/*
 * Copyright 2014 MongoDB, Inc.
 *
 * 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.
 */


#include "bson-atomic.h"


/*
 * We should only ever hit these on non-Windows systems, for which we require
 * pthread support. Therefore, we will avoid making a threading portability
 * for threads here and just use pthreads directly.
 */


#ifdef __BSON_NEED_BARRIER
#include <pthread.h>
static pthread_mutex_t gBarrier = PTHREAD_MUTEX_INITIALIZER;
void
bson_memory_barrier (void)
{
   pthread_mutex_lock (&gBarrier);
   pthread_mutex_unlock (&gBarrier);
}
#endif


#ifdef __BSON_NEED_ATOMIC_32
#include <pthread.h>
static pthread_mutex_t gSync32 = PTHREAD_MUTEX_INITIALIZER;
int32_t
bson_atomic_int_add (volatile int32_t *p, int32_t n)
{
   int ret;

   pthread_mutex_lock (&gSync32);
   *p += n;
   ret = *p;
   pthread_mutex_unlock (&gSync32);

   return ret;
}
#endif


#ifdef __BSON_NEED_ATOMIC_64
#include <pthread.h>
static pthread_mutex_t gSync64 = PTHREAD_MUTEX_INITIALIZER;
int64_t
bson_atomic_int64_add (volatile int64_t *p, int64_t n)
{
   int64_t ret;

   pthread_mutex_lock (&gSync64);
   *p += n;
   ret = *p;
   pthread_mutex_unlock (&gSync64);

   return ret;
}
#endif


/*
 * The logic in the header is such that __BSON_NEED_ATOMIC_WINDOWS should only
 * be defined if neither __BSON_NEED_ATOMIC_32 nor __BSON_NEED_ATOMIC_64 are.
 */


#ifdef __BSON_NEED_ATOMIC_WINDOWS
int32_t
bson_atomic_int_add (volatile int32_t *p, int32_t n)
{
   return InterlockedExchangeAdd (p, n) + n;
}


int64_t
bson_atomic_int64_add (volatile int64_t *p, int64_t n)
{
   return InterlockedExchangeAdd (p, n) + n;
}
#endif
