base58.go

package main

import (
	"math/big"
	"bytes"
)

var b58Alphabet = []byte("123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz")

//将字节数组转换成Base58
func Base58Encode(input []byte) []byte {
	var result []byte

	x:=big.NewInt(0).SetBytes(input)

	base:=big.NewInt(int64(len(b58Alphabet)))
	zero:=big.NewInt(0)
	mod:=&big.Int{}

	for x.Cmp(zero)!=0{
		x.DivMod(x,base,mod)
		result = append(result,b58Alphabet[mod.Int64()])
	}

	ReverseBytes(result)
	for b:=range input {
		if b == 0x00 {
			result = append([]byte{b58Alphabet[0]},result...)
		}else {
			break
		}
	}

	return result
}
//解码
func Base58Decode(input []byte) []byte {
	result := big.NewInt(0)
	zeroBytes := 0
	for b := range input {
		if b == 0x00 {
			zeroBytes++
		}
	}

	payload := input[zeroBytes:]
	for _, b := range payload {
		charIndex := bytes.IndexByte(b58Alphabet, b)
		result.Mul(result, big.NewInt(58))
		result.Add(result, big.NewInt(int64(charIndex)))
	}

	decoded:=result.Bytes()
	decoded = append(bytes.Repeat([]byte{byte(0x00)},zeroBytes),decoded...)
	return decoded
}