mapping.go

// Copyright 2023 Patrick Brosi
// Authors: info@patrickbrosi.de
//
// Use of this source code is governed by a GPL v2
// license that can be found in the LICENSE file

package gtfsparser

import (
	hex "encoding/hex"
	"errors"
	"fmt"
	"math"
	mail "net/mail"
	url "net/url"
	"regexp"
	"strings"
	"time"

	"github.com/public-transport/gtfsparser/gtfs"
	"github.com/valyala/fastjson/fastfloat"
)

// csv lookup structs
type Fields interface {
	FldName(idx int) string
}

func addiFields(header []string, flds Fields) []int {
	a := make([]int, 0)

	for i, name := range header {
		if len(name) != 0 && len(flds.FldName(i)) == 0 {
			a = append(a, i)
		}
	}

	return a
}

type TranslationFields struct {
	tableName   int
	fieldName   int
	language    int
	translation int
	recordId    int
	recordSubId int
	fieldValue  int
}

func (flds TranslationFields) FldName(idx int) (name string) {
	switch idx {
	case flds.tableName:
		return "table_name"
	case flds.fieldName:
		return "field_name"
	case flds.language:
		return "language"
	case flds.translation:
		return "translation"
	case flds.recordId:
		return "record_id"
	case flds.recordSubId:
		return "record_sub_id"
	case flds.fieldValue:
		return "field_value"
	default:
		return ""
	}
}

type AttributionFields struct {
	attributionId    int
	organizationName int
	isProducer       int
	isOperator       int
	isAuthority      int
	attributionUrl   int
	attributionEmail int
	attributionPhone int
	routeId          int
	agencyId         int
	tripId           int
}

func (flds AttributionFields) FldName(idx int) (name string) {
	switch idx {
	case flds.attributionId:
		return "attribution_id"
	case flds.organizationName:
		return "organization_name"
	case flds.isProducer:
		return "is_producer"
	case flds.isOperator:
		return "is_operator"
	case flds.isAuthority:
		return "is_authority"
	case flds.attributionUrl:
		return "attribution_url"
	case flds.attributionEmail:
		return "attribution_email"
	case flds.attributionPhone:
		return "attribution_phone"
	case flds.routeId:
		return "route_id"
	case flds.agencyId:
		return "agency_id"
	case flds.tripId:
		return "trip_id"
	default:
		return ""
	}
}

type LevelFields struct {
	levelId    int
	levelIndex int
	levelName  int
}

func (flds LevelFields) FldName(idx int) (name string) {
	switch idx {
	case flds.levelId:
		return "level_id"
	case flds.levelIndex:
		return "level_index"
	case flds.levelName:
		return "level_name"
	default:
		return ""
	}
}

type ShapeFields struct {
	shapeId           int
	shapeDistTraveled int
	shapePtLat        int
	shapePtLon        int
	shapePtSequence   int
}

func (flds ShapeFields) FldName(idx int) (name string) {
	switch idx {
	case flds.shapeId:
		return "shape_id"
	case flds.shapeDistTraveled:
		return "shape_dist_traveled"
	case flds.shapePtLat:
		return "shape_pt_lat"
	case flds.shapePtLon:
		return "shape_pt_lon"
	case flds.shapePtSequence:
		return "shape_pt_sequence"
	default:
		return ""
	}
}

type FeedInfoFields struct {
	feedPublisherName int
	feedPublisherUrl  int
	feedLang          int
	feedStartDate     int
	feedEndDate       int
	feedVersion       int
	feedContactEmail  int
	feedContactUrl    int
}

func (flds FeedInfoFields) FldName(idx int) (name string) {
	switch idx {
	case flds.feedPublisherName:
		return "feed_publisher_name"
	case flds.feedPublisherUrl:
		return "feed_publisher_url"
	case flds.feedLang:
		return "feed_lang"
	case flds.feedStartDate:
		return "feed_start_date"
	case flds.feedEndDate:
		return "feed_end_date"
	case flds.feedVersion:
		return "feed_version"
	case flds.feedContactEmail:
		return "feed_contact_email"
	case flds.feedContactUrl:
		return "feed_contact_url"
	default:
		return ""
	}
}

type TransferFields struct {
	FromStopId      int
	ToStopId        int
	FromRouteId     int
	ToRouteId       int
	FromTripId      int
	ToTripId        int
	TransferType    int
	MinTransferTime int
}

func (flds TransferFields) FldName(idx int) (name string) {
	switch idx {
	case flds.FromStopId:
		return "from_stop_id"
	case flds.ToStopId:
		return "to_stop_id"
	case flds.FromRouteId:
		return "from_route_id"
	case flds.ToRouteId:
		return "to_route_id"
	case flds.FromTripId:
		return "from_trip_id"
	case flds.ToTripId:
		return "to_trip_id"
	case flds.TransferType:
		return "transfer_type"
	case flds.MinTransferTime:
		return "min_transfer_time"
	default:
		return ""
	}
}

type CalendarFields struct {
	serviceId int
	monday    int
	tuesday   int
	wednesday int
	thursday  int
	friday    int
	saturday  int
	sunday    int
	startDate int
	endDate   int
}

func (flds CalendarFields) FldName(idx int) (name string) {
	switch idx {
	case flds.serviceId:
		return "service_id"
	case flds.monday:
		return "monday"
	case flds.tuesday:
		return "tuesday"
	case flds.wednesday:
		return "wednesday"
	case flds.thursday:
		return "thursday"
	case flds.friday:
		return "friday"
	case flds.saturday:
		return "saturday"
	case flds.sunday:
		return "sunday"
	case flds.startDate:
		return "start_date"
	case flds.endDate:
		return "end_date"
	default:
		return ""
	}
}

type FrequencyFields struct {
	tripId      int
	exactTimes  int
	startTime   int
	endTime     int
	headwaySecs int
}

func (flds FrequencyFields) FldName(idx int) (name string) {
	switch idx {
	case flds.tripId:
		return "trip_id"
	case flds.exactTimes:
		return "exact_times"
	case flds.startTime:
		return "start_time"
	case flds.endTime:
		return "end_time"
	case flds.headwaySecs:
		return "headway_secs"
	default:
		return ""
	}
}

type CalendarDatesFields struct {
	serviceId     int
	exceptionType int
	date          int
}

func (flds CalendarDatesFields) FldName(idx int) (name string) {
	switch idx {
	case flds.serviceId:
		return "service_id"
	case flds.exceptionType:
		return "exception_type"
	case flds.date:
		return "date"
	default:
		return ""
	}
}

type StopFields struct {
	stopId             int
	stopCode           int
	locationType       int
	stopName           int
	stopDesc           int
	stopLat            int
	stopLon            int
	zoneId             int
	stopUrl            int
	parentStation      int
	stopTimezone       int
	levelId            int
	platformCode       int
	wheelchairBoarding int
}

func (flds StopFields) FldName(idx int) (name string) {
	switch idx {
	case flds.stopId:
		return "stop_id"
	case flds.stopCode:
		return "stop_code"
	case flds.locationType:
		return "location_type"
	case flds.stopName:
		return "stop_name"
	case flds.stopDesc:
		return "stop_desc"
	case flds.stopLat:
		return "stop_lat"
	case flds.stopLon:
		return "stop_lon"
	case flds.zoneId:
		return "zone_id"
	case flds.stopUrl:
		return "stop_url"
	case flds.parentStation:
		return "parent_station"
	case flds.stopTimezone:
		return "stop_timezone"
	case flds.levelId:
		return "level_id"
	case flds.platformCode:
		return "platform_code"
	case flds.wheelchairBoarding:
		return "wheelchair_boarding"
	default:
		return ""
	}
}

type StopTimeFields struct {
	tripId            int
	stopId            int
	arrivalTime       int
	departureTime     int
	stopSequence      int
	stopHeadsign      int
	pickupType        int
	dropOffType       int
	continuousDropOff int
	continuousPickup  int
	shapeDistTraveled int
	timepoint         int
}

func (flds StopTimeFields) FldName(idx int) (name string) {
	switch idx {
	case flds.tripId:
		return "trip_id"
	case flds.stopId:
		return "stop_id"
	case flds.arrivalTime:
		return "arrival_time"
	case flds.departureTime:
		return "departure_time"
	case flds.stopSequence:
		return "stop_sequence"
	case flds.stopHeadsign:
		return "stop_headsign"
	case flds.pickupType:
		return "pickup_type"
	case flds.dropOffType:
		return "drop_off_type"
	case flds.continuousDropOff:
		return "continuous_drop_off"
	case flds.continuousPickup:
		return "continuous_pickup"
	case flds.shapeDistTraveled:
		return "shape_dist_traveled"
	case flds.timepoint:
		return "timepoint"
	default:
		return ""
	}
}

type FareAttributeFields struct {
	fareId           int
	price            int
	currencyType     int
	paymentMethod    int
	transfers        int
	transferDuration int
	agencyId         int
}

func (flds FareAttributeFields) FldName(idx int) (name string) {
	switch idx {
	case flds.fareId:
		return "fare_id"
	case flds.price:
		return "price"
	case flds.currencyType:
		return "currency_type"
	case flds.paymentMethod:
		return "payment_method"
	case flds.transfers:
		return "transfers"
	case flds.transferDuration:
		return "transfer_duration"
	case flds.agencyId:
		return "agency_id"
	default:
		return ""
	}
}

type FareRuleFields struct {
	fareId        int
	routeId       int
	originId      int
	destinationId int
	containsId    int
}

