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buffer.go
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buffer.go
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package utp
import (
"errors"
"io"
"math"
"sync"
"time"
)
type packetBuffer struct {
root *packetBufferNode
size int
begin int
}
type packetBufferNode struct {
p *packet
next *packetBufferNode
pushed time.Time
}
func newPacketBuffer(size, begin int) *packetBuffer {
return &packetBuffer{
size: size,
begin: begin,
}
}
func (b *packetBuffer) push(p *packet) error {
if int(p.header.seq) > b.begin+b.size-1 {
return errors.New("out of bounds")
} else if int(p.header.seq) < b.begin {
if int(p.header.seq)+math.MaxUint16 > b.begin+b.size-1 {
return errors.New("out of bounds")
}
}
if b.root == nil {
b.root = &packetBufferNode{}
}
n := b.root
i := b.begin
for {
if i == int(p.header.seq) {
n.p = p
n.pushed = time.Now()
return nil
} else if n.next == nil {
n.next = &packetBufferNode{}
}
n = n.next
i = (i + 1) % (math.MaxUint16 + 1)
}
return nil
}
func (b *packetBuffer) fetch(id uint16) *packet {
for p := b.root; p != nil; p = p.next {
if p.p != nil {
if p.p.header.seq < id {
p.p = nil
} else if p.p.header.seq == id {
r := p.p
p.p = nil
return r
}
}
}
return nil
}
func (b *packetBuffer) compact() {
for b.root != nil && b.root.p == nil {
b.root = b.root.next
b.begin = (b.begin + 1) % (math.MaxUint16 + 1)
}
}
func (b *packetBuffer) front() *packet {
if b.root == nil || b.root.p == nil {
return nil
}
return b.root.p
}
func (b *packetBuffer) frontPushedTime() (time.Time, error) {
if b.root == nil || b.root.p == nil {
return time.Time{}, errors.New("no first packet")
}
return b.root.pushed, nil
}
func (b *packetBuffer) fetchSequence() []*packet {
var a []*packet
for ; b.root != nil && b.root.p != nil; b.root = b.root.next {
a = append(a, b.root.p)
b.begin = (b.begin + 1) % (math.MaxUint16 + 1)
}
return a
}
func (b *packetBuffer) sequence() []*packet {
var a []*packet
n := b.root
for ; n != nil && n.p != nil; n = n.next {
a = append(a, n.p)
}
return a
}
func (b *packetBuffer) space() int {
s := b.size
for p := b.root; p != nil; p = p.next {
s--
}
return s
}
func (b *packetBuffer) empty() bool {
return b.root == nil
}
// test use only
func (b *packetBuffer) all() []*packet {
var a []*packet
for p := b.root; p != nil; p = p.next {
if p.p != nil {
a = append(a, p.p)
}
}
return a
}
func (b *packetBuffer) generateSelectiveACK() []byte {
if b.empty() {
return nil
}
var ack []byte
var bit uint
var octet byte
for p := b.root.next; p != nil; p = p.next {
if p.p != nil {
octet |= (1 << bit)
}
bit++
if bit == 8 {
ack = append(ack, octet)
bit = 0
octet = 0
}
}
if bit != 0 {
ack = append(ack, octet)
}
for len(ack) > 0 && ack[len(ack)-1] == 0 {
ack = ack[:len(ack)-1]
}
if len(ack) == 0 {
return nil
}
return ack
}
func (b *packetBuffer) processSelectiveACK(ack []byte) {
if b.empty() {
return
}
p := b.root.next
if p == nil {
return
}
for _, a := range ack {
for i := 0; i < 8; i++ {
acked := (a & 1) != 0
a >>= 1
if acked {
p.p = nil
}
p = p.next
if p == nil {
return
}
}
}
}
type packetRingBuffer struct {
b []*packet
begin int
s int
mutex sync.RWMutex
rch chan int
}
func newPacketRingBuffer(s int) *packetRingBuffer {
return &packetRingBuffer{
b: make([]*packet, s),
rch: make(chan int),
}
}
func (b *packetRingBuffer) size() int {
b.mutex.RLock()
defer b.mutex.RUnlock()
return b.s
}
func (b *packetRingBuffer) empty() bool {
return b.size() == 0
}
func (b *packetRingBuffer) push(p *packet) {
b.mutex.Lock()
defer b.mutex.Unlock()
b.b[(b.begin+b.s)%len(b.b)] = p
if b.s < len(b.b) {
b.s++
} else {
b.begin = (b.begin + 1) % len(b.b)
}
select {
case b.rch <- 0:
default:
}
}
func (b *packetRingBuffer) pop() *packet {
