/*
 * Copyright (c) 2017 Cisco and/or its affiliates.
 * 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 <config.h>

#include <parc/algol/parc_Object.h>
#include <parc/algol/parc_DisplayIndented.h>

#include <parc/concurrent/parc_AtomicUint32.h>

struct PARCAtomicUint32 {
    uint32_t value;
#ifdef PARCLibrary_DISABLE_ATOMICS
    pthread_mutex_t mutex;
#endif
};

static void
_parcAtomicUint32_Finalize(PARCAtomicUint32 **instancePtr)
{
    parcAssertNotNull(instancePtr, "Parameter must be a non-null pointer to a PARCAtomicUint32 pointer.");

    parcAtomicUint32_OptionalAssertValid((*instancePtr));

    /* cleanup the instance fields here */
}

parcObject_ImplementAcquire(parcAtomicUint32, PARCAtomicUint32);

parcObject_ImplementRelease(parcAtomicUint32, PARCAtomicUint32);

parcObject_ExtendPARCObject(PARCAtomicUint32, _parcAtomicUint32_Finalize, parcAtomicUint32_Copy, NULL, parcAtomicUint32_Equals, parcAtomicUint32_Compare, parcAtomicUint32_HashCode, NULL);


void
parcAtomicUint32_AssertValid(const PARCAtomicUint32 *instance)
{
    parcAssertTrue(parcAtomicUint32_IsValid(instance),
               "PARCAtomicUint32 is not valid.");
}

PARCAtomicUint32 *
parcAtomicUint32_Create(uint32_t value)
{
    PARCAtomicUint32 *result = parcObject_CreateAndClearInstance(PARCAtomicUint32);

#ifdef PARCLibrary_DISABLE_ATOMICS
    pthread_mutex_init(&result->mutex, NULL);
    result->value = value;
#else
    *result = value;
#endif

    return result;
}

int
parcAtomicUint32_Compare(const PARCAtomicUint32 *instance, const PARCAtomicUint32 *other)
{
    int32_t comparison = parcAtomicUint32_GetValue(instance) - parcAtomicUint32_GetValue(other);

    int result = 0;
    if (comparison < 0) {
        result = -1;
    } else if (comparison > 0) {
        result = 1;
    }

    return result;
}

PARCAtomicUint32 *
parcAtomicUint32_Copy(const PARCAtomicUint32 *original)
{
    PARCAtomicUint32 *result = parcAtomicUint32_Create(parcAtomicUint32_GetValue(original));

    return result;
}

bool
parcAtomicUint32_Equals(const PARCAtomicUint32 *x, const PARCAtomicUint32 *y)
{
    bool result = false;

    result = parcAtomicUint32_GetValue(x) == parcAtomicUint32_GetValue(y);

    return result;
}

PARCHashCode
parcAtomicUint32_HashCode(const PARCAtomicUint32 *instance)
{
    PARCHashCode result = (PARCHashCode) parcAtomicUint32_GetValue(instance);

    return result;
}

bool
parcAtomicUint32_IsValid(const PARCAtomicUint32 *instance)
{
    bool result = false;

    if (instance != NULL) {
        result = true;
    }

    return result;
}

uint32_t
parcAtomicUint32_GetValue(const PARCAtomicUint32 *instance)
{
#ifdef PARCLibrary_DISABLE_ATOMICS
    return instance->value;
#else
    return *instance;
#endif
}

uint32_t
parcAtomicUint32_AddImpl(PARCAtomicUint32 *value, uint32_t addend)
{
#ifdef PARCLibrary_DISABLE_ATOMICS
    pthread_mutex_lock(&value->mutex);
    value->value += addend;
    uint32_t result = value->value;
    pthread_mutex_unlock(&value->mutex);
    return result;
#else
    return __sync_add_and_fetch(value, addend);
#endif
}

uint32_t
parcAtomicUint32_SubtractImpl(PARCAtomicUint32 *value, uint32_t subtrahend)
{
#ifdef PARCLibrary_DISABLE_ATOMICS
    pthread_mutex_lock(&value->mutex);
    value->value -= subtrahend;
    uint32_t result = value->value;
    pthread_mutex_unlock(&value->mutex);
    return result;
#else
    return __sync_sub_and_fetch(value, subtrahend);
#endif
}

bool
parcAtomicUint32_CompareAndSwapImpl(PARCAtomicUint32 *value, uint32_t predicate, uint32_t newValue)
{
    bool result = false;
#ifdef PARCLibrary_DISABLE_ATOMICS
    pthread_mutex_lock(&value->mutex);
    if (value->value == predicate) {
        value->value = newValue;
        result = true;
    }
    pthread_mutex_unlock(&value->mutex);
    return result;
#else
    result = __sync_bool_compare_and_swap(value, predicate, newValue);
#endif
    return result;
}