/*

 * 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 javax.imageio.plugins.tiff.BaselineTIFFTagSet;

import java.io.IOException;

import java.util.zip.Deflater;

import javax.imageio.ImageWriteParam;

/**

 * Compressor superclass for Deflate and ZLib compression.

 */

public class TIFFDeflater extends TIFFCompressor {

    Deflater deflater;

    int predictor;

    public TIFFDeflater(String compressionType,

                        int compressionTagValue,

                        ImageWriteParam param,

                        int predictorValue) {

        super(compressionType, compressionTagValue, true);

        this.predictor = predictorValue;

        // Set the deflate level.

        int deflateLevel;

        if(param != null &&

           param.getCompressionMode() == ImageWriteParam.MODE_EXPLICIT) {

            float quality = param.getCompressionQuality();

            deflateLevel = (int)(1 + 8*quality);

        } else {

            deflateLevel = Deflater.DEFAULT_COMPRESSION;

        }

        this.deflater = new Deflater(deflateLevel);

    }

    public int encode(byte[] b, int off,

                      int width, int height,

                      int[] bitsPerSample,

                      int scanlineStride) throws IOException {

        int inputSize = height*scanlineStride;

        int blocks = (inputSize + 32767)/32768;

        // Worst case for Zlib deflate is input size + 5 bytes per 32k

        // block, plus 6 header bytes

        byte[] compData = new byte[inputSize + 5*blocks + 6];

        int numCompressedBytes = 0;

        if(predictor == BaselineTIFFTagSet.PREDICTOR_HORIZONTAL_DIFFERENCING) {

            int samplesPerPixel = bitsPerSample.length;

            int bitsPerPixel = 0;

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

                bitsPerPixel += bitsPerSample[i];

            }

            int bytesPerRow = (bitsPerPixel*width + 7)/8;

            byte[] rowBuf = new byte[bytesPerRow];

            int maxRow = height - 1;

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

                // Cannot modify b[] in place as it might be a data

                // array from the image being written so make a copy.

                System.arraycopy(b, off, rowBuf, 0, bytesPerRow);

                for(int j = bytesPerRow - 1; j >= samplesPerPixel; j--) {

                    rowBuf[j] -= rowBuf[j - samplesPerPixel];

                }

                deflater.setInput(rowBuf);

                if(i == maxRow) {

                    deflater.finish();

                }

                int numBytes = 0;

                while((numBytes = deflater.deflate(compData,

                                                   numCompressedBytes,

                                                   compData.length -

                                                   numCompressedBytes)) != 0) {

                    numCompressedBytes += numBytes;

                }

                off += scanlineStride;

            }

        } else {

            deflater.setInput(b, off, height*scanlineStride);

            deflater.finish();

            numCompressedBytes = deflater.deflate(compData);

        }

        deflater.reset();

        stream.write(compData, 0, numCompressedBytes);

        return numCompressedBytes;

    }

}