ProtoThreads多线程实例 - - Powered by Discuz!

/*
* Copyright (c) 2004-2006, 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.
*
* Author: Adam Dunkels <adam@sics.se>
*
* $Id: pt.h,v 1.6 2006/06/03 11:29:43 adam Exp $
*/
/**
* \addtogroup pt
* @{
*/
/**
* \file
* Protothreads implementation.
* \author
* Adam Dunkels <adam@sics.se>
*
*/
#ifndef __PT_H__
#define __PT_H__
#include "lc.inc"
struct pt {
lc_t lc;
};
#define PT_WAITING 0
#define PT_EXITED 1
#define PT_ENDED 2
#define PT_YIELDED 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 function.
*
* This macro is used to declare a protothread function. Protothreads
* function should be declared with this macro, but can also be
* declared as regular C functions that return an integer value.
*
* \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_WAITING)
/** @} */
/**
* \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__ */
/** @} */

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