mcs/class/corlib/System.Security.Cryptography/HashAlgorithm.cs

   1 //
   2 // System.Security.Cryptography HashAlgorithm Class implementation
   3 //
   4 // Authors:
   5 //      Matthew S. Ford (Matthew.S.Ford@Rose-Hulman.Edu)
   6 //      Sebastien Pouliot (sebastien@ximian.com)
   7 //
   8 // Copyright 2001 by Matthew S. Ford.
   9 // Portions (C) 2002 Motus Technologies Inc. (http://www.motus.com)
  10 // (C) 2004 Novell (http://www.novell.com)
  11 //
  12
  13 //
  14 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
  15 //
  16 // Permission is hereby granted, free of charge, to any person obtaining
  17 // a copy of this software and associated documentation files (the
  18 // "Software"), to deal in the Software without restriction, including
  19 // without limitation the rights to use, copy, modify, merge, publish,
  20 // distribute, sublicense, and/or sell copies of the Software, and to
  21 // permit persons to whom the Software is furnished to do so, subject to
  22 // the following conditions:
  23 //
  24 // The above copyright notice and this permission notice shall be
  25 // included in all copies or substantial portions of the Software.
  26 //
  27 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  28 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  29 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  30 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  31 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  32 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  33 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  34 //
  35
  36 using System.Globalization;
  37 using System.IO;
  38
  39 namespace System.Security.Cryptography {
  40
  41         public abstract class HashAlgorithm : ICryptoTransform {
  42
  43                 protected byte[] HashValue;
  44                 protected int HashSizeValue;
  45                 protected int State;
  46                 private bool disposed;
  47
  48                 protected HashAlgorithm ()
  49                 {
  50                         disposed = false;
  51                 }
  52
  53                 public virtual bool CanTransformMultipleBlocks {
  54                         get { return true; }
  55                 }
  56
  57                 public virtual bool CanReuseTransform {
  58                         get { return true; }
  59                 }
  60
  61                 public void Clear ()
  62                 {
  63                         // same as System.IDisposable.Dispose() which is documented
  64                         Dispose (true);
  65                 }
  66
  67                 public byte[] ComputeHash (byte[] input)
  68                 {
  69                         if (input == null)
  70                                 throw new ArgumentNullException ("input");
  71
  72                         return ComputeHash (input, 0, input.Length);
  73                 }
  74
  75                 public byte[] ComputeHash (byte[] buffer, int offset, int count)
  76                 {
  77                         if (disposed)
  78                                 throw new ObjectDisposedException ("HashAlgorithm");
  79                         if (buffer == null)
  80                                 throw new ArgumentNullException ("buffer");
  81                         if (offset < 0)
  82                                 throw new ArgumentOutOfRangeException ("offset", "< 0");
  83                         if (count < 0)
  84                                 throw new ArgumentException ("count", "< 0");
  85                         // ordered to avoid possible integer overflow
  86                         if (offset > buffer.Length - count) {
  87                                 throw new ArgumentException ("offset + count",
  88                                         Locale.GetText ("Overflow"));
  89                         }
  90
  91                         HashCore (buffer, offset, count);
  92                         HashValue = HashFinal ();
  93                         Initialize ();
  94
  95                         return HashValue;
  96                 }
  97
  98                 public byte[] ComputeHash (Stream inputStream)
  99                 {
 100                         // don't read stream unless object is ready to use
 101                         if (disposed)
 102                                 throw new ObjectDisposedException ("HashAlgorithm");
 103
 104                         byte[] buffer = new byte [4096];
 105                         int len = inputStream.Read (buffer, 0, 4096);
 106                         while (len > 0) {
 107                                 HashCore (buffer, 0, len);
 108                                 len = inputStream.Read (buffer, 0, 4096);
 109                         }
 110                         HashValue = HashFinal ();
 111                         Initialize ();
