1 files changed, 23 insertions, 21 deletions
diff --git a/message.go b/message.go
index fdb16b3..ccd455f 100644
--- a/message.go
+++ b/message.go
@@ -114,22 +114,14 @@ func (msg *Message) TryComputeLength() bool {
 	return true
 }
 
-// SetLength sets the length header parameter to n.
-func (msg *Message) SetLength(n int64) {
-	if n == 0 {
-		msg.SetParam("length", "")
-	} else {
-		setInt(msg, "length", n)
-	}
+// Intent retrieves the message header intent.
+func (msg *Message) Intent() string {
+	return msg.Header.Intent
 }
 
-// Length gets the length header parameter (or 0 if it's not set or invalid).
-func (msg *Message) Length() int64 {
-	n, err := getInt(msg, "length")
-	if err != nil {
-		return 0
-	}
-	return n
+// SetIntent sets the message header intent.
+func (msg *Message) SetIntent(s string) {
+	msg.Header.Intent = s
 }
 
 // Param retrieves a header parameter. It performs no value validation.
@@ -147,19 +139,29 @@ func (msg *Message) SetParam(key, value string) {
 	}
 }
 
-// Intent retrieves the message header intent.
-func (msg *Message) Intent() string {
-	return msg.Header.Intent
+// Length gets the length header parameter (or 0 if it's not set or invalid).
+func (msg *Message) Length() int64 {
+	n, err := getInt(msg, "length", 0)
+	if err != nil {
+		return 0
+	}
+	return n
 }
 
-// SetIntent sets the message header intent.
-func (msg *Message) SetIntent(s string) {
-	msg.Header.Intent = s
+// SetLength sets the length header parameter to n.
+//
+// If negative or zero, the parameter is unset.
+func (msg *Message) SetLength(n int64) {
+	if n <= 0 {
+		msg.SetParam("length", "")
+	} else {
+		setInt(msg, "length", n)
+	}
 }
 
 // Validate validates the message header parameter value format (length).
 func (msg *Message) Validate() error {
-	_, err := getInt(msg, "length")
+	_, err := getInt(msg, "length", 0)
 	return err
 }