Method fetch

bufreader/bufreader.go:75–96

fetch ensures the buffer contains at least 'need' bytes

(need int)

// fetch ensures the buffer contains at least 'need' bytes
func (br *Reader) fetch(need int) error {
	if br.finished || need <= len(br.buf) {
		return nil
	}

	b := make([]byte, need-len(br.buf))
	n, err := ioutil.TryReadFull(br.r, b)

	if errors.Is(err, io.EOF) {
		// If we reached EOF, we mark the reader as finished
		br.finished = true
	} else if err != nil {
		return err
	}

	if n > 0 {
		// append only those which we read in fact
		br.buf = append(br.buf, b[:n]...)
	}

	return nil
}