/*
 * Copyright © 2018, VideoLAN and dav1d authors
 * Copyright © 2018, Two Orioles, LLC
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "config.h"

#include "common/mem.h"

#include "src/ref.h"

static void default_free_callback(const uint8_t *const data, void *const user_data) {
    assert(data == user_data);
    dav1d_free_aligned(user_data);
}

Dav1dRef *dav1d_ref_create(const size_t size) {
    Dav1dRef *res;
    void *data = dav1d_alloc_aligned(size, 32);
    if (!data) {
        return NULL;
    }

    res = dav1d_ref_wrap(data, default_free_callback, data);
    if (!res) {
        dav1d_free_aligned(data);
    } else {
        res->data = data;
    }

    return res;
}

Dav1dRef *dav1d_ref_wrap(const uint8_t *const ptr,
                         void (*free_callback)(const uint8_t *data, void *user_data),
                         void *user_data)
{
    Dav1dRef *res = malloc(sizeof(Dav1dRef));
    if (!res) return NULL;

    res->data = NULL;
    res->const_data = ptr;
    atomic_init(&res->ref_cnt, 1);
    res->free_callback = free_callback;
    res->user_data = user_data;

    return res;
}

void dav1d_ref_inc(Dav1dRef *const ref) {
    atomic_fetch_add(&ref->ref_cnt, 1);
}

void dav1d_ref_dec(Dav1dRef **const pref) {
    assert(pref != NULL);

    Dav1dRef *const ref = *pref;
    if (!ref) return;

    if (atomic_fetch_sub(&ref->ref_cnt, 1) == 1) {
        ref->free_callback(ref->const_data, ref->user_data);
        free(ref);
    }
    *pref = NULL;
}

int dav1d_ref_is_writable(Dav1dRef *const ref) {
    return atomic_load(&ref->ref_cnt) == 1 && ref->data;
}