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types.go
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/
types.go
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package util
import (
"encoding"
"encoding/binary"
"errors"
"fmt"
"net"
"github.com/bradfitz/iter"
"github.com/anacrolix/torrent/bencode"
)
// Concatenated 6-byte peer addresses.
type CompactIPv4Peers []CompactPeer
var (
// This allows bencode.Unmarshal to do better than a string or []byte.
_ bencode.Unmarshaler = &CompactIPv4Peers{}
_ encoding.BinaryMarshaler = CompactIPv4Peers{}
)
// This allows bencode.Unmarshal to do better than a string or []byte.
func (me *CompactIPv4Peers) UnmarshalBencode(b []byte) (err error) {
var bb []byte
err = bencode.Unmarshal(b, &bb)
if err != nil {
return
}
*me, err = UnmarshalIPv4CompactPeers(bb)
return
}
func (me CompactIPv4Peers) MarshalBinary() (ret []byte, err error) {
ret = make([]byte, len(me)*6)
for i, cp := range me {
copy(ret[6*i:], cp.IP.To4())
binary.BigEndian.PutUint16(ret[6*i+4:], uint16(cp.Port))
}
return
}
// Represents peer address in either IPv6 or IPv4 form.
type CompactPeer struct {
IP net.IP
Port int
}
var (
_ bencode.Marshaler = &CompactPeer{}
_ bencode.Unmarshaler = &CompactPeer{}
)
func (me CompactPeer) MarshalBencode() (ret []byte, err error) {
ip := me.IP
if ip4 := ip.To4(); ip4 != nil {
ip = ip4
}
ret = make([]byte, len(ip)+2)
copy(ret, ip)
binary.BigEndian.PutUint16(ret[len(ip):], uint16(me.Port))
return bencode.Marshal(ret)
}
func (me *CompactPeer) UnmarshalBinary(b []byte) error {
switch len(b) {
case 18:
me.IP = make([]byte, 16)
case 6:
me.IP = make([]byte, 4)
default:
return fmt.Errorf("bad compact peer string: %q", b)
}
copy(me.IP, b)
b = b[len(me.IP):]
me.Port = int(binary.BigEndian.Uint16(b))
return nil
}
func (me *CompactPeer) UnmarshalBencode(b []byte) (err error) {
var _b []byte
err = bencode.Unmarshal(b, &_b)
if err != nil {
return
}
return me.UnmarshalBinary(_b)
}
func UnmarshalIPv4CompactPeers(b []byte) (ret []CompactPeer, err error) {
if len(b)%6 != 0 {
err = errors.New("bad length")
return
}
num := len(b) / 6
ret = make([]CompactPeer, num)
for i := range iter.N(num) {
off := i * 6
err = ret[i].UnmarshalBinary(b[off : off+6])
if err != nil {
return
}
}
return
}