1 /*

     2  * Copyright (c) 2005, 2015, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.  Oracle designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Oracle in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

    17  * You should have received a copy of the GNU General Public License version

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    25 package com.sun.imageio.plugins.tiff;

    26 

    27 import javax.imageio.plugins.tiff.BaselineTIFFTagSet;

    28 import java.io.IOException;

    29 import java.util.zip.Deflater;

    30 import javax.imageio.ImageWriteParam;

    31 

    32 /**

    33  * Compressor superclass for Deflate and ZLib compression.

    34  */

    35 public class TIFFDeflater extends TIFFCompressor {

    36 

    37     Deflater deflater;

    38     int predictor;

    39 

    40     public TIFFDeflater(String compressionType,

    41                         int compressionTagValue,

    42                         ImageWriteParam param,

    43                         int predictorValue) {

    44         super(compressionType, compressionTagValue, true);

    45 

    46         this.predictor = predictorValue;

    47 

    48         // Set the deflate level.

    49         int deflateLevel;

    50         if(param != null &&

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

    52             float quality = param.getCompressionQuality();

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

    54         } else {

    55             deflateLevel = Deflater.DEFAULT_COMPRESSION;

    56         }

    57 

    58         this.deflater = new Deflater(deflateLevel);

    59     }

    60 

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

    62                       int width, int height,

    63                       int[] bitsPerSample,

    64                       int scanlineStride) throws IOException {

    65 

    66         int inputSize = height*scanlineStride;

    67         int blocks = (inputSize + 32767)/32768;

    68 

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

    70         // block, plus 6 header bytes

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

    72 

    73         int numCompressedBytes = 0;

    74         if(predictor == BaselineTIFFTagSet.PREDICTOR_HORIZONTAL_DIFFERENCING) {

    75             int samplesPerPixel = bitsPerSample.length;

    76             int bitsPerPixel = 0;

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

    78                 bitsPerPixel += bitsPerSample[i];

    79             }

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

    81             byte[] rowBuf = new byte[bytesPerRow];

    82 

    83             int maxRow = height - 1;

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

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

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

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

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

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

    90                 }

    91 

    92                 deflater.setInput(rowBuf);

    93                 if(i == maxRow) {

    94                     deflater.finish();

    95                 }

    96 

    97                 int numBytes = 0;

    98                 while((numBytes = deflater.deflate(compData,

    99                                                    numCompressedBytes,

   100                                                    compData.length -

   101                                                    numCompressedBytes)) != 0) {

   102                     numCompressedBytes += numBytes;

   103                 }

   104 

   105                 off += scanlineStride;

   106             }

   107         } else {

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

   109             deflater.finish();

   110 

   111             numCompressedBytes = deflater.deflate(compData);

   112         }

   113 

   114         deflater.reset();

   115 

   116         stream.write(compData, 0, numCompressedBytes);

   117 

   118         return numCompressedBytes;

   119     }

   120 }