VILLASnode/include/villas/msg.h

/** Message related functions
 *
 * @file
 * @author Steffen Vogel <stvogel@eonerc.rwth-aachen.de>
 * @copyright 2017, Institute for Automation of Complex Power Systems, EONERC
 * @license GNU General Public License (version 3)
 *
 * VILLASnode
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *********************************************************************************/

#pragma once

/* Forward declarations. */
struct msg;
struct sample;

/** The maximum length of a packet which contains stuct msg. */
#define MSG_MAX_PACKET_LEN 1500

/** Swaps the byte-order of the message.
 *
 * Message are always transmitted in network (big endian) byte order.
 *
 * @param m A pointer to the message
 */
void msg_hdr_ntoh(struct msg *m);

void msg_hdr_hton(struct msg *m);

void msg_ntoh(struct msg *m);

void msg_hton(struct msg *m);

/** Check the consistency of a message.
 *
 * The functions checks the header fields of a message.
 *
 * @param m A pointer to the message
 * @retval 0 The message header is valid.
 * @retval <0 The message header is invalid.
 */
int msg_verify(struct msg *m);

/** Copy fields from \p msg into \p smp. */
int msg_to_sample(struct msg *msg, struct sample *smp);

/** Copy fields form \p smp into \p msg. */
int msg_from_sample(struct msg *msg, struct sample *smp);


/** Copy / read struct msg's from buffer \p buf to / fram samples \p smps. */
ssize_t msg_buffer_from_samples(struct sample *smps[], unsigned cnt, char *buf, size_t len);

/** Read struct sample's from buffer \p buf into samples \p smps. */
int msg_buffer_to_samples(struct sample *smps[], unsigned cnt, char *buf, size_t len);