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/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* CMetrics
* ========
* Copyright 2021-2022 The CMetrics Authors
*
* 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 <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <cmetrics/cmt_atomic.h>
pthread_mutex_t atomic_operation_lock;
static int atomic_operation_system_initialized = 0;
/* TODO: Determne if we want to keep this backend as well as how / if we want to handle
* pthread_mutex_unlock errors (investigate and understand what could cause them),
* as well as pthread_mutex_lock (determine if we want to apply some sort of retry
* limit there as well)
*
*/
inline int cmt_atomic_initialize()
{
int result;
if (0 == atomic_operation_system_initialized) {
result = pthread_mutex_init(&atomic_operation_lock, NULL);
if (0 != result) {
return 1;
}
atomic_operation_system_initialized = 1;
}
return 0;
}
inline int cmt_atomic_compare_exchange(uint64_t *storage,
uint64_t old_value, uint64_t new_value)
{
int result;
if (0 == atomic_operation_system_initialized) {
printf("CMT ATOMIC : Atomic operation backend not initalized\n");
exit(1);
}
result = pthread_mutex_lock(&atomic_operation_lock);
if (result != 0) {
return 0;
}
if (*storage == old_value) {
*storage = new_value;
result = 1;
}
else {
result = 0;
}
pthread_mutex_unlock(&atomic_operation_lock);
return result;
}
inline void cmt_atomic_store(uint64_t *storage, uint64_t new_value)
{
int result;
if (0 == atomic_operation_system_initialized) {
printf("CMT ATOMIC : Atomic operation backend not initalized\n");
exit(1);
}
result = pthread_mutex_lock(&atomic_operation_lock);
if (result != 0) {
/* We should notify the user somehow */
}
*storage = new_value;
pthread_mutex_unlock(&atomic_operation_lock);
}
inline uint64_t cmt_atomic_load(uint64_t *storage)
{
int result;
uint64_t retval;
if (0 == atomic_operation_system_initialized) {
printf("CMT ATOMIC : Atomic operation backend not initalized\n");
exit(1);
}
result = pthread_mutex_lock(&atomic_operation_lock);
if (result != 0) {
/* We should notify the user somehow */
}
retval = *storage;
pthread_mutex_unlock(&atomic_operation_lock);
return retval;
}
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