csu3_am335x/EVSE/GPL/open-plc-utils-0.3/mme/readmessage.c

/*====================================================================*
 *
 *   Copyright (c) 2013 Qualcomm Atheros, Inc.
 *
 *   All rights reserved.
 *
 *   Redistribution and use in source and binary forms, with or
 *   without modification, are permitted (subject to the limitations
 *   in the disclaimer below) provided that the following conditions
 *   are met:
 *
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   * Redistributions in binary form must reproduce the above
 *     copyright notice, this list of conditions and the following
 *     disclaimer in the documentation and/or other materials
 *     provided with the distribution.
 *
 *   * Neither the name of Qualcomm Atheros nor the names of
 *     its contributors may be used to endorse or promote products
 *     derived from this software without specific prior written
 *     permission.
 *
 *   NO EXPRESS OR IMPLIED LICENSES TO ANY PARTY'S PATENT RIGHTS ARE
 *   GRANTED BY THIS LICENSE. THIS SOFTWARE IS PROVIDED BY THE
 *   COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
 *   IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 *   WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 *   PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
 *   OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 *   NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 *   LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 *   HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 *   CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
 *   OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 *   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 *--------------------------------------------------------------------*/

/*====================================================================*
 *
 *   ssize_t readmessage (struct channel const * channel, struct message * message, uint8_t MMV, uint16_t MMTYPE);
 *
 *   plc.h
 *
 *   wait for a QCA vendor specific message of given MMV and MMTYPE;
 *   discard unwanted messages until the desired message arrives or
 *   the channel timeout expires; return packet length on success,
 *   0 on timeout or -1 on error;
 *
 *   see sendmessage for the send counterpart to this function;
 *
 *   a well designed UnwantedMessage function is critical here;
 *
 *   Contributor(s):
 *      Charles Maier
 *      Nathaniel Houghton
 *
 *--------------------------------------------------------------------*/

#ifndef READMESSAGE_SOURCE
#define READMESSAGE_SOURCE

#include <sys/time.h>
#include <memory.h>
#include <errno.h>

#include "../tools/error.h"
#include "../tools/timer.h"
#include "../plc/plc.h"

ssize_t readmessage (struct channel const * channel, struct message * message, uint8_t MMV, uint16_t MMTYPE)

{
	struct timeval ts;
	struct timeval tc;
	ssize_t length;
	if (gettimeofday (& ts, NULL) == - 1)
	{
		error (1, errno, CANT_START_TIMER);
	}
	while ((length = readpacket (channel, message, sizeof (* message))) >= 0)
	{
		if (! UnwantedMessage (message, length, MMV, MMTYPE))
		{
			return (length);
		}
		if (gettimeofday (& tc, NULL) == - 1)
		{
			error (1, errno, CANT_RESET_TIMER);
		}
		if (channel->timeout < 0)
		{
			continue;
		}
		if (channel->timeout > MILLISECONDS (ts, tc))
		{
			continue;
		}
		return (0);
	}
	return (- 1);
}

#endif