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package main
import (
"bufio"
"errors"
"fmt"
"io"
"log"
"strings"
)
func parseUint32Fast(s string) (int, error) {
sLen := len(s)
if sLen < 1 {
return -1, errors.New("zero length string")
}
if sLen > 10 {
return -1, errors.New("string too long")
}
n := 0
for i, ch := range []byte(s) {
ch -= '0'
if ch > 9 {
return -1, fmt.Errorf("invalid character '%s' at index %d", string(ch+'0'), i)
}
n = n*10 + int(ch)
}
return n, nil
}
func parseConfig(r io.Reader, puid int) (fid int, ok bool, err error) {
s := bufio.NewScanner(r)
var line, puid0 int
for s.Scan() {
line++
// <puid> <fid>
lf := strings.SplitN(s.Text(), " ", 2)
if len(lf) != 2 {
return -1, false, fmt.Errorf("invalid entry on line %d", line)
}
puid0, err = parseUint32Fast(lf[0])
if err != nil || puid0 < 1 {
return -1, false, fmt.Errorf("invalid parent uid on line %d", line)
}
ok = puid0 == puid
if ok {
// allowed fid range 0 to 99
if fid, err = parseUint32Fast(lf[1]); err != nil || fid < 0 || fid > 99 {
return -1, false, fmt.Errorf("invalid identity on line %d", line)
}
return
}
}
return -1, false, s.Err()
}
func mustParseConfig(r io.Reader, puid int) (int, bool) {
fid, ok, err := parseConfig(r, puid)
if err != nil {
log.Fatal(err)
}
return fid, ok
}
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