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Coin / src / threads / barrier.cpp

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#include <Inventor/C/threads/barrier.h>

#include <stdlib.h>
#include <stdio.h>
#include <assert.h>

#include <Inventor/C/threads/mutex.h>
#include <Inventor/C/threads/condvar.h>

#include "threads/barrierp.h"

/* ********************************************************************** */

/*
*/

cc_barrier *
cc_barrier_construct(unsigned int count)
{
  cc_barrier * barrier;
  barrier = (cc_barrier *) malloc(sizeof(cc_barrier));
  barrier->numthreads = count;
  barrier->counter = 0;
  barrier->mutex = cc_mutex_construct();
  barrier->condvar = cc_condvar_construct();
  return barrier;
}

/*
*/

void
cc_barrier_destruct(cc_barrier * barrier)
{
  assert(barrier != NULL);
         
  cc_condvar_wake_all(barrier->condvar);
  cc_condvar_destruct(barrier->condvar);
  cc_mutex_destruct(barrier->mutex);
  free(barrier);
}

/*
*/

int
cc_barrier_enter(cc_barrier * barrier)
{
  assert(barrier != NULL);
  cc_mutex_lock(barrier->mutex);
  barrier->counter++;
  if (barrier->counter == barrier->numthreads) {
    barrier->counter = 0;
    cc_condvar_wake_all(barrier->condvar);
    cc_mutex_unlock(barrier->mutex);
    return 1;
  }
  else {
    cc_condvar_wait(barrier->condvar, barrier->mutex);
    cc_mutex_unlock(barrier->mutex);
  }
  return 0;
}

/* ********************************************************************** */

/*!
  \class SbBarrier Inventor/threads/SbBarrier.h
  \brief The SbBarrier class implements the "barrier" multi-thread
  synchronization technique.
  \ingroup threads

  A barrier is a synchronization mechanism that is used for blocking
  threads as they enter the barrier until a given number of threads are
  blocked, at which point all the threads are released again.
*/

/*!
  \fn SbBarrier::SbBarrier(unsigned int count)

  Constructor.  The SbBarrier will be set for \c count number of
  threads.
*/

/*!
  \fn SbBarrier::~SbBarrier(void)

  Destructor.
*/

/*!
  \fn int SbBarrier::enter(void)

  This method blocks the calling thread on this barrier.  It returns
  when the given number of threads have been blocked. 1 is
  returned if the caller was the last thread to enter the barrier,
  0 otherwise.
*/

/* ********************************************************************** */