rem: *_l = PRESENCE_ETAG_L + CRLF_L - *_l;
context: int end_xpidf_doc(str* _b, int* _l){	if (*_l < (PRESENCE_ETAG_L + CRLF_L)) {		paerrno = PA_SMALL_BUFFER;		LOG(L_ERR, "end_xpidf_doc(): Buffer too small\n");		*_l = PRESENCE_ETAG_L + CRLF_L - *_l;		return -1;	}	str_append(_b, PRESENCE_ETAG CRLF, PRESENCE_ETAG_L + CRLF_L);	return 0;}