pt.h

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/*
 * 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>
 *
 */

#ifndef PT_H_
#define PT_H_

#ifndef LC_ADDRLABELS_H_
#define LC_ADDRLABELS_H_

typedef void * lc_t;

#define LC_INIT(s) s = NULL


#define LC_RESUME(s)                            \
  do {                                          \
    if(s != NULL) {                             \
      goto *s;                                  \
    }                                           \
  } while(0)

#define LC_SET(s)                               \
  do { ({ __label__ resume; resume: (s) = &&resume; }); }while(0)

#define LC_END(s)

#endif /* LC_ADDRLABELS_H_ */

struct pt {
  lc_t lc;
};

#define PT_WAITING 0
#define PT_YIELDED 1
#define PT_EXITED  2
#define PT_ENDED   3

#define PT_INIT(pt)   LC_INIT((pt)->lc)

#define PT_THREAD(name_args) char name_args

#define PT_BEGIN(pt) { char PT_YIELD_FLAG = 1; if (PT_YIELD_FLAG) {;} LC_RESUME((pt)->lc)

#define PT_END(pt) LC_END((pt)->lc); PT_YIELD_FLAG = 0; \
                   PT_INIT(pt); return PT_ENDED; }

#define PT_WAIT_UNTIL(pt, condition)            \
  do {                      \
    LC_SET((pt)->lc);               \
    if(!(condition)) {              \
      return PT_WAITING;            \
    }                       \
  } while(0)

#define PT_WAIT_WHILE(pt, cond)  PT_WAIT_UNTIL((pt), !(cond))

#define PT_WAIT_THREAD(pt, thread) PT_WAIT_WHILE((pt), PT_SCHEDULE(thread))

#define PT_SPAWN(pt, child, thread)     \
  do {                      \
    PT_INIT((child));               \
    PT_WAIT_THREAD((pt), (thread));     \
  } while(0)

#define PT_RESTART(pt)              \
  do {                      \
    PT_INIT(pt);                \
    return PT_WAITING;          \
  } while(0)

#define PT_EXIT(pt)             \
  do {                      \
    PT_INIT(pt);                \
    return PT_EXITED;           \
  } while(0)

#define PT_SCHEDULE(f) ((f) < PT_EXITED)

#define PT_YIELD(pt)                \
  do {                      \
    PT_YIELD_FLAG = 0;              \
    LC_SET((pt)->lc);               \
    if(PT_YIELD_FLAG == 0) {            \
      return PT_YIELDED;            \
    }                       \
  } while(0)

#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_ */