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