func (flds FareRuleFields) FldName(idx int) (name string) {
	switch idx {
	case flds.fareId:
		return "fare_id"
	case flds.routeId:
		return "route_id"
	case flds.originId:
		return "origin_id"
	case flds.destinationId:
		return "destination_id"
	case flds.containsId:
		return "contains_id"
	default:
		return ""
	}
}

type RouteFields struct {
	routeId           int
	agencyId          int
	routeShortName    int
	routeLongName     int
	routeDesc         int
	routeType         int
	routeUrl          int
	routeColor        int
	routeTextColor    int
	routeSortOrder    int
	continuousDropOff int
	continuousPickup  int
}

func (flds RouteFields) FldName(idx int) (name string) {
	switch idx {
	case flds.routeId:
		return "route_id"
	case flds.agencyId:
		return "agency_id"
	case flds.routeShortName:
		return "route_short_name"
	case flds.routeLongName:
		return "route_long_name"
	case flds.routeDesc:
		return "route_desc"
	case flds.routeType:
		return "route_type"
	case flds.routeUrl:
		return "route_url"
	case flds.routeColor:
		return "route_color"
	case flds.routeTextColor:
		return "route_text_color"
	case flds.routeSortOrder:
		return "route_sort_color"
	case flds.continuousDropOff:
		return "continuous_drop_off"
	case flds.continuousPickup:
		return "continuous_pickup"
	default:
		return ""
	}
}

type TripFields struct {
	tripId               int
	routeId              int
	serviceId            int
	tripHeadsign         int
	tripShortName        int
	directionId          int
	blockId              int
	shapeId              int
	wheelchairAccessible int
	bikesAllowed         int
}

func (flds TripFields) FldName(idx int) (name string) {
	switch idx {
	case flds.tripId:
		return "trip_id"
	case flds.routeId:
		return "route_id"
	case flds.serviceId:
		return "service_id"
	case flds.tripHeadsign:
		return "trip_headsign"
	case flds.tripShortName:
		return "trip_short_name"
	case flds.directionId:
		return "direction_id"
	case flds.blockId:
		return "block_id"
	case flds.shapeId:
		return "shape_id"
	case flds.wheelchairAccessible:
		return "wheelchair_accessible"
	case flds.bikesAllowed:
		return "bikes_allowed"
	default:
		return ""
	}
}

type AgencyFields struct {
	agencyId       int
	agencyName     int
	agencyUrl      int
	agencyTimezone int
	agencyLang     int
	agencyPhone    int
	agencyFareUrl  int
	agencyEmail    int
}

func (flds AgencyFields) FldName(idx int) (name string) {
	switch idx {
	case flds.agencyId:
		return "agency_id"
	case flds.agencyName:
		return "agency_name"
	case flds.agencyUrl:
		return "agency_url"
	case flds.agencyTimezone:
		return "agency_timezone"
	case flds.agencyLang:
		return "agency_lang"
	case flds.agencyPhone:
		return "agency_phone"
	case flds.agencyFareUrl:
		return "agency_fare_url"
	case flds.agencyEmail:
		return "agency_email"
	default:
		return ""
	}
}

type PathwayFields struct {
	pathwayId            int
	fromStopId           int
	toStopId             int
	pathwayMode          int
	isBidirectional      int
	length               int
	traversalTime        int
	stairCount           int
	maxSlope             int
	minWidth             int
	signpostedAs         int
	reversedSignpostedAs int
}

func (flds PathwayFields) FldName(idx int) (name string) {
	switch idx {
	case flds.pathwayId:
		return "pathway_id"
	case flds.fromStopId:
		return "from_stop_id"
	case flds.toStopId:
		return "to_stop_id"
	case flds.pathwayMode:
		return "pathway_mode"
	case flds.isBidirectional:
		return "is_bidirectional"
	case flds.length:
		return "length"
	case flds.traversalTime:
		return "traversal_time"
	case flds.stairCount:
		return "stair_count"
	case flds.maxSlope:
		return "max_slope"
	case flds.minWidth:
		return "min_width"
	case flds.signpostedAs:
		return "signposted_as"
	case flds.reversedSignpostedAs:
		return "reversed_signposted_as"
	default:
		return ""
	}
}

// custom error types for later checking
type StopNotFoundErr struct {
	prefix string
	sid    string
}

func (e *StopNotFoundErr) Error() string {
	return "no stop with id " + e.sid + " found"
}

func (e *StopNotFoundErr) StopId() string {
	return e.prefix + e.sid
}

type RouteNotFoundErr struct {
	prefix    string
	rid       string
	payloadId string
}

func (e *RouteNotFoundErr) Error() string {
	return "no route with id " + e.rid + " found"
}

func (e *RouteNotFoundErr) RouteId() string {
	return e.prefix + e.rid
}

func (e *RouteNotFoundErr) PayloadId() string {
	return e.prefix + e.payloadId
}

type TripNotFoundErr struct {
	prefix string
	tid    string
}

func (e *TripNotFoundErr) Error() string {
	return "no trip with id " + e.tid + " found"
}

func (e *TripNotFoundErr) TripId() string {
	return e.prefix + e.tid
}

func createTranslation(r []string, flds TranslationFields, feed *Feed, prefix string) (attr *gtfs.Translation, err error) {
	defer func() {
		if r := recover(); r != nil {
			err = r.(error)
		}
	}()

	tr := new(gtfs.Translation)
	tr.FieldName = getString(flds.fieldName, r, flds.FldName(flds.fieldName), true, true, "")
	tr.Translation = getString(flds.translation, r, flds.FldName(flds.translation), true, true, "")
	tr.FieldValue = getString(flds.fieldValue, r, flds.FldName(flds.fieldValue), false, false, "")
	tr.Language = getIsoLangCode(flds.language, r, flds.FldName(flds.language), false, false, feed)

	tableName := getString(flds.tableName, r, flds.FldName(flds.tableName), true, true, "")

	if !feed.opts.DryRun && !(tableName == "agency" || tableName == "stops" || tableName == "routes" || tableName == "trips" || tableName == "stop_times" || tableName == "feed_info" || tableName == "pathways" || tableName == "attributions" || tableName == "levels") {
		panic(fmt.Errorf("table_name must be one of: 'agency', 'stops', 'routes', 'trips', 'stop_times', 'feed_info', 'pathways', 'attributions', 'levels' (found '%s')", tableName))
	}

	strings.Replace(strings.ToLower(tableName), ".txt", "", 1)

	id := getString(flds.recordId, r, flds.FldName(flds.recordId), false, false, "")
	// subId := getString(flds.recordSubId, r, flds, false, false, "")

	if len(id) > 0 {
		if tableName == "agency" {
			if ag, ok := feed.Agencies[prefix+id]; ok {
				ag.Translations = append(ag.Translations, tr)
			} else {
				panic(fmt.Errorf("no agency with id %s found", id))
			}
		} else if tableName == "stops" {
			if st, ok := feed.Stops[prefix+id]; ok {
				st.Translations = append(st.Translations, tr)
			} else {
				panic(fmt.Errorf("no stop with id %s found", id))
			}
		} else if tableName == "trips" {
			if trip, ok := feed.Trips[prefix+id]; ok {
				if trip.Translations == nil {
					trans := make([]*gtfs.Translation, 0)
					trip.Translations = &trans
				}
				*trip.Translations = append(*trip.Translations, tr)
			} else {
				panic(&TripNotFoundErr{prefix, id})
			}
		} else if tableName == "feed_info" {
			panic(fmt.Errorf("cannot use record_id for table_name 'feed_info'"))
		} else if tableName == "pathways" {
			if pw, ok := feed.Pathways[prefix+id]; ok {
				pw.Translations = append(pw.Translations, tr)
			} else {
				panic(fmt.Errorf("no pathway with id %s found", id))
			}
		} else if tableName == "levels" {
			if lvl, ok := feed.Levels[prefix+id]; ok {
				lvl.Translations = append(lvl.Translations, tr)
			} else {
				panic(fmt.Errorf("no level with id %s found", id))
			}
		}
	}

	return tr, nil
}

func createAttribution(r []string, flds AttributionFields, feed *Feed, prefix string) (attr *gtfs.Attribution, ag *gtfs.Agency, route *gtfs.Route, trip *gtfs.Trip, err error) {
	defer func() {
		if r := recover(); r != nil {
			err = r.(error)
		}
	}()

	a := new(gtfs.Attribution)

	a.Id = prefix + getString(flds.attributionId, r, flds.FldName(flds.attributionId), false, false, "")
	a.Organization_name = getString(flds.organizationName, r, flds.FldName(flds.organizationName), true, true, feed.opts.EmptyStringRepl)
	a.Is_producer = getBool(flds.isProducer, r, flds.FldName(flds.isProducer), false, false, feed.opts.UseDefValueOnError, feed)
	a.Is_operator = getBool(flds.isOperator, r, flds.FldName(flds.isOperator), false, false, feed.opts.UseDefValueOnError, feed)
	a.Is_authority = getBool(flds.isAuthority, r, flds.FldName(flds.isAuthority), false, false, feed.opts.UseDefValueOnError, feed)

	a.Url = getURL(flds.attributionUrl, r, flds, false, feed.opts.UseDefValueOnError, feed)
	a.Email = getMail(flds.attributionEmail, r, flds, false, feed.opts.UseDefValueOnError, feed)
	a.Phone = getString(flds.attributionPhone, r, flds.FldName(flds.attributionPhone), false, false, feed.opts.EmptyStringRepl)

	routeId := getString(flds.routeId, r, flds.FldName(flds.routeId), false, false, "")
	agencyId := getString(flds.agencyId, r, flds.FldName(flds.agencyId), false, false, "")
	tripId := getString(flds.tripId, r, flds.FldName(flds.tripId), false, false, "")

