merklesum prints out the hashes of each chunk from a merkle tree.

merklesum.go

package main

import (
	"fmt"
	"github.com/vbatts/merkle"
	"io"
	"os"
)

func traverse(n *merkle.Node) *merkle.Node {
	if n == nil {
		return nil
	}
	traverse(n.Left)

	if n.Left == nil && n.Right == nil {
		check, _ := n.Checksum()
		fmt.Printf("%x\n", check)
	}

	traverse(n.Right)

	return nil
}

func main() {
	file := os.Args[1]
	f, err := os.Open(file)
	if err != nil {
		fmt.Fprintf(os.Stderr, err.Error())
		os.Exit(1)
	}

	h := merkle.NewHash(merkle.DefaultHashMaker, 4*1024)
	_, err = io.Copy(h, f)
	if err != nil {
		fmt.Fprintf(os.Stderr, err.Error())
		os.Exit(1)
	}

	h.Sum(nil)
	traverse(h.Root())
}