locodedb: allocate less, don't leave references to csv data (#60)

Author: roman-khimov

pkg/locodedb/calls.go

@@ -4,7 +4,6 @@ import (
 	"cmp"
 	"errors"
 	"slices"
-	"strings"
 )
 
 // ErrNotFound is returned when the record is not found in the location database.
@@ -52,10 +51,10 @@ func Get(locodeStr string) (Record, error) {
 	}
 
 	code := locodeStr[CountryCodeLen:]
-	n, _ := slices.BinarySearchFunc(cd.locodes, code, func(csv locodesCSV, s string) int {
-		return cmp.Compare(csv.code, s)
+	n, ok := slices.BinarySearchFunc(cd.locodes, code, func(csv locodesCSV, s string) int {
+		return cmp.Compare(codeFromCSV(&csv), s)
 	})
-	if n == len(cd.locodes) || strings.Compare(cd.locodes[n].code, code) != 0 {
+	if !ok {
 		return Record{}, ErrNotFound
 	}
 
@@ -69,14 +68,18 @@ func Get(locodeStr string) (Record, error) {
 	}, nil
 }
 
+func codeFromCSV(c *locodesCSV) string {
+	return locodeStrings[c.offset : c.offset+LocationCodeLen]
+}
+
 func locFromCSV(c *locodesCSV) string {
-	return locodeStrings[c.offset : c.offset+uint32(c.locationLen)]
+	return locodeStrings[c.offset+LocationCodeLen : c.offset+LocationCodeLen+uint32(c.locationLen)]
 }
 
 func divCodeFromCSV(c *locodesCSV) string {
-	return locodeStrings[c.offset+uint32(c.locationLen) : c.offset+uint32(c.locationLen)+uint32(c.subDivCodeLen)]
+	return locodeStrings[c.offset+LocationCodeLen+uint32(c.locationLen) : c.offset+LocationCodeLen+uint32(c.locationLen)+uint32(c.subDivCodeLen)]
 }
 
 func divNameFromCSV(c *locodesCSV) string {
-	return locodeStrings[c.offset+uint32(c.locationLen)+uint32(c.subDivCodeLen) : c.offset+uint32(c.locationLen)+uint32(c.subDivCodeLen)+uint32(c.subDivNameLen)]
+	return locodeStrings[c.offset+LocationCodeLen+uint32(c.locationLen)+uint32(c.subDivCodeLen) : c.offset+LocationCodeLen+uint32(c.locationLen)+uint32(c.subDivCodeLen)+uint32(c.subDivNameLen)]
 }

pkg/locodedb/utils.go

@@ -45,7 +45,6 @@ type countryData struct {
 type locodesCSV struct {
 	point         Point
 	offset        uint32
-	code          string
 	locationLen   uint8
 	subDivCodeLen uint8
 	subDivNameLen uint8
@@ -106,6 +105,7 @@ func unpackLocodesData(data []byte, mc map[countryCode]countryData) (string, err
 			subDivNameLen = uint8(len(record[4]))
 		)
 
+		b.WriteString(record[0][CountryCodeLen:])
 		b.WriteString(record[1])
 		b.WriteString(record[3])
 		b.WriteString(record[4])
@@ -132,7 +132,6 @@ func unpackLocodesData(data []byte, mc map[countryCode]countryData) (string, err
 		}
 		rec.locodes = append(rec.locodes, locodesCSV{
 			point:         Point{Latitude: float32(lat), Longitude: float32(lng)},
-			code:          record[0][CountryCodeLen:],
 			offset:        recOffset,
 			locationLen:   locationLen,
 			subDivCodeLen: subDivCodeLen,