/*
Copyright (C) 2012  Andriy Sukhynyuk, Vasyl Tkhir, Andriy Ivasiv

    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
    (at your option) 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/>.
*/
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <pthread.h>
#include "msgqueue.h"

pthread_mutex_t msg_lock = PTHREAD_MUTEX_INITIALIZER;

MSGBOX_ID create_msgbox() {
	MSGBOX_ID msgboxid;

	msgboxid = msgget(IPC_PRIVATE, 0666 | IPC_CREAT);
	if (msgboxid == INVALID_MSGBOX_ID) {
		return INVALID_MSGBOX_ID;
	}

	return msgboxid;
}

bool send_to_msgbox(
		MSGBOX_ID dest,
		BACMSG *msg) {

	int err;

	err = msgsnd(dest, msg, sizeof(BACMSG), 0);
	if (err) {
		return false;
	}
	return true;
}

BACMSG* recv_from_msgbox(
		MSGBOX_ID src,
		BACMSG *msg) {

	int recv_bytes;

	recv_bytes = msgrcv(src, msg, sizeof(BACMSG), 0, IPC_NOWAIT);
	if (recv_bytes > 0) {
		return msg;
	} else {
		return NULL;
	}
}

void del_msgbox(
		MSGBOX_ID msgboxid) {

	if (msgboxid == INVALID_MSGBOX_ID)
		return;
	else
		msgctl(msgboxid, IPC_RMID, NULL);
}

void free_data(
		MSG_DATA *data) {

	if (data->pdu) {
		free(data->pdu);
		data->pdu = NULL;
	}
	if (data) {
		free(data);
		data = NULL;
	}
}

void check_data(
		MSG_DATA *data) {

	// lock and decrement messages reference count
	pthread_mutex_lock(&msg_lock);
		if (--data->ref_count == 0) {
			free_data(data);
		}
	pthread_mutex_unlock(&msg_lock);
}