cmd/bzzhash: add swarm hashing tool

cmd/bzzhash/main.go

+// Copyright 2016 The go-ethereum Authors
+// This file is part of go-ethereum.
+//
+// go-ethereum is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// go-ethereum is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.
+
+// Command bzzhash computes a swarm tree hash.
+package main
+
+import (
+	"fmt"
+	"os"
+	"runtime"
+
+	"github.com/ethereum/go-ethereum/swarm/storage"
+)
+
+func main() {
+	runtime.GOMAXPROCS(runtime.NumCPU())
+
+	if len(os.Args) < 2 {
+		fmt.Println("Usage: bzzhash <file name>")
+		os.Exit(0)
+	}
+	f, err := os.Open(os.Args[1])
+	if err != nil {
+		fmt.Println("Error opening file " + os.Args[1])
+		os.Exit(1)
+	}
+
+	stat, _ := f.Stat()
+	chunker := storage.NewTreeChunker(storage.NewChunkerParams())
+	key, err := chunker.Split(f, stat.Size(), nil, nil, nil)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "%v\n", err)
+	} else {
+		fmt.Printf("%v\n", key)
+	}
+}