Simplify unmarshalling.

packages/ipp/setofstrings.go

@@ -2,7 +2,10 @@
 // SPDX-License-Identifier: BSD-3-Clause
 package ipp
 
-import "encoding/binary"
+import (
+	"bufio"
+	"encoding/binary"
+)
 
 // SetOfStrings is the strings attribute
 type SetOfStrings struct {
@@ -32,17 +35,37 @@ func (s *SetOfStrings) valueTag() tag {
 	return s.vTag
 }
 
-// func (k *keyWord) unmarshal(byteStream io.Reader) {
-// 	if len(k.values) == 0 {
-// 		var v string
-// 		k.name, v = unmarshalSingleValue(byteStream)
-// 		k.values = append(k.values, v)
-// 	} else {
-// 		var v string
-// 		_, v = unmarshalSingleValue(byteStream)
-// 		k.values = append(k.values, v)
-// 	}
-// }
+func (s *SetOfStrings) unmarshal(byteStream *bufio.Reader, valueTag tag) error {
+	var length uint16
+	s.vTag = valueTag
+	s.values = make([]string, 0, 1)
+	binary.Read(byteStream, binary.BigEndian, &length)
+	name := make([]byte, length)
+	if length > 0 {
+		binary.Read(byteStream, binary.BigEndian, name)
+	}
+	s.name = string(name)
+	binary.Read(byteStream, binary.BigEndian, &length)
+	for length > 0 {
+		valueBytes := make([]byte, length)
+		err := binary.Read(byteStream, binary.BigEndian, valueBytes)
+		if err != nil {
+			return err
+		}
+		s.values = append(s.values, string(valueBytes))
+		next, err := byteStream.Peek(3)
+		if err != nil {
+			break
+		}
+		if next[0] != byte(valueTag) || next[1] != 0x00 || next[2] != 0x00 {
+			break
+		}
+		// Remove the value tag with the zero length from the stream
+		byteStream.Discard(3)
+		binary.Read(byteStream, binary.BigEndian, &length)
+	}
+	return nil
+}
 
 func (s *SetOfStrings) marshal() []byte {
 	l := 5 + len(s.name) + len(s.values[0])
@@ -79,16 +102,3 @@ func (s *SetOfStrings) marshal() []byte {
 func (s *SetOfStrings) AddValue(v string) {
 	s.values = append(s.values, v)
 }
-
-func (s *SetOfStrings) size() int {
-	l := 1 + 2 // The value tag (0x44) + name-length field (2 bytes)
-	l += len(s.name)
-	l += 2 // value-length field (2 bytes)
-	l += len(s.values[0])
-	// Add all additional values
-	for _, v := range s.values[1:] {
-		l += 1 + 4 // The value tag (0x44) + 2 length fields (2 bytes)
-		l += len(v)
-	}
-	return l
-}