de.schlichtherle.truezip.zip.DefaultExtraField Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of truezip-driver-zip Show documentation

The file system driver family for ZIP and related archive file types. Add the JAR artifact of this module to the run time class path to make its file system drivers available for service location in the client API modules.

There is a newer version: 7.7.10

Show newest version

/*
 * Copyright (C) 2005-2013 Schlichtherle IT Services.
 * All rights reserved. Use is subject to license terms.
 */
package de.schlichtherle.truezip.zip;

import static java.lang.System.arraycopy;
import javax.annotation.CheckForNull;
import javax.annotation.concurrent.NotThreadSafe;

/**
 * Default implementation for an Extra Field in a Local or Central Header of a
 * ZIP file.
 *
 * @author Christian Schlichtherle
 */
@NotThreadSafe
final class DefaultExtraField extends ExtraField {

    private final short headerId;
    private @CheckForNull byte[] data;

    /**
     * Constructs a new extra field.
     *
     * @param  headerId an unsigned short integer (two bytes) indicating the
     *         type of the extra field.
     */
    DefaultExtraField(final int headerId) {
        assert UShort.check(headerId);
        this.headerId = (short) headerId;
    }

    @Override
    int getHeaderId() {
        return headerId & UShort.MAX_VALUE;
    }

    @Override
    int getDataSize() {
        final byte[] data = this.data;
        return null != data ? data.length : 0;
    }

    @Override
    void readFrom(final byte[] buf, final int off, final int len) {
        assert UShort.check(len);
        arraycopy(buf, off, this.data = new byte[len], 0, len);
    }

    @Override
    void writeTo(byte[] buf, int off) {
        final byte[] src = this.data;
        if (null != src) arraycopy(src, 0, buf, off, src.length);
    }
}