github.com/chain5j/chain5j-pkg@v1.0.7/crypto/base/base58/base58.go (about)

     1  // Package base58
     2  //
     3  // @author: xwc1125
     4  package base58
     5  
     6  import (
     7  	"bytes"
     8  	"math/big"
     9  )
    10  
    11  var b58Alphabet = []byte("123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz")
    12  
    13  // Encode encodes a byte array to Base58
    14  func Encode(input []byte) []byte {
    15  	var result []byte
    16  
    17  	x := big.NewInt(0).SetBytes(input)
    18  
    19  	base := big.NewInt(int64(len(b58Alphabet)))
    20  	zero := big.NewInt(0)
    21  	mod := &big.Int{}
    22  
    23  	for x.Cmp(zero) != 0 {
    24  		x.DivMod(x, base, mod)
    25  		result = append(result, b58Alphabet[mod.Int64()])
    26  	}
    27  
    28  	// https://en.bitcoin.it/wiki/Base58Check_encoding#Version_bytes
    29  	if input[0] == 0x00 {
    30  		result = append(result, b58Alphabet[0])
    31  	}
    32  
    33  	reverseBytes(result)
    34  
    35  	return result
    36  }
    37  
    38  // Decode decodes Base58-encoded data
    39  func Decode(input []byte) []byte {
    40  	result := big.NewInt(0)
    41  
    42  	for _, b := range input {
    43  		charIndex := bytes.IndexByte(b58Alphabet, b)
    44  		result.Mul(result, big.NewInt(58))
    45  		result.Add(result, big.NewInt(int64(charIndex)))
    46  	}
    47  
    48  	decoded := result.Bytes()
    49  
    50  	if input[0] == b58Alphabet[0] {
    51  		decoded = append([]byte{0x00}, decoded...)
    52  	}
    53  
    54  	return decoded
    55  }
    56  
    57  // ReverseBytes reverses a byte array
    58  func reverseBytes(data []byte) {
    59  	for i, j := 0, len(data)-1; i < j; i, j = i+1, j-1 {
    60  		data[i], data[j] = data[j], data[i]
    61  	}
    62  }