	if (len(routeId) != 0 && len(agencyId) != 0) || (len(routeId) != 0 && len(tripId) != 0) || (len(tripId) != 0 && len(agencyId) != 0) {
		return nil, nil, nil, nil, errors.New("only one of route_id, agency_id or trip_id can be set")
	}

	if len(agencyId) > 0 {
		if val, ok := feed.Agencies[prefix+agencyId]; ok {
			ag = val
		} else {
			panic(fmt.Errorf("no agency with id %s found", agencyId))
		}
	}

	if len(routeId) > 0 {
		if val, ok := feed.Routes[prefix+routeId]; ok {
			route = val
		} else {
			panic(&RouteNotFoundErr{prefix, routeId, ""})
		}
	}

	if len(tripId) > 0 {
		if val, ok := feed.Trips[prefix+tripId]; ok {
			trip = val
		} else {
			panic(&TripNotFoundErr{prefix, tripId})
		}
	}

	return a, ag, route, trip, nil
}

func createAgency(r []string, flds AgencyFields, feed *Feed, prefix string) (ag *gtfs.Agency, err error) {
	defer func() {
		if r := recover(); r != nil {
			err = r.(error)
		}
	}()
	a := new(gtfs.Agency)

	a.Id = prefix + getString(flds.agencyId, r, flds.FldName(flds.agencyId), false, false, "")
	a.Name = getString(flds.agencyName, r, flds.FldName(flds.agencyName), true, true, feed.opts.EmptyStringRepl)
	a.Url = getURL(flds.agencyUrl, r, flds, false, feed.opts.UseDefValueOnError, feed)
	a.Timezone = getTimezone(flds.agencyTimezone, r, flds, true, feed.opts.UseDefValueOnError, feed)
	a.Lang = getIsoLangCode(flds.agencyLang, r, flds.FldName(flds.agencyTimezone), false, feed.opts.UseDefValueOnError, feed)
	a.Phone = getString(flds.agencyPhone, r, flds.FldName(flds.agencyPhone), false, false, "")
	a.Fare_url = getURL(flds.agencyFareUrl, r, flds, false, feed.opts.UseDefValueOnError, feed)
	a.Email = getMail(flds.agencyEmail, r, flds, false, feed.opts.UseDefValueOnError, feed)

	return a, nil
}

func createFeedInfo(r []string, flds FeedInfoFields, feed *Feed) (fi *gtfs.FeedInfo, err error) {
	defer func() {
		if r := recover(); r != nil {
			err = r.(error)
		}
	}()
	f := new(gtfs.FeedInfo)

	f.Publisher_name = getString(flds.feedPublisherName, r, flds.FldName(flds.feedPublisherName), true, true, feed.opts.EmptyStringRepl)
	f.Publisher_url = getURL(flds.feedPublisherUrl, r, flds, true, feed.opts.UseDefValueOnError, feed)
	f.Lang = getString(flds.feedLang, r, flds.FldName(flds.feedLang), true, true, feed.opts.EmptyStringRepl)
	f.Start_date = getDate(flds.feedStartDate, r, flds, false, feed.opts.UseDefValueOnError, feed)
	f.End_date = getDate(flds.feedEndDate, r, flds, false, feed.opts.UseDefValueOnError, feed)
	f.Version = getString(flds.feedVersion, r, flds.FldName(flds.feedVersion), false, false, "")
	f.Contact_email = getMail(flds.feedContactEmail, r, flds, false, feed.opts.UseDefValueOnError, feed)
	f.Contact_url = getURL(flds.feedContactUrl, r, flds, false, feed.opts.UseDefValueOnError, feed)

	return f, nil
}

func createFrequency(r []string, flds FrequencyFields, feed *Feed, prefix string) (tr *gtfs.Trip, freq *gtfs.Frequency, err error) {
	defer func() {
		if r := recover(); r != nil {
			err = r.(error)
		}
	}()
	a := new(gtfs.Frequency)
	var trip *gtfs.Trip

	tripid := prefix + getString(flds.tripId, r, flds.FldName(flds.tripId), true, true, "")

	if val, ok := feed.Trips[tripid]; ok {
		trip = val
	} else {
		panic(&TripNotFoundErr{prefix, r[flds.tripId]})
	}

	a.Exact_times = getBool(flds.exactTimes, r, flds.FldName(flds.exactTimes), false, false, feed.opts.UseDefValueOnError, feed)
	a.Start_time = getTime(flds.startTime, r, flds.FldName(flds.startTime))
	a.End_time = getTime(flds.endTime, r, flds.FldName(flds.endTime))

	if a.Start_time.SecondsSinceMidnight() > a.End_time.SecondsSinceMidnight() {
		panic(errors.New("frequency has start_time > end_time"))
	}

	a.Headway_secs = getPositiveInt(flds.headwaySecs, r, flds.FldName(flds.headwaySecs), true)

	if !feed.opts.DryRun {
		if trip.Frequencies == nil {
			freqs := make([]*gtfs.Frequency, 0)
			trip.Frequencies = &freqs
		}
		*trip.Frequencies = append(*trip.Frequencies, a)
	}

	return trip, a, nil
}

func createRoute(r []string, flds RouteFields, feed *Feed, prefix string) (route *gtfs.Route, err error) {
	defer func() {
		if r := recover(); r != nil {
			err = r.(error)
		}
	}()
	a := new(gtfs.Route)
	a.Id = prefix + getString(flds.routeId, r, flds.FldName(flds.routeId), true, true, "")

	var aID = prefix + getString(flds.agencyId, r, flds.FldName(flds.agencyId), false, false, "")

	if len(aID) != len(prefix) {
		if val, ok := feed.Agencies[aID]; ok {
			a.Agency = val
		} else {
			if feed.opts.UseDefValueOnError {
				if len(feed.Agencies) == 1 {
					a.Agency = nil
				} else {
					return nil, errors.New("agency with id " + getString(flds.agencyId, r, flds.FldName(flds.agencyId), false, false, "") + " not found or erroneous, cannot fall back to no agency as there is more than one agency in agency.txt")
				}
			} else {
				return nil, errors.New("no agency with id " + getString(flds.agencyId, r, flds.FldName(flds.agencyId), false, false, "") + " found")
			}
		}
	} else if len(prefix) == 0 && len(feed.Agencies) == 1 {
		// if no agency is specified and we only have one agency in agencies.txt, use it here
		for _, ag := range feed.Agencies {
			a.Agency = ag
			break
		}
	} else if len(prefix) > 0 {
		c := 0
		aId := ""
		// if no agency is specified and we only have one agency in agencies.txt, use it here
		for _, ag := range feed.Agencies {
			if strings.HasPrefix(ag.Id, prefix) {
				aId = ag.Id
				c += 1
			}
		}

		if c == 1 {
			a.Agency = feed.Agencies[aId]
		} else {
			return nil, errors.New("no agency given for route " + a.Id + ", an agency is required as there is more than one agency in agency.txt")
		}
	} else {
		return nil, errors.New("no agency given for route " + a.Id + ", an agency is required as there is more than one agency in agency.txt")
	}

	a.Short_name = getString(flds.routeShortName, r, flds.FldName(flds.routeShortName), false, false, "")
	a.Long_name = getString(flds.routeLongName, r, flds.FldName(flds.routeLongName), false, false, "")

	if feed.opts.RemoveFillers {
		a.Short_name = removeFillers(a.Short_name)
		a.Long_name = removeFillers(a.Long_name)
	}

	if len(a.Short_name) == 0 && len(a.Long_name) == 0 {
		if feed.opts.UseDefValueOnError {
			a.Short_name = "-"
		} else {
			return nil, errors.New("either route_short_name or route_long_name are required")
		}
	}

	if a.Short_name == a.Long_name {
		a.Long_name = ""
	}

	a.Desc = getString(flds.routeDesc, r, flds.FldName(flds.routeDesc), false, false, "")

	if feed.opts.RemoveFillers {
		a.Desc = removeFillers(a.Desc)
	}

	a.Type = int16(getRangeInt(flds.routeType, r, flds.FldName(flds.routeType), true, 0, 1702)) // allow extended route types


	a.Url = getURL(flds.routeUrl, r, flds, false, feed.opts.UseDefValueOnError, feed)
	a.Color = getColor(flds.routeColor, r, flds.FldName(flds.routeColor), false, "ffffff", feed.opts.UseDefValueOnError, feed)
	a.Text_color = getColor(flds.routeTextColor, r, flds.FldName(flds.routeTextColor), false, "000000", feed.opts.UseDefValueOnError, feed)
	a.Sort_order = getPositiveIntWithDefault(flds.routeSortOrder, r, flds.FldName(flds.routeSortOrder), -1, feed.opts.UseDefValueOnError, feed)
	a.Continuous_pickup = int8(getRangeIntWithDefault(flds.continuousPickup, r, flds.FldName(flds.routeSortOrder), 0, 3, 1, feed.opts.UseDefValueOnError, feed))
	a.Continuous_drop_off = int8(getRangeIntWithDefault(flds.continuousDropOff, r, flds.FldName(flds.continuousDropOff), 0, 3, 1, feed.opts.UseDefValueOnError, feed))

	return a, nil
}

func createServiceFromCalendar(r []string, flds CalendarFields, feed *Feed, prefix string) (s *gtfs.Service, err error) {
	defer func() {
		if r := recover(); r != nil {
			err = r.(error)
		}
	}()

	service := gtfs.EmptyService()
	service.SetId(prefix + getString(flds.serviceId, r, flds.FldName(flds.serviceId), true, true, ""))

