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

   1 //
   2 // System.Security.Cryptography.HashAlgorithm.cs
   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         [ComVisible (true)]
  39         public abstract class HashAlgorithm : ICryptoTransform {
  40
  41                 protected internal byte[] HashValue;
  42                 protected int HashSizeValue;
  43                 protected int State;
  44                 private bool disposed;
  45
  46                 protected HashAlgorithm ()
  47                 {
  48                         disposed = false;
  49                 }
  50
  51                 public virtual bool CanTransformMultipleBlocks {
  52                         get { return true; }
  53                 }
  54
  55                 public virtual bool CanReuseTransform {
  56                         get { return true; }
  57                 }
  58
  59                 public void Clear ()
  60                 {
  61                         // same as System.IDisposable.Dispose() which is documented
  62                         Dispose (true);
  63                 }
  64
  65                 public byte[] ComputeHash (byte[] buffer)
  66                 {
  67                         if (buffer == null)
  68                                 throw new ArgumentNullException ("buffer");
  69
  70                         return ComputeHash (buffer, 0, buffer.Length);
  71                 }
  72
  73                 public byte[] ComputeHash (byte[] buffer, int offset, int count)
  74                 {
  75                         if (disposed)
  76                                 throw new ObjectDisposedException ("HashAlgorithm");
  77                         if (buffer == null)
  78                                 throw new ArgumentNullException ("buffer");
  79                         if (offset < 0)
  80                                 throw new ArgumentOutOfRangeException ("offset", "< 0");
  81                         if (count < 0)
  82                                 throw new ArgumentException ("count", "< 0");
  83                         // ordered to avoid possible integer overflow
  84                         if (offset > buffer.Length - count) {
  85                                 throw new ArgumentException ("offset + count",
  86                                         Locale.GetText ("Overflow"));
  87                         }
  88
  89                         HashCore (buffer, offset, count);
  90                         HashValue = HashFinal ();
  91                         Initialize ();
  92
  93                         return HashValue;
  94                 }
  95
  96                 public byte[] ComputeHash (Stream inputStream)
  97                 {
  98                         // don't read stream unless object is ready to use
  99                         if (disposed)
 100                                 throw new ObjectDisposedException ("HashAlgorithm");
 101
 102                         byte[] buffer = new byte [4096];
 103                         int len = inputStream.Read (buffer, 0, 4096);
 104                         while (len > 0) {
 105                                 HashCore (buffer, 0, len);
 106                                 len = inputStream.Read (buffer, 0, 4096);
 107                         }
 108                         HashValue = HashFinal ();
 109                         Initialize ();
 110                         return HashValue;
 111                 }
 112
 113                 public static HashAlgorithm Create ()
 114                 {
 115                         return Create ("System.Security.Cryptography.HashAlgorithm");
 116                 }
 117
 118                 public static HashAlgorithm Create (string hashName)
 119                 {
 120                         return (HashAlgorithm) CryptoConfig.CreateFromName (hashName);
 121                 }
 122
 123                 public virtual byte[] Hash {
 124                         get {
 125                                 if (HashValue == null) {
 126                                         throw new CryptographicUnexpectedOperationException (
 127                                                 Locale.GetText ("No hash value computed."));
 128                                 }
 129                                 return HashValue;
 130                         }
 131                 }
 132
 133                 protected abstract void HashCore (byte[] array, int ibStart, int cbSize);
 134
 135                 protected abstract byte[] HashFinal ();
 136
 137                 public virtual int HashSize {
 138                         get { return HashSizeValue; }
 139                 }
 140
 141                 public abstract void Initialize ();
 142
 143                 protected virtual void Dispose (bool disposing)
 144                 {
 145                         disposed = true;
 146                 }
 147
 148                 public virtual int InputBlockSize {
 149                         get { return 1; }
 150                 }
 151
 152                 public virtual int OutputBlockSize {
 153                         get { return 1; }
 154                 }
 155
 156                 void IDisposable.Dispose ()
 157                 {
 158                         Dispose (true);
 159                         GC.SuppressFinalize (this);  // Finalization is now unnecessary
 160                 }
 161
 162                 // LAMESPEC: outputBuffer is optional in 2.0 (i.e. can be null).
 163                 // However a null outputBuffer would throw a ExecutionEngineException under 1.x
 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
 169                         if (inputOffset < 0)
 170                                 throw new ArgumentOutOfRangeException ("inputOffset", "< 0");
 171                         if (inputCount < 0)
 172                                 throw new ArgumentException ("inputCount");
 173
 174                         // ordered to avoid possible integer overflow
 175                         if ((inputOffset < 0) || (inputOffset > inputBuffer.Length - inputCount))
 176                                 throw new ArgumentException ("inputBuffer");
 177
 178                         if (outputBuffer != null) {
 179                                 if (outputOffset < 0) {
 180                                         throw new ArgumentOutOfRangeException ("outputOffset", "< 0");
 181                                 }
 182                                 // ordered to avoid possible integer overflow
 183                                 if (outputOffset > outputBuffer.Length - inputCount) {
 184                                         throw new ArgumentException ("outputOffset + inputCount",
 185                                                 Locale.GetText ("Overflow"));
 186                                 }
 187                         }
 188
 189                         HashCore (inputBuffer, inputOffset, inputCount);
 190
 191                         if (outputBuffer != null)
 192                                 Buffer.BlockCopy (inputBuffer, inputOffset, outputBuffer, outputOffset, inputCount);
 193
 194                         return inputCount;
 195                 }
 196
 197                 public byte[] TransformFinalBlock (byte[] inputBuffer, int inputOffset, int inputCount)
 198                 {
 199                         if (inputBuffer == null)
 200                                 throw new ArgumentNullException ("inputBuffer");
 201                         if (inputCount < 0)
 202                                 throw new ArgumentException ("inputCount");
 203                         // ordered to avoid possible integer overflow
 204                         if (inputOffset > inputBuffer.Length - inputCount) {
 205                                 throw new ArgumentException ("inputOffset + inputCount",
 206                                         Locale.GetText ("Overflow"));
 207                         }
 208
 209                         byte[] outputBuffer = new byte [inputCount];
 210
 211                         // note: other exceptions are handled by Buffer.BlockCopy
 212                         Buffer.BlockCopy (inputBuffer, inputOffset, outputBuffer, 0, inputCount);
 213
 214                         HashCore (inputBuffer, inputOffset, inputCount);
 215                         HashValue = HashFinal ();
 216                         Initialize ();
 217
 218                         return outputBuffer;
 219                 }
 220         }
 221 }