Source for java.util.zip.Checksum

   1: /* Checksum.java - Interface to compute a data checksum
   2:    Copyright (C) 1999, 2000, 2001 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: /*
  41:  * Written using on-line Java Platform 1.2 API Specification, as well
  42:  * as "The Java Class Libraries", 2nd edition (Addison-Wesley, 1998).
  43:  * Status:  Believed complete and correct.
  44:  */
  45: 
  46: /**
  47:  * Interface to compute a data checksum used by checked input/output streams.
  48:  * A data checksum can be updated by one byte or with a byte array. After each
  49:  * update the value of the current checksum can be returned by calling
  50:  * <code>getValue</code>. The complete checksum object can also be reset
  51:  * so it can be used again with new data.
  52:  *
  53:  * @see CheckedInputStream
  54:  * @see CheckedOutputStream
  55:  *
  56:  * @author Per Bothner
  57:  * @author Jochen Hoenicke
  58:  */
  59: public interface Checksum
  60: {
  61:   /**
  62:    * Returns the data checksum computed so far.
  63:    */
  64:   long getValue();
  65: 
  66:   /**
  67:    * Resets the data checksum as if no update was ever called.
  68:    */
  69:   void reset();
  70: 
  71:   /**
  72:    * Adds one byte to the data checksum.
  73:    *
  74:    * @param bval the data value to add. The high byte of the int is ignored.
  75:    */
  76:   void update (int bval);
  77: 
  78:   /**
  79:    * Adds the byte array to the data checksum.
  80:    *
  81:    * @param buf the buffer which contains the data
  82:    * @param off the offset in the buffer where the data starts
  83:    * @param len the length of the data
  84:    */
  85:   void update (byte[] buf, int off, int len);
  86: }