diff options
Diffstat (limited to 'libjava/java/util/zip/Inflater.java')
| -rw-r--r-- | libjava/java/util/zip/Inflater.java | 196 |
1 files changed, 170 insertions, 26 deletions
diff --git a/libjava/java/util/zip/Inflater.java b/libjava/java/util/zip/Inflater.java index c1d7741..28e89ea 100644 --- a/libjava/java/util/zip/Inflater.java +++ b/libjava/java/util/zip/Inflater.java @@ -1,5 +1,5 @@ /* Inflater.java - Decompress a data stream - Copyright (C) 1999, 2000 Free Software Foundation, Inc. + Copyright (C) 1999, 2000, 2001, 2003 Free Software Foundation, Inc. This file is part of GNU Classpath. @@ -39,87 +39,231 @@ package java.util.zip; import gnu.gcj.RawData; -/** - * @author Tom Tromey - * @date May 17, 1999 - */ - /* Written using on-line Java Platform 1.2 API Specification * and JCL book. * Believed complete and correct. */ +/** + * Inflater is used to decompress data that has been compressed according + * to the "deflate" standard described in rfc1950. + * + * The usage is as following. First you have to set some input with + * <code>setInput()</code>, then inflate() it. If inflate doesn't + * inflate any bytes there may be three reasons: + * <ul> + * <li>needsInput() returns true because the input buffer is empty. + * You have to provide more input with <code>setInput()</code>. + * NOTE: needsInput() also returns true when, the stream is finished. + * </li> + * <li>needsDictionary() returns true, you have to provide a preset + * dictionary with <code>setDictionary()</code>.</li> + * <li>finished() returns true, the inflater has finished.</li> + * </ul> + * Once the first output byte is produced, a dictionary will not be + * needed at a later stage. + * + * @author John Leuner, Jochen Hoenicke + * @author Tom Tromey + * @date May 17, 1999 + * @since JDK 1.1 + */ public class Inflater { - public native void end (); + // The zlib stream. + private RawData zstream; + + // True if finished. + private boolean is_finished; + + // True if dictionary needed. + private boolean dict_needed; + + /** + * Creates a new inflater. + */ + public Inflater () + { + this (false); + } + + /** + * Creates a new inflater. + * @param nowrap true if no header and checksum field appears in the + * stream. This is used for GZIPed input. For compatibility with + * Sun JDK you should provide one byte of input more than needed in + * this case. + */ + public Inflater (boolean noHeader) + { + init (noHeader); + } + /** + * Finalizes this object. + */ protected void finalize () { end (); } + /** + * Frees all objects allocated by the inflater. There's no reason + * to call this, since you can just rely on garbage collection (even + * for the Sun implementation). Exists only for compatibility + * with Sun's JDK, where the compressor allocates native memory. + * If you call any method (even reset) afterwards the behaviour is + * <i>undefined</i>. + * @deprecated Just clear all references to inflater instead. + */ + public native void end (); + + /** + * Returns true, if the inflater has finished. This means, that no + * input is needed and no output can be produced. + */ public synchronized boolean finished () { return is_finished; } + /** + * Gets the adler checksum. This is either the checksum of all + * uncompressed bytes returned by inflate(), or if needsDictionary() + * returns true (and thus no output was yet produced) this is the + * adler checksum of the expected dictionary. + * @returns the adler checksum. + */ public native int getAdler (); + + /** + * Gets the number of unprocessed input. Useful, if the end of the + * stream is reached and you want to further process the bytes after + * the deflate stream. + * @return the number of bytes of the input which were not processed. + */ public native int getRemaining (); + + /** + * Gets the total number of processed compressed input bytes. + * @return the total number of bytes of processed input bytes. + */ public native int getTotalIn (); + + /** + * Gets the total number of output bytes returned by inflate(). + * @return the total number of output bytes. + */ public native int getTotalOut (); + /** + * Inflates the compressed stream to the output buffer. If this + * returns 0, you should check, whether needsDictionary(), + * needsInput() or finished() returns true, to determine why no + * further output is produced. + * @param buffer the output buffer. + * @return the number of bytes written to the buffer, 0 if no further + * output can be produced. + * @exception DataFormatException if deflated stream is invalid. + * @exception IllegalArgumentException if buf has length 0. + */ public int inflate (byte[] buf) throws DataFormatException { return inflate (buf, 0, buf.length); } + /** + * Inflates the compressed stream to the output buffer. If this + * returns 0, you should check, whether needsDictionary(), + * needsInput() or finished() returns true, to determine why no + * further output is produced. + * @param buffer the output buffer. + * @param off the offset into buffer where the output should start. + * @param len the maximum length of the output. + * @return the number of bytes written to the buffer, 0 if no further + * output can be produced. + * @exception DataFormatException if deflated stream is invalid. + * @exception IndexOutOfBoundsException if the off and/or len are wrong. + */ public native int inflate (byte[] buf, int off, int len) throws DataFormatException; private native void init (boolean noHeader); - public Inflater () - { - this (false); - } - - public Inflater (boolean noHeader) - { - init (noHeader); - } - + /** + * Returns true, if a preset dictionary is needed to inflate the input. + */ public synchronized boolean needsDictionary () { return dict_needed; } + /** + * Returns true, if the input buffer is empty. + * You should then call setInput(). <br> + * + * <em>NOTE</em>: This method also returns true when the stream is finished. + */ public synchronized boolean needsInput () { return getRemaining () == 0; } + /** + * Resets the inflater so that a new stream can be decompressed. All + * pending input and output will be discarded. + */ public native void reset (); + /** + * Sets the preset dictionary. This should only be called, if + * needsDictionary() returns true and it should set the same + * dictionary, that was used for deflating. The getAdler() + * function returns the checksum of the dictionary needed. + * @param buffer the dictionary. + * @exception IllegalStateException if no dictionary is needed. + * @exception IllegalArgumentException if the dictionary checksum is + * wrong. + */ public void setDictionary (byte[] buf) { setDictionary (buf, 0, buf.length); } + /** + * Sets the preset dictionary. This should only be called, if + * needsDictionary() returns true and it should set the same + * dictionary, that was used for deflating. The getAdler() + * function returns the checksum of the dictionary needed. + * @param buffer the dictionary. + * @param off the offset into buffer where the dictionary starts. + * @param len the length of the dictionary. + * @exception IllegalStateException if no dictionary is needed. + * @exception IllegalArgumentException if the dictionary checksum is + * wrong. + * @exception IndexOutOfBoundsException if the off and/or len are wrong. + */ public native void setDictionary (byte[] buf, int off, int len); + /** + * Sets the input. This should only be called, if needsInput() + * returns true. + * @param buffer the input. + * @exception IllegalStateException if no input is needed. + */ public void setInput (byte[] buf) { setInput (buf, 0, buf.length); } + /** + * Sets the input. This should only be called, if needsInput() + * returns true. + * @param buffer the input. + * @param off the offset into buffer where the input starts. + * @param len the length of the input. + * @exception IllegalStateException if no input is needed. + * @exception IndexOutOfBoundsException if the off and/or len are wrong. + */ public native void setInput (byte[] buf, int off, int len); - - // The zlib stream. - private RawData zstream; - - // True if finished. - private boolean is_finished; - - // True if dictionary needed. - private boolean dict_needed; } |