Merge packet list and window into cache.

client.go

@@ -16,8 +16,7 @@ import (
 	"sync/atomic"
 	"time"
 
-	"sfu/packetlist"
-	"sfu/packetwindow"
+	"sfu/packetcache"
 
 	"github.com/gorilla/websocket"
 	"github.com/pion/rtcp"
@@ -288,7 +287,7 @@ func addUpConn(c *client, id string) (*upConnection, error) {
 		}
 		track := &upTrack{
 			track:      remote,
-			list:       packetlist.New(32),
+			cache:      packetcache.New(32),
 			maxBitrate: ^uint64(0),
 		}
 		u.tracks = append(u.tracks, track)
@@ -310,11 +309,10 @@ func addUpConn(c *client, id string) (*upConnection, error) {
 }
 
 func upLoop(conn *upConnection, track *upTrack) {
-	buf := make([]byte, packetlist.BufSize)
+	buf := make([]byte, packetcache.BufSize)
 	var packet rtp.Packet
 	var local []*downTrack
 	var localTime time.Time
-	window := packetwindow.New()
 	for {
 		now := time.Now()
 		if now.Sub(localTime) > time.Second/2 {
@@ -336,9 +334,9 @@ func upLoop(conn *upConnection, track *upTrack) {
 			continue
 		}
 
-		window.Set(packet.SequenceNumber)
-		if packet.SequenceNumber-window.First() > 24 {
-			first, bitmap := window.Get17()
+		first := track.cache.Store(packet.SequenceNumber, buf[:i])
+		if packet.SequenceNumber-first > 24 {
+			first, bitmap := track.cache.BitmapGet()
 			if bitmap != ^uint16(0) {
 				err := conn.sendNACK(track, first, ^bitmap)
 				if err != nil {
@@ -347,8 +345,6 @@ func upLoop(conn *upConnection, track *upTrack) {
 			}
 		}
 
-		track.list.Store(packet.SequenceNumber, buf[:i])
-
 		for _, l := range local {
 			if l.muted() {
 				continue
@@ -648,7 +644,7 @@ func sendRecovery(p *rtcp.TransportLayerNack, track *downTrack) {
 	var packet rtp.Packet
 	for _, nack := range p.Nacks {
 		for _, seqno := range nack.PacketList() {
-			raw := track.remote.list.Get(seqno)
+			raw := track.remote.cache.Get(seqno)
 			if raw != nil {
 				err := packet.Unmarshal(raw)
 				if err != nil {

group.go

@@ -15,14 +15,14 @@ import (
 	"sync/atomic"
 	"time"
 
-	"sfu/packetlist"
+	"sfu/packetcache"
 
 	"github.com/pion/webrtc/v2"
 )
 
 type upTrack struct {
 	track      *webrtc.Track
-	list       *packetlist.List
+	cache      *packetcache.Cache
 	maxBitrate uint64
 	lastPLI    uint64
 

packetcache/packetcache.go

@@ -0,0 +1,104 @@
+package packetcache
+
+import (
+	"sync"
+)
+
+const BufSize = 1500
+
+type entry struct {
+	seqno  uint16
+	length int
+	buf    [BufSize]byte
+}
+
+type Cache struct {
+	mu      sync.Mutex
+	first   uint16 // the first seqno
+	bitmap  uint32
+	tail    int // the next entry to be rewritten
+	entries []entry
+}
+
+func New(capacity int) *Cache {
+	return &Cache{
+		entries: make([]entry, capacity),
+	}
+}
+
+// Set a bit in the bitmap, shifting first if necessary.
+func (cache *Cache) set(seqno uint16) {
+	if cache.bitmap == 0 {
+		cache.first = seqno
+		cache.bitmap = 1
+		return
+	}
+
+	if ((seqno - cache.first) & 0x8000) != 0 {
+		return
+	}
+
+	if seqno == cache.first {
+		cache.bitmap >>= 1
+		cache.first += 1
+		for (cache.bitmap & 1) == 1 {
+			cache.bitmap >>= 1
+			cache.first += 1
+		}
+		return
+	}
+
+	if seqno-cache.first < 32 {
+		cache.bitmap |= (1 << uint16(seqno-cache.first))
+		return
+	}
+
+	shift := seqno - cache.first - 31
+	cache.bitmap >>= shift
+	cache.first += shift
+	cache.bitmap |= (1 << uint16(seqno-cache.first))
+	return
+}
+
+// Store a packet, setting bitmap at the same time
+func (cache *Cache) Store(seqno uint16, buf []byte) uint16 {
+	cache.mu.Lock()
+	defer cache.mu.Unlock()
+
+	cache.set(seqno)
+
+	cache.entries[cache.tail].seqno = seqno
+	copy(cache.entries[cache.tail].buf[:], buf)
+	cache.entries[cache.tail].length = len(buf)
+	cache.tail = (cache.tail + 1) % len(cache.entries)
+
+	return cache.first
+}
+
+func (cache *Cache) Get(seqno uint16) []byte {
+	cache.mu.Lock()
+	defer cache.mu.Unlock()
+
+	for i := range cache.entries {
+		if cache.entries[i].length == 0 ||
+			cache.entries[i].seqno != seqno {
+			continue
+		}
+		buf := make([]byte, cache.entries[i].length)
+		copy(buf, cache.entries[i].buf[:])
+		return buf
+	}
+	return nil
+}
+
+// Shift 17 bits out of the bitmap, return first index and remaining 16.
+func (cache *Cache) BitmapGet() (uint16, uint16) {
+	cache.mu.Lock()
+	defer cache.mu.Unlock()
+
+	first := cache.first
+	bitmap := uint16((cache.bitmap >> 1) & 0xFFFF)
+	cache.bitmap >>= 17
+	cache.first += 17
+	return first, bitmap
+}

