| /* |
| * 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 |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| package com.sun.imageio.plugins.tiff; |
| |
| import javax.imageio.plugins.tiff.BaselineTIFFTagSet; |
| import java.io.IOException; |
| |
| public class TIFFPackBitsCompressor extends TIFFCompressor { |
| |
| public TIFFPackBitsCompressor() { |
| super("PackBits", BaselineTIFFTagSet.COMPRESSION_PACKBITS, true); |
| } |
| |
| /** |
| * Performs PackBits compression for a single buffer of data. |
| * This should be called for each row of each tile. The returned |
| * value is the offset into the output buffer after compression. |
| */ |
| private static int packBits(byte[] input, int inOffset, int inCount, |
| byte[] output, int outOffset) { |
| int inMax = inOffset + inCount - 1; |
| int inMaxMinus1 = inMax - 1; |
| |
| while(inOffset <= inMax) { |
| int run = 1; |
| byte replicate = input[inOffset]; |
| while(run < 127 && inOffset < inMax && |
| input[inOffset] == input[inOffset+1]) { |
| run++; |
| inOffset++; |
| } |
| if(run > 1) { |
| inOffset++; |
| output[outOffset++] = (byte)(-(run - 1)); |
| output[outOffset++] = replicate; |
| } |
| |
| run = 0; |
| int saveOffset = outOffset; |
| while(run < 128 && |
| ((inOffset < inMax && |
| input[inOffset] != input[inOffset+1]) || |
| (inOffset < inMaxMinus1 && |
| input[inOffset] != input[inOffset+2]))) { |
| run++; |
| output[++outOffset] = input[inOffset++]; |
| } |
| if(run > 0) { |
| output[saveOffset] = (byte)(run - 1); |
| outOffset++; |
| } |
| |
| if(inOffset == inMax) { |
| if(run > 0 && run < 128) { |
| output[saveOffset]++; |
| output[outOffset++] = input[inOffset++]; |
| } else { |
| output[outOffset++] = (byte)0; |
| output[outOffset++] = input[inOffset++]; |
| } |
| } |
| } |
| |
| return outOffset; |
| } |
| |
| public int encode(byte[] b, int off, |
| int width, int height, |
| int[] bitsPerSample, |
| int scanlineStride) throws IOException { |
| int bitsPerPixel = 0; |
| for (int i = 0; i < bitsPerSample.length; i++) { |
| bitsPerPixel += bitsPerSample[i]; |
| } |
| int bytesPerRow = (bitsPerPixel*width + 7)/8; |
| int bufSize = (bytesPerRow + (bytesPerRow + 127)/128); |
| byte[] compData = new byte[bufSize]; |
| |
| int bytesWritten = 0; |
| |
| for(int i = 0; i < height; i++) { |
| int bytes = packBits(b, off, scanlineStride, compData, 0); |
| off += scanlineStride; |
| bytesWritten += bytes; |
| stream.write(compData, 0, bytes); |
| } |
| |
| return bytesWritten; |
| } |
| } |