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https://github.com/jech/galene.git
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Remodularise packet cache.
This commit is contained in:
Juliusz Chroboczek
parent
a233f10b0b
commit
44ae9f82d3
2 changed files with 127 additions and 98 deletions
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@ -6,7 +6,7 @@ import (
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)
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const BufSize = 1500
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const maxKeyframe = 1024
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const maxFrame = 1024
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type entry struct {
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seqno uint16
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@ -14,6 +14,17 @@ type entry struct {
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buf [BufSize]byte
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}
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type bitmap struct {
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valid bool
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first uint16
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bitmap uint32
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}
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type frame struct {
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timestamp uint32
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entries []entry
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}
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type Cache struct {
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mu sync.Mutex
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//stats
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@ -24,13 +35,10 @@ type Cache struct {
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lost uint32
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totalLost uint32
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// bitmap
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bitmapValid bool
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first uint16
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bitmap uint32
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bitmap bitmap
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// buffered keyframe
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kfTimestamp uint32
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kfEntries []entry
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// packet cache
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keyframe frame
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// the actual cache
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tail uint16
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entries []entry
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}
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@ -56,35 +64,118 @@ func seqnoInvalid(seqno, reference uint16) bool {
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return false
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}
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// Set a bit in the bitmap, shifting first if necessary.
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func (cache *Cache) set(seqno uint16) {
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if !cache.bitmapValid || seqnoInvalid(seqno, cache.first) {
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cache.first = seqno
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cache.bitmap = 1
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cache.bitmapValid = true
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// set sets a bit in the bitmap, shifting if necessary
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func (bitmap *bitmap) set(seqno uint16) {
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if !bitmap.valid || seqnoInvalid(seqno, bitmap.first) {
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bitmap.first = seqno
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bitmap.bitmap = 1
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bitmap.valid = true
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return
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}
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if ((seqno - cache.first) & 0x8000) != 0 {
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if ((seqno - bitmap.first) & 0x8000) != 0 {
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return
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}
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if seqno-cache.first >= 32 {
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shift := seqno - cache.first - 31
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cache.bitmap >>= shift
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cache.first += shift
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if seqno-bitmap.first >= 32 {
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shift := seqno - bitmap.first - 31
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bitmap.bitmap >>= shift
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bitmap.first += shift
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}
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if (cache.bitmap & 1) == 1 {
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ones := bits.TrailingZeros32(^cache.bitmap)
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cache.bitmap >>= ones
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cache.first += uint16(ones)
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if (bitmap.bitmap & 1) == 1 {
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ones := bits.TrailingZeros32(^bitmap.bitmap)
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bitmap.bitmap >>= ones
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bitmap.first += uint16(ones)
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}
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cache.bitmap |= (1 << uint16(seqno-cache.first))
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bitmap.bitmap |= (1 << uint16(seqno-bitmap.first))
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return
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}
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// BitmapGet shifts up to 17 bits out of the bitmap. It returns a boolean
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// indicating if any were 0, the index of the first 0 bit, and a bitmap
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// indicating any 0 bits after the first one.
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func (cache *Cache) BitmapGet(next uint16) (bool, uint16, uint16) {
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cache.mu.Lock()
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defer cache.mu.Unlock()
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return cache.bitmap.get(next)
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}
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func (bitmap *bitmap) get(next uint16) (bool, uint16, uint16) {
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first := bitmap.first
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count := next - first
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if (count&0x8000) != 0 || count == 0 {
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// next is in the past
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return false, first, 0
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}
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if count > 17 {
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count = 17
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}
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bm := (^bitmap.bitmap) & ^((^uint32(0)) << count)
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bitmap.bitmap >>= count
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bitmap.first += count
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if bm == 0 {
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return false, first, 0
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}
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if (bm & 1) == 0 {
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count := bits.TrailingZeros32(bm)
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bm >>= count
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first += uint16(count)
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}
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return true, first, uint16(bm >> 1)
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}
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func (frame *frame) store(seqno uint16, timestamp uint32, first bool, data []byte) {
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if first {
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if frame.timestamp != timestamp {
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frame.timestamp = timestamp
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frame.entries = frame.entries[:0]
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}
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} else if len(frame.entries) > 0 {
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if frame.timestamp != timestamp {
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return
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}
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} else {
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return
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}
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i := 0
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for i < len(frame.entries) {
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if frame.entries[i].seqno >= seqno {
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break
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}
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i++
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}
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if i < len(frame.entries) && frame.entries[i].seqno == seqno {
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// duplicate
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return
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}
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if len(frame.entries) >= maxFrame {
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// overflow
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return
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}
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e := entry{
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seqno: seqno,
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length: uint16(len(data)),
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}
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copy(e.buf[:], data)
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if i >= len(frame.entries) {
