/*

 * This file is part of libbluray

 * Copyright (C) 2013  Petri Hintukainen <phintuka@users.sourceforge.net>

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library. If not, see

 * <http://www.gnu.org/licenses/>.

 */

#if HAVE_CONFIG_H

#include "config.h"

#endif

#include "refcnt.h"

#include "logging.h"

#include "mutex.h"

#include <stdlib.h>

#include <string.h>

/*

 *

 */

typedef struct {

  BD_MUTEX mutex;   /* initialized only if counted == 1 */

  int      count;   /* reference count */

  unsigned counted; /* 1 if this object is ref-counted */

} BD_REFCNT;

/*

 *

 */

void bd_refcnt_inc(const void *obj)

{

    if (!obj) {

        return;

    }

    BD_REFCNT *ref = &(((BD_REFCNT *)(intptr_t)obj)[-1]);

    if (!ref->counted) {

        bd_mutex_init(&ref->mutex);

        ref->counted = 1;

        ref->count = 2;

        return;

    }

    bd_mutex_lock(&ref->mutex);

    ++ref->count;

    bd_mutex_unlock(&ref->mutex);

}

void bd_refcnt_dec(const void *obj)

{

    if (!obj) {

        return;

    }

    BD_REFCNT *ref = &((BD_REFCNT *)(intptr_t)obj)[-1];

    if (ref->counted) {

        int count;

        bd_mutex_lock(&ref->mutex);

        count = --ref->count;

        bd_mutex_unlock(&ref->mutex);

        if (count > 0) {

            return;

        }

        bd_mutex_destroy(&ref->mutex);

    }

    free(ref);

}

void *refcnt_realloc(void *obj, size_t sz)

{

    sz += sizeof(BD_REFCNT);

    if (obj) {

        if (((BD_REFCNT *)obj)[-1].counted) {

            bd_refcnt_dec(obj);

            BD_DEBUG(DBG_CRIT, "refcnt_realloc(): realloc locked object !\n");

            obj = NULL;

        }

    }

    if (obj) {

        obj = realloc(&((BD_REFCNT *)obj)[-1], sz);

        if (!obj) {

            return NULL;

        }

    } else {

        obj = realloc(NULL, sz);

        if (!obj) {

            return NULL;

        }

        memset(obj, 0, sizeof(BD_REFCNT));

    }

    return &((BD_REFCNT *)obj)[1];

}