报错切片越界

per = make(map[string]interface{})

f, _ := os.Open("D:\\GoPoject\\initype\\src\\ini\\gconfig.ini")

buf := bufio.NewReader(f)
for {

    l, err := buf.ReadString('\n')

    line := strings.TrimSpace(l)

    if err != nil {
        if err != io.EOF {

        }
        if len(line) == 0 {
            break
        }
    }
    switch {
    case len(line) == 0:

    case line[0] == '[' && line[len(line)-1] == ']':
        section := strings.TrimSpace(line[1 : len(line)-1])
        fmt.Println(section)
    default:

        i := strings.IndexAny(line, "=")
        per[strings.TrimSpace(line[0:i])] = strings.TrimSpace(line[i+1:])
    }
}

for k, v := range per {
    fmt.Println(k, v)
}

报错panic: runtime error: slice bounds out of range