1 files changed, 71 insertions, 0 deletions
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..d73db50
--- /dev/null
+++ b/main.go
@@ -0,0 +1,71 @@
+package main
+
+import (
+	"encoding/hex"
+	"flag"
+	"fmt"
+	"golang.org/x/crypto/sha3"
+	"hash"
+	"io"
+	"os"
+)
+
+var (
+	algo = flag.String("algo", "256", "Which algo should be used (224,256,384,512)")
+)
+
+var algos = map[string]func() hash.Hash{
+	"256": sha3.New256,
+	"224": sha3.New224,
+	"384": sha3.New384,
+	"512": sha3.New512,
+}
+
+func main() {
+	flag.Parse()
+
+	files := append([]string{}, flag.Args()...)
+
+	if len(files) == 0 {
+		files = append(files, "-")
+	}
+
+	for _, fn := range files {
+		if !doFile(fn) {
+			os.Exit(1)
+		}
+	}
+}
+
+func doFile(fn string) bool {
+	var r io.Reader
+
+	if fn == "-" {
+		r = os.Stdin
+	} else {
+		f, err := os.Open(fn)
+		if err != nil {
+			fmt.Fprintln(os.Stderr, err)
+			return false
+		}
+		defer f.Close()
+
+		r = f
+	}
+
+	gethash, ok := algos[*algo]
+	if !ok {
+		fmt.Fprintf(os.Stderr, "Unknown algo: %s\n", *algo)
+		return false
+	}
+
+	hash := gethash()
+
+	if _, err := io.Copy(hash, r); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		return false
+	}
+
+	fmt.Printf("%s  %s\n", hex.EncodeToString(hash.Sum([]byte{})), fn)
+	return true
+}