packetcache/packetcache_test.go

@@ -0,0 +1,158 @@
+package packetcache
+
+import (
+	"bytes"
+	"math/rand"
+	"testing"
+
+	"github.com/pion/rtcp"
+)
+
+func randomBuf() []byte {
+	length := rand.Int31n(BufSize-1) + 1
+	buf := make([]byte, length)
+	rand.Read(buf)
+	return buf
+}
+
+func TestCache(t *testing.T) {
+	buf1 := randomBuf()
+	buf2 := randomBuf()
+	cache := New(16)
+	cache.Store(13, buf1)
+	cache.Store(17, buf2)
+
+	if bytes.Compare(cache.Get(13), buf1) != 0 {
+		t.Errorf("Couldn't get 13")
+	}
+	if bytes.Compare(cache.Get(17), buf2) != 0 {
+		t.Errorf("Couldn't get 17")
+	}
+	if cache.Get(42) != nil {
+		t.Errorf("Creation ex nihilo")
+	}
+}
+
+func TestCacheOverflow(t *testing.T) {
+	cache := New(16)
+
+	for i := 0; i < 32; i++ {
+		cache.Store(uint16(i), []byte{uint8(i)})
+	}
+
+	for i := 0; i < 32; i++ {
+		buf := cache.Get(uint16(i))
+		if i < 16 {
+			if buf != nil {
+				t.Errorf("Creation ex nihilo: %v", i)
+			}
+		} else {
+			if len(buf) != 1 || buf[0] != uint8(i) {
+				t.Errorf("Expected [%v], got %v", i, buf)
+			}
+		}
+	}
+}
+
+func TestBitmap(t *testing.T) {
+	value := uint64(0xcdd58f1e035379c0)
+	packet := make([]byte, 1)
+
+	cache := New(16)
+
+	var first uint16
+	for i := 0; i < 64; i++ {
+		if (value & (1 << i)) != 0 {
+			first = cache.Store(uint16(42 + i), packet)
+		}
+	}
+
+	value >>= uint16(first - 42)
+	if uint32(value) != cache.bitmap {
+		t.Errorf("Got %b, expected %b", cache.bitmap, value)
+	}
+}
+
+func TestBitmapWrap(t *testing.T) {
+	value := uint64(0xcdd58f1e035379c0)
+	packet := make([]byte, 1)
+
+	cache := New(16)
+
+	cache.Store(0x7000, packet)
+	cache.Store(0xA000, packet)
+
+	var first uint16
+	for i := 0; i < 64; i++ {
+		if (value & (1 << i)) != 0 {
+			first = cache.Store(uint16(42 + i), packet)
+		}
+	}
+
+	value >>= uint16(first - 42)
+	if uint32(value) != cache.bitmap {
+		t.Errorf("Got %b, expected %b", cache.bitmap, value)
+	}
+}
+
+func TestBitmapGet(t *testing.T) {
+	value := uint64(0xcdd58f1e035379c0)
+	packet := make([]byte, 1)
+
+	cache := New(16)
+
+	for i := 0; i < 64; i++ {
+		if (value & (1 << i)) != 0 {
+			cache.Store(uint16(42 + i), packet)
+		}
+	}
+
+	pos := uint16(42)
+	for cache.bitmap != 0 {
+		first, bitmap := cache.BitmapGet()
+		if first < pos || first >= pos+64 {
+			t.Errorf("First is %v, pos is %v", first, pos)
+		}
+		value >>= (first - pos)
+		pos = first
+		if (value & 1) != 0 {
+			t.Errorf("Value is odd")
+		}
+		value >>= 1
+		pos += 1
+		if bitmap != uint16(value&0xFFFF) {
+			t.Errorf("Got %b, expected %b", bitmap, (value & 0xFFFF))
+		}
+		value >>= 16
+		pos += 16
+	}
+	if value != 0 {
+		t.Errorf("Value is %v", value)
+	}
+}
+
+func TestBitmapPacket(t *testing.T) {
+	value := uint64(0xcdd58f1e035379c0)
+	packet := make([]byte, 1)
+
+	cache := New(16)
+
+	for i := 0; i < 64; i++ {
+		if (value & (1 << i)) != 0 {
+			cache.Store(uint16(42 + i), packet)
+		}
+	}
+
+	first, bitmap := cache.BitmapGet()
+
+	p := rtcp.NackPair{first, rtcp.PacketBitmap(^bitmap)}
+	pl := p.PacketList()
+
+	for _, s := range pl {
+		if s < 42 || s >= 42+64 {
+			if (value & (1 << (s - 42))) != 0 {
+				t.Errorf("Bit %v unexpectedly set", s-42)
+			}
+		}
+	}
+}

