"crypto/sha512"

	marks int

	marks     int
	blobIndex map[[64]byte]int

	hash := sha512.Sum512(data)
	if mark, ok := f.blobIndex[hash]; ok {
		return mark
	}

	if f.blobIndex == nil {
		f.blobIndex = make(map[[64]byte]int)
	}
	f.blobIndex[hash] = b.Mark