The Protothreads Library 1.4: lc-switch.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 Contiki operating system.
+00030  *
+00031  * Author: Adam Dunkels <adam@sics.se>
+00032  *
+00033  * $Id: lc-switch.h,v 1.4 2006/06/03 11:29:43 adam Exp $
+00034  */
+00035 
+00036 /**
+00037  * \addtogroup lc
+00038  * @{
+00039  */
+00040 
+00041 /**
+00042  * \file
+00043  * Implementation of local continuations based on switch() statment
+00044  * \author Adam Dunkels <adam@sics.se>
+00045  *
+00046  * This implementation of local continuations uses the C switch()
+00047  * statement to resume execution of a function somewhere inside the
+00048  * function's body. The implementation is based on the fact that
+00049  * switch() statements are able to jump directly into the bodies of
+00050  * control structures such as if() or while() statmenets.
+00051  *
+00052  * This implementation borrows heavily from Simon Tatham's coroutines
+00053  * implementation in C:
+00054  * http://www.chiark.greenend.org.uk/~sgtatham/coroutines.html
+00055  */
+00056 
+00057 #ifndef __LC_SWITCH_H__
+00058 #define __LC_SWITCH_H__
+00059 
+00060 /* WARNING! lc implementation using switch() does not work if an
+00061    LC_SET() is done within another switch() statement! */
+00062 
+00063 /** \hideinitializer */
+00064 typedef unsigned short lc_t;
+00065 
+00066 #define LC_INIT(s) s = 0;
+00067 
+00068 #define LC_RESUME(s) switch(s) { case 0:
+00069 
+00070 #define LC_SET(s) s = __LINE__; case __LINE__:
+00071 
+00072 #define LC_END(s) }
+00073 
+00074 #endif /* __LC_SWITCH_H__ */
+00075 
+00076 /** @} */
+