vendor/github.com/mr-tron/base58/examples/wif/main.go

   1 package main
   2
   3 import (
   4         "bytes"
   5         "crypto/sha256"
   6         "encoding/hex"
   7         "flag"
   8         "fmt"
   9         "io"
  10         "io/ioutil"
  11         "os"
  12
  13         "github.com/mr-tron/base58"
  14 )
  15
  16 func checkSum(b []byte) []byte {
  17         sh1, sh2 := sha256.New(), sha256.New()
  18         sh1.Write(b)
  19         sh2.Write(sh1.Sum(nil))
  20         return sh2.Sum(nil)
  21 }
  22
  23 func main() {
  24         var (
  25                 err error
  26                 bin []byte
  27
  28                 help     = flag.Bool("h", false, "display this message")
  29                 lnBreak  = flag.Int("b", 76, "break encoded string into num character lines. Use 0 to disable line wrapping")
  30                 input    = flag.String("i", "-", `input file (use: "-" for stdin)`)
  31                 output   = flag.String("o", "-", `output file (use: "-" for stdout)`)
  32                 decode   = flag.Bool("d", false, `decode input`)
  33                 check    = flag.Bool("k", false, `use sha256 check`)
  34                 useError = flag.Bool("e", false, `write error to stderr`)
  35         )
  36
  37         flag.Parse()
  38
  39         if *help {
  40                 flag.Usage()
  41                 os.Exit(0)
  42         }
  43
  44         fin, fout := os.Stdin, os.Stdout
  45         if *input != "-" {
  46                 if fin, err = os.Open(*input); err != nil {
  47                         fmt.Fprintln(os.Stderr, "input file err:", err)
  48                         os.Exit(1)
  49                 }
  50         }
  51
  52         if *output != "-" {
  53                 if fout, err = os.Create(*output); err != nil {
  54                         fmt.Fprintln(os.Stderr, "output file err:", err)
  55                         os.Exit(1)
  56                 }
  57         }
  58
  59         if bin, err = ioutil.ReadAll(fin); err != nil {
  60                 fmt.Fprintln(os.Stderr, "read input err:", err)
  61                 os.Exit(1)
  62         }
  63
  64         if *decode {
  65                 decoded, err := base58.Decode(string(bin))
  66                 if err != nil {
  67                         fmt.Fprintln(os.Stderr, "decode input err:", err)
  68                         os.Exit(1)
  69                 }
  70
  71                 var checkResult bool
  72                 if *check {
  73                         chk := len(decoded) - 4
  74                         decodedCk := decoded[chk:]
  75                         decoded = decoded[:chk]
  76                         sum := checkSum(decoded)
  77                         checkResult = hex.EncodeToString(sum[:4]) == hex.EncodeToString(decodedCk)
  78                 }
  79
  80                 _, err = io.Copy(fout, bytes.NewReader(decoded))
  81                 if err != nil {
  82                         fmt.Fprintln(os.Stderr, err)
  83                         os.Exit(1)
  84                 }
  85
  86                 if *check && !checkResult {
  87                         if *useError {
  88                                 fmt.Fprintf(os.Stderr, "%t\n", false)
  89                         }
  90                         os.Exit(3)
  91                 }
  92
  93                 os.Exit(0)
  94         }
  95
  96         if *check {
  97                 sum := checkSum(bin)
  98                 bin = append(bin, sum[:4]...)
  99         }
 100
 101         encoded := base58.Encode(bin)
 102
 103         if *lnBreak > 0 {
 104                 lines := (len(encoded) / *lnBreak) + 1
 105                 for i := 0; i < lines; i++ {
 106                         start := i * *lnBreak
 107                         end := start + *lnBreak
 108                         if i == lines-1 {
 109                                 fmt.Fprintln(fout, encoded[start:])
 110                                 return
 111                         }
 112                         fmt.Fprintln(fout, encoded[start:end])
 113                 }
 114         }
 115         fmt.Fprintln(fout, encoded)
 116 }