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 // Copyright (C) 2004-2006 Novell, Inc (http://www.novell.com)
  11 //
  12 // Permission is hereby granted, free of charge, to any person obtaining
  13 // a copy of this software and associated documentation files (the
  14 // "Software"), to deal in the Software without restriction, including
  15 // without limitation the rights to use, copy, modify, merge, publish,
  16 // distribute, sublicense, and/or sell copies of the Software, and to
  17 // permit persons to whom the Software is furnished to do so, subject to
  18 // the following conditions:
  19 //
  20 // The above copyright notice and this permission notice shall be
  21 // included in all copies or substantial portions of the Software.
  22 //
  23 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  27 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  28 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  29 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  30 //
  31
  32 using System.Globalization;
  33 using System.IO;
  34 using System.Runtime.InteropServices;
  35
  36 namespace System.Security.Cryptography {
  37
  38 #if NET_2_0
  39         [ComVisible (true)]
  40 #endif
  41         public abstract class HashAlgorithm : ICryptoTransform {
  42
  43 #if NET_2_0
  44                 protected internal byte[] HashValue;
  45 #else
  46                 protected byte[] HashValue;
  47 #endif
  48                 protected int HashSizeValue;
  49                 protected int State;
  50                 private bool disposed;
  51
  52                 protected HashAlgorithm ()
  53                 {
  54                         disposed = false;
  55                 }
  56
  57                 public virtual bool CanTransformMultipleBlocks {
  58                         get { return true; }
  59                 }
  60
  61                 public virtual bool CanReuseTransform {
  62                         get { return true; }
  63                 }
  64
  65                 public void Clear ()
  66                 {
  67                         // same as System.IDisposable.Dispose() which is documented
  68                         Dispose (true);
  69                 }
  70
  71                 public byte[] ComputeHash (byte[] input)
  72                 {
  73                         if (input == null)
  74                                 throw new ArgumentNullException ("input");
  75
  76                         return ComputeHash (input, 0, input.Length);
  77                 }
  78
  79                 public byte[] ComputeHash (byte[] buffer, int offset, int count)
  80                 {
  81                         if (disposed)
  82                                 throw new ObjectDisposedException ("HashAlgorithm");
  83                         if (buffer == null)
  84                                 throw new ArgumentNullException ("buffer");
  85                         if (offset < 0)
  86                                 throw new ArgumentOutOfRangeException ("offset", "< 0");
  87                         if (count < 0)
  88                                 throw new ArgumentException ("count", "< 0");
  89                         // ordered to avoid possible integer overflow
  90                         if (offset > buffer.Length - count) {
  91                                 throw new ArgumentException ("offset + count",
  92                                         Locale.GetText ("Overflow"));
  93                         }
  94
  95                         HashCore (buffer, offset, count);
  96                         HashValue = HashFinal ();
  97                         Initialize ();
  98
  99                         return HashValue;
 100                 }
 101
 102                 public byte[] ComputeHash (Stream inputStream)
 103                 {
 104                         // don't read stream unless object is ready to use
 105                         if (disposed)
 106                                 throw new ObjectDisposedException ("HashAlgorithm");
 107
 108                         byte[] buffer = new byte [4096];
 109                         int len = inputStream.Read (buffer, 0, 4096);
 110                         while (len > 0) {
 111                                 HashCore (buffer, 0, len);
 112                                 len = inputStream.Read (buffer, 0, 4096);
 113                         }
 114                         HashValue = HashFinal ();
 115                         Initialize ();
 116                         return HashValue;
 117                 }
 118
 119                 public static HashAlgorithm Create ()
 120                 {
 121                         return Create ("System.Security.Cryptography.HashAlgorithm");
 122                 }
 123
 124                 public static HashAlgorithm Create (string hashName)
 125                 {
 126                         return (HashAlgorithm) CryptoConfig.CreateFromName (hashName);
 127                 }
 128
 129                 public virtual byte[] Hash {
 130                         get {
 131                                 if (HashValue == null) {
 132                                         throw new CryptographicUnexpectedOperationException (
 133                                                 Locale.GetText ("No hash value computed."));
 134                                 }
 135                                 return HashValue;
 136                         }
 137                 }
 138
 139                 protected abstract void HashCore (byte[] rgb, int start, int size);
 140
 141                 protected abstract byte[] HashFinal ();
 142
 143                 public virtual int HashSize {
 144                         get { return HashSizeValue; }
 145                 }
 146
 147                 public abstract void Initialize ();
 148
 149                 protected virtual void Dispose (bool disposing)
 150                 {
 151                         disposed = true;
 152                 }
 153
 154                 public virtual int InputBlockSize {
 155                         get { return 1; }
 156                 }
 157
 158                 public virtual int OutputBlockSize {
 159                         get { return 1; }
 160                 }
 161
 162                 void IDisposable.Dispose ()
 163                 {
 164                         Dispose (true);
 165                         GC.SuppressFinalize (this);  // Finalization is now unnecessary
 166                 }
 167
 168                 // LAMESPEC: outputBuffer is optional in 2.0 (i.e. can be null).
