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1: /* Inflater.java - Decompress a data stream 2: Copyright (C) 1999, 2000, 2001, 2003 Free Software Foundation, Inc. 3: 4: This file is part of GNU Classpath. 5: 6: GNU Classpath is free software; you can redistribute it and/or modify 7: it under the terms of the GNU General Public License as published by 8: the Free Software Foundation; either version 2, or (at your option) 9: any later version. 10: 11: GNU Classpath is distributed in the hope that it will be useful, but 12: WITHOUT ANY WARRANTY; without even the implied warranty of 13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14: General Public License for more details. 15: 16: You should have received a copy of the GNU General Public License 17: along with GNU Classpath; see the file COPYING. If not, write to the 18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19: 02110-1301 USA. 20: 21: Linking this library statically or dynamically with other modules is 22: making a combined work based on this library. Thus, the terms and 23: conditions of the GNU General Public License cover the whole 24: combination. 25: 26: As a special exception, the copyright holders of this library give you 27: permission to link this library with independent modules to produce an 28: executable, regardless of the license terms of these independent 29: modules, and to copy and distribute the resulting executable under 30: terms of your choice, provided that you also meet, for each linked 31: independent module, the terms and conditions of the license of that 32: module. An independent module is a module which is not derived from 33: or based on this library. If you modify this library, you may extend 34: this exception to your version of the library, but you are not 35: obligated to do so. If you do not wish to do so, delete this 36: exception statement from your version. */ 37: 38: package java.util.zip; 39: 40: import gnu.gcj.RawData; 41: 42: /* Written using on-line Java Platform 1.2 API Specification 43: * and JCL book. 44: * Believed complete and correct. 45: */ 46: 47: /** 48: * Inflater is used to decompress data that has been compressed according 49: * to the "deflate" standard described in rfc1950. 50: * 51: * The usage is as following. First you have to set some input with 52: * <code>setInput()</code>, then inflate() it. If inflate doesn't 53: * inflate any bytes there may be three reasons: 54: * <ul> 55: * <li>needsInput() returns true because the input buffer is empty. 56: * You have to provide more input with <code>setInput()</code>. 57: * NOTE: needsInput() also returns true when, the stream is finished. 58: * </li> 59: * <li>needsDictionary() returns true, you have to provide a preset 60: * dictionary with <code>setDictionary()</code>.</li> 61: * <li>finished() returns true, the inflater has finished.</li> 62: * </ul> 63: * Once the first output byte is produced, a dictionary will not be 64: * needed at a later stage. 65: * 66: * @author John Leuner, Jochen Hoenicke 67: * @author Tom Tromey 68: * @date May 17, 1999 69: * @since JDK 1.1 70: */ 71: public class Inflater 72: { 73: // The zlib stream. 74: private RawData zstream; 75: 76: // True if finished. 77: private boolean is_finished; 78: 79: // True if dictionary needed. 80: private boolean dict_needed; 81: 82: /** 83: * Creates a new inflater. 84: */ 85: public Inflater () 86: { 87: this (false); 88: } 89: 90: /** 91: * Creates a new inflater. 92: * @param nowrap true if no header and checksum field appears in the 93: * stream. This is used for GZIPed input. For compatibility with 94: * Sun JDK you should provide one byte of input more than needed in 95: * this case. 96: */ 97: public Inflater (boolean noHeader) 98: { 99: init (noHeader); 100: } 101: 102: /** 103: * Finalizes this object. 104: */ 105: protected void finalize () 106: { 107: end (); 108: } 109: 110: /** 111: * Frees all objects allocated by the inflater. There's no reason 112: * to call this, since you can just rely on garbage collection (even 113: * for the Sun implementation). Exists only for compatibility 114: * with Sun's JDK, where the compressor allocates native memory. 115: * If you call any method (even reset) afterwards the behaviour is 116: * <i>undefined</i>. 117: * @deprecated Just clear all references to inflater instead. 118: */ 119: public native void end (); 120: 121: /** 122: * Returns true, if the inflater has finished. This means, that no 123: * input is needed and no output can be produced. 124: */ 125: public synchronized boolean finished () 126: { 127: return is_finished; 128: } 129: 130: /** 131: * Gets the adler checksum. This is either the checksum of all 132: * uncompressed bytes returned by inflate(), or if needsDictionary() 133: * returns true (and thus no output was yet produced) this is the 134: * adler checksum of the expected dictionary. 135: * @returns the adler checksum. 