func main() {
useSHA := flag.String("use-sha", "", "<default>=no hashing, 1=sha1, 256=sha256, 512=sha512, blake=blake2b")
useBH := flag.Bool("use-bh", false, "whether we buzhash the bytes")
flag.Parse(true)
flag.Usage = func() {
fmt.Printf("%s <big-file>\n", os.Args[0])
flag.PrintDefaults()
return
}
if len(flag.Args()) < 1 {
flag.Usage()
return
}
p := flag.Args()[0]
bh := buzhash.NewBuzHash(64 * 8)
f, _ := os.Open(p)
defer f.Close()
t0 := time.Now()
buf := make([]byte, 4*1024)
l := uint64(0)
var h hash.Hash
if *useSHA == "1" {
h = sha1.New()
} else if *useSHA == "256" {
h = sha256.New()
} else if *useSHA == "512" {
h = sha512.New()
} else if *useSHA == "blake" {
h = blake2.NewBlake2B()
}
for {
n, err := f.Read(buf)
l += uint64(n)
if err == io.EOF {
break
}
s := buf[:n]
if h != nil {
h.Write(s)
}
if *useBH {
bh.Write(s)
}
}
t1 := time.Now()
d := t1.Sub(t0)
fmt.Printf("Read %s in %s (%s/s)\n", humanize.Bytes(l), d, humanize.Bytes(uint64(float64(l)/d.Seconds())))
digest := []byte{}
if h != nil {
fmt.Printf("%x\n", h.Sum(digest))
}
}
func newRollingValueHasher() *rollingValueHasher {
pattern, window := chunkingConfig()
rv := &rollingValueHasher{
bz: buzhash.NewBuzHash(window),
pattern: pattern,
window: window,
}
rv.enc = newValueEncoder(rv, nil)
return rv
}