Simplify unmarshalling.

packages/ipp/setofintegers.go

@@ -0,0 +1,56 @@
+// Copyright 2021, Henrik Sölver henrik.solver@gmail.com
+// SPDX-License-Identifier: BSD-3-Clause
+package ipp
+
+import (
+	"bufio"
+	"encoding/binary"
+	"fmt"
+)
+
+// setOfIntegers is a helper type that is used to handle integer types
+// which only differs in tag value.
+type setOfIntegers struct {
+	name   string
+	values []int32
+}
+
+func unmarshalIntegers(byteStream *bufio.Reader, valueTag tag) (*setOfIntegers, error) {
+
+	s := new(setOfIntegers)
+	s.values = make([]int32, 0, 1)
+
+	var length uint16
+	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)
+	if length != 4 {
+		return nil, fmt.Errorf("wrong value-length of integer attribute %v", length)
+	}
+	var value int32 //valueBytes := make([]byte, length)
+	for length > 0 {
+		err := binary.Read(byteStream, binary.BigEndian, &value)
+		if err != nil {
+			return nil, err
+		}
+		s.values = append(s.values, value)
+		next, err := byteStream.Peek(3)
+		if err != nil {
+			// end of byte stream
+			break
+		}
+		if next[0] != byte(valueTag) || next[1] != 0x00 || next[2] != 0x00 {
+			// End of attribute
+			break
+		}
+		// Remove the value tag with the zero length from the stream
+		byteStream.Discard(3)
+		binary.Read(byteStream, binary.BigEndian, &length)
+	}
+
+	return s, nil
+}