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 *  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
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 *  Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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package java.lang.foreign;

import java.util.Objects;
import java.util.Optional;

/**
 * A padding layout. A padding layout specifies the size of extra space which is typically not accessed by applications,
 * and is typically used for aligning member layouts around word boundaries.
 *
 * @implSpec
 * This class is immutable, thread-safe and <a href="{@docRoot}/java.base/java/lang/doc-files/ValueBased.html">value-based</a>.
 */
/* package-private */ final class PaddingLayout extends AbstractLayout implements MemoryLayout {

    PaddingLayout(long size) {
        this(size, 1, Optional.empty());
    }

    PaddingLayout(long size, long alignment, Optional<String> name) {
        super(size, alignment, name);
    }

    @Override
    public String toString() {
        return decorateLayoutString("x" + bitSize());
    }

    @Override
    public boolean equals(Object other) {
        if (this == other) {
            return true;
        }
        if (!super.equals(other)) {
            return false;
        }
        if (!(other instanceof PaddingLayout p)) {
            return false;
        }
        return bitSize() == p.bitSize();
    }

    @Override
    public int hashCode() {
        return Objects.hash(super.hashCode(), bitSize());
    }

    @Override
    PaddingLayout dup(long alignment, Optional<String> name) {
        return new PaddingLayout(bitSize(), alignment, name);
    }

    @Override
    public boolean hasNaturalAlignment() {
        return true;
    }

    //hack: the declarations below are to make javadoc happy; we could have used generics in AbstractLayout
    //but that causes issues with javadoc, see JDK-8224052

    /**
     * {@inheritDoc}
     */
    @Override
    public PaddingLayout withName(String name) {
        return (PaddingLayout)super.withName(name);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public PaddingLayout withBitAlignment(long alignmentBits) {
        return (PaddingLayout)super.withBitAlignment(alignmentBits);
    }
}