	// fill daybitmap
	service.SetDaymap(1, getBool(flds.monday, r, flds.FldName(flds.monday), true, false, feed.opts.UseDefValueOnError, feed))
	service.SetDaymap(2, getBool(flds.tuesday, r, flds.FldName(flds.tuesday), true, false, feed.opts.UseDefValueOnError, feed))
	service.SetDaymap(3, getBool(flds.wednesday, r, flds.FldName(flds.wednesday), true, false, feed.opts.UseDefValueOnError, feed))
	service.SetDaymap(4, getBool(flds.thursday, r, flds.FldName(flds.thursday), true, false, feed.opts.UseDefValueOnError, feed))
	service.SetDaymap(5, getBool(flds.friday, r, flds.FldName(flds.friday), true, false, feed.opts.UseDefValueOnError, feed))
	service.SetDaymap(6, getBool(flds.saturday, r, flds.FldName(flds.saturday), true, false, feed.opts.UseDefValueOnError, feed))
	service.SetDaymap(0, getBool(flds.sunday, r, flds.FldName(flds.sunday), true, false, feed.opts.UseDefValueOnError, feed))
	service.SetStart_date(getDate(flds.startDate, r, flds, true, false, feed))
	service.SetEnd_date(getDate(flds.endDate, r, flds, true, false, feed))

	if service.End_date().GetTime().Before(service.Start_date().GetTime()) {
		return nil, errors.New("Service " + getString(flds.serviceId, r, flds.FldName(flds.serviceId), true, true, "") + " has end date before start date")
	}

	return service, nil
}

func createServiceFromCalendarDates(r []string, flds CalendarDatesFields, feed *Feed, filterDateStart gtfs.Date, filterDateEnd gtfs.Date, prefix string) (s *gtfs.Service, err error) {
	defer func() {
		if r := recover(); r != nil {
			err = r.(error)
		}
	}()
	update := false
	var service *gtfs.Service

	// first, check if the service already exists
	if val, ok := feed.Services[prefix+getString(flds.serviceId, r, flds.FldName(flds.serviceId), true, true, "")]; ok {
		service = val
		update = true
	} else {
		service = gtfs.EmptyService()
		service.SetId(prefix + getString(flds.serviceId, r, flds.FldName(flds.serviceId), true, true, ""))
	}

	// create exception
	t := getRangeInt(flds.exceptionType, r, flds.FldName(flds.exceptionType), true, 1, 2)
	date := getDate(flds.date, r, flds, true, false, feed)

	// may be nil during dry run
	if service != nil {
		if _, ok := service.Exceptions()[date]; ok {
			return nil, errors.New("Date exception for service id " + getString(flds.serviceId, r, flds.FldName(flds.serviceId), true, true, "") + " defined 2 times for one date")
		}
		if (filterDateEnd.IsEmpty() || !date.GetTime().After(filterDateEnd.GetTime())) &&
			(filterDateStart.IsEmpty() || !date.GetTime().Before(filterDateStart.GetTime())) {
			service.SetExceptionTypeOn(date, int8(t))
		}
	}

	if update {
		return nil, nil
	}
	return service, nil
}

func createStop(r []string, flds StopFields, feed *Feed, prefix string) (s *gtfs.Stop, pid string, err error) {
	defer func() {
		if r := recover(); r != nil {
			err = r.(error)
		}
	}()
	a := new(gtfs.Stop)
	parentId := ""

	a.Id = prefix + getString(flds.stopId, r, flds.FldName(flds.stopId), true, true, "")
	a.Code = getString(flds.stopCode, r, flds.FldName(flds.stopCode), false, false, "")
	a.Location_type = int8(getRangeIntWithDefault(flds.locationType, r, flds.FldName(flds.locationType), 0, 4, 0, feed.opts.UseDefValueOnError, feed))
	a.Name = getString(flds.stopName, r, flds.FldName(flds.stopName), a.Location_type < 3, a.Location_type < 3, feed.opts.EmptyStringRepl)
	a.Desc = getString(flds.stopDesc, r, flds.FldName(flds.stopDesc), false, false, "")

	if feed.opts.RemoveFillers {
		a.Desc = removeFillers(a.Desc)
		a.Code = removeFillers(a.Code)
	}

	if a.Location_type < 3 {
		a.Lat = getFloat(flds.stopLat, r, flds.FldName(flds.stopLat), true)
		a.Lon = getFloat(flds.stopLon, r, flds.FldName(flds.stopLon), true)
	} else {
		lat := getNullableFloat(flds.stopLat, r, flds.FldName(flds.stopLat), feed.opts.UseDefValueOnError, feed)
		lon := getNullableFloat(flds.stopLon, r, flds.FldName(flds.stopLon), feed.opts.UseDefValueOnError, feed)

		if !math.IsNaN(float64(lat)) && !math.IsNaN(float64(lon)) {
			a.Lat = lat
			a.Lon = lon
		} else if !math.IsNaN(float64(lat)) {
			locErr := fmt.Errorf("stop_lat and stop_lon are optional for location_type=%d, but only stop_lon was ommitted here, and stop_lat was defined", a.Location_type)
			if feed.opts.UseDefValueOnError {
				feed.warn(locErr)
				a.Lat = float32(math.NaN())
				a.Lon = float32(math.NaN())
			} else {
				panic(locErr)
			}
		} else if !math.IsNaN(float64(lon)) {
			locErr := fmt.Errorf("stop_lat and stop_lon are optional for location_type=%d, but only stop_lat was ommitted here, and stop_lon was defined", a.Location_type)
			if feed.opts.UseDefValueOnError {
				feed.warn(locErr)
				a.Lat = float32(math.NaN())
				a.Lon = float32(math.NaN())
			} else {
				panic(locErr)
			}
		} else {
			a.Lat = float32(math.NaN())
			a.Lon = float32(math.NaN())
		}
	}

	// check for incorrect coordinates
	if a.HasLatLon() && math.Abs(float64(a.Lat)) > 90 {
		panic(fmt.Errorf("expected coordinate (lat, lon), instead found (%f, %f), latitude is not in the allowed range [-90, 90]", a.Lat, a.Lon))
	}

	if a.HasLatLon() && math.Abs(float64(a.Lon)) > 180 {
		panic(fmt.Errorf("expected coordinate (lat, lon), instead found (%f, %f), longitude is not in the allowed range [-180, 180]", a.Lat, a.Lon))
	}

	// check for 0,0 coordinates, which are most definitely an error
	if a.HasLatLon() && feed.opts.CheckNullCoordinates && math.Abs(float64(a.Lat)) < 0.0001 && math.Abs(float64(a.Lon)) < 0.0001 {
		panic(fmt.Errorf("expected coordinate (lat, lon), instead found (0, 0), which is in the middle of the atlantic"))
	}

	a.Zone_id = prefix + getString(flds.zoneId, r, flds.FldName(flds.zoneId), false, false, "")
	if len(a.Zone_id) == len(prefix) {
		a.Zone_id = ""
	}
	a.Url = getURL(flds.stopUrl, r, flds, false, feed.opts.UseDefValueOnError, feed)

	// will be filled later on
	a.Parent_station = nil

	if a.Location_type > 1 {
		parentId = prefix + getString(flds.parentStation, r, flds.FldName(flds.parentStation), true, true, "")
	} else if a.Location_type == 0 {
		parentId = prefix + getString(flds.parentStation, r, flds.FldName(flds.parentStation), false, false, "")
	} else {
		if len(getString(flds.parentStation, r, flds.FldName(flds.parentStation), false, false, "")) > 0 {
			panic(fmt.Errorf("'parent_station' cannot be defined for location_type=1"))
		}
	}

	a.Timezone = getTimezone(flds.stopTimezone, r, flds, false, feed.opts.UseDefValueOnError, feed)
	a.Wheelchair_boarding = int8(getRangeIntWithDefault(flds.wheelchairBoarding, r, flds.FldName(flds.wheelchairBoarding), 0, 2, 0, feed.opts.UseDefValueOnError, feed))
	a.Level = nil

	levelId := prefix + getString(flds.levelId, r, flds.FldName(flds.levelId), false, false, "")

	if len(levelId) > len(prefix) {
		if val, ok := feed.Levels[levelId]; ok {
			a.Level = val
		} else {
			panic(errors.New("no level with id " + getString(flds.levelId, r, flds.FldName(flds.levelId), false, true, "") + " found"))
		}
	}

	a.Platform_code = getString(flds.platformCode, r, flds.FldName(flds.platformCode), false, false, "")

	return a, parentId, nil
}

func reserveStopTime(r []string, flds StopTimeFields, feed *Feed, prefix string) (err error) {
	defer func() {
		if r := recover(); r != nil {
			err = r.(error)
		}
	}()
	var trip *gtfs.Trip

	if val, ok := feed.Trips[prefix+getString(flds.tripId, r, flds.FldName(flds.tripId), true, true, "")]; ok {
		trip = val
	} else {
		panic(&TripNotFoundErr{prefix, getString(flds.tripId, r, flds.FldName(flds.tripId), true, true, "")})
	}

	if _, ok := feed.Stops[prefix+getString(flds.stopId, r, flds.FldName(flds.stopId), true, true, "")]; ok {
		trip.StopTimes[0].SetSequence(trip.StopTimes[0].Sequence() + 1)
	}

	return nil
}

func createStopTime(r []string, flds *StopTimeFields, feed *Feed, prefix string) (t *gtfs.Trip, stopTimeSeq int, err error) {
	defer func() {
		if r := recover(); r != nil {
			err = r.(error)
		}
	}()
	a := gtfs.StopTime{}
	a.SetHeadsign(&feed.emptyString)
	var trip *gtfs.Trip

