queue.c

来自「pixil 最新的嵌入linux 應用程序集,別的地方很難下載」· C语言 代码 · 共 91 行

/*                                                                       
 * Copyright (c) 2003 Century Software, Inc.   All Rights Reserved.     
 *                                                                       
 * This file is part of the PIXIL Operating Environment                 
 *                                                                       
 * The use, copying and distribution of this file is governed by one    
 * of two licenses, the PIXIL Commercial License, or the GNU General    
 * Public License, version 2.                                           
 *                                                                       
 * Licensees holding a valid PIXIL Commercial License may use this file 
 * in accordance with the PIXIL Commercial License Agreement provided   
 * with the Software. Others are governed under the terms of the GNU   
 * General Public License version 2.                                    
 *                                                                       
 * This file may be distributed and/or modified under the terms of the  
 * GNU General Public License version 2 as published by the Free        
 * Software Foundation and appearing in the file LICENSE.GPL included   
 * in the packaging of this file.                                      
 *                                                                       
 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING  
 * THE WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A            
 * PARTICULAR PURPOSE.                                                  
 *                                                                       
 * RESTRICTED RIGHTS LEGEND                                             
 *                                                                     
 * Use, duplication, or disclosure by the government is subject to      
 * restriction as set forth in paragraph (b)(3)(b) of the Rights in     
 * Technical Data and Computer Software clause in DAR 7-104.9(a).       
 *                                                                      
 * See http://www.pixil.org/gpl/ for GPL licensing       
 * information.                                                         
 *                                                                      
 * See http://www.pixil.org/license.html or              
 * email [e-mail] for information about the PIXIL   
 * Commercial License Agreement, or if any conditions of this licensing 
 * are not clear to you.                                                
 */


#include <stdlib.h>

#include <ipc/colosseum.h>
#include "server.h"

int
queue_add_packet(cl_app_struct * app, cl_pkt_buff * pkt)
{

    /* If the queue is full, then bail */
    if (app->cl_queue.head == app->cl_queue.tail)
	return (-1);

    app->cl_queue.ring[app->cl_queue.head] = pkt;
    app->cl_queue.head = (app->cl_queue.head + 1) % app->cl_queue.size;
    return (0);
}

cl_pkt_buff *
queue_get_packet(cl_app_struct * app)
{

    int next = (app->cl_queue.tail + 1) % app->cl_queue.size;

    if (next == app->cl_queue.head)
	return (0);
    app->cl_queue.tail = next;
    return (app->cl_queue.ring[next]);
}

cl_pkt_buff *
queue_peek_packet(cl_app_struct * app)
{

    int next = (app->cl_queue.tail + 1) % app->cl_queue.size;

    if (next == app->cl_queue.head)
	return (0);
    return (app->cl_queue.ring[next]);
}

int
data_in_queue(cl_app_struct * app)
{

    int next = (app->cl_queue.tail + 1) % app->cl_queue.size;
    if (next == app->cl_queue.head)
	return (0);
    else
	return (1);
}