packetlist/packetlist.go

@@ -1,51 +0,0 @@
-package packetlist
-
-import (
-	"sync"
-)
-
-const BufSize = 1500
-
-type entry struct {
-	seqno  uint16
-	length int
-	buf    [BufSize]byte
-}
-
-type List struct {
-	mu      sync.Mutex
-	tail    int
-	entries []entry
-}
-
-func New(capacity int) *List {
-	return &List{
-		entries: make([]entry, capacity),
-	}
-}
-
-func (list *List) Store(seqno uint16, buf []byte) {
-	list.mu.Lock()
-	defer list.mu.Unlock()
-	list.entries[list.tail].seqno = seqno
-	copy(list.entries[list.tail].buf[:], buf)
-	list.entries[list.tail].length = len(buf)
-	list.tail = (list.tail + 1) % len(list.entries)
-
-}
-
-func (list *List) Get(seqno uint16) []byte {
-	list.mu.Lock()
-	defer list.mu.Unlock()
-
-	for i := range list.entries {
-		if list.entries[i].length == 0 ||
-			list.entries[i].seqno != seqno {
-			continue
-		}
-		buf := make([]byte, list.entries[i].length)
-		copy(buf, list.entries[i].buf[:])
-		return buf
-	}
-	return nil
-}

packetlist/packetlist_test.go

@@ -1,53 +0,0 @@
-package packetlist
-
-import (
-	"bytes"
-	"math/rand"
-	"testing"
-)
-
-func randomBuf() []byte {
-	length := rand.Int31n(BufSize-1) + 1
-	buf := make([]byte, length)
-	rand.Read(buf)
-	return buf
-}
-
-func TestList(t *testing.T) {
-	buf1 := randomBuf()
-	buf2 := randomBuf()
-	list := New(16)
-	list.Store(13, buf1)
-	list.Store(17, buf2)
-
-	if bytes.Compare(list.Get(13), buf1) != 0 {
-		t.Errorf("Couldn't get 13")
-	}
-	if bytes.Compare(list.Get(17), buf2) != 0 {
-		t.Errorf("Couldn't get 17")
-	}
-	if list.Get(42) != nil {
-		t.Errorf("Creation ex nihilo")
-	}
-}
-
-func TestOverflow(t *testing.T) {
-	list := New(16)
-
-	for i := 0; i < 32; i++ {
-		list.Store(uint16(i), []byte{uint8(i)})
-	}
-
-	for i := 0; i < 32; i++ {
-		buf := list.Get(uint16(i))
-		if i < 16 {
-			if buf != nil {
-				t.Errorf("Creation ex nihilo: %v", i)
-			}
-		} else {
-			if len(buf) != 1 || buf[0] != uint8(i) {
-				t.Errorf("Expected [%v], got %v", i, buf)
-			}
-		}
-	}
-}

