof")
	}
	var rhs big.Int
	var dummy big.Int
	ch := sw.lastChallenge
	for i := 0; i < sw.chunks; i++ {
		f, err := keyedPRFBig(sw.fKey, sw.prime, i)
		if err != nil {
			return false, err
		}
		v, err := keyedPRFBig(ch.Key, ch.Vmax, i)
		if err != nil {
			return false, err
		}
		rhs.Add(&rhs, dummy.Mul(v, f))
	}
	for j := 0; j < ch.Sectors; j++ {
		alpha, err := keyedPRFBig(sw.alphaKey, sw.prime, j)
		if err != nil {
			return false, err
		}
		rhs.Add(&rhs, dummy.Mul(alpha, &proof.Mu[j]))
	}
	dummy.DivMod(&rhs, sw.prime, &rhs)
	if proof.Sigma.Cmp(&rhs) == 0 {
		return true, nil
	}
	return false, nil
}

func main() {
	var s string
	var n, two, tmp big.Int
	two.SetInt64(2)

	in, _ := os.Open("10519.in")
	defer in.Close()
	out, _ := os.Create("10519.out")
	defer out.Close()

	for {
		if _, err := fmt.Fscanf(in, "%s", &s); err != nil {
			break
		}
		if s == "0" {
			fmt.Fprintln(out, 1)
			continue
		}
		n.SetString(s, 10)
		tmp.Mul(&n, &n)
		tmp.Sub(&tmp, &n)
		tmp.Add(&tmp, &two)
		fmt.Fprintln(out, &tmp)
	}
}

func (block *Block) PayFee(addr []byte, fee *big.Int) bool {
	contract := block.state.GetContract(addr)
	// If we can't pay the fee return
	if contract == nil || contract.Amount.Cmp(fee) < 0 /* amount < fee */ {
		fmt.Println("Contract has insufficient funds", contract.Amount, fee)

		return false
	}

	base := new(big.Int)
	contract.Amount = base.Sub(contract.Amount, fee)
	block.state.trie.Update(string(addr), string(contract.RlpEncode()))

	data := block.state.trie.Get(string(block.Coinbase))

	// Get the ether (Coinbase) and add the fee (gief fee to miner)
	ether := NewAccountFromData([]byte(data))

	base = new(big.Int)
	ether.Amount = base.Add(ether.Amount, fee)

	block.state.trie.Update(string(block.Coinbase), string(ether.RlpEncode()))

	return true
}

// GenerateKey generates a public and private key pair using random source rand.
func GenerateKey(rand io.Reader) (priv PrivateKey, err error) {
	/* See Certicom's SEC1 3.2.1, pg.23 */
	/* See NSA's Suite B Implementer’s Guide to FIPS 186-3 (ECDSA) A.1.1, pg.18 */

	/* Select private key d randomly from [1, n) */

	/* Read N bit length random bytes + 64 extra bits  */
	b := make([]byte, secp256k1.N.BitLen()/8+8)
	_, err = io.ReadFull(rand, b)
	if err != nil {
		return priv, fmt.Errorf("Reading random reader: %v", err)
	}

	d := new(big.Int).SetBytes(b)

	/* Mod n-1 to shift d into [0, n-1) range */
	d.Mod(d, new(big.Int).Sub(secp256k1.N, big.NewInt(1)))
	/* Add one to shift d to [1, n) range */
	d.Add(d, big.NewInt(1))

	priv.D = d

	/* Derive public key from private key */
	priv.derive()

	return priv, nil
}

// powerOffset computes the offset by (n + 2^exp) % (2^mod)
func powerOffset(id []byte, exp int, mod int) []byte {
	// Copy the existing slice
	off := make([]byte, len(id))
	copy(off, id)

	// Convert the ID to a bigint
	idInt := big.Int{}
	idInt.SetBytes(id)

	// Get the offset
	two := big.NewInt(2)
	offset := big.Int{}
	offset.Exp(two, big.NewInt(int64(exp)), nil)

	// Sum
	sum := big.Int{}
	sum.Add(&idInt, &offset)

	// Get the ceiling
	ceil := big.Int{}
	ceil.Exp(two, big.NewInt(int64(mod)), nil)

	// Apply the mod
	idInt.Mod(&sum, &ceil)

	// Add together
	return idInt.Bytes()
}

// (n - 2^(k-1)) mod 2^m
func calcLastFinger(n []byte, k int) (string, []byte) {

	// convert the n to a bigint
	nBigInt := big.Int{}
	nBigInt.SetBytes(n)

	// get the right addend, i.e. 2^(k-1)
	two := big.NewInt(2)
	addend := big.Int{}
	addend.Exp(two, big.NewInt(int64(k-1)), nil)

	addend.Mul(&addend, big.NewInt(-1))
	//Soustraction
	neg := big.Int{}
	neg.Add(&addend, &nBigInt)

	// calculate 2^m
	m := 160
	ceil := big.Int{}
	ceil.Exp(two, big.NewInt(int64(m)), nil)

	// apply the mod
	result := big.Int{}
	result.Mod(&neg, &ceil)

	resultBytes := result.Bytes()
	resultHex := fmt.Sprintf("%x", resultBytes)

	return resultHex, resultBytes
}

// (n + 2^(k-1)) mod (2^m)
func calcFinger(n []byte, k int, m int) (string, []byte) {

	// convert the n to a bigint
	nBigInt := big.Int{}
	nBigInt.SetBytes(n)

	// get the right addend, i.e. 2^(k-1)
	two := big.NewInt(2)
	addend := big.Int{}
	addend.Exp(two, big.NewInt(int64(k-1)), nil)

	// calculate sum
	sum := big.Int{}
	sum.Add(&nBigInt, &addend)

	// calculate 2^m
	ceil := big.Int{}
	ceil.Exp(two, big.NewInt(int64(m)), nil)

	// apply the mod
	result := big.Int{}
	result.Mod(&sum, &ceil)

	resultBytes := result.Bytes()
	resultHex := fmt.Sprintf("%x", resultBytes)

	return resultHex, resultBytes
}

func CalculateBlockReward(block *Block, uncleLength int) *big.Int {
	base := new(big.Int)
	for i := 0; i < uncleLength; i++ {
		base.Add(base, UncleInclusionReward)
	}
	return base.Add(base, BlockReward)
}

// signRFC6979 generates a deterministic ECDSA signature according to RFC 6979
// and BIP 62.
func signRFC6979(privateKey *PrivateKey, hash []byte) (*Signature, error) {

	privkey := privateKey.ToECDSA()
	N := order
	k := NonceRFC6979(privkey.D, hash, nil, nil)
	inv := new(big.Int).ModInverse(k, N)
	r, _ := privkey.Curve.ScalarBaseMult(k.Bytes())
	if r.Cmp(N) == 1 {
		r.Sub(r, N)
	}

	if r.Sign() == 0 {
		return nil, errors.New("calculated R is zero")
	}

	e := hashToInt(hash, privkey.Curve)
	s := new(big.Int).Mul(privkey.D, r)
	s.Add(s, e)
	s.Mul(s, inv)
	s.Mod(s, N)

	if s.Cmp(halforder) == 1 {
		s.Sub(N, s)
	}
	if s.Sign() == 0 {
		return nil, errors.New("calculated S is zero")
	}
	return &Signature{R: r, S: s}, nil
}