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frame.entries = append(frame.entries, e)
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return
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}
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frame.entries = append(frame.entries, entry{})
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copy(frame.entries[i+1:], frame.entries[i:])
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frame.entries[i] = e
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}
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// Store a packet, setting bitmap at the same time
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func (cache *Cache) Store(seqno uint16, timestamp uint32, keyframe bool, buf []byte) (uint16, uint16) {
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cache.mu.Lock()
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@ -108,38 +199,9 @@ func (cache *Cache) Store(seqno uint16, timestamp uint32, keyframe bool, buf []b
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}
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}
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}
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cache.set(seqno)
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cache.bitmap.set(seqno)
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doit := false
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if keyframe {
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if cache.kfTimestamp != timestamp {
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cache.kfTimestamp = timestamp
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cache.kfEntries = cache.kfEntries[:0]
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}
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doit = true
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} else if len(cache.kfEntries) > 0 {
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doit = cache.kfTimestamp == timestamp
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}
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if doit {
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i := 0
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for i < len(cache.kfEntries) {
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if cache.kfEntries[i].seqno >= seqno {
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break
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}
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i++
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}
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if i >= len(cache.kfEntries) || cache.kfEntries[i].seqno != seqno {
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if len(cache.kfEntries) >= maxKeyframe {
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cache.kfEntries = cache.kfEntries[:maxKeyframe-1]
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}
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cache.kfEntries = append(cache.kfEntries, entry{})
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copy(cache.kfEntries[i+1:], cache.kfEntries[i:])
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}
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cache.kfEntries[i].seqno = seqno
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cache.kfEntries[i].length = uint16(len(buf))
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copy(cache.kfEntries[i].buf[:], buf)
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}
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cache.keyframe.store(seqno, timestamp, keyframe, buf)
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i := cache.tail
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cache.entries[i].seqno = seqno
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@ -147,7 +209,7 @@ func (cache *Cache) Store(seqno uint16, timestamp uint32, keyframe bool, buf []b
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cache.entries[i].length = uint16(len(buf))
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cache.tail = (i + 1) % uint16(len(cache.entries))
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return cache.first, i
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return cache.bitmap.first, i
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}
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func (cache *Cache) Expect(n int) {
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@ -176,7 +238,7 @@ func (cache *Cache) Get(seqno uint16, result []byte) uint16 {
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cache.mu.Lock()
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defer cache.mu.Unlock()
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n := get(seqno, cache.kfEntries, result)
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n := get(seqno, cache.keyframe.entries, result)
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if n > 0 {
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return n
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}
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@ -209,11 +271,11 @@ func (cache *Cache) Keyframe() (uint32, []uint16) {
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cache.mu.Lock()
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defer cache.mu.Unlock()
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seqnos := make([]uint16, len(cache.kfEntries))
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for i := range cache.kfEntries {
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seqnos[i] = cache.kfEntries[i].seqno
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seqnos := make([]uint16, len(cache.keyframe.entries))
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for i := range cache.keyframe.entries {
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seqnos[i] = cache.keyframe.entries[i].seqno
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}
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return cache.kfTimestamp, seqnos
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return cache.keyframe.timestamp, seqnos
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}
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func (cache *Cache) resize(capacity int) {
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@ -269,39 +331,6 @@ func (cache *Cache) ResizeCond(capacity int) bool {
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return true
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}
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// Shift up to 17 bits out of the bitmap. Return a boolean indicating if
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// any were 0, the index of the first 0 bit, and a bitmap indicating any
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// 0 bits after the first one.
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func (cache *Cache) BitmapGet(next uint16) (bool, uint16, uint16) {
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cache.mu.Lock()
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defer cache.mu.Unlock()
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first := cache.first
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count := next - first
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if (count&0x8000) != 0 || count == 0 {
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// next is in the past
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return false, first, 0
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}
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if count > 17 {
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count = 17
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}
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bitmap := (^cache.bitmap) & ^((^uint32(0)) << count)
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cache.bitmap >>= count
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cache.first += count
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if bitmap == 0 {
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return false, first, 0
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}
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if (bitmap & 1) == 0 {
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count := bits.TrailingZeros32(bitmap)
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bitmap >>= count
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first += uint16(count)
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}
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return true, first, uint16(bitmap >> 1)
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}
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func (cache *Cache) GetStats(reset bool) (uint32, uint32, uint32, uint32) {
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cache.mu.Lock()
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defer cache.mu.Unlock()
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@ -223,8 +223,8 @@ func TestBitmap(t *testing.T) {
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}
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value >>= uint16(first - 42)
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if uint32(value) != cache.bitmap {
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t.Errorf("Got %b, expected %b", cache.bitmap, value)
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if uint32(value) != cache.bitmap.bitmap {
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t.Errorf("Got %b, expected %b", cache.bitmap.bitmap, value)
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}
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}
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@ -245,8 +245,8 @@ func TestBitmapWrap(t *testing.T) {
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}
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value >>= uint16(first - 42)
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if uint32(value) != cache.bitmap {
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t.Errorf("Got %b, expected %b", cache.bitmap, value)
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if uint32(value) != cache.bitmap.bitmap {
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t.Errorf("Got %b, expected %b", cache.bitmap.bitmap, value)
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}
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}
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@ -263,7 +263,7 @@ func TestBitmapGet(t *testing.T) {
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}
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pos := uint16(42)
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for cache.bitmap != 0 {
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for cache.bitmap.bitmap != 0 {
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found, first, bitmap := cache.BitmapGet(42 + 65)
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if first < pos || first >= pos+64 {
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t.Errorf("First is %v, pos is %v", first, pos)
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