You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: decoder.go
    path of file: ./repos/scan4all/vendor/github.com/jcmturner/rpc/v2/ndr
    
    the code of the file until where you have to start completion: // Package ndr provides the ability to unmarshal NDR encoded byte steams into Go data structures
package ndr

import (
	"bufio"
	"fmt"
	"io"
	"reflect"
	"strings"
)

// Struct tag values
const (
	TagConformant = "conformant"
	TagVarying    = "varying"
	TagPointer    = "pointer"
	TagPipe       = "pipe"
)

// Decoder unmarshals NDR byte stream data into a Go struct representation
type Decoder struct {
	r             *bufio.Reader //
    
func (dec *Decoder) isPointer(v reflect.Value, tag reflect.StructTag, def *[]deferedPtr) (bool, error) {
	// Pointer so defer filling the referent
	ndrTag := parseTags(tag)
	if ndrTag.HasValue(TagPointer) {
		p, err := dec.readUint32()
		if err != nil {
			return true, fmt.Errorf("could not read pointer: %v", err)
		}
		ndrTag.delete(TagPointer)
		if p != 0 {
			// if pointer is not zero add to the deferred items at end of stream
			*def = append(*def, deferedPtr{v, ndrTag.StructTag()})
		}
		return true, nil
	}
	return false, nil
}