PD_TEXT_ID_INFO_HDR_LEN
if (buf_len < PD_TEXT_ID_INFO_HDR_LEN)
data_len = data_len + PD_TEXT_ID_INFO_HDR_LEN;
scnprintf(&buf[PD_TEXT_ID_INFO_HDR_LEN], buf_len - PD_TEXT_ID_INFO_HDR_LEN, "%s",