 112                         return HashValue;
 113                 }
 114
 115                 public static HashAlgorithm Create ()
 116                 {
 117                         return Create ("System.Security.Cryptography.HashAlgorithm");
 118                 }
 119
 120                 public static HashAlgorithm Create (string hashName)
 121                 {
 122                         return (HashAlgorithm) CryptoConfig.CreateFromName (hashName);
 123                 }
 124
 125                 public virtual byte[] Hash {
 126                         get {
 127                                 if (HashValue == null) {
 128                                         throw new CryptographicUnexpectedOperationException (
 129                                                 Locale.GetText ("No hash value computed."));
 130                                 }
 131                                 return HashValue;
 132                         }
 133                 }
 134
 135                 protected abstract void HashCore (byte[] rgb, int start, int size);
 136
 137                 protected abstract byte[] HashFinal ();
 138
 139                 public virtual int HashSize {
 140                         get { return HashSizeValue; }
 141                 }
 142
 143                 public abstract void Initialize ();
 144
 145                 protected virtual void Dispose (bool disposing)
 146                 {
 147                         disposed = true;
 148                 }
 149
 150                 public virtual int InputBlockSize {
 151                         get { return 1; }
 152                 }
 153
 154                 public virtual int OutputBlockSize {
 155                         get { return 1; }
 156                 }
 157
 158                 void IDisposable.Dispose ()
 159                 {
 160                         Dispose (true);
 161                         GC.SuppressFinalize (this);  // Finalization is now unnecessary
 162                 }
 163
 164                 public int TransformBlock (byte[] inputBuffer, int inputOffset, int inputCount, byte[] outputBuffer, int outputOffset)
 165                 {
 166                         if (inputBuffer == null)
 167                                 throw new ArgumentNullException ("inputBuffer");
 168                         if (outputBuffer == null)
 169                                 throw new ArgumentNullException ("outputBuffer");
 170
 171                         if (inputOffset < 0)
 172                                 throw new ArgumentOutOfRangeException ("inputOffset", "< 0");
 173                         if (inputCount < 0)
 174                                 throw new ArgumentException ("inputCount");
 175
 176                         // ordered to avoid possible integer overflow
 177                         if ((inputOffset < 0) || (inputOffset > inputBuffer.Length - inputCount))
 178                                 throw new ArgumentException ("inputBuffer");
 179                         // ordered to avoid possible integer overflow
 180                         if ((outputOffset < 0) || (outputOffset > outputBuffer.Length - inputCount))
 181                                 throw new IndexOutOfRangeException ("outputBuffer");
 182
 183                         // note: other exceptions are handled by Buffer.BlockCopy
 184                         Buffer.BlockCopy (inputBuffer, inputOffset, outputBuffer, outputOffset, inputCount);
 185                         HashCore (inputBuffer, inputOffset, inputCount);
 186
 187                         return inputCount;
 188                 }
 189
 190                 public byte[] TransformFinalBlock (byte[] inputBuffer, int inputOffset, int inputCount)
 191                 {
 192                         if (inputBuffer == null)
 193                                 throw new ArgumentNullException ("inputBuffer");
 194                         if (inputCount < 0)
 195                                 throw new ArgumentException ("inputCount");
 196                         // ordered to avoid possible integer overflow
 197                         if (inputOffset > inputBuffer.Length - inputCount) {
 198                                 throw new ArgumentException ("inputOffset + inputCount",
 199                                         Locale.GetText ("Overflow"));
 200                         }
 201
 202                         byte[] outputBuffer = new byte [inputCount];
 203
 204                         // note: other exceptions are handled by Buffer.BlockCopy
 205                         Buffer.BlockCopy (inputBuffer, inputOffset, outputBuffer, 0, inputCount);
 206
 207                         HashCore (inputBuffer, inputOffset, inputCount);
 208                         HashValue = HashFinal ();
 209                         Initialize ();
 210
 211                         return outputBuffer;
 212                 }
 213         }
 214 }