/* * Copyright (c) 2004-2005, Swedish Institute of Computer Science. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright *    notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright *    notice, this list of conditions and the following disclaimer in the *    documentation and/or other materials provided with the distribution. * 3. Neither the name of the Institute nor the names of its contributors *    may be used to endorse or promote products derived from this software *    without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * This file is part of the Contiki operating system. * * Author: Adam Dunkels <adam@sics.se> * * $Id: pt.h,v 1.7 2006/10/02 07:52:56 adam Exp $ *//** * \addtogroup pt * @{ *//** * \file * Protothreads implementation. * \author * Adam Dunkels <adam@sics.se> * */#ifndef __PT_H__#define __PT_H__#include "lc.h"struct pt {  lc_t lc;};#define PT_WAITING 0#define PT_YIELDED 1#define PT_EXITED  2#define PT_ENDED   3/** * \name Initialization * @{ *//** * Initialize a protothread. * * Initializes a protothread. Initialization must be done prior to * starting to execute the protothread. * * \param pt A pointer to the protothread control structure. * * \sa PT_SPAWN() * * \hideinitializer */#define PT_INIT(pt)   LC_INIT((pt)->lc)/** @} *//** * \name Declaration and definition * @{ *//** * Declaration of a protothread. * * This macro is used to declare a protothread. All protothreads must * be declared with this macro. * * \param name_args The name and arguments of the C function * implementing the protothread. * * \hideinitializer */#define PT_THREAD(name_args) char name_args/** * Declare the start of a protothread inside the C function * implementing the protothread. * * This macro is used to declare the starting point of a * protothread. It should be placed at the start of the function in * which the protothread runs. All C statements above the PT_BEGIN() * invokation will be executed each time the protothread is scheduled. * * \param pt A pointer to the protothread control structure. * * \hideinitializer */#define PT_BEGIN(pt) { char PT_YIELD_FLAG = 1; LC_RESUME((pt)->lc)/** * Declare the end of a protothread. * * This macro is used for declaring that a protothread ends. It must * always be used together with a matching PT_BEGIN() macro. * * \param pt A pointer to the protothread control structure. * * \hideinitializer */#define PT_END(pt) LC_END((pt)->lc); PT_YIELD_FLAG = 0; \                   PT_INIT(pt); return PT_ENDED; }/** @} *//** * \name Blocked wait * @{ *//** * Block and wait until condition is true. * * This macro blocks the protothread until the specified condition is * true. * * \param pt A pointer to the protothread control structure. * \param condition The condition. * * \hideinitializer */#define PT_WAIT_UNTIL(pt, condition)	        \  do {						\    LC_SET((pt)->lc);				\    if(!(condition)) {				\      return PT_WAITING;			\    }						\  } while(0)/** * Block and wait while condition is true. * * This function blocks and waits while condition is true. See * PT_WAIT_UNTIL(). * * \param pt A pointer to the protothread control structure. * \param cond The condition. * * \hideinitializer */#define PT_WAIT_WHILE(pt, cond)  PT_WAIT_UNTIL((pt), !(cond))/** @} *//** * \name Hierarchical protothreads * @{ *//** * Block and wait until a child protothread completes. * * This macro schedules a child protothread. The current protothread * will block until the child protothread completes. * * \note The child protothread must be manually initialized with the * PT_INIT() function before this function is used. * * \param pt A pointer to the protothread control structure. * \param thread The child protothread with arguments * * \sa PT_SPAWN() * * \hideinitializer */#define PT_WAIT_THREAD(pt, thread) PT_WAIT_WHILE((pt), PT_SCHEDULE(thread))/** * Spawn a child protothread and wait until it exits. * * This macro spawns a child protothread and waits until it exits. The * macro can only be used within a protothread. * * \param pt A pointer to the protothread control structure. * \param child A pointer to the child protothread's control structure. * \param thread The child protothread with arguments * * \hideinitializer */#define PT_SPAWN(pt, child, thread)		\  do {						\    PT_INIT((child));				\    PT_WAIT_THREAD((pt), (thread));		\  } while(0)/** @} *//** * \name Exiting and restarting * @{ *//** * Restart the protothread. * * This macro will block and cause the running protothread to restart * its execution at the place of the PT_BEGIN() call. * * \param pt A pointer to the protothread control structure. * * \hideinitializer */#define PT_RESTART(pt)				\  do {						\    PT_INIT(pt);				\    return PT_WAITING;			\  } while(0)/** * Exit the protothread. * * This macro causes the protothread to exit. If the protothread was * spawned by another protothread, the parent protothread will become * unblocked and can continue to run. * * \param pt A pointer to the protothread control structure. * * \hideinitializer */#define PT_EXIT(pt)				\  do {						\    PT_INIT(pt);				\    return PT_EXITED;			\  } while(0)/** @} *//** * \name Calling a protothread * @{ *//** * Schedule a protothread. * * This function shedules a protothread. The return value of the * function is non-zero if the protothread is running or zero if the * protothread has exited. * * \param f The call to the C function implementing the protothread to * be scheduled * * \hideinitializer */#define PT_SCHEDULE(f) ((f) < PT_EXITED)/** @} *//** * \name Yielding from a protothread * @{ *//** * Yield from the current protothread. * * This function will yield the protothread, thereby allowing other * processing to take place in the system. * * \param pt A pointer to the protothread control structure. * * \hideinitializer */#define PT_YIELD(pt)				\  do {						\    PT_YIELD_FLAG = 0;				\    LC_SET((pt)->lc);				\    if(PT_YIELD_FLAG == 0) {			\      return PT_YIELDED;			\    }						\  } while(0)/** * \brief      Yield from the protothread until a condition occurs. * \param pt   A pointer to the protothread control structure. * \param cond The condition. * *             This function will yield the protothread, until the *             specified condition evaluates to true. * * * \hideinitializer */#define PT_YIELD_UNTIL(pt, cond)		\  do {						\    PT_YIELD_FLAG = 0;				\    LC_SET((pt)->lc);				\    if((PT_YIELD_FLAG == 0) || !(cond)) {	\      return PT_YIELDED;			\    }						\  } while(0)/** @} */#endif /* __PT_H__ *//** @} */