From f1a3b3138457e1fd470ce7ff847a2116437ef790 Mon Sep 17 00:00:00 2001
From: Miek Gieben <miek@miek.nl>
Date: Wed, 11 Jan 2012 20:33:38 +0100
Subject: [PATCH] Make a packStructCompress() to leave packStruct() simpler

---
 dnssec.go |  8 ++++----
 msg.go    | 14 ++++++++++----
 nsec3.go  |  2 +-
 tsig.go   |  6 +++---
 4 files changed, 18 insertions(+), 12 deletions(-)

diff --git a/dnssec.go b/dnssec.go
index f780b21d..b660b87a 100644
--- a/dnssec.go
+++ b/dnssec.go
@@ -91,7 +91,7 @@ func (k *RR_DNSKEY) KeyTag() uint16 {
 		keywire.Algorithm = k.Algorithm
 		keywire.PublicKey = k.PublicKey
 		wire := make([]byte, DefaultMsgSize)
-		n, ok := packStruct(keywire, wire, 0, nil, false)
+		n, ok := packStruct(keywire, wire, 0)
 		if !ok {
 			return 0
 		}
@@ -126,7 +126,7 @@ func (k *RR_DNSKEY) ToDS(h int) *RR_DS {
 	keywire.Algorithm = k.Algorithm
 	keywire.PublicKey = k.PublicKey
 	wire := make([]byte, DefaultMsgSize)
-	n, ok := packStruct(keywire, wire, 0, nil, false)
+	n, ok := packStruct(keywire, wire, 0)
 	if !ok {
 		return nil
 	}
@@ -205,7 +205,7 @@ func (s *RR_RRSIG) Sign(k PrivateKey, rrset RRset) error {
 
 	// Create the desired binary blob
 	signdata := make([]byte, DefaultMsgSize)
-	n, ok := packStruct(sigwire, signdata, 0, nil, false)
+	n, ok := packStruct(sigwire, signdata, 0)
 	if !ok {
 		return ErrPack
 	}
@@ -300,7 +300,7 @@ func (s *RR_RRSIG) Verify(k *RR_DNSKEY, rrset RRset) error {
 	sigwire.SignerName = strings.ToLower(s.SignerName)
 	// Create the desired binary blob
 	signeddata := make([]byte, DefaultMsgSize)
-	n, ok := packStruct(sigwire, signeddata, 0, nil, false)
+	n, ok := packStruct(sigwire, signeddata, 0)
 	if !ok {
 		return ErrPack
 	}
diff --git a/msg.go b/msg.go
index 826bc3d7..2789ac23 100644
--- a/msg.go
+++ b/msg.go
@@ -542,7 +542,13 @@ func structValue(any interface{}) reflect.Value {
 	return reflect.ValueOf(any).Elem()
 }
 
-func packStruct(any interface{}, msg []byte, off int, compression map[string]int, compress bool) (off1 int, ok bool) {
+func packStruct(any interface{}, msg []byte, off int) (off1 int, ok bool) {
+	off, ok = packStructValue(structValue(any), msg, off, nil, false)
+	return off, ok
+}
+
+
+func packStructCompress(any interface{}, msg []byte, off int, compression map[string]int, compress bool) (off1 int, ok bool) {
 	off, ok = packStructValue(structValue(any), msg, off, compression, compress)
 	return off, ok
 }
@@ -878,7 +884,7 @@ func packRR(rr RR, msg []byte, off int, compression map[string]int, compress boo
 		return len(msg), false
 	}
 
-	off1, ok = packStruct(rr, msg, off, compression, compress)
+	off1, ok = packStructCompress(rr, msg, off, compression, compress)
 	if !ok {
 		return len(msg), false
 	}
@@ -1019,9 +1025,9 @@ func (dns *Msg) Pack() (msg []byte, ok bool) {
 
 	// Pack it in: header and then the pieces.
 	off := 0
-	off, ok = packStruct(&dh, msg, off, compression, dns.Compress)
+	off, ok = packStructCompress(&dh, msg, off, compression, dns.Compress)
 	for i := 0; i < len(question); i++ {
-		off, ok = packStruct(&question[i], msg, off, compression, dns.Compress)
+		off, ok = packStructCompress(&question[i], msg, off, compression, dns.Compress)
 		//                println("Question", off)
 	}
 	for i := 0; i < len(answer); i++ {
diff --git a/nsec3.go b/nsec3.go
index 852b9ad0..da42d827 100644
--- a/nsec3.go
+++ b/nsec3.go
@@ -17,7 +17,7 @@ func HashName(label string, ha, iter int, salt string) string {
 	saltwire := new(saltWireFmt)
 	saltwire.Salt = salt
 	wire := make([]byte, DefaultMsgSize)
-	n, ok := packStruct(saltwire, wire, 0, nil, false)
+	n, ok := packStruct(saltwire, wire, 0)
 	if !ok {
 		return ""
 	}
diff --git a/tsig.go b/tsig.go
index 309facd9..e86ca2ce 100644
--- a/tsig.go
+++ b/tsig.go
@@ -161,7 +161,7 @@ func tsigBuffer(msgbuf []byte, rr *RR_TSIG, requestMAC string, timersOnly bool)
 		m.MACSize = uint16(len(requestMAC) / 2)
 		m.MAC = requestMAC
 		macbuf = make([]byte, len(requestMAC)) // reqmac should be twice as long
-		n, _ := packStruct(m, macbuf, 0, nil, false)
+		n, _ := packStruct(m, macbuf, 0)
 		macbuf = macbuf[:n]
 	}
 
@@ -170,7 +170,7 @@ func tsigBuffer(msgbuf []byte, rr *RR_TSIG, requestMAC string, timersOnly bool)
 		tsig := new(timerWireFmt)
 		tsig.TimeSigned = rr.TimeSigned
 		tsig.Fudge = rr.Fudge
-		n, _ := packStruct(tsig, tsigvar, 0, nil, false)
+		n, _ := packStruct(tsig, tsigvar, 0)
 		tsigvar = tsigvar[:n]
 	} else {
 		tsig := new(tsigWireFmt)
@@ -183,7 +183,7 @@ func tsigBuffer(msgbuf []byte, rr *RR_TSIG, requestMAC string, timersOnly bool)
 		tsig.Error = rr.Error
 		tsig.OtherLen = rr.OtherLen
 		tsig.OtherData = rr.OtherData
-		n, _ := packStruct(tsig, tsigvar, 0, nil, false)
+		n, _ := packStruct(tsig, tsigvar, 0)
 		tsigvar = tsigvar[:n]
 	}
 	if rr.MAC != "" {