Source for gnu.java.security.hash.IMessageDigest

   1: /* IMessageDigest.java --
   2:    Copyright (C) 2001, 2002, 2006 Free Software Foundation, Inc.
   3: 
   4: This file is a 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 of the License, or (at
   9: your option) 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; if not, write to the Free Software
  18: Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
  19: 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: 
  39: package gnu.java.security.hash;
  40: 
  41: /**
  42:  * The basic visible methods of any hash algorithm.
  43:  * <p>
  44:  * A hash (or message digest) algorithm produces its output by iterating a basic
  45:  * compression function on blocks of data.
  46:  */
  47: public interface IMessageDigest
  48:     extends Cloneable
  49: {
  50:   /**
  51:    * Returns the canonical name of this algorithm.
  52:    *
  53:    * @return the canonical name of this instance.
  54:    */
  55:   String name();
  56: 
  57:   /**
  58:    * Returns the output length in bytes of this message digest algorithm.
  59:    *
  60:    * @return the output length in bytes of this message digest algorithm.
  61:    */
  62:   int hashSize();
  63: 
  64:   /**
  65:    * Returns the algorithm's (inner) block size in bytes.
  66:    *
  67:    * @return the algorithm's inner block size in bytes.
  68:    */
  69:   int blockSize();
  70: 
  71:   /**
  72:    * Continues a message digest operation using the input byte.
  73:    *
  74:    * @param b the input byte to digest.
  75:    */
  76:   void update(byte b);
  77: 
  78:   /**
  79:    * Continues a message digest operation, by filling the buffer, processing
  80:    * data in the algorithm's HASH_SIZE-bit block(s), updating the context and
  81:    * count, and buffering the remaining bytes in buffer for the next operation.
  82:    *
  83:    * @param in the input block.
  84:    */
  85:   void update(byte[] in);
  86: 
  87:   /**
  88:    * Continues a message digest operation, by filling the buffer, processing
  89:    * data in the algorithm's HASH_SIZE-bit block(s), updating the context and
  90:    * count, and buffering the remaining bytes in buffer for the next operation.
  91:    *
  92:    * @param in the input block.
  93:    * @param offset start of meaningful bytes in input block.
  94:    * @param length number of bytes, in input block, to consider.
  95:    */
  96:   void update(byte[] in, int offset, int length);
  97: 
  98:   /**
  99:    * Completes the message digest by performing final operations such as padding
 100:    * and resetting the instance.
 101:    *
 102:    * @return the array of bytes representing the hash value.
 103:    */
 104:   byte[] digest();
 105: 
 106:   /**
 107:    * Resets the current context of this instance clearing any eventually cached
 108:    * intermediary values.
 109:    */
 110:   void reset();
 111: 
 112:   /**
 113:    * A basic test. Ensures that the digest of a pre-determined message is equal
 114:    * to a known pre-computed value.
 115:    *
 116:    * @return <code>true</code> if the implementation passes a basic self-test.
 117:    *         Returns <code>false</code> otherwise.
 118:    */
 119:   boolean selfTest();
 120: 
 121:   /**
 122:    * Returns a clone copy of this instance.
 123:    *
 124:    * @return a clone copy of this instance.
 125:    */
 126:   Object clone();
 127: }