/*

 * Copyright (c) 2005, 2015, 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

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 */

package com.sun.imageio.plugins.tiff;

import java.io.IOException;

public class TIFFPackBitsUtil {

    byte[] dstData = new byte[8192];

    int dstIndex = 0;

    public TIFFPackBitsUtil() {

    }

    private void ensureCapacity(int bytesToAdd) {

        if (dstIndex + bytesToAdd > dstData.length) {

            byte[] newDstData = new byte[Math.max((int)(dstData.length*1.2f),

                                                  dstIndex + bytesToAdd)];

            System.arraycopy(dstData, 0, newDstData, 0, dstData.length);

            dstData = newDstData;

        }

    }

    public byte[] decode(byte[] srcData) throws IOException {

        int inIndex = 0;

        while (inIndex < srcData.length) {

            byte b = srcData[inIndex++];

            if (b >= 0 && b <= 127) {

                // Literal run packet

                ensureCapacity(b + 1);

                for (int i = 0; i < b + 1; i++) {

                    dstData[dstIndex++] = srcData[inIndex++];

                }

            } else if (b <= -1 && b >= -127) {

                // 2-byte encoded run packet

                byte repeat = srcData[inIndex++];

                ensureCapacity(-b + 1);

                for (int i = 0; i < (-b + 1); i++) {

                    dstData[dstIndex++] = repeat;

                }

            } else {

                // No-op packet, do nothing

                ++inIndex;

            }

        }

        byte[] newDstData = new byte[dstIndex];

        System.arraycopy(dstData, 0, newDstData, 0, dstIndex);

        return newDstData;

    }

}