1 package main
2
3 import (
4 "fmt"
5 "io"
6 "os"
7
8 "github.com/cespare/xxhash/v2"
9 )
10
11 func main() {
12 if contains(os.Args[1:], "-h") {
13 fmt.Fprintf(os.Stderr, `Usage:
14 %s [filenames]
15 If no filenames are provided or only - is given, input is read from stdin.
16 `, os.Args[0])
17 os.Exit(1)
18 }
19 if len(os.Args) < 2 || len(os.Args) == 2 && os.Args[1] == "-" {
20 printHash(os.Stdin, "-")
21 return
22 }
23 for _, path := range os.Args[1:] {
24 f, err := os.Open(path)
25 if err != nil {
26 fmt.Fprintln(os.Stderr, err)
27 continue
28 }
29 printHash(f, path)
30 f.Close()
31 }
32 }
33
34 func contains(ss []string, s string) bool {
35 for _, s1 := range ss {
36 if s1 == s {
37 return true
38 }
39 }
40 return false
41 }
42
43 func printHash(r io.Reader, name string) {
44 h := xxhash.New()
45 if _, err := io.Copy(h, r); err != nil {
46 fmt.Fprintln(os.Stderr, err)
47 return
48 }
49 fmt.Printf("%016x %s\n", h.Sum64(), name)
50 }
51
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