frostfs-node/pkg/util/locode/table/csv/calls.go
Leonard Lyubich 6829048124 [] locode: Implement csv UN/LOCODE table
Define csv UN/LOCODE table. Implement iterator over table entries. Implement
method that resolves country/subdivision code pair to subdivision name.

Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
2021-02-09 11:05:55 +03:00

120 lines
2.5 KiB
Go

package csvlocode
import (
"encoding/csv"
"io"
"os"
"strings"
"github.com/nspcc-dev/neofs-node/pkg/util/locode"
locodedb "github.com/nspcc-dev/neofs-node/pkg/util/locode/db"
"github.com/pkg/errors"
)
var errInvalidRecord = errors.New("invalid table record")
// IterateAll scans table record one-by-one, parses UN/LOCODE record
// from it and passes it to f.
//
// Returns f's errors directly.
func (t *Table) IterateAll(f func(locode.Record) error) error {
const wordsPerRecord = 12
return t.scanWords(t.paths, wordsPerRecord, func(words []string) error {
lc, err := locode.FromString(strings.Join(words[1:3], " "))
if err != nil {
return err
}
record := locode.Record{
Ch: words[0],
LOCODE: *lc,
Name: words[3],
NameWoDiacritics: words[4],
SubDiv: words[5],
Function: words[6],
Status: words[7],
Date: words[8],
IATA: words[9],
Coordinates: words[10],
Remarks: words[11],
}
return f(record)
})
}
// SubDivName scans table record one-by-one, and returns subdivision name
// on country and subdivision codes match.
//
// Returns locodedb.ErrSubDivNotFound if no entry matches.
func (t *Table) SubDivName(countryCode *locodedb.CountryCode, name string) (subDiv string, err error) {
const wordsPerRecord = 4
err = t.scanWords([]string{t.subDivPath}, wordsPerRecord, func(words []string) error {
if words[0] == countryCode.String() && words[1] == name {
subDiv = words[2]
return errScanInt
}
return nil
})
if err == nil && subDiv == "" {
err = locodedb.ErrSubDivNotFound
}
return
}
var errScanInt = errors.New("interrupt scan")
func (t *Table) scanWords(paths []string, fpr int, wordsHandler func([]string) error) error {
var (
rdrs = make([]io.Reader, 0, len(t.paths))
closers = make([]io.Closer, 0, len(t.paths))
)
for i := range paths {
file, err := os.OpenFile(paths[i], os.O_RDONLY, t.mode)
if err != nil {
return err
}
rdrs = append(rdrs, file)
closers = append(closers, file)
}
defer func() {
for i := range closers {
_ = closers[i].Close()
}
}()
r := csv.NewReader(io.MultiReader(rdrs...))
r.ReuseRecord = true
r.FieldsPerRecord = fpr
for {
words, err := r.Read()
if err != nil {
if errors.Is(err, io.EOF) {
break
}
return err
} else if len(words) != fpr {
return errInvalidRecord
}
if err := wordsHandler(words); err != nil {
if errors.Is(err, errScanInt) {
break
}
return err
}
}
return nil
}