/*

 * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.

 * 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

 * questions.

*/

package jdk.internal.jimage;

import java.nio.ByteOrder;

import java.util.ArrayList;

import java.util.List;

public final class BasicImageWriter {

    public static final String IMAGE_EXT = ".jimage";

    public static final String BOOT_NAME = "bootmodules";

    public static final String BOOT_IMAGE_NAME = BOOT_NAME + IMAGE_EXT;

    private ByteOrder byteOrder;

    private ImageStringsWriter strings;

    private int length;

    private int[] redirect;

    private ImageLocationWriter[] locations;

    private List<ImageLocationWriter> input;

    private ImageStream headerStream;

    private ImageStream redirectStream;

    private ImageStream locationOffsetStream;

    private ImageStream locationStream;

    private ImageStream allIndexStream;

    public BasicImageWriter() {

        this(ByteOrder.nativeOrder());

    }

    public BasicImageWriter(ByteOrder byteOrder) {

        this.byteOrder = byteOrder;

        this.input = new ArrayList<>();

        this.strings = new ImageStringsWriter();

        this.headerStream = new ImageStream(byteOrder);

        this.redirectStream = new ImageStream(byteOrder);

        this.locationOffsetStream = new ImageStream(byteOrder);

        this.locationStream = new ImageStream(byteOrder);

        this.allIndexStream = new ImageStream(byteOrder);

    }

    public ByteOrder getByteOrder() {

        return byteOrder;

    }

    public int addString(String string) {

        return addString(new UTF8String(string));

    }

    public int addString(UTF8String string) {

        return strings.add(string);

    }

    public String getString(int offset) {

        UTF8String utf8 = strings.get(offset);

        return utf8 != null? utf8.toString() : null;

    }

    public void addLocation(String fullname, long contentOffset,

            long compressedSize, long uncompressedSize) {

        ImageLocationWriter location =

                ImageLocationWriter.newLocation(new UTF8String(fullname), strings,

                        contentOffset, compressedSize, uncompressedSize);

        input.add(location);

        length++;

    }

    ImageLocationWriter[] getLocations() {

        return locations;

    }

    int getLocationsCount() {

        return input.size();

    }

    private void generatePerfectHash() {

        PerfectHashBuilder<ImageLocationWriter> builder =

            new PerfectHashBuilder<>(

                new PerfectHashBuilder.Entry<ImageLocationWriter>().getClass(),

                new PerfectHashBuilder.Bucket<ImageLocationWriter>().getClass());

        input.forEach((location) -> {

            builder.put(location.getFullName(), location);

        });

        builder.generate();

        length = builder.getCount();

        redirect = builder.getRedirect();

        PerfectHashBuilder.Entry<ImageLocationWriter>[] order = builder.getOrder();

        locations = new ImageLocationWriter[length];

        for (int i = 0; i < length; i++) {

            locations[i] = order[i].getValue();

        }

    }

    private void prepareStringBytes() {

        strings.getStream().align(2);

    }

    private void prepareRedirectBytes() {

        for (int i = 0; i < length; i++) {

            redirectStream.putInt(redirect[i]);

        }

    }

    private void prepareLocationBytes() {

        // Reserve location offset zero for empty locations

        locationStream.put(ImageLocationWriter.ATTRIBUTE_END << 3);

        for (int i = 0; i < length; i++) {

            ImageLocationWriter location = locations[i];

            if (location != null) {

                location.writeTo(locationStream);

            }

        }

        locationStream.align(2);

    }

    private void prepareOffsetBytes() {

        for (int i = 0; i < length; i++) {

            ImageLocationWriter location = locations[i];

            int offset = location != null ? location.getLocationOffset() : 0;

            locationOffsetStream.putInt(offset);

        }

    }

    private void prepareHeaderBytes() {

        ImageHeader header = new ImageHeader(input.size(), length,

                locationStream.getSize(), strings.getSize());

        header.writeTo(headerStream);

    }

    private void prepareTableBytes() {

        allIndexStream.put(headerStream);

        allIndexStream.put(redirectStream);

        allIndexStream.put(locationOffsetStream);

        allIndexStream.put(locationStream);

        allIndexStream.put(strings.getStream());

    }

    public byte[] getBytes() {

        if (allIndexStream.getSize() == 0) {

            generatePerfectHash();

            prepareStringBytes();

            prepareRedirectBytes();

            prepareLocationBytes();

            prepareOffsetBytes();

            prepareHeaderBytes();

            prepareTableBytes();

        }

        return allIndexStream.toArray();

    }

    ImageLocationWriter find(UTF8String key) {

        int index = redirect[key.hashCode() % length];

        if (index < 0) {

            index = -index - 1;

        } else {

            index = key.hashCode(index) % length;

        }

        return locations[index];

    }

}