 169                 // However a null outputBuffer would throw a ExecutionEngineException under 1.x
 170                 public int TransformBlock (byte[] inputBuffer, int inputOffset, int inputCount, byte[] outputBuffer, int outputOffset)
 171                 {
 172                         if (inputBuffer == null)
 173                                 throw new ArgumentNullException ("inputBuffer");
 174
 175                         if (inputOffset < 0)
 176                                 throw new ArgumentOutOfRangeException ("inputOffset", "< 0");
 177                         if (inputCount < 0)
 178                                 throw new ArgumentException ("inputCount");
 179
 180                         // ordered to avoid possible integer overflow
 181                         if ((inputOffset < 0) || (inputOffset > inputBuffer.Length - inputCount))
 182                                 throw new ArgumentException ("inputBuffer");
 183
 184                         if (outputBuffer != null) {
 185                                 if (outputOffset < 0) {
 186 #if NET_2_0
 187                                         throw new ArgumentOutOfRangeException ("outputOffset", "< 0");
 188 #else
 189                                         throw new IndexOutOfRangeException ("outputBuffer");
 190 #endif
 191                                 }
 192                                 // ordered to avoid possible integer overflow
 193                                 if (outputOffset > outputBuffer.Length - inputCount) {
 194 #if NET_2_0
 195                                         throw new ArgumentException ("outputOffset + inputCount",
 196                                                 Locale.GetText ("Overflow"));
 197 #else
 198                                         throw new IndexOutOfRangeException ("outputBuffer");
 199 #endif
 200                                 }
 201                         }
 202
 203                         HashCore (inputBuffer, inputOffset, inputCount);
 204
 205                         if (outputBuffer != null)
 206                                 Buffer.BlockCopy (inputBuffer, inputOffset, outputBuffer, outputOffset, inputCount);
 207
 208                         return inputCount;
 209                 }
 210
 211                 public byte[] TransformFinalBlock (byte[] inputBuffer, int inputOffset, int inputCount)
 212                 {
 213                         if (inputBuffer == null)
 214                                 throw new ArgumentNullException ("inputBuffer");
 215                         if (inputCount < 0)
 216                                 throw new ArgumentException ("inputCount");
 217                         // ordered to avoid possible integer overflow
 218                         if (inputOffset > inputBuffer.Length - inputCount) {
 219                                 throw new ArgumentException ("inputOffset + inputCount",
 220                                         Locale.GetText ("Overflow"));
 221                         }
 222
 223                         byte[] outputBuffer = new byte [inputCount];
 224
 225                         // note: other exceptions are handled by Buffer.BlockCopy
 226                         Buffer.BlockCopy (inputBuffer, inputOffset, outputBuffer, 0, inputCount);
 227
 228                         HashCore (inputBuffer, inputOffset, inputCount);
 229                         HashValue = HashFinal ();
 230                         Initialize ();
 231
 232                         return outputBuffer;
 233                 }
 234         }
 235 }