支持GB28181三种推流

jitterbuffer/priority_queue.go

@@ -0,0 +1,189 @@
+// SPDX-FileCopyrightText: 2023 The Pion community <https://pion.ly>
+// SPDX-License-Identifier: MIT
+
+package jitterbuffer
+
+import (
+	"errors"
+
+	"github.com/pion/rtp"
+)
+
+// PriorityQueue provides a linked list sorting of RTP packets by SequenceNumber
+type PriorityQueue struct {
+	next   *node
+	length uint16
+}
+
+type node struct {
+	val      *rtp.Packet
+	next     *node
+	prev     *node
+	priority uint16
+}
+
+var (
+	// ErrInvalidOperation may be returned if a Pop or Find operation is performed on an empty queue
+	ErrInvalidOperation = errors.New("attempt to find or pop on an empty list")
+	// ErrNotFound will be returned if the packet cannot be found in the queue
+	ErrNotFound = errors.New("priority not found")
+)
+
+// NewQueue will create a new PriorityQueue whose order relies on monotonically
+// increasing Sequence Number, wrapping at MaxUint16, so
+// a packet with sequence number MaxUint16 - 1 will be after 0
+func NewQueue() *PriorityQueue {
+	return &PriorityQueue{
+		next:   nil,
+		length: 0,
+	}
+}
+
+func newNode(val *rtp.Packet, priority uint16) *node {
+	return &node{
+		val:      val,
+		prev:     nil,
+		next:     nil,
+		priority: priority,
+	}
+}
+
+// Find a packet in the queue with the provided sequence number,
+// regardless of position (the packet is retained in the queue)
+func (q *PriorityQueue) Find(sqNum uint16) (*rtp.Packet, error) {
+	next := q.next
+	for next != nil {
+		if next.priority == sqNum {
+			return next.val, nil
+		}
+		next = next.next
+	}
+
+	return nil, ErrNotFound
+}
+
+// Push will insert a packet in to the queue in order of sequence number
+func (q *PriorityQueue) Push(val *rtp.Packet, priority uint16) {
+	newPq := newNode(val, priority)
+	if q.next == nil {
+		q.next = newPq
+		q.length++
+		return
+	}
+	if priority < q.next.priority {
+		newPq.next = q.next
+		q.next.prev = newPq
+		q.next = newPq
+		q.length++
+		return
+	}
+	head := q.next
+	prev := q.next
+	for head != nil {
+		if priority <= head.priority {
+			break
+		}
+		prev = head
+		head = head.next
+	}
+	if head == nil {
+		if prev != nil {
+			prev.next = newPq
+		}
+		newPq.prev = prev
+	} else {
+		newPq.next = head
+		newPq.prev = prev
+		if prev != nil {
+			prev.next = newPq
+		}
+		head.prev = newPq
+	}
+	q.length++
+}
+
+// Length will get the total length of the queue
+func (q *PriorityQueue) Length() uint16 {
+	return q.length
+}
+
+// Pop removes the first element from the queue, regardless
+// sequence number
+func (q *PriorityQueue) Pop() (*rtp.Packet, error) {
+	if q.next == nil {
+		return nil, ErrInvalidOperation
+	}
+	val := q.next.val
+	q.length--
+	q.next = q.next.next
+	return val, nil
+}
+
+// PopAt removes an element at the specified sequence number (priority)
+func (q *PriorityQueue) PopAt(sqNum uint16) (*rtp.Packet, error) {
+	if q.next == nil {
+		return nil, ErrInvalidOperation
+	}
+	if q.next.priority == sqNum {
+		val := q.next.val
+		q.next = q.next.next
+		q.length--
+		return val, nil
+	}
+	pos := q.next
+	prev := q.next.prev
+	for pos != nil {
+		if pos.priority == sqNum {
+			val := pos.val
+			prev.next = pos.next
+			if prev.next != nil {
+				prev.next.prev = prev
+			}
+			q.length--
+			return val, nil
+		}
+		prev = pos
+		pos = pos.next
+	}
+	return nil, ErrNotFound
+}
+
+// PopAtTimestamp removes and returns a packet at the given RTP Timestamp, regardless
+// sequence number order
+func (q *PriorityQueue) PopAtTimestamp(timestamp uint32) (*rtp.Packet, error) {
+	if q.next == nil {
+		return nil, ErrInvalidOperation
+	}
+	if q.next.val.Timestamp == timestamp {
+		val := q.next.val
+		q.next = q.next.next
+		q.length--
+		return val, nil
+	}
+	pos := q.next
+	prev := q.next.prev
+	for pos != nil {
+		if pos.val.Timestamp == timestamp {
+			val := pos.val
+			prev.next = pos.next
+			if prev.next != nil {
+				prev.next.prev = prev
+			}
+			q.length--
+			return val, nil
+		}
+		prev = pos
+		pos = pos.next
+	}
+	return nil, ErrNotFound
+}
+
+// Clear will empty a PriorityQueue
+func (q *PriorityQueue) Clear() {
+	next := q.next
+	q.length = 0
+	for next != nil {
+		next.prev = nil
+		next = next.next
+	}
+}