if b.empty() {
return nil
}
b.mutex.Lock()
defer b.mutex.Unlock()
p := b.b[b.begin]
b.begin = (b.begin + 1) % len(b.b)
b.s--
return p
}
func (b *packetRingBuffer) popOne(timeout time.Duration) (*packet, error) {
t := time.NewTimer(timeout)
defer t.Stop()
if timeout == 0 {
t.Stop()
}
if b.empty() {
select {
case <-b.rch:
case <-t.C:
return nil, errTimeout
}
}
return b.pop(), nil
}
type byteRingBuffer struct {
b []byte
begin int
s int
mutex sync.RWMutex
rch chan int
closech chan int
closechMutex sync.Mutex
}
func newByteRingBuffer(s int) *byteRingBuffer {
return &byteRingBuffer{
b: make([]byte, s),
rch: make(chan int),
closech: make(chan int),
}
}
func (r *byteRingBuffer) size() int {
r.mutex.RLock()
defer r.mutex.RUnlock()
return r.s
}
func (r *byteRingBuffer) space() int {
r.mutex.RLock()
defer r.mutex.RUnlock()
return len(r.b) - r.s
}
func (r *byteRingBuffer) empty() bool {
return r.size() == 0
}
func (r *byteRingBuffer) Write(b []byte) (int, error) {
r.mutex.Lock()
defer r.mutex.Unlock()
for len(b) > 0 {
end := (r.begin + r.s) % len(r.b)
n := copy(r.b[end:], b)
b = b[n:]
s := r.s + n
if s > len(r.b) {
r.begin = (r.begin + s - len(r.b)) % len(r.b)
r.s = len(r.b)
} else {
r.s += n
}
}
select {
case r.rch <- 0:
case <-r.closech:
return 0, io.EOF
default:
}
return len(b), nil
}
func (r *byteRingBuffer) ReadTimeout(b []byte, timeout time.Duration) (int, error) {
t := time.NewTimer(timeout)
defer t.Stop()
if timeout == 0 {
t.Stop()
}
if r.empty() {
select {
case <-r.rch:
case <-t.C:
return 0, errTimeout
case <-r.closech:
return 0, io.EOF
}
}
l := r.size()
if l > len(b) {
l = len(b)
}
r.mutex.Lock()
defer r.mutex.Unlock()
if r.begin+l > len(r.b) {
n := copy(b, r.b[r.begin:])
n = copy(b[n:], r.b[:])
r.begin = n
} else {
copy(b, r.b[r.begin:r.begin+l])
r.begin = (r.begin + l) % len(r.b)
}
r.s -= l
return l, nil
}
func (r *byteRingBuffer) Close() error {
r.closechMutex.Lock()
defer r.closechMutex.Unlock()
select {
case <-r.closech:
return errClosing
default:
close(r.closech)
}
return nil
}
type rateLimitedBuffer struct {
wch chan<- []byte
closech chan int
closechMutex sync.Mutex
size uint32
sizech chan uint32
sizeMutex sync.Mutex
}
func newRateLimitedBuffer(ch chan<- []byte, size uint32) *rateLimitedBuffer {
return &rateLimitedBuffer{
wch: ch,
closech: make(chan int),
size: size,
sizech: make(chan uint32),
}
}
func (r *rateLimitedBuffer) WriteTimeout(b []byte, timeout time.Duration) (int, error) {
t := time.NewTimer(timeout)
defer t.Stop()
if timeout == 0 {
t.Stop()
}
for wrote := uint32(0); wrote < uint32(len(b)); {
r.sizeMutex.Lock()
s := r.size
r.sizeMutex.Unlock()
if s == 0 {
select {
case ns := <-r.sizech:
s = ns
case <-r.closech:
return 0, errClosing
}
}
if s > uint32(len(b))-wrote {
s = uint32(len(b)) - wrote
}
select {
case r.wch <- append([]byte{}, b[wrote:wrote+s]...):
wrote += s
r.sizeMutex.Lock()
r.size -= uint32(s)
r.sizeMutex.Unlock()
case <-r.closech:
return 0, errClosing
case <-t.C:
return 0, errTimeout
}
}
return len(b), nil
}
func (r *rateLimitedBuffer) Reset(size uint32) {
r.sizeMutex.Lock()
defer r.sizeMutex.Unlock()
r.size = size
select {
case r.sizech <- size:
default:
}
}
func (r *rateLimitedBuffer) Close() error {
r.closechMutex.Lock()
defer r.closechMutex.Unlock()
select {
case <-r.closech:
return errClosing
default:
close(r.closech)
}
return nil
}
type baseDelayBuffer struct {
b [6]uint32
last int
min uint32
}
func (b *baseDelayBuffer) Push(val uint32) {
t := time.Now()
i := t.Second()/20 + (t.Minute()%2)*3
if b.last == i {
if b.b[i] > val {
b.b[i] = val
}
} else {
b.b[i] = val
b.last = i
}
min := val
for _, v := range b.b {
if v > 0 && min > v {
min = v
}
}
b.min = min
}
func (b *baseDelayBuffer) Min() uint32 {
return b.min
}