1 2 /* ==================================================================== 3 * The Apache Software License, Version 1.1 4 * 5 * Copyright (c) 2002 The Apache Software Foundation. All rights 6 * reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in 17 * the documentation and/or other materials provided with the 18 * distribution. 19 * 20 * 3. The end-user documentation included with the redistribution, 21 * if any, must include the following acknowledgment: 22 * "This product includes software developed by the 23 * Apache Software Foundation (http://www.apache.org/)." 24 * Alternately, this acknowledgment may appear in the software itself, 25 * if and wherever such third-party acknowledgments normally appear. 26 * 27 * 4. The names "Apache" and "Apache Software Foundation" and 28 * "Apache POI" must not be used to endorse or promote products 29 * derived from this software without prior written permission. For 30 * written permission, please contact apache@apache.org. 31 * 32 * 5. Products derived from this software may not be called "Apache", 33 * "Apache POI", nor may "Apache" appear in their name, without 34 * prior written permission of the Apache Software Foundation. 35 * 36 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED 37 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 38 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 39 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR 40 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 41 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 42 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF 43 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 44 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 45 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 46 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 47 * SUCH DAMAGE. 48 * ==================================================================== 49 * 50 * This software consists of voluntary contributions made by many 51 * individuals on behalf of the Apache Software Foundation. For more 52 * information on the Apache Software Foundation, please see 53 * <http://www.apache.org/>. 54 */ 55 56 package org.apache.poi.poifs.storage; 57 58 import java.io.*; 59 60 import java.util.*; 61 62 import org.apache.poi.poifs.common.POIFSConstants; 63 64 /** 65 * Storage for documents that are too small to use regular 66 * DocumentBlocks for their data 67 * 68 * @author Marc Johnson (mjohnson at apache dot org) 69 */ 70 71 public class SmallDocumentBlock 72 implements BlockWritable, ListManagedBlock 73 { 74 private byte[] _data; 75 private static final byte _default_fill = ( byte ) 0xff; 76 private static final int _block_size = 64; 77 private static final int _blocks_per_big_block = 78 POIFSConstants.BIG_BLOCK_SIZE / _block_size; 79 80 private SmallDocumentBlock(final byte [] data, final int index) 81 { 82 this(); 83 System.arraycopy(data, index * _block_size, _data, 0, _block_size); 84 } 85 86 private SmallDocumentBlock() 87 { 88 _data = new byte[ _block_size ]; 89 } 90 91 /** 92 * convert a single long array into an array of SmallDocumentBlock 93 * instances 94 * 95 * @param array the byte array to be converted 96 * @param size the intended size of the array (which may be smaller) 97 * 98 * @return an array of SmallDocumentBlock instances, filled from 99 * the array 100 */ 101 102 public static SmallDocumentBlock [] convert(final byte [] array, 103 final int size) 104 { 105 SmallDocumentBlock[] rval = 106 new SmallDocumentBlock[ (size + _block_size - 1) / _block_size ]; 107 int offset = 0; 108 109 for (int k = 0; k < rval.length; k++) 110 { 111 rval[ k ] = new SmallDocumentBlock(); 112 if (offset < array.length) 113 { 114 int length = Math.min(_block_size, array.length - offset); 115 116 System.arraycopy(array, offset, rval[ k ]._data, 0, length); 117 if (length != _block_size) 118 { 119 Arrays.fill(rval[ k ]._data, length, _block_size, 120 _default_fill); 121 } 122 } 123 else 124 { 125 Arrays.fill(rval[ k ]._data, _default_fill); 126 } 127 offset += _block_size; 128 } 129 return rval; 130 } 131 132 /** 133 * fill out a List of SmallDocumentBlocks so that it fully occupies 134 * a set of big blocks 135 * 136 * @param blocks the List to be filled out 137 * 138 * @return number of big blocks the list encompasses 139 */ 140 141 public static int fill(final List blocks) 142 { 143 int count = blocks.size(); 144 int big_block_count = (count + _blocks_per_big_block - 1) 145 / _blocks_per_big_block; 146 int full_count = big_block_count * _blocks_per_big_block; 147 148 for (; count < full_count; count++) 149 { 150 