/
gohashin.go
236 lines (215 loc) · 4.79 KB
/
gohashin.go
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package main
import (
"crypto/md5"
"crypto/sha1"
"crypto/sha256"
"crypto/sha512"
"errors"
"fmt"
"hash"
"io"
"os"
"path/filepath"
"runtime"
"sort"
"sync"
"sync/atomic"
"text/tabwriter"
"github.com/spf13/pflag"
)
type hashWriter struct {
h hash.Hash
name string
}
// TODO: we can make this so that we don't need for it to be atomic
type atomicWriter struct {
w io.Writer
err atomic.Value
}
type errorValue struct {
Err error
}
func (w *atomicWriter) write(p []byte) (int, error) {
n, err := w.w.Write(p)
if err != nil {
return n, err
}
if n != len(p) {
return n, io.ErrShortWrite
}
return n, nil
}
func (w *atomicWriter) Write(p []byte) (int, error) {
if err := w.Error(); err != nil {
return 0, err
}
n, err := w.write(p)
if err != nil {
w.err.Store(&errorValue{err})
}
return n, err
}
func (w *atomicWriter) Error() error {
if v := w.err.Load(); v != nil {
return v.(*errorValue).Err
}
return nil
}
type multiWriter struct {
writers []*atomicWriter
ch []chan []byte
wg sync.WaitGroup
closed bool
}
func NewMultiWriter(writers ...io.Writer) *multiWriter {
aws := make([]*atomicWriter, len(writers))
for i := range writers {
aws[i] = &atomicWriter{w: writers[i]}
}
return &multiWriter{writers: aws}
}
func (t *multiWriter) lazyInit() {
if t.ch != nil {
return
}
n := len(t.writers)
t.ch = make([]chan []byte, n)
t.wg.Add(n)
for i := range t.ch {
t.ch[i] = make(chan []byte, 1)
go func(w *atomicWriter, ch chan []byte) {
defer t.wg.Done()
for p := range ch {
_, _ = w.Write(p)
}
}(t.writers[i], t.ch[i])
}
}
func (t *multiWriter) Error() error {
for _, w := range t.writers {
if err := w.Error(); err != nil {
return err
}
}
return nil
}
func (t *multiWriter) Write(p []byte) (int, error) {
if err := t.Error(); err != nil {
return 0, err
}
if t.ch == nil {
t.lazyInit()
}
b := make([]byte, len(p))
copy(b, p)
for _, ch := range t.ch {
ch <- b
}
return len(p), nil
}
func (t *multiWriter) Close() error {
if t.ch == nil {
return errors.New("multiWriter: never initialized")
}
if t.closed {
return errors.New("multiWriter: already closed")
}
t.closed = true
for i := range t.ch {
close(t.ch[i])
}
t.wg.Wait()
return t.Error()
}
func main() {
printSize := pflag.Bool("size", false, "print size")
hashMD5 := pflag.Bool("md5", false, "calculate md5")
hashSHA1 := pflag.Bool("sha1", false, "calculate sha1")
hashSHA224 := pflag.Bool("sha224", false, "calculate sha224")
hashSHA256 := pflag.Bool("sha256", false, "calculate sha256")
hashSHA384 := pflag.Bool("sha384", false, "calculate SHA384")
hashSHA512_224 := pflag.Bool("sha512_224", false, "calculate SHA512_224")
hashSHA512_256 := pflag.Bool("sha512_256", false, "calculate SHA512_256")
hashSHA512 := pflag.Bool("sha512", false, "calculate sha512")
pflag.Parse()
// default to MD5
if !*hashMD5 && !*hashSHA1 && !*hashSHA224 && !*hashSHA256 &&
!*hashSHA384 && !*hashSHA512_224 && !*hashSHA512_256 && !*hashSHA512 {
*hashMD5 = true
}
var hashes []hashWriter
if *hashMD5 {
hashes = append(hashes, hashWriter{md5.New(), "md5"})
}
if *hashSHA1 {
hashes = append(hashes, hashWriter{sha1.New(), "sha1"})
}
if *hashSHA224 {
hashes = append(hashes, hashWriter{sha256.New224(), "sha224"})
}
if *hashSHA256 {
hashes = append(hashes, hashWriter{sha256.New(), "sha256"})
}
if *hashSHA384 {
hashes = append(hashes, hashWriter{sha512.New384(), "sha384"})
}
if *hashSHA512_224 {
hashes = append(hashes, hashWriter{sha512.New512_224(), "sha512_224"})
}
if *hashSHA512_256 {
hashes = append(hashes, hashWriter{sha512.New512_256(), "sha512_256"})
}
if *hashSHA512 {
hashes = append(hashes, hashWriter{sha512.New(), "sha512"})
}
writers := []io.Writer{os.Stdout}
for _, h := range hashes {
writers = append(writers, h.h)
}
sort.Slice(hashes, func(i, j int) bool {
return hashes[i].name < hashes[j].name
})
buf := make([]byte, 64*1024)
w := NewMultiWriter(writers...)
size, err := io.CopyBuffer(w, os.Stdin, buf)
if err != nil {
Fatal(err)
}
if err := w.Close(); err != nil {
Fatal(err)
}
tw := tabwriter.NewWriter(os.Stderr, 2, 0, 2, ' ', 0)
for _, h := range hashes {
_, err := fmt.Fprintf(tw, "%s:\t%x\n", h.name, h.h.Sum(nil))
if err != nil {
Fatal(err)
}
}
if *printSize {
_, err := fmt.Fprintf(tw, "%s:\t%d\n", "size", size)
if err != nil {
Fatal(err)
}
}
if err := tw.Flush(); err != nil {
Fatal(err)
}
}
func Fatal(err interface{}) {
if err == nil {
return
}
var format string
if _, file, line, ok := runtime.Caller(1); ok && file != "" {
format = fmt.Sprintf("Error (%s:%d)", filepath.Base(file), line)
} else {
format = "Error"
}
switch err.(type) {
case error, string:
fmt.Fprintf(os.Stderr, "%s: %s\n", format, err)
default:
fmt.Fprintf(os.Stderr, "%s: %#v\n", format, err)
}
os.Exit(1)
}