bundles/org.simantics.compressions/src/org/simantics/compressions/impl/CompressingOutputStream.java

   1 /*******************************************************************************\r
   2  * Copyright (c) 2007, 2012 Association for Decentralized Information Management\r
   3  * in Industry THTH ry.\r
   4  * All rights reserved. This program and the accompanying materials\r
   5  * are made available under the terms of the Eclipse Public License v1.0\r
   6  * which accompanies this distribution, and is available at\r
   7  * http://www.eclipse.org/legal/epl-v10.html\r
   8  *\r
   9  * Contributors:\r
  10  *     VTT Technical Research Centre of Finland - initial API and implementation\r
  11  *******************************************************************************/\r
  12 package org.simantics.compressions.impl;\r
  13 \r
  14 import java.io.File;\r
  15 import java.io.FileNotFoundException;\r
  16 import java.io.FileOutputStream;\r
  17 import java.io.IOException;\r
  18 import java.io.OutputStream;\r
  19 import java.nio.ByteBuffer;\r
  20 import java.nio.ByteOrder;\r
  21 import java.nio.IntBuffer;\r
  22 import java.nio.channels.WritableByteChannel;\r
  23 \r
  24 /**\r
  25  * @author Hannu Niemist&ouml;\r
  26  * @author Tuukka Lehtonen\r
  27  */\r
  28 public abstract class CompressingOutputStream extends OutputStream {\r
  29 \r
  30     protected static final int    BLOCK_SIZE = 1024 * 1024;\r
  31 \r
  32     protected OutputStream        stream;\r
  33     protected WritableByteChannel channel;\r
  34     protected ByteBuffer          compressed;\r
  35     protected byte[]              compressedArray;\r
  36     protected ByteBuffer          uncompressed;\r
  37     protected IntBuffer           header;\r
  38     protected int                 bytes      = 0;\r
  39 \r
  40     public CompressingOutputStream(File file) throws FileNotFoundException {\r
  41         this(new FileOutputStream(file));\r
  42     }\r
  43 \r
  44     public CompressingOutputStream(FileOutputStream stream) {\r
  45         this(stream, stream.getChannel());\r
  46     }\r
  47 \r
  48     public CompressingOutputStream(OutputStream stream) {\r
  49         this(stream, null);\r
  50     }\r
  51 \r
  52     public CompressingOutputStream(OutputStream stream, WritableByteChannel channel) {\r
  53         this.stream = stream;\r
  54         this.channel = channel;\r
  55         uncompressed = allocateBuffer(BLOCK_SIZE);\r
  56     }\r
  57 \r
  58     @Override\r
  59     public void write(int b) throws IOException {\r
  60         if(uncompressed.remaining() == 0)\r
  61             flushBuffer();\r
  62         uncompressed.put((byte)b);\r
  63         ++bytes;\r
  64     }\r
  65 \r
  66     @Override\r
  67     public void write(byte[] b, int off, int len) throws IOException {\r
  68         bytes += len;\r
  69         while(len > 0) {\r
  70             int s = Math.min(len, uncompressed.remaining());\r
  71             uncompressed.put(b, off, s);\r
  72             len -= s;\r
  73             off += s;\r
  74             if(uncompressed.remaining() == 0)\r
  75                 flushBuffer();\r
  76         }\r
  77     }\r
  78 \r
  79     @Override\r
  80     public void close() throws IOException {\r
  81         try {\r
  82             flushBuffer();\r
  83 \r
  84             if (channel != null) {\r
  85                 header.position(0);\r
  86                 header.put(0);\r
  87                 header.put(0);\r
  88                 compressed.position(0);\r
  89                 compressed.limit(8);\r
  90                 channel.write(compressed);\r
  91             } else if (stream != null) {\r
  92                 stream.write(new byte[8]);\r
  93             }\r
  94             //System.out.println("Wrote " + bytes + " uncompressed bytes.");\r
  95         } finally {\r
  96             if (channel != null) {\r
  97                 channel.close();\r
  98                 channel = null;\r
  99             }\r
 100             if (stream != null) {\r
 101                 stream.close();\r
 102                 stream = null;\r
 103             }\r
 104         }\r
 105     }\r
 106 \r
 107     private void flushBuffer() throws IOException {\r
 108         int uncompressedSize = uncompressed.position();\r
 109         uncompressed.position(0);\r
 110         int maxCompressedSize = compressBound(uncompressedSize) + 8;\r
 111         if(compressed == null || compressed.capacity() < maxCompressedSize) {\r
 112             compressed = allocateBuffer(maxCompressedSize);\r
 113             compressed.order(ByteOrder.LITTLE_ENDIAN);\r
 114             header = compressed.asIntBuffer();\r
 115             if (channel == null)\r
 116                 compressedArray = new byte[maxCompressedSize];\r
 117         }\r
 118         int compressedSize = compress(uncompressed, 0, uncompressedSize, \r
 119                 compressed, 8);\r
 120         header.position(0);\r
 121         header.put(compressedSize);\r
 122         header.put(uncompressedSize);\r
 123         compressed.position(0);\r
 124         compressed.limit(compressedSize+8);\r
 125         if (channel != null) {\r
 126             channel.write(compressed);\r
 127         } else {\r
 128             compressed.get(compressedArray, 0, compressedSize+8);\r
 129             stream.write(compressedArray, 0, compressedSize+8);\r
 130         }\r
 131     }\r
 132 \r
 133     protected abstract int compressBound(int inputSize);\r
 134 \r
 135     protected abstract int compress(ByteBuffer uncompressed, int uncompressedOffset, int uncompressedSize,\r
 136             ByteBuffer compressed, int compressedOffset) throws IOException;\r
 137 \r
 138     protected abstract ByteBuffer allocateBuffer(int capacity);\r
 139 \r
 140 }