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: generate.go
    path of file: ./repos/scan4all/vendor/github.com/miekg/dns
    
    the code of the file until where you have to start completion: package dns

import (
	"bytes"
	"fmt"
	"io"
	"strconv"
	"strings"
)

// Parse the $GENERATE statement as used in BIND9 zones.
// See http://www.zytrax.com/books/dns/ch8/generate.html for instance.
// We are called after '$GENERATE '. After which we expect:
// * the range (12-24/2)
// * lhs (ownername)
// * [[ttl][class]]
// * type
// * rhs (rdata)
// But we are lazy here, only the range is parsed *all* occurrences
// of $ after that are interpreted.
func (zp *ZoneParser) generate(l lex) (RR, bool) {
	token := l.token
	step := int64(1)
	if i := strings.IndexByte(token, '/'); i >= 0 {
		if i+1 == len(token) {
			return zp.setParseError("bad step in $GENERATE range", l)
		}


    
func modToPrintf(s string) (string, int64, string) {
	// Modifier is { offset [ ,width [ ,base ] ] } - provide default
	// values for optional width and type, if necessary.
	var offStr, widthStr, base string
	switch xs := strings.Split(s, ","); len(xs) {
	case 1:
		offStr, widthStr, base = xs[0], "0", "d"
	case 2:
		offStr, widthStr, base = xs[0], xs[1], "d"
	case 3:
		offStr, widthStr, base = xs[0], xs[1], xs[2]
	default:
		return "", 0, "bad modifier in $GENERATE"
	}

	switch base {
	case "o", "d", "x", "X":
	default:
		return "", 0, "bad base in $GENERATE"
	}

	offset, err := strconv.ParseInt(offStr, 10, 64)
	if err != nil {
		return "", 0, "bad offset in $GENERATE"
	}

	width, err := strconv.ParseInt(widthStr, 10, 64)
	if err != nil || width < 0 || width > 255 {
		return "", 0, "bad width in $GENERATE"
	}

	if width == 0 {
		return "%" + base, offset, ""
	}

	return "%0" + widthStr + base, offset, ""
}