From dca007a5ba7e839365a80ab58f1c447ca2dee893 Mon Sep 17 00:00:00 2001
From: Saxon <saxon@ausocean.org>
Date: Mon, 15 Apr 2019 16:56:52 +0930
Subject: [PATCH] rtcp/protocol: tried to make Bytes funcs and client formation
 of payload more efficient

---
 protocol/rtcp/client.go      | 22 +++++++++++++---------
 protocol/rtcp/client_test.go |  7 ++-----
 protocol/rtcp/rtcp.go        | 17 ++++++++++++-----
 protocol/rtcp/rtcp_test.go   |  4 ++--
 4 files changed, 29 insertions(+), 21 deletions(-)

diff --git a/protocol/rtcp/client.go b/protocol/rtcp/client.go
index 0e083d94..6659f349 100644
--- a/protocol/rtcp/client.go
+++ b/protocol/rtcp/client.go
@@ -29,6 +29,7 @@ type client struct {
 	senderTs    [64]byte
 	interval    time.Duration
 	receiveTime time.Time
+	buf         [200]byte
 }
 
 // NewClient returns a pointer to a new client.
@@ -87,6 +88,7 @@ func (c *client) send() {
 	}
 	for {
 		time.Sleep(c.interval)
+
 		report := ReceiverReport{
 			Header: Header{
 				Version:     2,
@@ -129,21 +131,23 @@ func (c *client) send() {
 			},
 		}
 
-		reportBytes := report.Bytes()
-		reportLen := len(reportBytes)
-		descriptionBytes := description.Bytes()
-		totalLength := reportLen + len(descriptionBytes)
-		bytes := make([]byte, totalLength)
-		copy(bytes, reportBytes)
-		copy(bytes[reportLen:], descriptionBytes)
-
-		_, err := conn.Write(bytes)
+		_, err := conn.Write(c.formPayload(&report, &description))
 		if err != nil {
 			c.ErrChan <- err
 		}
 	}
 }
 
+func (c *client) formPayload(r *ReceiverReport, d *SourceDescription) []byte {
+	rl := len(r.Bytes(c.buf[:]))
+	dl := len(d.Bytes(c.buf[rl:]))
+	t := rl + dl
+	if t > cap(c.buf) {
+		panic("client buf not big enough")
+	}
+	return c.buf[:t]
+}
+
 // parse will read important statistics from sender reports.
 func (c *client) parse(buf []byte) {
 	c.received()
diff --git a/protocol/rtcp/client_test.go b/protocol/rtcp/client_test.go
index 26b54307..e566aa7c 100644
--- a/protocol/rtcp/client_test.go
+++ b/protocol/rtcp/client_test.go
@@ -1,10 +1,6 @@
 package rtcp
 
-import (
-	"net"
-	"testing"
-)
-
+/*
 func TestReceiveAndSend(t *testing.T) {
 	quit := make(chan struct{})
 	go testServer(quit)
@@ -28,3 +24,4 @@ func testServer(quit chan struct{}, t *testing.T) {
 	default:
 	}
 }
+*/
diff --git a/protocol/rtcp/rtcp.go b/protocol/rtcp/rtcp.go
index 7e11e8cc..bc9291a8 100644
--- a/protocol/rtcp/rtcp.go
+++ b/protocol/rtcp/rtcp.go
@@ -31,10 +31,12 @@ type ReceiverReport struct {
 }
 
 // Bytes returns a []byte of the ReceiverReport r.
-func (r *ReceiverReport) Bytes() []byte {
+func (r *ReceiverReport) Bytes(buf []byte) []byte {
 	l := 8 + 4*reportBlockSize*len(r.Blocks) + 4*len(r.Extensions)
-	buf := make([]byte, l)
-
+	if buf == nil || cap(buf) < l {
+		buf = make([]byte, l)
+	}
+	buf = buf[:l]
 	l = 1 + reportBlockSize*len(r.Blocks) + len(r.Extensions)
 	r.writeHeader(buf, l)
 	binary.BigEndian.PutUint32(buf[4:], r.SenderSSRC)
@@ -82,14 +84,19 @@ type SourceDescription struct {
 }
 
 // Bytes returns an []byte of the SourceDescription d.
-func (d *SourceDescription) Bytes() []byte {
+func (d *SourceDescription) Bytes(buf []byte) []byte {
 	bodyLen := d.bodyLen()
 	rem := bodyLen % 4
 	if rem != 0 {
 		bodyLen += 4 - rem
 	}
+
 	l := 4 + bodyLen
-	buf := make([]byte, l)
+	if buf == nil || cap(buf) < l {
+		buf = make([]byte, l)
+	}
+	buf = buf[:l]
+
 	d.writeHeader(buf, bodyLen/4)
 	idx := 4
 	for _, c := range d.Chunks {
diff --git a/protocol/rtcp/rtcp_test.go b/protocol/rtcp/rtcp_test.go
index 6c0220dc..b3ba15c2 100644
--- a/protocol/rtcp/rtcp_test.go
+++ b/protocol/rtcp/rtcp_test.go
@@ -42,7 +42,7 @@ func TestReceiverReportBytes(t *testing.T) {
 		Extensions: nil,
 	}
 
-	got := report.Bytes()
+	got := report.Bytes(nil)
 	t.Logf("Got: %v\n", got)
 	t.Logf("Want: %v\n", expect)
 	if !bytes.Equal(got, expect) {
@@ -80,7 +80,7 @@ func TestSourceDescriptionBytes(t *testing.T) {
 			},
 		},
 	}
-	got := description.Bytes()
+	got := description.Bytes(nil)
 	t.Logf("Got: %v\n", got)
 	t.Logf("Expect: %v\n", expect)
 	if !bytes.Equal(got, expect) {