packetwindow/packetwindow.go

@@ -1,76 +0,0 @@
-package packetwindow
-
-import (
-	"fmt"
-)
-
-type Window struct {
-	first  uint16
-	bitmap uint32
-}
-
-func New() *Window {
-	return &Window{}
-}
-
-func (w *Window) String() string {
-	buf := make([]byte, 32)
-	for i := 0; i < 32; i++ {
-		if (w.bitmap & (1 << i)) != 0 {
-			buf[i] = '1'
-		} else {
-			buf[i] = '0'
-		}
-	}
-
-	return fmt.Sprintf("[%04x %s]", w.first, buf)
-}
-
-func (w *Window) First() uint16 {
-	return w.first
-}
-
-func (w *Window) Reset() {
-	w.bitmap = 0
-}
-
-func (w *Window) Set(seqno uint16) {
-	if w.bitmap == 0 {
-		w.first = seqno
-		w.bitmap = 1
-		return
-	}
-
-	if ((seqno - w.first) & 0x8000) != 0 {
-		return
-	}
-
-	if seqno == w.first {
-		w.bitmap >>= 1
-		w.first += 1
-		for (w.bitmap & 1) == 1 {
-			w.bitmap >>= 1
-			w.first += 1
-		}
-		return
-	}
-
-	if seqno - w.first < 32 {
-		w.bitmap |= (1 << uint16(seqno - w.first))
-		return
-	}
-
-	shift := seqno - w.first - 31
-	w.bitmap >>= shift
-	w.first += shift
-	w.bitmap |= (1 << uint16(seqno - w.first))
-	return
-}
-
-func (w *Window) Get17() (uint16, uint16) {
-	first := w.first
-	bitmap := uint16((w.bitmap >> 1) & 0xFFFF)
-	w.bitmap >>= 17
-	w.first += 17
-	return first, bitmap
-}

packetwindow/packetwindow_test.go

@@ -1,102 +0,0 @@
-package packetwindow
-
-import (
-	"testing"
-
-	"github.com/pion/rtcp"
-)
-
-func TestWindow(t *testing.T) {
-	value := uint64(0xcdd58f1e035379c0)
-
-	w := New()
-
-	for i := 0; i < 64; i++ {
-		if (value & (1 << i)) != 0 {
-			w.Set(uint16(42 + i))
-		}
-	}
-
-	value >>= uint16(w.first - 42)
-	if uint32(value) != w.bitmap {
-		t.Errorf("Got %b, expected %b", w.bitmap, value)
-	}
-}
-
-func TestWindowWrap(t *testing.T) {
-	value := uint64(0xcdd58f1e035379c0)
-
-	w := New()
-
-	w.Set(0x7000)
-	w.Set(0xA000)
-	for i := 0; i < 64; i++ {
-		if (value & (1 << i)) != 0 {
-			w.Set(uint16(42 + i))
-		}
-	}
-
-	value >>= uint16(w.first - 42)
-	if uint32(value) != w.bitmap {
-		t.Errorf("Got %b, expected %b", w.bitmap, value)
-	}
-}
-
-func TestWindowGet(t *testing.T) {
-	value := uint64(0xcdd58f1e035379c0)
-
-	w := New()
-
-	for i := 0; i < 64; i++ {
-		if (value & (1 << i)) != 0 {
-			w.Set(uint16(42 + i))
-		}
-	}
-
-	pos := uint16(42)
-	for w.bitmap != 0 {
-		first, bitmap := w.Get17()
-		if first < pos || first >= pos+64 {
-			t.Errorf("First is %v, pos is %v", first, pos)
-		}
-		value >>= (first - pos)
-		pos = first
-		if (value & 1) != 0 {
-			t.Errorf("Value is odd")
-		}
-		value >>= 1
-		pos += 1
-		if bitmap != uint16(value&0xFFFF) {
-			t.Errorf("Got %b, expected %b", bitmap, (value & 0xFFFF))
-		}
-		value >>= 16
-		pos += 16
-	}
-	if value != 0 {
-		t.Errorf("Value is %v", value)
-	}
-}
-
-func TestWindowPacket(t *testing.T) {
-	value := uint64(0xcdd58f1e035379c0)
-	w := New()
-
-	for i := 0; i < 64; i++ {
-		if (value & (1 << i)) != 0 {
-			w.Set(uint16(42 + i))
-		}
-	}
-
-	first, bitmap := w.Get17()
-
-	p := rtcp.NackPair{first, rtcp.PacketBitmap(^bitmap)}
-	list := p.PacketList()
-
-	for _, s := range list {
-		if s < 42 || s >= 42 + 64 {
-			if (value & (1 << (s - 42))) != 0 {
-				t.Errorf("Bit %v unexpectedly set", s - 42)
-			}
-		}
-	}
-}