only create bufferedreader when necessary

common/crypto/auth.go

@@ -86,6 +86,7 @@ type AuthenticationReader struct {
 	auth         Authenticator
 	reader       *buf.BufferedReader
 	sizeParser   ChunkSizeDecoder
+	sizeBytes    []byte
 	transferType protocol.TransferType
 	padding      PaddingLengthGenerator
 	size         uint16
@@ -95,13 +96,20 @@ type AuthenticationReader struct {
 }
 
 func NewAuthenticationReader(auth Authenticator, sizeParser ChunkSizeDecoder, reader io.Reader, transferType protocol.TransferType, paddingLen PaddingLengthGenerator) *AuthenticationReader {
-	return &AuthenticationReader{
+	r := &AuthenticationReader{
 		auth:         auth,
-		reader:       &buf.BufferedReader{Reader: buf.NewReader(reader)},
 		sizeParser:   sizeParser,
 		transferType: transferType,
 		padding:      paddingLen,
+		sizeBytes:    make([]byte, sizeParser.SizeBytes()),
 	}
+	if breader, ok := reader.(*buf.BufferedReader); ok {
+		breader.Direct = false
+		r.reader = breader
+	} else {
+		r.reader = &buf.BufferedReader{Reader: buf.NewReader(reader)}
+	}
+	return r
 }
 
 func (r *AuthenticationReader) readSize() (uint16, uint16, error) {
@@ -109,15 +117,14 @@ func (r *AuthenticationReader) readSize() (uint16, uint16, error) {
 		r.hasSize = false
 		return r.size, r.paddingLen, nil
 	}
-	sizeBytes := make([]byte, r.sizeParser.SizeBytes())
-	if _, err := io.ReadFull(r.reader, sizeBytes); err != nil {
+	if _, err := io.ReadFull(r.reader, r.sizeBytes); err != nil {
 		return 0, 0, err
 	}
 	var padding uint16
 	if r.padding != nil {
 		padding = r.padding.NextPaddingLen()
 	}
-	size, err := r.sizeParser.Decode(sizeBytes)
+	size, err := r.sizeParser.Decode(r.sizeBytes)
 	return size, padding, err
 }
 

common/crypto/chunk.go

@@ -71,11 +71,17 @@ type ChunkStreamReader struct {
 }
 
 func NewChunkStreamReader(sizeDecoder ChunkSizeDecoder, reader io.Reader) *ChunkStreamReader {
-	return &ChunkStreamReader{
+	r := &ChunkStreamReader{
 		sizeDecoder: sizeDecoder,
-		reader:      &buf.BufferedReader{Reader: buf.NewReader(reader)},
 		buffer:      make([]byte, sizeDecoder.SizeBytes()),
 	}
+	if breader, ok := reader.(*buf.BufferedReader); ok {
+		r.reader = breader
+	} else {
+		r.reader = &buf.BufferedReader{Reader: buf.NewReader(reader)}
+	}
+
+	return r
 }
 
 func (r *ChunkStreamReader) readSize() (uint16, error) {