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Implement ToBitmap.

This commit is contained in:
Juliusz Chroboczek 2020-10-12 14:35:35 +02:00
parent 5e130122f5
commit 9f6e23aaf3
2 changed files with 55 additions and 0 deletions

View file

@ -526,3 +526,21 @@ func (cache *Cache) GetStats(reset bool) (uint32, uint32, uint32, uint32) {
}
return expected, lost, totalLost, eseqno
}
// ToBitmap takes a non-empty sorted list of seqnos, and computes a bitmap
// covering a prefix of the list. It returns the part of the list that
// couldn't be covered.
func ToBitmap(seqnos []uint16) (first uint16, bitmap uint16, remain []uint16) {
first = seqnos[0]
bitmap = uint16(0)
remain = seqnos[1:]
for len(remain) > 0 {
delta := remain[0] - first - 1
if delta >= 16 {
break
}
bitmap = bitmap | (1 << delta)
remain = remain[1:]
}
return
}

View file

@ -3,6 +3,7 @@ package packetcache
import (
"bytes"
"math/rand"
"reflect"
"sync"
"testing"
@ -457,3 +458,39 @@ func BenchmarkCachePutGetAt(b *testing.B) {
}
wg.Wait()
}
func TestToBitmap(t *testing.T) {
l := []uint16{18, 19, 32, 38}
bb := uint16(1 | 1<<(32-18-1))
f, b, r := ToBitmap(l)
if f != 18 || b != bb {
t.Errorf("Expected %v %v, Got %v %v", 18, bb, f, b)
}
if len(r) != 1 || r[0] != 38 {
t.Errorf("Expected [38], got %v", r)
}
f2, b2, r2 := ToBitmap(r)
if f2 != 38 || b2 != 0 || len(r2) != 0 {
t.Errorf("Expected 38 0, got %v %v %v", f2, b2, r2)
}
}
func TestToBitmapNack(t *testing.T) {
l := []uint16{18, 19, 32, 38}
var nacks []rtcp.NackPair
m := l
for len(m) > 0 {
var f, b uint16
f, b, m = ToBitmap(m)
nacks = append(nacks, rtcp.NackPair{f, rtcp.PacketBitmap(b)})
}
var n []uint16
for len(nacks) > 0 {
n = append(n, nacks[0].PacketList()...)
nacks = nacks[1:]
}
if !reflect.DeepEqual(l, n) {
t.Errorf("Expected %v, got %v", l, n)
}
}