Golang siphash.Hash函数代码示例

func makeId(dv driver.Value) uint64 {
	switch vt := dv.(type) {
	case int:
		return uint64(vt)
	case int64:
		return uint64(vt)
	case []byte:
		return siphash.Hash(0, 1, vt)
		// iv, err := strconv.ParseUint(string(vt), 10, 64)
		// if err != nil {
		// 	u.Warnf("could not create id: %v  for %v", err, dv)
		// }
		// return iv
	case string:
		return siphash.Hash(0, 1, []byte(vt))
		// iv, err := strconv.ParseUint(vt, 10, 64)
		// if err != nil {
		// 	u.Warnf("could not create id: %v  for %v", err, dv)
		// }
		// return iv
	case *Key:
		//u.Infof("got %#v", vt)
		return vt.Id
	case datasource.KeyCol:
		//u.Infof("got %#v", vt)
		return makeId(vt.Val)
	default:
		//u.LogTracef(u.WARN, "wat")
		u.Warnf("not implemented conversion: %T", dv)
	}
	return 0
}

// New Replica Factor 1 with random
func New(randomized bool) *RF1R {
	res := RF1R{}

	if randomized {
		res.hasher1 = func(b []byte) uint64 { return siphash.Hash(0, 0, b) }
		res.hasher2 = func(b []byte) uint64 { return siphash.Hash(2, 3, b) }
	} else {
		res.hasher1 = func(b []byte) uint64 { return siphash.Hash(0, 0, b) }
		res.hasher2 = func(b []byte) uint64 { return siphash.Hash(0, 0, b) }
	}

	return &res
}

func BenchmarkSipHashFast(b *testing.B) {
	var key0, key1 uint64 = 0, 1
	b.StartTimer()
	for i := 0; i < b.N; i++ {
		siphash.Hash(key0, key1, []byte("Hello World"))
	}
}

func (t *T) Add(key string, val interface{}) {

	newitem := slruItem{0, key, val, siphash.Hash(0, 0, stringToSlice(key))}

	oitem, evicted := t.lru.add(newitem)
	if !evicted {
		return
	}

	// estimate count of what will be evicted from slru
	victim := t.slru.victim()
	if victim == nil {
		t.slru.add(oitem)
		return
	}

	if !t.bouncer.allow(oitem.keyh) {
		return
	}

	vcount := t.c.estimate(victim.keyh)
	ocount := t.c.estimate(oitem.keyh)

	if ocount < vcount {
		return
	}

	t.slru.add(oitem)
}

// New Replica Factor 1 with random
func New() *RF2 {
	res := RF2{}

	res.hasher = func(b []byte) uint64 { return siphash.Hash(0, 0, b) }

	return &res
}

func main() {

	verbose := flag.Bool("v", false, "verbose")

	flag.Parse()

	scanner := bufio.NewScanner(os.Stdin)

	w := bufio.NewWriter(os.Stdout)
	defer w.Flush()

	for scanner.Scan() {

		fname := scanner.Text()

		b, err := ioutil.ReadFile(fname)
		if err != nil {
			log.Println(err)
			continue
		}

		sip := siphash.Hash(0, 0, b)

		data, err := lz4.Encode(nil, b)
		if err != nil {
			log.Println("error packing: ", err)
			continue
		}

		const headerSize = 4 + 8 + 2 + 4 // + len(fname)

		h := struct {
			PacketSize       uint32
			SipHash          uint64
			Fname            []byte `binpack:"lenprefix=uint16"`
			UncompressedSize uint32
		}{
			PacketSize:       uint32(headerSize + len(fname) + len(data)),
			SipHash:          sip,
			Fname:            []byte(fname),
			UncompressedSize: uint32(len(b)),
		}

		if *verbose {
			log.Printf("%s: %d -> %d\n", fname, len(b), len(data))
		}

		err = binpack.Write(w, binary.LittleEndian, h)
		if err != nil {
			log.Printf("error writing header %+v\n", err)
			break
		}

		_, err = w.Write(data)
		if err != nil {
			log.Printf("error writing %+v\n", err)
			break
		}
	}
}

func (c *OneConnection) SendCmpctBlk(hash *btc.Uint256) {
	crec := GetchBlockForBIP152(hash)
	if crec == nil {
		fmt.Println(c.ConnID, "cmpctblock not sent for", hash.String())
		return
	}

	k0 := binary.LittleEndian.Uint64(crec.BIP152[8:16])
	k1 := binary.LittleEndian.Uint64(crec.BIP152[16:24])

