Avoid RTPBuffer allocation

internal/rtpbuffer/rtpbuffer.go

@@ -4,9 +4,7 @@
 // Package rtpbuffer provides a buffer for storing RTP packets
 package rtpbuffer
 
-import (
-	"fmt"
-)
+import "fmt"
 
 const (
 	// Uint16SizeHalf is half of a math.Uint16.
@@ -26,25 +24,30 @@ type RTPBuffer struct {
 
 // NewRTPBuffer constructs a new RTPBuffer.
 func NewRTPBuffer(size uint16) (*RTPBuffer, error) {
-	allowedSizes := make([]uint16, 0)
-	correctSize := false
+	if err := IsBufferSizeValid(size); err != nil {
+		return nil, err
+	}
+
+	return &RTPBuffer{
+		packets: make([]*RetainablePacket, size),
+		size:    size,
+	}, nil
+}
+
+func IsBufferSizeValid(size uint16) error {
 	for i := 0; i < 16; i++ {
 		if size == 1<<i {
-			correctSize = true
-
-			break
+			return nil
 		}
-		allowedSizes = append(allowedSizes, 1<<i)
 	}
 
-	if !correctSize {
-		return nil, fmt.Errorf("%w: %d is not a valid size, allowed sizes: %v", ErrInvalidSize, size, allowedSizes)
+	// Only build allowedSizes if we actually need the error
+	allowedSizes := make([]uint16, 0)
+	for i := 0; i < 16; i++ {
+		allowedSizes = append(allowedSizes, 1<<i)
 	}
 
-	return &RTPBuffer{
-		packets: make([]*RetainablePacket, size),
-		size:    size,
-	}, nil
+	return fmt.Errorf("%w: %d is not a valid size, allowed sizes: %v", ErrInvalidSize, size, allowedSizes)
 }
 
 // Add places the RetainablePacket in the RTPBuffer.

pkg/nack/generator_interceptor.go

@@ -10,6 +10,7 @@ import (
 	"time"
 
 	"github.com/pion/interceptor"
+	"github.com/pion/interceptor/internal/rtpbuffer"
 	"github.com/pion/logging"
 	"github.com/pion/rtcp"
 )
@@ -39,7 +40,7 @@ func (g *GeneratorInterceptorFactory) NewInterceptor(_ string) (interceptor.Inte
 		}
 	}
 
-	if _, err := newReceiveLog(generatorInterceptor.size); err != nil {
+	if err := rtpbuffer.IsBufferSizeValid(generatorInterceptor.size); err != nil {
 		return nil, err
 	}
 

pkg/nack/receive_log.go

@@ -4,7 +4,6 @@
 package nack
 
 import (
-	"fmt"
 	"sync"
 
 	"github.com/pion/interceptor/internal/rtpbuffer"
@@ -20,19 +19,8 @@ type receiveLog struct {
 }
 
 func newReceiveLog(size uint16) (*receiveLog, error) {
-	allowedSizes := make([]uint16, 0)
-	correctSize := false
-	for i := 6; i < 16; i++ {
-		if size == 1<<i {
-			correctSize = true
-
-			break
-		}
-		allowedSizes = append(allowedSizes, 1<<i)
-	}
-
-	if !correctSize {
-		return nil, fmt.Errorf("%w: %d is not a valid size, allowed sizes: %v", ErrInvalidSize, size, allowedSizes)
+	if err := rtpbuffer.IsBufferSizeValid(size); err != nil {
+		return nil, err
 	}
 
 	return &receiveLog{

pkg/nack/responder_interceptor.go

@@ -37,7 +37,7 @@ func (r *ResponderInterceptorFactory) NewInterceptor(_ string) (interceptor.Inte
 		responderInterceptor.packetFactory = rtpbuffer.NewPacketFactoryCopy()
 	}
 
-	if _, err := rtpbuffer.NewRTPBuffer(responderInterceptor.size); err != nil {
+	if err := rtpbuffer.IsBufferSizeValid(responderInterceptor.size); err != nil {
 		return nil, err
 	}