golang[46]-区块链-比特币真实挖矿过程实现

package main

import (
	"bytes"
	"encoding/binary"
	"log"
	"fmt"
	"encoding/hex"
	"crypto/sha256"
	"strconv"
	"math"
	"math/big"
)

var (

	maxnonce int32 = math.MaxInt32
)

type Block struct{
	version int32
	prevBlockHash []byte
	merkleroot [] byte
	hash []byte
	time int32
	bits int32
	nonce int32

}



//将类型转化为了字节数组
func IntToHex(num int32) []byte{
		buff := new(bytes.Buffer)
//binary.LittleEndian 小端模式
		err:= binary.Write(buff,binary.LittleEndian,num)

		if err!=nil{
			log.Panic(err)
		}

		return buff.Bytes()

}


//将类型转化为了字节数组
func IntToHex2(num int32) []byte{
	buff := new(bytes.Buffer)
	//binary.LittleEndian 小端模式
	err:= binary.Write(buff,binary.BigEndian,num)

	if err!=nil{
		log.Panic(err)
	}

	return buff.Bytes()

}
//字节反转
func ReverseBytes4(data []byte){
	for i,j :=0,len(data) - 1;i<j;i,j = i+1,j - 1{
		data[i],data[j] = data[j],data[i]
	}
}
//序列化
func (block *Block) serialize() []byte{


	result := bytes.Join(
		[][]byte{
			IntToHex(block.version),
			block.prevBlockHash,
			block.merkleroot,
			IntToHex(block.time),
			IntToHex(block.bits),
			IntToHex(block.nonce)},
		[]byte{},
	)

	return result

}



func main(){


	//前一个区块的hash
	prev,_ := hex.DecodeString("000000000000000016145aa12fa7e81a304c38aec3d7c5208f1d33b587f966a6")
	ReverseBytes4(prev)
	fmt.Printf("%x\n",prev)

	//默克尔根
	merkleroot,_ := hex.DecodeString("3a4f410269fcc4c7885770bc8841ce6781f15dd304ae5d2770fc93a21dbd70d7")
	ReverseBytes4(merkleroot)
	fmt.Printf("%x\n",merkleroot)

	//初始化区块
	block := &Block{
		2,
		prev,
		merkleroot,
		[]byte{},
		1418755780,
		404454260,
		0,
	}


	//目标hash
	//fmt.Printf("targethash:%x",CalculateTargetFast(IntToHex2(block.bits)))
	targetHash:=CalculateTargetFast(IntToHex2(block.bits))

	//目标hash转换为bit.int
	var tartget big.Int
	tartget.SetBytes(targetHash)

	//当前hash
	var currenthash big.Int


	//一直计算到最大值，	block.nonce的值不断变化
	for  block.nonce < maxnonce{


		//序列化，block.nonce的值不断变化带来序列化的变化
		data:= block.serialize()
		//double hash
		fitstHash := sha256.Sum256(data)
		secondhash := sha256.Sum256(fitstHash[:])

		//反转
		ReverseBytes4(secondhash[:])
		fmt.Printf("nonce:%d,  currenthash:%x\n",block.nonce,secondhash)
		currenthash.SetBytes(secondhash[:])
		//比较
		if currenthash.Cmp(&tartget) == -1{
			break
		}else{
			block.nonce++
		}
	}

}


//18   1B7B74

//计算困难度
func CalculateTargetFast(bits []byte) []byte{

		var result []byte
		//第一个字节  计算指数
		exponent := bits[:1]
		fmt.Printf("%x\n",exponent)

		//计算后面3个系数
		coeffient:= bits[1:]
	fmt.Printf("%x\n",coeffient)


		//将字节，他的16进制为"18"  转化为了string "18"
		str:= hex.EncodeToString(exponent)  //"18"
		fmt.Printf("str=%s\n",str)
	   //将字符串18转化为了10进制int64 24
		exp,_:=strconv.ParseInt(str,16,8)

			fmt.Printf("exp=%d\n",exp)
		//拼接，计算出目标hash
		result  = append(bytes.Repeat([]byte{0x00},32-int(exp)),coeffient...)
		result  =  append(result,bytes.Repeat([]byte{0x00},32-len(result))...)


	return result
}