diff options
Diffstat (limited to 'libjava/java/util/zip/Adler32.java')
| -rw-r--r-- | libjava/java/util/zip/Adler32.java | 104 |
1 files changed, 65 insertions, 39 deletions
diff --git a/libjava/java/util/zip/Adler32.java b/libjava/java/util/zip/Adler32.java index e7afeabde16..989a2049283 100644 --- a/libjava/java/util/zip/Adler32.java +++ b/libjava/java/util/zip/Adler32.java @@ -1,18 +1,31 @@ -/* Copyright (C) 1999 Free Software Foundation - - This file is part of libgcj. - -This software is copyrighted work licensed under the terms of the -Libgcj License. Please consult the file "LIBGCJ_LICENSE" for -details. */ +/* Adler.java - Computes Adler32 data checksum of a data stream + Copyright (C) 1999, 2000 Free Software Foundation, Inc. + +This file is part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2, or (at your option) +any later version. + +GNU Classpath 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 for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; see the file COPYING. If not, write to the +Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA +02111-1307 USA. + +As a special exception, if you link this library with other files to +produce an executable, this library does not by itself cause the +resulting executable to be covered by the GNU General Public License. +This exception does not however invalidate any other reasons why the +executable file might be covered by the GNU General Public License. */ package java.util.zip; -/** - * @author Per Bothner - * @date April 6, 1999. - */ - /* * Written using on-line Java Platform 1.2 API Specification, as well * as "The Java Class Libraries", 2nd edition (Addison-Wesley, 1998). @@ -20,31 +33,67 @@ package java.util.zip; * Status: Believed complete and correct. */ +/** + * Computes Adler32 data checksum of a data stream. + * The actual Adler32 algorithm is described in RFC 1950 + * (ZLIB Compressed Data Format Specification version 3.3). + * Can be used to get the CRC32 over a stream if used with checked input/output + * streams. + * + * @see InflaterInputStream + * @see InflaterOutputStream + * + * @author Per Bothner + * @date April 6, 1999. + */ public class Adler32 implements Checksum { - private static int BASE = 65521; /* largest prime smaller than 65536 */ + /** largest prime smaller than 65536 */ + private static int BASE = 65521; + private int s1; private int s2; + /** + * Creates an Adler32 data checksum. + */ public Adler32 () { reset(); } + /** + * Resets the Adler32 data checksum as if no update was ever called. + */ public void reset () { s1 = 1; s2 = 0; } + /** + * Adds one byte to the data checksum. + * + * @param bval the data value to add. The high byte of the int is ignored. + */ public void update (int bval) { s1 = (s1 + (bval & 0xFF)) % BASE; s2 = (s1 + s2) % BASE; } + /** + * Adds the complete byte array to the data checksum. + */ public void update (byte[] buffer) { update(buffer, 0, buffer.length); } + /** + * Adds the byte array to the data checksum. + * + * @param buf the buffer which contains the data + * @param off the offset in the buffer where the data starts + * @param len the length of the data + */ public void update (byte[] buf, int off, int len) { int s1 = this.s1; @@ -68,34 +117,11 @@ public class Adler32 implements Checksum this.s2 = s2; } + /** + * Returns the Adler32 data checksum computed so far. + */ public long getValue() { return ((long) s2 << 16) + s1; } } - - - - - - - - - - - - - - - - - - - - - - - - - - |