	tripId := prefix + getString(flds.tripId, r, flds.FldName(flds.tripId), true, true, "")

	if feed.lastTrip != nil && feed.lastTrip.Id == tripId {
		trip = feed.lastTrip
	} else {
		trip = feed.Trips[tripId]
		feed.lastTrip = trip
	}

	if trip == nil {
		panic(&TripNotFoundErr{prefix, getString(flds.tripId, r, flds.FldName(flds.tripId), true, true, "")})
	}

	if !feed.opts.DateFilterStart.IsEmpty() || !feed.opts.DateFilterEnd.IsEmpty() {
		// this trip will later be deleted - dont store stop times for it!
		s := trip.Service
		if (s.IsEmpty() && s.Start_date().IsEmpty() && s.End_date().IsEmpty()) || s.GetFirstActiveDate().IsEmpty() {
			return trip, a.Sequence(), nil
		}
	}

	if trip.Id != tripId {
		trip.Id = tripId
		if trip.StopTimes[0].Sequence() == 0 {
			trip.StopTimes = trip.StopTimes[:len(trip.StopTimes)-1]
		} else {
			trip.StopTimes = make(gtfs.StopTimes, 0, trip.StopTimes[0].Sequence())
		}
	}

	if val, ok := feed.Stops[prefix+getString(flds.stopId, r, flds.FldName(flds.stopId), true, true, "")]; ok {
		a.SetStop(val)
	} else {
		panic(&StopNotFoundErr{prefix, getString(flds.stopId, r, flds.FldName(flds.stopId), true, true, "")})
	}

	if a.Stop().Location_type != 0 {
		panic(errors.New("Stop " + a.Stop().Id + " (" + a.Stop().Name + ") has location_type != 0, cannot be used in stop_times.txt!"))
	}

	a.SetArrival_time(getTime(flds.arrivalTime, r, flds.FldName(flds.arrivalTime)))
	a.SetDeparture_time(getTime(flds.departureTime, r, flds.FldName(flds.departureTime)))

	if a.Arrival_time().Empty() && !a.Departure_time().Empty() {
		if feed.opts.UseDefValueOnError {
			a.SetArrival_time(a.Departure_time())
		} else {
			panic(errors.New("Missing arrival time for " + getString(flds.stopId, r, flds.FldName(flds.stopId), true, true, "") + ""))
		}
	}

	if !a.Arrival_time().Empty() && a.Departure_time().Empty() {
		if feed.opts.UseDefValueOnError {
			a.SetDeparture_time(a.Arrival_time())
		} else {
			panic(errors.New("Missing departure time for " + getString(flds.stopId, r, flds.FldName(flds.stopId), true, true, "") + ""))
		}
	}

	if a.Arrival_time().SecondsSinceMidnight() > a.Departure_time().SecondsSinceMidnight() {
		panic(errors.New("Departure before arrival at stop " + getString(flds.stopId, r, flds.FldName(flds.stopId), true, true, "") + ""))
	}

	a.SetSequence(getRangeInt(flds.stopSequence, r, flds.FldName(flds.stopSequence), true, 0, int(^uint32(0)>>1)))

	/*
	* There used to be logic here to store a custom headsign,
	* if different from the default trip headsign.
	* However, this causes a massive amount of inescapable allocation (>25% of all allocations).
	* The code was likely defunct anyways, as the flds.stopSequence ID is negative, and for fields that are
	* not required getString simply returned an empty string anyways.
	 */
	a.SetHeadsign(trip.Headsign)

	a.SetPickup_type(uint8(getRangeInt(flds.pickupType, r, flds.FldName(flds.pickupType), false, 0, 3)))
	a.SetDrop_off_type(uint8(getRangeInt(flds.dropOffType, r, flds.FldName(flds.dropOffType), false, 0, 3)))
	a.SetContinuous_pickup(uint8(getRangeIntWithDefault(flds.continuousPickup, r, flds.FldName(flds.continuousPickup), 0, 3, 1, feed.opts.UseDefValueOnError, feed)))
	a.SetContinuous_drop_off(uint8(getRangeIntWithDefault(flds.continuousDropOff, r, flds.FldName(flds.continuousDropOff), 0, 3, 1, feed.opts.UseDefValueOnError, feed)))
	dist := getNullableFloat(flds.shapeDistTraveled, r, flds.FldName(flds.shapeDistTraveled), feed.opts.UseDefValueOnError, feed)
	a.SetShape_dist_traveled(dist)
	a.SetTimepoint(getBool(flds.timepoint, r, flds.FldName(flds.timepoint), false, !a.Arrival_time().Empty() && !a.Departure_time().Empty(), feed.opts.UseDefValueOnError, feed))

	if (a.Arrival_time().Empty() || a.Departure_time().Empty()) && a.Timepoint() {
		locErr := errors.New("stops with timepoint=1 cannot have empty arrival or departure time")
		if feed.opts.UseDefValueOnError {
			a.SetTimepoint(false)
			feed.warn(locErr)
		} else if !feed.opts.DropErroneous {
			panic(locErr)
		}
		feed.warn(locErr)
	}

	trip.StopTimes = append(trip.StopTimes, a)

	return trip, a.Sequence(), nil
}

func createTrip(r []string, flds TripFields, feed *Feed, prefix string) (t *gtfs.Trip, err error) {
	defer func() {
		if r := recover(); r != nil {
			err = r.(error)
		}
	}()
	a := new(gtfs.Trip)
	a.Id = prefix + getString(flds.tripId, r, flds.FldName(flds.tripId), true, true, "")

	if val, ok := feed.Routes[prefix+getString(flds.routeId, r, flds.FldName(flds.routeId), true, true, "")]; ok {
		a.Route = val
	} else {
		panic(&RouteNotFoundErr{prefix, getString(flds.routeId, r, flds.FldName(flds.routeId), true, true, ""), getString(flds.tripId, r, flds.FldName(flds.tripId), true, true, "")})
	}

	if val, ok := feed.Services[prefix+getString(flds.serviceId, r, flds.FldName(flds.serviceId), true, true, "")]; ok {
		a.Service = val
	} else {
		panic(fmt.Errorf("no service with id %s found", getString(flds.serviceId, r, flds.FldName(flds.serviceId), true, true, "")))
	}

	toDel := false

	if !feed.opts.DateFilterStart.IsEmpty() || !feed.opts.DateFilterEnd.IsEmpty() {
		// this trip will later be deleted - dont store or parse additional fields (strings) for it
		s := a.Service
		if (s.IsEmpty() && s.Start_date().IsEmpty() && s.End_date().IsEmpty()) || s.GetFirstActiveDate().IsEmpty() {
			toDel = true
		}
	}

	if toDel {
		return a, nil
	}

	headsign := getString(flds.tripHeadsign, r, flds.FldName(flds.tripHeadsign), false, false, "")

	a.Headsign = &feed.emptyString

	if len(headsign) > 0 {
		if *feed.lastString != headsign {
			feed.lastString = &headsign
		}
		a.Headsign = feed.lastString
	}

	shortName := getString(flds.tripShortName, r, flds.FldName(flds.tripShortName), false, false, "")
	if len(shortName) > 0 {
		a.Short_name = &shortName
	}
	a.Direction_id = int8(getRangeIntWithDefault(flds.directionId, r, flds.FldName(flds.directionId), 0, 1, -1, feed.opts.UseDefValueOnError, feed))
	blockid := prefix + getString(flds.blockId, r, flds.FldName(flds.blockId), false, false, "")
	if len(blockid) != len(prefix) {
		a.Block_id = &blockid
	}

	if !feed.opts.DropShapes {
		shapeID := prefix + getString(flds.shapeId, r, flds.FldName(flds.shapeId), false, false, "")

		if len(shapeID) > len(prefix) {
			if val, ok := feed.Shapes[shapeID]; ok {
				a.Shape = val
			} else {
				locErr := fmt.Errorf("no shape with id %s found", shapeID)
				if len(feed.opts.PolygonFilter) > 0 {
					a.Shape = nil
				} else if feed.opts.UseDefValueOnError {
					feed.warn(locErr)
					a.Shape = nil
				} else {
					return nil, locErr
				}
			}
		}
	}

	a.Wheelchair_accessible = int8(getRangeIntWithDefault(flds.wheelchairAccessible, r, flds.FldName(flds.wheelchairAccessible), 0, 2, 0, feed.opts.UseDefValueOnError, feed))
	a.Bikes_allowed = int8(getRangeIntWithDefault(flds.bikesAllowed, r, flds.FldName(flds.bikesAllowed), 0, 2, 0, feed.opts.UseDefValueOnError, feed))

	return a, nil
}

func reserveShapePoint(r []string, flds ShapeFields, feed *Feed, prefix string) (err error) {
	defer func() {
		if r := recover(); r != nil {
			err = r.(error)
		}
	}()

	shapeID := prefix + getString(flds.shapeId, r, flds.FldName(flds.shapeId), true, true, "")
	var shape *gtfs.Shape

	lat := getFloat(flds.shapePtLat, r, flds.FldName(flds.shapePtLat), true)
	lon := getFloat(flds.shapePtLon, r, flds.FldName(flds.shapePtLon), true)

	// check if any defined PolygonFilter contains the shape point
	contains := true
	for _, poly := range feed.opts.PolygonFilter {
		contains = false
		if poly.PolyContains(float64(lon), float64(lat)) {
			contains = true
			break
		}
	}

	if val, ok := feed.Shapes[shapeID]; ok {
		shape = val
		if contains {
			shape.Points[0].Sequence = shape.Points[0].Sequence + 1
		}
	} else {
		// create new shape
		shape = new(gtfs.Shape)
		if contains {
			shape.Points = append(shape.Points, gtfs.ShapePoint{Lat: 0, Lon: 0, Sequence: 1, Dist_traveled: 0})
		} else {
			shape.Points = append(shape.Points, gtfs.ShapePoint{Lat: 0, Lon: 0, Sequence: 0, Dist_traveled: 0})
		}