blocks.add(makeEmptySmallDocumentBlock()); 151 } 152 return big_block_count; 153 } 154 155 /** 156 * Factory for creating SmallDocumentBlocks from DocumentBlocks 157 * 158 * @param store the original DocumentBlocks 159 * @param size the total document size 160 * 161 * @return an array of new SmallDocumentBlocks instances 162 * 163 * @exception IOException on errors reading from the DocumentBlocks 164 * @exception ArrayIndexOutOfBoundsException if, somehow, the store 165 * contains less data than size indicates 166 */ 167 168 public static SmallDocumentBlock [] convert(final BlockWritable [] store, 169 final int size) 170 throws IOException, ArrayIndexOutOfBoundsException 171 { 172 ByteArrayOutputStream stream = new ByteArrayOutputStream(); 173 174 for (int j = 0; j < store.length; j++) 175 { 176 store[ j ].writeBlocks(stream); 177 } 178 byte[] data = stream.toByteArray(); 179 SmallDocumentBlock[] rval = 180 new SmallDocumentBlock[ convertToBlockCount(size) ]; 181 182 for (int index = 0; index < rval.length; index++) 183 { 184 rval[ index ] = new SmallDocumentBlock(data, index); 185 } 186 return rval; 187 } 188 189 /** 190 * create a list of SmallDocumentBlock's from raw data 191 * 192 * @param blocks the raw data containing the SmallDocumentBlock 193 * data 194 * 195 * @return a List of SmallDocumentBlock's extracted from the input 196 * 197 * @exception IOException 198 */ 199 200 public static List extract(ListManagedBlock [] blocks) 201 throws IOException 202 { 203 List sdbs = new ArrayList(); 204 205 for (int j = 0; j < blocks.length; j++) 206 { 207 byte[] data = blocks[ j ].getData(); 208 209 for (int k = 0; k < _blocks_per_big_block; k++) 210 { 211 sdbs.add(new SmallDocumentBlock(data, k)); 212 } 213 } 214 return sdbs; 215 } 216 217 /** 218 * read data from an array of SmallDocumentBlocks 219 * 220 * @param blocks the blocks to read from 221 * @param buffer the buffer to write the data into 222 * @param offset the offset into the array of blocks to read from 223 */ 224 225 public static void read(final BlockWritable [] blocks, 226 final byte [] buffer, final int offset) 227 { 228 int firstBlockIndex = offset / _block_size; 229 int firstBlockOffset = offset % _block_size; 230 int lastBlockIndex = (offset + buffer.length - 1) / _block_size; 231 232 if (firstBlockIndex == lastBlockIndex) 233 { 234 System.arraycopy( 235 (( SmallDocumentBlock ) blocks[ firstBlockIndex ])._data, 236 firstBlockOffset, buffer, 0, buffer.length); 237 } 238 else 239 { 240 int buffer_offset = 0; 241 242 System.arraycopy( 243 (( SmallDocumentBlock ) blocks[ firstBlockIndex ])._data, 244 firstBlockOffset, buffer, buffer_offset, 245 _block_size - firstBlockOffset); 246 buffer_offset += _block_size - firstBlockOffset; 247 for (int j = firstBlockIndex + 1; j < lastBlockIndex; j++) 248 { 249 System.arraycopy((( SmallDocumentBlock ) blocks[ j ])._data, 250 0, buffer, buffer_offset, _block_size); 251 buffer_offset += _block_size; 252 } 253 System.arraycopy( 254 (( SmallDocumentBlock ) blocks[ lastBlockIndex ])._data, 0, 255 buffer, buffer_offset, buffer.length - buffer_offset); 256 } 257 } 258 259 /** 260 * Calculate the storage size of a set of SmallDocumentBlocks 261 * 262 * @param size number of SmallDocumentBlocks 263 * 264 * @return total size 265 */ 266 267 public static int calcSize(int size) 268 { 269 return size * _block_size; 270 } 271 272 private static SmallDocumentBlock makeEmptySmallDocumentBlock() 273 { 274 SmallDocumentBlock block = new SmallDocumentBlock(); 275 276 Arrays.fill(block._data, _default_fill); 277 return block; 278 } 279 280 private static int convertToBlockCount(final int size) 281 { 282 return (size + _block_size - 1) / _block_size; 283 } 284 285 /* ********** START implementation of BlockWritable ********** */ 286 287 /** 288 * Write the storage to an OutputStream 289 * 290 * @param stream the OutputStream to which the stored data should 291 * be written 292 * 293 * @exception IOException on problems writing to the specified 294 * stream 295 */ 296 297 public void writeBlocks(final OutputStream stream) 298 throws IOException 299 { 300 stream.write(_data); 301 } 302 303 /* ********** END implementation of BlockWritable ********** */ 304 /* ********** START implementation of ListManagedBlock ********** */ 305 306 /** 307 * Get the data from the block 308 * 309 * @return the block's data as a byte array 310 * 311 * @exception IOException if there is no data 312 */ 313 314 public byte [] getData() 315 throws IOException 316 { 317 return _data; 318 } 319 320 /* ********** END implementation of ListManagedBlock ********** */ 321 } // end public class SmallDocumentBlock 322 323