	msg := new(bytes.Buffer)
	msg.Write(crec.Data[:80])
	msg.Write(crec.BIP152[:8])
	btc.WriteVlen(msg, uint64(len(crec.Block.Txs)-1)) // all except coinbase
	for i := 1; i < len(crec.Block.Txs); i++ {
		var lsb [8]byte
		var hasz *btc.Uint256
		if c.Node.SendCmpctVer == 2 {
			hasz = crec.Block.Txs[i].WTxID()
		} else {
			hasz = crec.Block.Txs[i].Hash
		}
		binary.LittleEndian.PutUint64(lsb[:], siphash.Hash(k0, k1, hasz.Hash[:]))
		msg.Write(lsb[:6])
	}
	msg.Write([]byte{1}) // one preffiled tx
	msg.Write([]byte{0}) // coinbase - index 0
	if c.Node.SendCmpctVer == 2 {
		msg.Write(crec.Block.Txs[0].Raw) // coinbase - index 0
	} else {
		crec.Block.Txs[0].WriteSerialized(msg) // coinbase - index 0
	}
	c.SendRawMsg("cmpctblock", msg.Bytes())
}

// Hash returns a simhash value for the document returned by the scanner
func Hash(scanner FeatureScanner) uint64 {
	var signs [64]int64

	for scanner.Scan() {
		b := scanner.Bytes()
		h := siphash.Hash(0, 0, b)

		for i := 0; i < 64; i++ {
			negate := int(h) & 1
			// if negate is 1, we will negate '-1', below
			r := (-1 ^ -negate) + negate
			signs[i] += int64(r)
			h >>= 1
		}
	}

	var shash uint64

	// TODO: can probably be done with SSE?
	for i := 63; i >= 0; i-- {
		shash <<= 1
		shash |= uint64(signs[i]>>63) & 1
	}

	return shash
}

func (t *T) Get(key string) (interface{}, bool) {

	t.w++
	if t.w == t.samples {
		t.c.reset()
		t.bouncer.reset()
		t.w = 0
	}

	val, ok := t.data[key]
	if !ok {
		keyh := siphash.Hash(0, 0, stringToSlice(key))
		t.c.add(keyh)
		return nil, false
	}

	item := val.Value.(*slruItem)

	t.c.add(item.keyh)

	v := item.value
	if item.listid == 0 {
		t.lru.get(val)
	} else {
		t.slru.get(val)
	}

	return v, true
}

func main() {

	f := flag.String("f", "/dev/stdin", "input file")
	n := flag.Int("n", 100e6, "cardinality estimate of set")
	fprate := flag.Float64("fp", 0.00000001, "false positive rate")

	flag.Parse()

	file, err := os.Open(*f)
	if err != nil {
		log.Fatal(err)
	}

	var lines int
	b := bloomf.New(*n, *fprate, func(b []byte) uint64 { return siphash.Hash(0, 0, b) })
	scanner := bufio.NewScanner(file)

	for scanner.Scan() {
		lines++
		if !b.Lookup(scanner.Bytes()) {
			os.Stdout.Write(scanner.Bytes())
			os.Stdout.Write([]byte("\n"))
		}
		b.Insert(scanner.Bytes())
		if lines%(1<<20) == 0 {
			log.Println(lines)
		}
	}
}

func (d *Dict) Set(key []byte, value interface{}) {
	p := siphash.Hash(d.k0, d.k1, key) % dictSize
	node := d.data[p]
	if node == nil {
		d.data[p] = &dictNode{
			k:    key,
			v:    value,
			next: nil,
		}
		d.size += 1
		return
	}
	for {
		if bytes.Equal(node.k, key) {
			node.v = value
			return
		}
		if node.next != nil {
			node = node.next
			continue
		}
		node.next = &dictNode{
			k:    key,
			v:    value,
			next: nil,
		}
		d.size += 1
		return
	}
}

func (d *Dict) Delete(key []byte) {
	p := siphash.Hash(d.k0, d.k1, key) % dictSize
	node := d.data[p]
	if node == nil {
		return
	}
	if bytes.Equal(node.k, key) {
		d.data[p] = nil
		d.size -= 1
		return
	}
	next := node.next
	for {
		if next == nil {
			return
		}
		if bytes.Equal(next.k, key) {
			node.next = next.next
			d.size -= 1
			return
		}
		next = node.next
	}
	panic("unreachable code")
}

func main() {

	scan := bufio.NewScanner(os.Stdin)

	for scan.Scan() {
		u := siphash.Hash(0, 0, scan.Bytes())
		fmt.Printf("%016x\n", u)
	}
}

func hashOne(k0, k1 uint64, r io.Reader, name string) {
	buf, err := ioutil.ReadAll(r)
	if err != nil {
		log.Println(name, err)
		return
	}
	h := siphash.Hash(k0, k1, buf)
	fmt.Printf("%016x %s\n", h, name)
}

func sipuintptr(s []uintptr) uint64 {

	b := make([]byte, len(s)*8)

	for i, v := range s {
		binary.LittleEndian.PutUint64(b[i*8:], uint64(v))
	}

	return siphash.Hash(0, 0, b)
}