		// push it onto the shape map
		feed.Shapes[shapeID] = shape
	}

	return nil
}

func createShapePoint(r []string, flds ShapeFields, feed *Feed, prefix string) (s *gtfs.Shape, sp *gtfs.ShapePoint, err error) {
	defer func() {
		if r := recover(); r != nil {
			err = r.(error)
		}
	}()

	shapeID := prefix + getString(flds.shapeId, r, flds.FldName(flds.shapeId), true, true, "")
	var shape *gtfs.Shape

	if feed.lastShape != nil && feed.lastShape.Id == shapeID {
		shape = feed.lastShape
	} else {
		shape = feed.Shapes[shapeID]
		feed.lastShape = shape
	}

	if shape.Id != shapeID {
		shape.Id = shapeID
		shape.Points = make(gtfs.ShapePoints, 0, shape.Points[0].Sequence)
	}

	dist := getNullableFloat(flds.shapeDistTraveled, r, flds.FldName(flds.shapeDistTraveled), feed.opts.UseDefValueOnError, feed)

	lat := getFloat(flds.shapePtLat, r, flds.FldName(flds.shapePtLat), true)
	lon := getFloat(flds.shapePtLon, r, flds.FldName(flds.shapePtLon), true)

	// check for incorrect coordinates
	if math.Abs(float64(lat)) > 90 {
		panic(fmt.Errorf("expected coordinate (lat, lon), instead found (%f, %f), latitude is not in the allowed range [-90, 90]", lat, lon))
	}

	if math.Abs(float64(lon)) > 180 {
		panic(fmt.Errorf("expected coordinate (lat, lon), instead found (%f, %f), longitude is not in the allowed range [-180, 180]", lat, lon))
	}

	// check for 0,0 coordinates, which are most definitely an error
	if feed.opts.CheckNullCoordinates && math.Abs(float64(lat)) < 0.0001 && math.Abs(float64(lon)) < 0.0001 {
		panic(fmt.Errorf("expected coordinate (lat, lon), instead found (0, 0), which is in the middle of the atlantic"))
	}

	// check if any defined PolygonFilter contains the shape point
	contains := true
	for _, poly := range feed.opts.PolygonFilter {
		contains = false
		if poly.PolyContains(float64(lon), float64(lat)) {
			contains = true
			break
		}
	}

	if !contains {
		return shape, nil, nil
	}

	p := gtfs.ShapePoint{
		Lat:           lat,
		Lon:           lon,
		Sequence:      uint32(getRangeInt(flds.shapePtSequence, r, flds.FldName(flds.shapePtSequence), true, 0, int(^uint32(0)))),
		Dist_traveled: dist,
	}

	shape.Points = append(shape.Points, p)

	return shape, &p, nil
}

func createFareAttribute(r []string, flds FareAttributeFields, feed *Feed, prefix string) (fa *gtfs.FareAttribute, err error) {
	defer func() {
		if r := recover(); r != nil {
			err = r.(error)
		}
	}()

	a := new(gtfs.FareAttribute)

	a.Id = prefix + getString(flds.fareId, r, flds.FldName(flds.fareId), true, true, "")
	a.Price = getString(flds.price, r, flds.FldName(flds.price), false, false, "")
	if feed.opts.UseDefValueOnError {
		a.Currency_type = getString(flds.currencyType, r, flds.FldName(flds.currencyType), true, true, "XXX")
	} else {
		a.Currency_type = getString(flds.currencyType, r, flds.FldName(flds.currencyType), true, true, "")
	}
	a.Payment_method = getRangeInt(flds.paymentMethod, r, flds.FldName(flds.paymentMethod), false, 0, 1)
	a.Transfers = getRangeIntWithDefault(flds.transfers, r, flds.FldName(flds.transfers), 0, 2, -1, feed.opts.UseDefValueOnError, feed)
	a.Transfer_duration = getPositiveInt(flds.transferDuration, r, flds.FldName(flds.transferDuration), false)

	aID := prefix + getString(flds.agencyId, r, flds.FldName(flds.agencyId), false, false, "")

	if len(aID) != len(prefix) {
		if val, ok := feed.Agencies[aID]; ok {
			a.Agency = val
		} else {
			if feed.opts.UseDefValueOnError {
				a.Agency = nil
			} else {
				return nil, errors.New("no agency with id " + getString(flds.agencyId, r, flds.FldName(flds.agencyId), false, false, "") + " found")
			}
		}
	} else {
		if len(prefix) > 0 {
			prefixCount := 0
			foundId := ""
			for i := range feed.Agencies {
				if strings.HasPrefix(i, prefix) {
					prefixCount = prefixCount + 1
					foundId = i
				}
			}
			if prefixCount > 1 {
				return nil, errors.New("expected a non-empty value for 'agency_id', as there are multiple agencies defined in agency.txt")
			} else if prefixCount == 1 {
				a.Agency = feed.Agencies[foundId]
			}
		} else {
			if len(feed.Agencies) > 1 {
				return nil, errors.New("expected a non-empty value for 'agency_id', as there are multiple agencies defined in agency.txt")
			}
		}
	}

	return a, nil
}

func createFareRule(r []string, flds FareRuleFields, feed *Feed, prefix string) (fare *gtfs.FareAttribute, rl *gtfs.FareAttributeRule, err error) {
	defer func() {
		if r := recover(); r != nil {
			err = r.(error)
		}
	}()

	var fareattr *gtfs.FareAttribute
	var fareid string = prefix + getString(flds.fareId, r, flds.FldName(flds.fareId), true, true, "")

	// first, check if the service already exists
	if val, ok := feed.FareAttributes[fareid]; ok {
		fareattr = val
	} else {
		panic(fmt.Errorf("no fare attribute with id %s found", fareid))
	}

	// create fare attribute
	rule := new(gtfs.FareAttributeRule)

	routeID := prefix + getString(flds.routeId, r, flds.FldName(flds.routeId), false, false, "")

	if len(routeID) > len(prefix) {
		if val, ok := feed.Routes[routeID]; ok {
			rule.Route = val
		} else {
			panic(&RouteNotFoundErr{prefix, routeID, ""})
		}
	}

	rule.Origin_id = prefix + getString(flds.originId, r, flds.FldName(flds.originId), false, false, "")
	rule.Destination_id = prefix + getString(flds.destinationId, r, flds.FldName(flds.destinationId), false, false, "")
	rule.Contains_id = prefix + getString(flds.containsId, r, flds.FldName(flds.containsId), false, false, "")

	fareattr.Rules = append(fareattr.Rules, rule)

	return fareattr, rule, nil
}

func createTransfer(r []string, flds TransferFields, feed *Feed, prefix string) (tk gtfs.TransferKey, tv gtfs.TransferVal, err error) {
	defer func() {
		if r := recover(); r != nil {
			err = r.(error)
		}
	}()

	from_sid := getString(flds.FromStopId, r, flds.FldName(flds.FromStopId), false, false, "")
	to_sid := getString(flds.ToStopId, r, flds.FldName(flds.ToStopId), false, false, "")

	from_rid := getString(flds.FromRouteId, r, flds.FldName(flds.FromRouteId), false, false, "")
	to_rid := getString(flds.ToRouteId, r, flds.FldName(flds.ToRouteId), false, false, "")

	from_tid := getString(flds.FromTripId, r, flds.FldName(flds.FromTripId), false, false, "")
	to_tid := getString(flds.ToTripId, r, flds.FldName(flds.ToTripId), false, false, "")

	if len(from_sid) > 0 {
		if val, ok := feed.Stops[prefix+from_sid]; ok {
			tk.From_stop = val
		} else {
			panic(&StopNotFoundErr{prefix, from_sid})
		}
	}

	if len(to_sid) > 0 {
		if val, ok := feed.Stops[prefix+to_sid]; ok {
			tk.To_stop = val
		} else {
			panic(&StopNotFoundErr{prefix, to_sid})
		}
	}

	if len(from_rid) > 0 {
		if val, ok := feed.Routes[prefix+from_rid]; ok {
			tk.From_route = val
		} else {
			panic(&RouteNotFoundErr{prefix, from_rid, ""})
		}
	}

	if len(to_rid) > 0 {
		if val, ok := feed.Routes[prefix+to_rid]; ok {
			tk.To_route = val
		} else {
			panic(&RouteNotFoundErr{prefix, to_rid, ""})
		}
	}

	if len(from_tid) > 0 {
		if val, ok := feed.Trips[prefix+from_tid]; ok {
			tk.From_trip = val
		} else {
			panic(&TripNotFoundErr{prefix, from_tid})
		}
	}

	if len(to_tid) > 0 {
		if val, ok := feed.Trips[prefix+to_tid]; ok {
			tk.To_trip = val
		} else {
			panic(&TripNotFoundErr{prefix, to_tid})
		}
	}

	if tk.From_stop == nil && tk.From_route == nil && tk.From_trip == nil {
		panic(fmt.Errorf("either from_stop_id, from_route_id, or from_trip_id must be set"))
	}

	if tk.To_stop == nil && tk.To_route == nil && tk.To_trip == nil {
		panic(fmt.Errorf("either to_stop_id, to_route_id, or to_trip_id must be set"))
	}

