PR 649: adding compression (second code review)

Author: Brigitte Lamarche

compress.go

@@ -10,9 +10,6 @@ const (
 	minCompressLength = 50
 )
 
-var (
-	blankHeader = []byte{0, 0, 0, 0, 0, 0, 0}
-)
 
 type packetReader interface {
 	readNext(need int) ([]byte, error)
@@ -146,17 +143,16 @@ func (cw *compressedWriter) Write(data []byte) (int, error) {
 	}
 
 	totalBytes := len(data)
-
 	length := len(data) - 4
-
 	maxPayloadLength := maxPacketSize - 4
+	blankHeader := make([]byte, 7)
 
 	for length >= maxPayloadLength {
 		payload := data[:maxPayloadLength]
 		payloadLen := len(payload)
 
 		bytesBuf := &bytes.Buffer{}
-		bytesBuf.Write(blankHeader)
+		bytesBuf.Write(blankHeader) 
 		cw.zw.Reset(bytesBuf)
 		_, err := cw.zw.Write(payload)
 		if err != nil {
@@ -167,7 +163,7 @@ func (cw *compressedWriter) Write(data []byte) (int, error) {
 		// if compression expands the payload, do not compress
 		compressedPayload := bytesBuf.Bytes()
 		if len(compressedPayload) > maxPayloadLength {
-			compressedPayload = append(blankHeader, payload...)
+			compressedPayload = append(blankHeader, payload...) 
 			payloadLen = 0
 		}
 
@@ -184,7 +180,7 @@ func (cw *compressedWriter) Write(data []byte) (int, error) {
 
 	// do not attempt compression if packet is too small
 	if payloadLen < minCompressLength {
-		err := cw.writeToNetwork(append(blankHeader, data...), 0)
+		err := cw.writeToNetwork(append(blankHeader, data...), 0) 
 		if err != nil {
 			return 0, err
 		}
@@ -203,7 +199,7 @@ func (cw *compressedWriter) Write(data []byte) (int, error) {
 	compressedPayload := bytesBuf.Bytes()
 
 	if len(compressedPayload) > len(data) {
-		compressedPayload = append(blankHeader, data...)
+		compressedPayload = append(blankHeader, data...) 
 		payloadLen = 0
 	}