136: */ 137: public native int getAdler (); 138: 139: /** 140: * Gets the number of unprocessed input. Useful, if the end of the 141: * stream is reached and you want to further process the bytes after 142: * the deflate stream. 143: * @return the number of bytes of the input which were not processed. 144: */ 145: public native int getRemaining (); 146: 147: /** 148: * Gets the total number of processed compressed input bytes. 149: * @return the total number of bytes of processed input bytes. 150: */ 151: public native int getTotalIn (); 152: 153: /** 154: * Gets the total number of output bytes returned by inflate(). 155: * @return the total number of output bytes. 156: */ 157: public native int getTotalOut (); 158: 159: /** 160: * Inflates the compressed stream to the output buffer. If this 161: * returns 0, you should check, whether needsDictionary(), 162: * needsInput() or finished() returns true, to determine why no 163: * further output is produced. 164: * @param buffer the output buffer. 165: * @return the number of bytes written to the buffer, 0 if no further 166: * output can be produced. 167: * @exception DataFormatException if deflated stream is invalid. 168: * @exception IllegalArgumentException if buf has length 0. 169: */ 170: public int inflate (byte[] buf) throws DataFormatException 171: { 172: return inflate (buf, 0, buf.length); 173: } 174: 175: /** 176: * Inflates the compressed stream to the output buffer. If this 177: * returns 0, you should check, whether needsDictionary(), 178: * needsInput() or finished() returns true, to determine why no 179: * further output is produced. 180: * @param buffer the output buffer. 181: * @param off the offset into buffer where the output should start. 182: * @param len the maximum length of the output. 183: * @return the number of bytes written to the buffer, 0 if no further 184: * output can be produced. 185: * @exception DataFormatException if deflated stream is invalid. 186: * @exception IndexOutOfBoundsException if the off and/or len are wrong. 187: */ 188: public native int inflate (byte[] buf, int off, int len) 189: throws DataFormatException; 190: 191: private native void init (boolean noHeader); 192: 193: /** 194: * Returns true, if a preset dictionary is needed to inflate the input. 195: */ 196: public synchronized boolean needsDictionary () 197: { 198: return dict_needed; 199: } 200: 201: /** 202: * Returns true, if the input buffer is empty. 203: * You should then call setInput(). <br> 204: * 205: * <em>NOTE</em>: This method also returns true when the stream is finished. 206: */ 207: public synchronized boolean needsInput () 208: { 209: return getRemaining () == 0; 210: } 211: 212: /** 213: * Resets the inflater so that a new stream can be decompressed. All 214: * pending input and output will be discarded. 215: */ 216: public native void reset (); 217: 218: /** 219: * Sets the preset dictionary. This should only be called, if 220: * needsDictionary() returns true and it should set the same 221: * dictionary, that was used for deflating. The getAdler() 222: * function returns the checksum of the dictionary needed. 223: * @param buffer the dictionary. 224: * @exception IllegalStateException if no dictionary is needed. 225: * @exception IllegalArgumentException if the dictionary checksum is 226: * wrong. 227: */ 228: public void setDictionary (byte[] buf) 229: { 230: setDictionary (buf, 0, buf.length); 231: } 232: 233: /** 234: * Sets the preset dictionary. This should only be called, if 235: * needsDictionary() returns true and it should set the same 236: * dictionary, that was used for deflating. The getAdler() 237: * function returns the checksum of the dictionary needed. 238: * @param buffer the dictionary. 239: * @param off the offset into buffer where the dictionary starts. 240: * @param len the length of the dictionary. 241: * @exception IllegalStateException if no dictionary is needed. 242: * @exception IllegalArgumentException if the dictionary checksum is 243: * wrong. 244: * @exception IndexOutOfBoundsException if the off and/or len are wrong. 245: */ 246: public native void setDictionary (byte[] buf, int off, int len); 247: 248: /** 249: * Sets the input. This should only be called, if needsInput() 250: * returns true. 251: * @param buffer the input. 252: * @exception IllegalStateException if no input is needed. 253: */ 254: public void setInput (byte[] buf) 255: { 256: setInput (buf, 0, buf.length); 257: } 258: 259: /** 260: * Sets the input. This should only be called, if needsInput() 261: * returns true. 262: * @param buffer the input. 263: * @param off the offset into buffer where the input starts. 264: * @param len the length of the input. 265: * @exception IllegalStateException if no input is needed. 266: * @exception IndexOutOfBoundsException if the off and/or len are wrong. 267: */ 268: public native void setInput (byte[] buf, int off, int len); 269: }