p99_notifier.h

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/* This may look like nonsense, but it really is -*- mode: C; coding: utf-8 -*- */
/*                                                                              */
/* Except for parts copied from previous work and as explicitly stated below,   */
/* the author and copyright holder for this work is                             */
/* (C) copyright  2012-2014 Jens Gustedt, INRIA, France                         */
/*                                                                              */
/* This file is free software; it is part of the P99 project.                   */
/*                                                                              */
/* Licensed under the Apache License, Version 2.0 (the "License");              */
/* you may not use this file except in compliance with the License.             */
/* You may obtain a copy of the License at                                      */
/*                                                                              */
/*     http://www.apache.org/licenses/LICENSE-2.0                               */
/*                                                                              */
/* Unless required by applicable law or agreed to in writing, software          */
/* distributed under the License is distributed on an "AS IS" BASIS,            */
/* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.     */
/* See the License for the specific language governing permissions and          */
/* limitations under the License.                                               */
/*                                                                              */
#ifndef P99_NOTIFIER_H
#define P99_NOTIFIER_H
 
#include "p99_futex.h"
 
#ifdef P00_DOXYGEN
struct p99_notifier { };
#else
typedef p99_futex p99_notifier;
#endif
 
P99_DEFARG_DOCU(p99_notifier_init)
p99_inline
p99_notifier* p99_notifier_init(p99_notifier* p00_n, unsigned p00_v) {
  return p99_futex_init(p00_n, p00_v);
}
 
#ifndef DOXYGEN
#define p99_notifier_init(...) P99_CALL_DEFARG(p99_notifier_init, 2, __VA_ARGS__)
#define p99_notifier_init_defarg_1() 0U
#endif
 
 
p99_inline
void p99_notifier_destroy(p99_notifier* p00_n) {
  p99_futex_destroy(p00_n);
}
 
P99_DEFARG_DOCU(p99_notifier_block)
P00_FUTEX_INLINE(p99_notifier_block)
void p99_notifier_block(p99_notifier volatile* p00_n, unsigned p00_v) {
  P99_FUTEX_COMPARE_EXCHANGE(p00_n, p00_act,
                             /* wait for p00_v */
                             (p00_act == p00_v),
                             /* never update */
                             p00_act,
                             /* never wakeup others */
                             0u, 0u);
}
 
#ifndef DOXYGEN
#define p99_notifier_block(...) P99_CALL_DEFARG(p99_notifier_block, 2, __VA_ARGS__)
#define p99_notifier_block_defarg_1() 1U
#endif
 
# define P99_NOTIFIER_INITIALIZER P99_FUTEX_INITIALIZER(0u)
 
p99_inline
unsigned p99_notifier_load(p99_notifier volatile* p00_n) {
  return p99_futex_load(p00_n);
}
 
P99_DEFARG_DOCU(p99_notifier_set)
P99_SETJMP_INLINE(p99_notifier_set)
void p99_notifier_set(p99_notifier volatile* p00_n, unsigned p00_v) {
  if (p00_v)
    P99_FUTEX_COMPARE_EXCHANGE(p00_n,
                               // name of the local variable
                               p00_l,
                               // never wait
                               true,
                               // the new value
                               p00_v,
                               // no enforced wake up
                               0u,
                               // wake up all waiters only if there was a change
                               ((p00_l != p00_v) ? P99_FUTEX_MAX_WAITERS : 0u));
  else
    P99_FUTEX_COMPARE_EXCHANGE(p00_n,
                               // name of the local variable
                               p00_l,
                               // never wait
                               true,
                               // the new value
                               p00_v,
                               // never wake up anybody
                               0u, 0u);
}
 
#ifndef DOXYGEN
#define p99_notifier_set(...) P99_CALL_DEFARG(p99_notifier_set, 2, __VA_ARGS__)
#define p99_notifier_set_defarg_1() 1U
#endif
 
p99_inline
void p99_notifier_unset(p99_notifier volatile* p00_n) {
  p99_futex_exchange(p00_n, 0u, 1u, 0u, 0u, 0u);
}
 
#endif