uIP 1.0: uip/lc-addrlabels.h Source File

00001 /*
+00002  * Copyright (c) 2004-2005, Swedish Institute of Computer Science.
+00003  * All rights reserved.
+00004  *
+00005  * Redistribution and use in source and binary forms, with or without
+00006  * modification, are permitted provided that the following conditions
+00007  * are met:
+00008  * 1. Redistributions of source code must retain the above copyright
+00009  *    notice, this list of conditions and the following disclaimer.
+00010  * 2. Redistributions in binary form must reproduce the above copyright
+00011  *    notice, this list of conditions and the following disclaimer in the
+00012  *    documentation and/or other materials provided with the distribution.
+00013  * 3. Neither the name of the Institute nor the names of its contributors
+00014  *    may be used to endorse or promote products derived from this software
+00015  *    without specific prior written permission.
+00016  *
+00017  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
+00018  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+00019  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+00020  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
+00021  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+00022  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+00023  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+00024  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+00025  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+00026  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+00027  * SUCH DAMAGE.
+00028  *
+00029  * This file is part of the uIP TCP/IP stack
+00030  *
+00031  * Author: Adam Dunkels <adam@sics.se>
+00032  *
+00033  * $Id: lc-addrlabels.h,v 1.3 2006/06/12 08:00:30 adam Exp $
+00034  */
+00035 
+00036 /**
+00037  * \addtogroup lc
+00038  * @{
+00039  */
+00040 
+00041 /**
+00042  * \file
+00043  * Implementation of local continuations based on the "Labels as
+00044  * values" feature of gcc
+00045  * \author
+00046  * Adam Dunkels <adam@sics.se>
+00047  *
+00048  * This implementation of local continuations is based on a special
+00049  * feature of the GCC C compiler called "labels as values". This
+00050  * feature allows assigning pointers with the address of the code
+00051  * corresponding to a particular C label.
+00052  *
+00053  * For more information, see the GCC documentation:
+00054  * http://gcc.gnu.org/onlinedocs/gcc/Labels-as-Values.html
+00055  *
+00056  * Thanks to dividuum for finding the nice local scope label
+00057  * implementation.
+00058  */
+00059 
+00060 #ifndef __LC_ADDRLABELS_H__
+00061 #define __LC_ADDRLABELS_H__
+00062 
+00063 /** \hideinitializer */
+00064 typedef void * lc_t;
+00065 
+00066 #define LC_INIT(s) s = NULL
+00067 
+00068 
+00069 #define LC_RESUME(s)                            \
+00070   do {                                          \
+00071     if(s != NULL) {                             \
+00072       goto *s;                                  \
+00073     }                                           \
+00074   } while(0)
+00075 
+00076 #define LC_SET(s)                               \
+00077   do { ({ __label__ resume; resume: (s) = &&resume; }); }while(0)
+00078 
+00079 #define LC_END(s)
+00080 
+00081 #endif /* __LC_ADDRLABELS_H__ */
+00082 
+00083 /**  @} */
+