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package main
import (
"encoding/base32"
"encoding/binary"
"fmt"
"strings"
)
var b32 = base32.StdEncoding.WithPadding(base32.NoPadding)
func encodeID(id int64) (string, error) {
if id < 0 {
return "", fmt.Errorf("id out of range: %d", id)
}
buf := make([]byte, 8)
binary.BigEndian.PutUint64(buf, uint64(id))
// Trim leading zero bytes, keep at least 2 bytes (4 chars).
i := 0
for i < 6 && buf[i] == 0 {
i++
}
return b32.EncodeToString(buf[i:]), nil
}
func decodeID(s string) (int64, error) {
s = strings.ToUpper(s)
buf, err := b32.DecodeString(s)
if err != nil {
return 0, fmt.Errorf("invalid short id: %w", err)
}
if len(buf) == 0 || len(buf) > 8 {
return 0, fmt.Errorf("invalid short id")
}
padded := make([]byte, 8)
copy(padded[8-len(buf):], buf)
return int64(binary.BigEndian.Uint64(padded)), nil
}
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