_ Git - BoarSSL/blob - Crypto/DigestCore.cs

   1 /*
   2  * Copyright (c) 2017 Thomas Pornin <pornin@bolet.org>
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining
   5  * a copy of this software and associated documentation files (the
   6  * "Software"), to deal in the Software without restriction, including
   7  * without limitation the rights to use, copy, modify, merge, publish,
   8  * distribute, sublicense, and/or sell copies of the Software, and to
   9  * permit persons to whom the Software is furnished to do so, subject to
  10  * the following conditions:
  11  *
  12  * The above copyright notice and this permission notice shall be
  13  * included in all copies or substantial portions of the Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  16  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  17  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  18  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  19  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  20  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  21  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  22  * SOFTWARE.
  23  */
  24
  25 using System;
  26
  27 namespace Crypto {
  28
  29 /*
  30  * This class is a convenient base class for implementations of IDigest.
  31  * Hash function implementations must implement:
  32  *    int DigestSize { get; }
  33  *    int BlockSize { get; }
  34  *    int PaddingOverhead { get; }
  35  *    void Update(byte b)
  36  *    void Update(byte[] buf, int off, int len)
  37  *    void DoPartial(byte[] outBuf, int off)
  38  *    void Reset()
  39  *    IDigest Dup()
  40  *
  41  * Implementations SHOULD provide overrides for:
  42  *    void CurrentState(byte[], int)
  43  *
  44  * In this class:
  45  *    Update(byte[]) calls Update(byte[],int,int)
  46  *    DoPartial() calls DoPartial(byte[],int)
  47  *    DoFinal() calls DoPartial() and Reset()
  48  *    DoFinal(byte[],int) calls DoPartial(byte[],int) and Reset()
  49  */
  50
  51 public abstract class DigestCore : IDigest {
  52
  53         /* see IDigest */
  54         public abstract string Name { get; }
  55
  56         /* see IDigest */
  57         public abstract int DigestSize { get; }
  58
  59         /* see IDigest */
  60         public abstract int BlockSize { get; }
  61
  62         /* see IDigest */
  63         public abstract void Update(byte b);
  64
  65         /* see IDigest */
  66         public virtual void Update(byte[] buf)
  67         {
  68                 Update(buf, 0, buf.Length);
  69         }
  70
  71         /* see IDigest */
  72         public abstract void Update(byte[] buf, int off, int len);
  73
  74         /* see IDigest */
  75         public abstract void DoPartial(byte[] outBuf, int off);
  76
  77         /* see IDigest */
  78         public virtual byte[] DoPartial()
  79         {
  80                 byte[] buf = new byte[DigestSize];
  81                 DoPartial(buf, 0);
  82                 return buf;
  83         }
  84
  85         /* see IDigest */
  86         public virtual void DoFinal(byte[] outBuf, int off)
  87         {
  88                 DoPartial(outBuf, off);
  89                 Reset();
  90         }
  91
  92         /* see IDigest */
  93         public virtual byte[] DoFinal()
  94         {
  95                 byte[] r = DoPartial();
  96                 Reset();
  97                 return r;
  98         }
  99
 100         /* see IDigest */
 101         public abstract void Reset();
 102
 103         /* see IDigest */
 104         public abstract IDigest Dup();
 105
 106         /*
 107          * Default implementation throws a NotSupportedException.
 108          */
 109         public virtual void CurrentState(byte[] outBuf, int off)
 110         {
 111                 throw new NotSupportedException();
 112         }
 113
 114         /* see IDigest */
 115         public virtual byte[] Hash(byte[] buf)
 116         {
 117                 return Hash(buf, 0, buf.Length);
 118         }
 119
 120         /* see IDigest */
 121         public virtual byte[] Hash(byte[] buf, int off, int len)
 122         {
 123                 IDigest h = Dup();
 124                 h.Reset();
 125                 h.Update(buf, off, len);
 126                 return h.DoFinal();
 127         }
 128 }
 129
 130 }