photoprism/pkg/s2/prefix.go

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package s2
import (
"strings"
)
var TokenPrefix = "s2:"
// NormalizeToken removes the prefix from a token and converts all characters to lower case.
func NormalizeToken(token string) string {
token = strings.ToLower(token)
token = strings.TrimSpace(token)
if strings.HasPrefix(token, TokenPrefix) {
return token[len(TokenPrefix):]
}
return token
}
// Prefix adds a token prefix if not exists.
func Prefix(token string) string {
if len(token) < 3 {
return token
}
if strings.HasPrefix(token, TokenPrefix) {
return token
}
return TokenPrefix + token
}
// PrefixedToken returns the prefixed S2 cell token for coordinates using the default level.
func PrefixedToken(lat, lng float64) string {
return Prefix(Token(lat, lng))
}
// Range returns a token range for finding nearby locations.
func PrefixedRange(token string, levelUp int) (min, max string) {
min, max = Range(token, levelUp)
return Prefix(min), Prefix(max)
}