	tv.Transfer_type = getRangeInt(flds.TransferType, r, flds.FldName(flds.TransferType), false, 0, 5)
	tv.Min_transfer_time = getPositiveIntWithDefault(flds.MinTransferTime, r, flds.FldName(flds.MinTransferTime), -1, feed.opts.UseDefValueOnError, feed)

	return tk, tv, nil
}

func createPathway(r []string, flds PathwayFields, feed *Feed, prefix string) (t *gtfs.Pathway, err error) {
	defer func() {
		if r := recover(); r != nil {
			err = r.(error)
		}
	}()

	a := new(gtfs.Pathway)

	a.Id = prefix + getString(flds.pathwayId, r, flds.FldName(flds.pathwayId), true, true, "")

	if val, ok := feed.Stops[prefix+getString(flds.fromStopId, r, flds.FldName(flds.fromStopId), true, true, "")]; ok {
		a.From_stop = val
		if a.From_stop.Location_type == 1 {
			panic(errors.New("Stop for 'from_stop_id' with id " + getString(flds.fromStopId, r, flds.FldName(flds.fromStopId), true, true, "") + " has location_type=1 (Station). Only stops/platforms (location_type=0), entrances/exits (location_type=2), generic nodes (location_type=3) or boarding areas (location_type=4) are allowed here"))
		}
	} else {
		panic(&StopNotFoundErr{prefix, getString(flds.fromStopId, r, flds.FldName(flds.fromStopId), true, true, "")})
	}

	if val, ok := feed.Stops[prefix+getString(flds.toStopId, r, flds.FldName(flds.toStopId), true, true, "")]; ok {
		a.To_stop = val
		if a.To_stop.Location_type == 1 {
			panic(errors.New("Stop for 'to_stop_id' with id " + getString(flds.toStopId, r, flds.FldName(flds.toStopId), true, true, "") + " has location_type=1 (Station). Only stops/platforms (location_type=0), entrances/exits (location_type=2), generic nodes (location_type=3) or boarding areas (location_type=4) are allowed here"))
		}
	} else {
		panic(&StopNotFoundErr{prefix, getString(flds.toStopId, r, flds.FldName(flds.toStopId), true, true, "")})
	}

	a.Mode = uint8(getRangeInt(flds.pathwayMode, r, flds.FldName(flds.pathwayMode), true, 1, 7))
	a.Is_bidirectional = getBool(flds.isBidirectional, r, flds.FldName(flds.isBidirectional), true, false, feed.opts.UseDefValueOnError, feed)

	length := getNullableFloat(flds.length, r, flds.FldName(flds.length), feed.opts.UseDefValueOnError, feed)
	a.Length = length

	a.Traversal_time = int(getPositiveIntWithDefault(flds.traversalTime, r, flds.FldName(flds.traversalTime), -1, feed.opts.UseDefValueOnError, feed))

	a.Stair_count = getIntWithDefault(flds.stairCount, r, flds.FldName(flds.stairCount), 0, feed.opts.UseDefValueOnError, feed)
	a.Max_slope = getNullableFloat(flds.maxSlope, r, flds.FldName(flds.maxSlope), feed.opts.UseDefValueOnError, feed)
	if math.IsNaN(float64(a.Max_slope)) {
		a.Max_slope = 0
	}

	width := getNullablePositiveFloat(flds.minWidth, r, flds, feed.opts.UseDefValueOnError, feed)
	a.Min_width = width

	a.Signposted_as = getString(flds.signpostedAs, r, flds.FldName(flds.signpostedAs), false, false, "")
	a.Reversed_signposted_as = getString(flds.reversedSignpostedAs, r, flds.FldName(flds.reversedSignpostedAs), false, false, "")

	return a, nil
}

func createLevel(r []string, flds LevelFields, feed *Feed, idprefix string) (t *gtfs.Level, err error) {
	defer func() {
		if r := recover(); r != nil {
			err = r.(error)
		}
	}()

	a := new(gtfs.Level)

	a.Id = idprefix + getString(flds.levelId, r, flds.FldName(flds.levelId), true, true, "")
	a.Index = getNullableFloat(flds.levelIndex, r, flds.FldName(flds.levelIndex), feed.opts.UseDefValueOnError, feed)
	if math.IsNaN(float64(a.Index)) {
		a.Index = 0
	}
	a.Name = getString(flds.levelName, r, flds.FldName(flds.levelName), false, false, "")

	return a, nil
}

func getString(id int, r []string, fldName string, req bool, nonempty bool, emptyrepl string) string {
	if id >= 0 {
		trimmed := ""
		if id < len(r) {
			trimmed = r[id]
		}
		if nonempty && trimmed == "" {
			if len(emptyrepl) > 0 {
				return emptyrepl
			} else {
				panic(fmt.Errorf("expected non-empty string for field '%s'", fldName))
			}
		} else {
			return trimmed
		}
	} else if req {
		panic(fmt.Errorf("expected required field '%s'", fldName))
	}
	return ""
}

func trimQuotes(s string) string {
	return strings.TrimSpace(strings.Trim(strings.TrimSpace(s), "«»'\"`‹›„“‟”’‘‛"))
}

func removeFillers(s string) string {
	if s == "." || s == "-" || s == ".." || s == "..." || s == "?" {
		return ""
	}
	return s
}

func getURL(id int, r []string, flds Fields, req bool, ignErrs bool, feed *Feed) *url.URL {
	val := ""
	if id >= 0 && id < len(r) {
		val = r[id]
	}

	if len(val) == 0 && !req {
		return nil
	}

	if len(trimQuotes(val)) > 0 {
		u, e := url.ParseRequestURI(trimQuotes(val))

		// try out various heuristics
		if e != nil {
			u, e = url.ParseRequestURI("http://" + trimQuotes(val))
		}

		if e != nil {
			// full URL somewhere inside the field
			pattern := regexp.MustCompile(`https?:\/\/(www\.)?[-a-zA-Z0-9@:%._\+~#=]{1,256}\.[a-zA-Z0-9()]{1,6}\b([-a-zA-Z0-9()@:%_\+.~#?&//=]*)`)

			u, e = url.ParseRequestURI(pattern.FindString(val))
		}

		if e != nil {
			// url without http/s somewhere inside the field
			pattern := regexp.MustCompile(`[-a-zA-Z0-9@:%._\+~#=]{1,256}\.[a-zA-Z0-9()]{1,6}\b([-a-zA-Z0-9()@:%_\+.~#?&//=]*)`)
			found := pattern.FindString(val)

			if len(found) > 0 {
				found = "http://" + found
				u, e = url.ParseRequestURI(found)
			}
		}

		if e != nil {
			locErr := fmt.Errorf("'%s' is not a valid url", errFldPrep(val))
			if req || !ignErrs {
				panic(locErr)
			} else {
				feed.warn(locErr)
				return nil
			}
		}
		return u
	} else if req {
		panic(fmt.Errorf("expected required field '%s'", flds.FldName(id)))
	}
	return nil
}

func getMail(id int, r []string, flds Fields, req bool, ignErrs bool, feed *Feed) *mail.Address {
	if id >= 0 && id < len(r) && len(r[id]) > 0 {
		u, e := mail.ParseAddress(r[id])
		if e != nil {
			locErr := fmt.Errorf("'%s' is not a valid email address", errFldPrep(r[id]))
			if req || !ignErrs {
				panic(locErr)
			} else {
				feed.warn(locErr)
				return nil
			}
		}
		return u
	} else if req {
		panic(fmt.Errorf("expected required field '%s'", flds.FldName(id)))
	}
	return nil
}

func getTimezone(id int, r []string, flds Fields, req bool, ignErrs bool, feed *Feed) *time.Location {
	if id >= 0 && id < len(r) && len(r[id]) > 0 {
		tz, e := time.LoadLocation(r[id])
		if e != nil && (req || !ignErrs) {
			panic(e)
		} else if e != nil {
			feed.warn(e)
			return tz
		}
		return tz
	} else if req {
		panic(fmt.Errorf("expected required field '%s'", flds.FldName(id)))
	}
	emptyTz, _ := time.LoadLocation("")

	return emptyTz
}

func getIsoLangCode(id int, r []string, fldName string, req bool, ignErrs bool, feed *Feed) gtfs.LanguageISO6391 {
	if id >= 0 && id < len(r) && len(r[id]) > 0 {
		l, e := gtfs.NewLanguageISO6391(r[id])
		if e != nil && (req || !ignErrs) {
			panic(e)
		} else if e != nil {
			feed.warn(e)
			return l
		}
		return l
	} else if req {
		panic(fmt.Errorf("expected required field '%s'", fldName))
	}
	l, _ := gtfs.NewLanguageISO6391("")
	return l
}

func getColor(id int, r []string, fldName string, req bool, def string, ignErrs bool, feed *Feed) string {
	if id >= 0 && id < len(r) && len(r[id]) > 0 {
		if len(r[id]) != 6 {
			locErr := fmt.Errorf("expected six-character hexadecimal number as color for field '%s' (found: %s)", fldName, errFldPrep(r[id]))
			if ignErrs {
				feed.warn(locErr)
				return def
			}
			panic(locErr)
		}

		if _, e := hex.DecodeString(r[id]); e != nil {
			locErr := fmt.Errorf("expected hexadecimal number as color for field '%s' (found: %s)", fldName, r[id])
			if ignErrs {
				feed.warn(locErr)
				return def
			}
			panic(locErr)
		}
		return strings.ToUpper(r[id])
	} else if req {
		locErr := fmt.Errorf("expected required field '%s'", fldName)
		if ignErrs {
			feed.warn(locErr)
			return def
		}
		panic(locErr)
	}
	return strings.ToUpper(def)
}

