1 /* 2 * Copyright (c) 2004-2005, Swedish Institute of Computer Science. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the Institute nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * This file is part of the uIP TCP/IP stack 30 * 31 * Author: Adam Dunkels <[email protected]> 32 * 33 * $Id: lc-switch.h,v 1.2 2006/06/12 08:00:30 adam Exp $ 34 */ 35 36 /** 37 * \addtogroup lc 38 * @{ 39 */ 40 41 /** 42 * \file 43 * Implementation of local continuations based on switch() statment 44 * \author Adam Dunkels <[email protected]> 45 * 46 * This implementation of local continuations uses the C switch() 47 * statement to resume execution of a function somewhere inside the 48 * function's body. The implementation is based on the fact that 49 * switch() statements are able to jump directly into the bodies of 50 * control structures such as if() or while() statmenets. 51 * 52 * This implementation borrows heavily from Simon Tatham's coroutines 53 * implementation in C: 54 * http://www.chiark.greenend.org.uk/~sgtatham/coroutines.html 55 */ 56 57 #ifndef __LC_SWITCH_H__ 58 #define __LC_SWTICH_H__ 59 60 /* WARNING! lc implementation using switch() does not work if an 61 LC_SET() is done within another switch() statement! */ 62 63 /** \hideinitializer */ 64 typedef unsigned short lc_t; 65 66 #define LC_INIT(s) s = 0; 67 68 #define LC_RESUME(s) switch(s) { case 0: 69 70 #define LC_SET(s) s = __LINE__; case __LINE__: 71 72 #define LC_END(s) } 73 74 #endif /* __LC_SWITCH_H__ */ 75 76 /** @} */ 77