YTSFlix_Go/vendor/github.com/anacrolix/torrent/misc.go

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2018-11-04 14:58:15 +00:00
package torrent
import (
"errors"
"net"
"github.com/anacrolix/missinggo"
"golang.org/x/time/rate"
"github.com/anacrolix/torrent/metainfo"
pp "github.com/anacrolix/torrent/peer_protocol"
)
type chunkSpec struct {
Begin, Length pp.Integer
}
type request struct {
Index pp.Integer
chunkSpec
}
func (r request) ToMsg(mt pp.MessageType) pp.Message {
return pp.Message{
Type: mt,
Index: r.Index,
Begin: r.Begin,
Length: r.Length,
}
}
func newRequest(index, begin, length pp.Integer) request {
return request{index, chunkSpec{begin, length}}
}
func newRequestFromMessage(msg *pp.Message) request {
switch msg.Type {
case pp.Request, pp.Cancel, pp.Reject:
return newRequest(msg.Index, msg.Begin, msg.Length)
case pp.Piece:
return newRequest(msg.Index, msg.Begin, pp.Integer(len(msg.Piece)))
default:
panic(msg.Type)
}
}
// The size in bytes of a metadata extension piece.
func metadataPieceSize(totalSize int, piece int) int {
ret := totalSize - piece*(1<<14)
if ret > 1<<14 {
ret = 1 << 14
}
return ret
}
// Return the request that would include the given offset into the torrent data.
func torrentOffsetRequest(torrentLength, pieceSize, chunkSize, offset int64) (
r request, ok bool) {
if offset < 0 || offset >= torrentLength {
return
}
r.Index = pp.Integer(offset / pieceSize)
r.Begin = pp.Integer(offset % pieceSize / chunkSize * chunkSize)
r.Length = pp.Integer(chunkSize)
pieceLeft := pp.Integer(pieceSize - int64(r.Begin))
if r.Length > pieceLeft {
r.Length = pieceLeft
}
torrentLeft := torrentLength - int64(r.Index)*pieceSize - int64(r.Begin)
if int64(r.Length) > torrentLeft {
r.Length = pp.Integer(torrentLeft)
}
ok = true
return
}
func torrentRequestOffset(torrentLength, pieceSize int64, r request) (off int64) {
off = int64(r.Index)*pieceSize + int64(r.Begin)
if off < 0 || off >= torrentLength {
panic("invalid request")
}
return
}
func validateInfo(info *metainfo.Info) error {
if len(info.Pieces)%20 != 0 {
return errors.New("pieces has invalid length")
}
if info.PieceLength == 0 {
if info.TotalLength() != 0 {
return errors.New("zero piece length")
}
} else {
if int((info.TotalLength()+info.PieceLength-1)/info.PieceLength) != info.NumPieces() {
return errors.New("piece count and file lengths are at odds")
}
}
return nil
}
func chunkIndexSpec(index pp.Integer, pieceLength, chunkSize pp.Integer) chunkSpec {
ret := chunkSpec{pp.Integer(index) * chunkSize, chunkSize}
if ret.Begin+ret.Length > pieceLength {
ret.Length = pieceLength - ret.Begin
}
return ret
}
func connLessTrusted(l, r *connection) bool {
return l.netGoodPiecesDirtied() < r.netGoodPiecesDirtied()
}
func connIsIpv6(nc interface {
LocalAddr() net.Addr
}) bool {
ra := nc.LocalAddr()
rip := missinggo.AddrIP(ra)
return rip.To4() == nil && rip.To16() != nil
}
func clamp(min, value, max int64) int64 {
if min > max {
panic("harumph")
}
if value < min {
value = min
}
if value > max {
value = max
}
return value
}
func max(as ...int64) int64 {
ret := as[0]
for _, a := range as[1:] {
if a > ret {
ret = a
}
}
return ret
}
func min(as ...int64) int64 {
ret := as[0]
for _, a := range as[1:] {
if a < ret {
ret = a
}
}
return ret
}
var unlimited = rate.NewLimiter(rate.Inf, 0)
type (
pieceIndex = int
InfoHash = metainfo.Hash
)