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/* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 2; tab-width: 2 -*- */
/*
* message_queue.c
* Copyright (C) Oliver 2008 <o.m.schinagl@student.tue.nl>
*
* main.c 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.
*
* main.c 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/>.
*/
#ifdef G_OS_WIN32
#define WIN32_LEAN_AND_MEAN 1
#include <windows.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "message_queue.h"
#define MAX_MESSAGES MESSAGE_WINDOW_SIZE
struct messageq_s messageq[MAX_MESSAGES];
static int messageq_index, messageq_serial;
static int messageq_last_free;
void messageq_init(void)
{
int i;
messageq_index = 0;
messageq_serial = 0;
messageq_last_free = 0;
for( i = 0; i < MAX_MESSAGES; i++) {
messageq[i].sender = 0;
messageq[i].recipient = 0;
messageq[i].payload = NULL;
messageq[i].payload_size = 0;
}
}
static void msgcpy(struct messageq_s *dest, const struct messageq_s *src)
{
dest->sender = src->sender;
dest->recipient = src->recipient;
dest->payload = (void *)malloc(src->payload_size);
memcpy(dest->payload, src->payload, src->payload_size);
dest->payload_size = src->payload_size;
}
static void msgfree(int index) {
messageq[index].sender = 0;
messageq[index].recipient = 0;
free(messageq[index].payload);
messageq[index].payload_size = 0;
}
struct messageq_s *messageq_get(int recipient)
{
int i;
i = messageq_index;
while (messageq[i].recipient != recipient && i != (messageq_index -1)) {
i = (i < MAX_MESSAGES -1) ? i +1 : 0;
}
/*
* We found the message for our recipient. We'll now set the recipient field to 0 since the recipient
* should know the message was for him, he asked for it. This is needed to prefent the above loop
* to find the same message again, since the message will stay alive in the system until its expired.
*/
messageq[i].recipient = MESSAGE_NONE;
return &messageq[i];
}
void messageq_send(struct messageq_s *message)
{
/* Before sending the message, we clean out old cruft. We do this here
* since we will be overwriting the contens of the message here anyway.
*/
msgfree(messageq_index);
msgcpy(&messageq[messageq_index], message);
messageq_index = ++messageq_serial %MAX_MESSAGES;
}
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