func getIntWithDefault(id int, r []string, fldName string, def int, ignErrs bool, feed *Feed) int {
	if id >= 0 && id < len(r) && len(r[id]) > 0 {
		num, err := fastfloat.ParseInt64(r[id])
		if err != nil {
			locErr := fmt.Errorf("expected integer for field '%s', found '%s'", fldName, errFldPrep(r[id]))
			if ignErrs {
				feed.warn(locErr)
				return def
			}
			panic(locErr)
		}
		return int(num)
	}
	return def
}

func getPositiveInt(id int, r []string, fldName string, req bool) int {
	if id >= 0 && id < len(r) && len(r[id]) > 0 {
		num, err := fastfloat.ParseInt64(r[id])
		if err != nil || num < 0 {
			panic(fmt.Errorf("expected positive integer for field '%s', found '%s'", fldName, errFldPrep(r[id])))
		}
		return int(num)
	} else if req {
		panic(fmt.Errorf("expected required field '%s'", fldName))
	}
	return 0
}

func getPositiveIntWithDefault(id int, r []string, fldName string, def int, ignErrs bool, feed *Feed) int {
	if id >= 0 && id < len(r) && len(r[id]) > 0 {
		num, err := fastfloat.ParseInt64(r[id])
		if err != nil || num < 0 {
			locErr := fmt.Errorf("expected positive integer for field '%s', found '%s'", fldName, errFldPrep(r[id]))
			if ignErrs {
				feed.warn(locErr)
				return def
			}
			panic(locErr)
		}
		return int(num)
	}
	return def
}

func getRangeInt(id int, r []string, fldName string, req bool, min int, max int) int {
	if id >= 0 && id < len(r) && len(r[id]) > 0 {
		num, err := fastfloat.ParseInt64(r[id])
		if err != nil {
			panic(fmt.Errorf("expected integer for field '%s', found '%s'", fldName, errFldPrep(r[id])))
		}

		if int(num) > max || int(num) < min {
			panic(fmt.Errorf("expected integer between %d and %d for field '%s', found %s", min, max, fldName, errFldPrep(r[id])))
		}

		return int(num)
	} else if req {
		panic(fmt.Errorf("expected required field '%s'", fldName))
	}
	return 0
}

func getRangeIntWithDefault(id int, r []string, fldName string, min int, max int, def int, ignErrs bool, feed *Feed) int {
	if id >= 0 && id < len(r) && len(r[id]) > 0 {
		num, err := fastfloat.ParseInt64(r[id])
		if err != nil {
			locErr := fmt.Errorf("expected integer for field '%s', found '%s'", fldName, errFldPrep(r[id]))
			if ignErrs {
				feed.warn(locErr)
				return def
			}
			panic(locErr)
		}

		if int(num) > max || int(num) < min {
			locErr := fmt.Errorf("expected integer between %d and %d for field '%s', found %s", min, max, fldName, errFldPrep(r[id]))
			if ignErrs {
				feed.warn(locErr)
				return def
			}
			panic(locErr)
		}

		return int(num)
	}
	return def
}

func getFloat(id int, r []string, fldName string, req bool) float32 {
	if id >= 0 && id < len(r) && len(r[id]) > 0 {
		num, err := fastfloat.Parse(r[id])
		if err != nil || math.IsNaN(num) {
			// try with comma as decimal separator
			num, err = fastfloat.Parse(strings.Replace(r[id], ",", "", 1))
		}
		if err != nil || math.IsNaN(num) {
			panic(fmt.Errorf("expected float for field '%s', found '%s'", fldName, errFldPrep(r[id])))
		}
		return float32(num)
	} else if req {
		panic(fmt.Errorf("expected required field '%s'", fldName))
	}
	return -1
}

func getTime(id int, r []string, fldName string) gtfs.Time {
	if id < 0 {
		panic(fmt.Errorf("expected required field '%s'", fldName))
	}

	if id >= len(r) || len(r[id]) == 0 {
		return gtfs.Time{Second: int8(-1), Minute: int8(-1), Hour: int8(-1)}
	}

	// Use strings.Cut here as this function is very hot due to being called from createStopTimes, and splitting would allocate.
	// This is also the reason for the somewhat clunky variable pre-allocation and error handler structure.
	var hour, minute, second int64
	var e error
	var hourStr, minuteStr, secondStr string
	var found bool
	remaining := r[id]

	hourStr, remaining, found = strings.Cut(remaining, ":")
	if !found || len(hourStr) == 0 {
		goto fail
	}

	hour, e = fastfloat.ParseInt64(hourStr)
	if e != nil {
		goto fail
	}

	minuteStr, remaining, found = strings.Cut(remaining, ":")
	if !found || len(minuteStr) != 2 {
		goto fail
	}

	minute, e = fastfloat.ParseInt64(minuteStr)
	if e != nil {
		goto fail
	}

	secondStr, _, _ = strings.Cut(remaining, ":")
	if len(secondStr) != 2 {
		goto fail
	}

	second, e = fastfloat.ParseInt64(secondStr)
	if e != nil {
		goto fail
	}

	if hour > 127 {
		panic(fmt.Errorf("max representable time is '127:59:59', found '%s' for field %s", errFldPrep(r[id]), fldName))
	}

	return gtfs.Time{Hour: int8(hour), Minute: int8(minute), Second: int8(second)}

fail:
	panic(fmt.Errorf("expected HH:MM:SS time for field '%s', found '%s' (%s)", fldName, errFldPrep(r[id]), e.Error()))
}

func getNullablePositiveFloat(id int, r []string, flds Fields, ignErrs bool, feed *Feed) float32 {
	if id >= 0 && id < len(r) && len(r[id]) > 0 {
		num, err := fastfloat.Parse(r[id])
		if err != nil || math.IsNaN(num) {
			// try with comma as decimal separator
			num, err = fastfloat.Parse(strings.Replace(r[id], ",", "", 1))
		}
		if err != nil || math.IsNaN(num) || num < 0 {
			locErr := fmt.Errorf("expected positive float for field '%s', found '%s'", flds.FldName(id), errFldPrep(r[id]))
			if ignErrs {
				feed.warn(locErr)
				return float32(math.NaN())
			}
			panic(locErr)
		}
		return float32(num)
	}
	return float32(math.NaN())
}

func getNullableFloat(id int, r []string, fldName string, ignErrs bool, feed *Feed) float32 {
	if id >= 0 && id < len(r) && len(r[id]) > 0 {
		num, err := fastfloat.Parse(r[id])
		if err != nil || math.IsNaN(num) {
			// try with comma as decimal separator
			num, err = fastfloat.Parse(strings.Replace(r[id], ",", "", 1))
		}
		if err != nil || math.IsNaN(num) {
			locErr := fmt.Errorf("expected float for field '%s', found '%s'", fldName, errFldPrep(r[id]))
			if ignErrs {
				feed.warn(locErr)
				return float32(math.NaN())
			}
			panic(locErr)
		}
		return float32(num)
	}
	return float32(math.NaN())
}

func getBool(id int, r []string, fldName string, req bool, def bool, ignErrs bool, feed *Feed) bool {
	val := ""
	if id >= 0 && id < len(r) {
		val = r[id]
	}
	if len(val) > 0 {
		num, err := fastfloat.ParseInt64(val)
		if err != nil || (num != 0 && num != 1) {
			locErr := fmt.Errorf("expected 1 or 0 for field '%s', found '%s'", fldName, errFldPrep(val))
			if ignErrs {
				feed.warn(locErr)
				return def
			}
			panic(locErr)
		}
		return num == 1
	} else if req {
		locErr := fmt.Errorf("expected required field '%s'", fldName)
		if ignErrs {
			feed.warn(locErr)
			return def
		}
		panic(locErr)
	}
	return def
}

func getDate(id int, r []string, flds Fields, req bool, ignErrs bool, feed *Feed) gtfs.Date {
	if id < 0 || id >= len(r) || len(r[id]) == 0 {
		if req {
			locErr := fmt.Errorf("expected required field '%s'", flds.FldName(id))
			if ignErrs {
				feed.warn(locErr)
				return gtfs.Date{}
			}
			panic(locErr)
		} else {
			return gtfs.Date{}
		}
	}

	str := r[id]

	var day, month, year int64
	var e error
	if len(str) < 8 {
		e = fmt.Errorf("only has %d characters, expected 8", len(str))
	}
	if e == nil {
		day, e = fastfloat.ParseInt64(str[6:8])
	}
	if e == nil {
		month, e = fastfloat.ParseInt64(str[4:6])
	}
	if e == nil {
		year, e = fastfloat.ParseInt64(str[0:4])
	}

	if e == nil && day < 1 || day > 31 {
		e = fmt.Errorf("day must be in the range [1, 31]")
	}

	if e == nil && month < 1 || month > 12 {
		e = fmt.Errorf("month must be in the range [1, 12]")
	}

	if e == nil && year < 1900 || year > (1900+255) {
		e = fmt.Errorf("date must be in the range [19000101, 21551231]")
	}

	if e != nil {
		locErr := fmt.Errorf("expected YYYYMMDD date for field '%s', found '%s' (%s)", flds.FldName(id), errFldPrep(str), e.Error())
		if !ignErrs {
			panic(locErr)
		}
		feed.warn(locErr)
	}
	return gtfs.NewDate(uint8(day), uint8(month), uint16(year))
}

func errFldPrep(val string) string {
	a := strings.Replace(val, "\r", "<CR>", -1)
	a = strings.Replace(a, "\n", "<LF>", -1)
	a = strings.Replace(a, "\025", "<NL>", -1)
	return a
}