cmd/netstring/main.go

   1 /*
   2 netstring -- netstring format serialization library
   3 Copyright (C) 2015-2020 Sergey Matveev <stargrave@stargrave.org>
   4
   5 This program is free software: you can redistribute it and/or modify
   6 it under the terms of the GNU General Public License as published by
   7 the Free Software Foundation, version 3 of the License.
   8
   9 This program is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 GNU General Public License for more details.
  13
  14 You should have received a copy of the GNU General Public License
  15 along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16 */
  17
  18 package main
  19
  20 import (
  21         "flag"
  22         "fmt"
  23         "io"
  24         "os"
  25         "strconv"
  26
  27         "go.cypherpunks.ru/netstring/v2"
  28 )
  29
  30 func usage() {
  31         fmt.Fprintf(os.Stderr, "ns -- Work with netstring encoded files\n\n")
  32         fmt.Fprintf(os.Stderr, "Usage: %s list FILE\n", os.Args[0])
  33         fmt.Fprintf(os.Stderr, "       %s read FILE CHUNK > data\n", os.Args[0])
  34         fmt.Fprintf(os.Stderr, "       %s write FILE ... > data\n", os.Args[0])
  35         os.Exit(1)
  36 }
  37
  38 func main() {
  39         flag.Usage = usage
  40         flag.Parse()
  41         if len(os.Args) < 3 {
  42                 usage()
  43         }
  44         switch os.Args[1] {
  45         case "list":
  46                 fd, err := os.Open(os.Args[2])
  47                 if err != nil {
  48                         panic(err)
  49                 }
  50                 r := netstring.NewReader(fd)
  51                 for i := 0; ; i++ {
  52                         size, err := r.Next()
  53                         if err == io.EOF {
  54                                 break
  55                         }
  56                         if err != nil {
  57                                 panic(err)
  58                         }
  59                         fmt.Printf("%d\t%d\n", i, size)
  60                         r.Discard()
  61                 }
  62         case "read":
  63                 if len(os.Args) != 4 {
  64                         usage()
  65                 }
  66                 chunk, err := strconv.Atoi(os.Args[3])
  67                 if err != nil {
  68                         panic(err)
  69                 }
  70                 fd, err := os.Open(os.Args[2])
  71                 if err != nil {
  72                         panic(err)
  73                 }
  74                 r := netstring.NewReader(fd)
  75                 for i := 0; i < chunk; i++ {
  76                         _, err = r.Next()
  77                         if err != nil {
  78                                 panic(err)
  79                         }
  80                         r.Discard()
  81                 }
  82                 _, err = r.Next()
  83                 if err != nil {
  84                         panic(err)
  85                 }
  86                 if _, err = io.Copy(os.Stdout, r); err != nil {
  87                         panic(err)
  88                 }
  89         case "write":
  90                 w := netstring.NewWriter(os.Stdout)
  91                 for i, fn := range os.Args[2:] {
  92                         fd, err := os.Open(fn)
  93                         if err != nil {
  94                                 panic(err)
  95                         }
  96                         fi, err := fd.Stat()
  97                         if err != nil {
  98                                 panic(err)
  99                         }
 100                         size := uint64(fi.Size())
 101                         if _, err = w.WriteSize(size); err != nil {
 102                                 panic(err)
 103                         }
 104                         if _, err = io.Copy(w, fd); err != nil {
 105                                 panic(err)
 106                         }
 107                         fmt.Fprintf(os.Stderr, "%d\t%d\t%s\n", i, size, fn)
 108                 }
 109         }
 110 }