/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

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

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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 General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

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

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

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 */

package sun.java2d.marlin;

import static sun.java2d.marlin.MarlinConst.LOG_UNSAFE_MALLOC;

import jdk.internal.misc.Unsafe;

import jdk.internal.ref.CleanerFactory;

/**

 *

 * @author bourgesl

 */

final class OffHeapArray  {

    // unsafe reference

    static final Unsafe UNSAFE;

    // size of int / float

    static final int SIZE_INT;

    static {

        UNSAFE   = Unsafe.getUnsafe();

        SIZE_INT = Unsafe.ARRAY_INT_INDEX_SCALE;

    }

    /* members */

    long address;

    long length;

    int  used;

    OffHeapArray(final Object parent, final long len) {

        // note: may throw OOME:

        this.address = UNSAFE.allocateMemory(len);

        this.length  = len;

        this.used    = 0;

        if (LOG_UNSAFE_MALLOC) {

            MarlinUtils.logInfo(System.currentTimeMillis()

                                + ": OffHeapArray.allocateMemory =   "

                                + len + " to addr = " + this.address);

        }

        // Register a cleaning function to ensure freeing off-heap memory:

        CleanerFactory.cleaner().register(parent, () -> this.free());

    }

    /*

     * As realloc may change the address, updating address is MANDATORY

     * @param len new array length

     * @throws OutOfMemoryError if the allocation is refused by the system

     */

    void resize(final long len) {

        // note: may throw OOME:

        this.address = UNSAFE.reallocateMemory(address, len);

        this.length  = len;

        if (LOG_UNSAFE_MALLOC) {

            MarlinUtils.logInfo(System.currentTimeMillis()

                                + ": OffHeapArray.reallocateMemory = "

                                + len + " to addr = " + this.address);

        }

    }

    void free() {

        UNSAFE.freeMemory(this.address);

        if (LOG_UNSAFE_MALLOC) {

            MarlinUtils.logInfo(System.currentTimeMillis()

                                + ": OffHeapArray.freeMemory =       "

                                + this.length

                                + " at addr = " + this.address);

        }

    }

    void fill(final byte val) {

        UNSAFE.setMemory(this.address, this.length, val);

    }

}