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) 2004-2005 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
  35 namespace System.Security.Cryptography {
  36
  37         public abstract class HashAlgorithm : ICryptoTransform {
  38
  39                 protected byte[] HashValue;
  40                 protected int HashSizeValue;
  41                 protected int State;
  42                 private bool disposed;
  43
  44                 protected HashAlgorithm ()
  45                 {
  46                         disposed = false;
  47                 }
  48
  49                 public virtual bool CanTransformMultipleBlocks {
  50                         get { return true; }
  51                 }
  52
  53                 public virtual bool CanReuseTransform {
  54                         get { return true; }
  55                 }
  56
  57                 public void Clear ()
  58                 {
  59                         // same as System.IDisposable.Dispose() which is documented
  60                         Dispose (true);
  61                 }
  62
  63                 public byte[] ComputeHash (byte[] input)
  64                 {
  65                         if (input == null)
  66                                 throw new ArgumentNullException ("input");
  67
  68                         return ComputeHash (input, 0, input.Length);
  69                 }
  70
  71                 public byte[] ComputeHash (byte[] buffer, int offset, int count)
  72                 {
  73                         if (disposed)
  74                                 throw new ObjectDisposedException ("HashAlgorithm");
  75                         if (buffer == null)
  76                                 throw new ArgumentNullException ("buffer");
  77                         if (offset < 0)
  78                                 throw new ArgumentOutOfRangeException ("offset", "< 0");
  79                         if (count < 0)
  80                                 throw new ArgumentException ("count", "< 0");
  81                         // ordered to avoid possible integer overflow
  82                         if (offset > buffer.Length - count) {
  83                                 throw new ArgumentException ("offset + count",
  84                                         Locale.GetText ("Overflow"));
  85                         }
  86
  87                         HashCore (buffer, offset, count);
  88                         HashValue = HashFinal ();
  89                         Initialize ();
  90
  91                         return HashValue;
  92                 }
  93
  94                 public byte[] ComputeHash (Stream inputStream)
  95                 {
  96                         // don't read stream unless object is ready to use
  97                         if (disposed)
  98                                 throw new ObjectDisposedException ("HashAlgorithm");
  99
 100                         byte[] buffer = new byte [4096];
 101                         int len = inputStream.Read (buffer, 0, 4096);
 102                         while (len > 0) {
 103                                 HashCore (buffer, 0, len);
 104                                 len = inputStream.Read (buffer, 0, 4096);
 105                         }
 106                         HashValue = HashFinal ();
 107                         Initialize ();
 108                         return HashValue;
 109                 }
 110
 111                 public static HashAlgorithm Create ()
 112                 {
 113                         return Create ("System.Security.Cryptography.HashAlgorithm");
 114                 }
 115
 116                 public static HashAlgorithm Create (string hashName)
 117                 {
 118                         return (HashAlgorithm) CryptoConfig.CreateFromName (hashName);
 119                 }
 120
 121                 public virtual byte[] Hash {
 122                         get {
 123                                 if (HashValue == null) {
 124                                         throw new CryptographicUnexpectedOperationException (
 125                                                 Locale.GetText ("No hash value computed."));
 126                                 }
 127                                 return HashValue;
 128                         }
 129                 }
 130
 131                 protected abstract void HashCore (byte[] rgb, int start, int size);
 132
 133                 protected abstract byte[] HashFinal ();
 134
 135                 public virtual int HashSize {
 136                         get { return HashSizeValue; }
 137                 }
 138
 139                 public abstract void Initialize ();
 140
 141                 protected virtual void Dispose (bool disposing)
 142                 {
 143                         disposed = true;
 144                 }
 145
 146                 public virtual int InputBlockSize {
 147                         get { return 1; }
 148                 }
 149
 150                 public virtual int OutputBlockSize {
 151                         get { return 1; }
 152                 }
 153
 154                 void IDisposable.Dispose ()
 155                 {
 156                         Dispose (true);
 157                         GC.SuppressFinalize (this);  // Finalization is now unnecessary
 158                 }
 159
 160                 public int TransformBlock (byte[] inputBuffer, int inputOffset, int inputCount, byte[] outputBuffer, int outputOffset)
 161                 {
 162                         if (inputBuffer == null)
 163                                 throw new ArgumentNullException ("inputBuffer");
 164                         if (outputBuffer == null)
 165                                 throw new ArgumentNullException ("outputBuffer");
 166
 167                         if (inputOffset < 0)
 168                                 throw new ArgumentOutOfRangeException ("inputOffset", "< 0");
 169                         if (inputCount < 0)
 170                                 throw new ArgumentException ("inputCount");
 171
 172                         // ordered to avoid possible integer overflow
 173                         if ((inputOffset < 0) || (inputOffset > inputBuffer.Length - inputCount))
 174                                 throw new ArgumentException ("inputBuffer");
 175                         if (outputOffset < 0) {
 176 #if NET_2_0
 177                                 throw new ArgumentOutOfRangeException ("outputOffset", "< 0");
 178 #else
 179                                 throw new IndexOutOfRangeException ("outputBuffer");
 180 #endif
 181                         }
 182                         if (outputOffset > outputBuffer.Length - inputCount) {
 183 #if NET_2_0
 184                                 throw new ArgumentException ("outputOffset + inputCount",
 185                                         Locale.GetText ("Overflow"));
 186 #else
 187                                 throw new IndexOutOfRangeException ("outputBuffer");
 188 #endif
 189                         }
 190                         // ordered to avoid possible integer overflow
 191
 192                         // note: other exceptions are handled by Buffer.BlockCopy
 193                         Buffer.BlockCopy (inputBuffer, inputOffset, outputBuffer, outputOffset, inputCount);
 194                         HashCore (inputBuffer, inputOffset, inputCount);
 195
 196                         return inputCount;
 197                 }
 198
 199                 public byte[] TransformFinalBlock (byte[] inputBuffer, int inputOffset, int inputCount)
 200                 {
 201                         if (inputBuffer == null)
 202                                 throw new ArgumentNullException ("inputBuffer");
 203                         if (inputCount < 0)
 204                                 throw new ArgumentException ("inputCount");
 205                         // ordered to avoid possible integer overflow
 206                         if (inputOffset > inputBuffer.Length - inputCount) {
 207                                 throw new ArgumentException ("inputOffset + inputCount",
 208                                         Locale.GetText ("Overflow"));
 209                         }
 210
 211                         byte[] outputBuffer = new byte [inputCount];
 212
 213                         // note: other exceptions are handled by Buffer.BlockCopy
 214                         Buffer.BlockCopy (inputBuffer, inputOffset, outputBuffer, 0, inputCount);
 215
 216                         HashCore (inputBuffer, inputOffset, inputCount);
 217                         HashValue = HashFinal ();
 218                         Initialize ();
 219
 220                         return outputBuffer;
 221                 }
 222         }
 223 }