class/corlib/System/BitConverter.cs

   1 //
   2 // System.BitConverter.cs
   3 //
   4 // Author:
   5 //   Matt Kimball (matt@kimball.net)
   6 //
   7 //
   8 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
   9 //
  10 // Permission is hereby granted, free of charge, to any person obtaining
  11 // a copy of this software and associated documentation files (the
  12 // "Software"), to deal in the Software without restriction, including
  13 // without limitation the rights to use, copy, modify, merge, publish,
  14 // distribute, sublicense, and/or sell copies of the Software, and to
  15 // permit persons to whom the Software is furnished to do so, subject to
  16 // the following conditions:
  17 //
  18 // The above copyright notice and this permission notice shall be
  19 // included in all copies or substantial portions of the Software.
  20 //
  21 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  22 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  23 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  24 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  25 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  26 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  27 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  28 //
  29
  30 using System.Text;
  31
  32 namespace System
  33 {
  34         public
  35         static
  36         class BitConverter
  37         {
  38                 static readonly bool SwappedWordsInDouble = DoubleWordsAreSwapped ();
  39                 public static readonly bool IsLittleEndian = AmILittleEndian ();
  40
  41                 static unsafe bool AmILittleEndian ()
  42                 {
  43                         // binary representations of 1.0:
  44                         // big endian: 3f f0 00 00 00 00 00 00
  45                         // little endian: 00 00 00 00 00 00 f0 3f
  46                         // arm fpa little endian: 00 00 f0 3f 00 00 00 00
  47                         double d = 1.0;
  48                         byte *b = (byte*)&d;
  49                         return (b [0] == 0);
  50                 }
  51
  52                 static unsafe bool DoubleWordsAreSwapped ()
  53                 {
  54                         // binary representations of 1.0:
  55                         // big endian: 3f f0 00 00 00 00 00 00
  56                         // little endian: 00 00 00 00 00 00 f0 3f
  57                         // arm fpa little endian: 00 00 f0 3f 00 00 00 00
  58                         double d = 1.0;
  59                         byte *b = (byte*)&d;
  60                         return b [2] == 0xf0;
  61                 }
  62
  63                 public static long DoubleToInt64Bits (double value)
  64                 {
  65                         return ToInt64 (GetBytes (value), 0);
  66                 }
  67
  68                 public static double Int64BitsToDouble (long value)
  69                 {
  70                         return ToDouble (GetBytes (value), 0);
  71                 }
  72
  73                 internal static double InternalInt64BitsToDouble (long value)
  74                 {
  75                         return SwappableToDouble (GetBytes (value), 0);
  76                 }
  77
  78                 unsafe static byte[] GetBytes (byte *ptr, int count)
  79                 {
  80                         byte [] ret = new byte [count];
  81
  82                         for (int i = 0; i < count; i++) {
  83                                 ret [i] = ptr [i];
  84                         }
  85
  86                         return ret;
  87                 }
  88
  89                 unsafe public static byte[] GetBytes (bool value)
  90                 {
  91                         return GetBytes ((byte *) &value, 1);
  92                 }
  93
  94                 unsafe public static byte[] GetBytes (char value)
  95                 {
  96                         return GetBytes ((byte *) &value, 2);
  97                 }
  98
  99                 unsafe public static byte[] GetBytes (short value)
 100                 {
 101                         return GetBytes ((byte *) &value, 2);
 102                 }
 103
 104                 unsafe public static byte[] GetBytes (int value)
 105                 {
 106                         return GetBytes ((byte *) &value, 4);
 107                 }
 108
 109                 unsafe public static byte[] GetBytes (long value)
 110                 {
 111                         return GetBytes ((byte *) &value, 8);
 112                 }
 113
 114                 [CLSCompliant (false)]
 115                 unsafe public static byte[] GetBytes (ushort value)
 116                 {
 117                         return GetBytes ((byte *) &value, 2);
 118                 }
 119
 120                 [CLSCompliant (false)]
 121                 unsafe public static byte[] GetBytes (uint value)
 122                 {
 123                         return GetBytes ((byte *) &value, 4);
 124                 }
 125
 126                 [CLSCompliant (false)]
 127                 unsafe public static byte[] GetBytes (ulong value)
 128                 {
 129                         return GetBytes ((byte *) &value, 8);
 130                 }
 131
 132                 unsafe public static byte[] GetBytes (float value)
 133                 {
 134                         return GetBytes ((byte *) &value, 4);
 135                 }
 136
 137                 unsafe public static byte[] GetBytes (double value)
 138                 {
 139                         if (SwappedWordsInDouble) {
 140                                 byte[] data = new byte [8];
 141                                 byte *p = (byte*)&value;
 142                                 data [0] = p [4];
 143                                 data [1] = p [5];
 144                                 data [2] = p [6];
 145                                 data [3] = p [7];
 146                                 data [4] = p [0];
 147                                 data [5] = p [1];
 148                                 data [6] = p [2];
 149                                 data [7] = p [3];
 150                                 return data;
 151                         } else {
 152                                 return GetBytes ((byte *) &value, 8);
 153                         }
 154                 }
 155
 156                 unsafe static void PutBytes (byte *dst, byte[] src, int start_index, int count)
 157                 {
 158                         if (src == null)
 159                                 throw new ArgumentNullException ("value");
 160
 161                         if (start_index < 0 || (start_index > src.Length - 1))
 162                                 throw new ArgumentOutOfRangeException ("startIndex", "Index was"
 163                                         + " out of range. Must be non-negative and less than the"
 164                                         + " size of the collection.");
 165
 166                         // avoid integer overflow (with large pos/neg start_index values)
 167                         if (src.Length - count < start_index)
 168                                 throw new ArgumentException ("Destination array is not long"
 169                                         + " enough to copy all the items in the collection."
 170                                         + " Check array index and length.");
 171
 172                         for (int i = 0; i < count; i++)
 173                                 dst[i] = src[i + start_index];
 174                 }
 175
 176                 unsafe public static bool ToBoolean (byte[] value, int startIndex)
 177                 {
 178                         if (value == null)
 179                                 throw new ArgumentNullException ("value");
 180
 181                         if (startIndex < 0 || (startIndex > value.Length - 1))
 182                                 throw new ArgumentOutOfRangeException ("startIndex", "Index was"
 183                                         + " out of range. Must be non-negative and less than the"
 184                                         + " size of the collection.");
 185
 186                         if (value [startIndex] != 0)
 187                                 return true;
 188
 189                         return false;
 190                 }
 191
 192                 unsafe public static char ToChar (byte[] value, int startIndex)
 193                 {
 194                         char ret;
 195
 196                         PutBytes ((byte *) &ret, value, startIndex, 2);
 197
 198                         return ret;
 199                 }
 200
 201                 unsafe public static short ToInt16 (byte[] value, int startIndex)
 202                 {
 203                         short ret;
 204
 205                         PutBytes ((byte *) &ret, value, startIndex, 2);
 206
 207                         return ret;
 208                 }
 209
 210                 unsafe public static int ToInt32 (byte[] value, int startIndex)
 211                 {
 212                         int ret;
 213
 214                         PutBytes ((byte *) &ret, value, startIndex, 4);
 215
 216                         return ret;
 217                 }
 218
 219                 unsafe public static long ToInt64 (byte[] value, int startIndex)
 220                 {
 221                         long ret;
 222
 223                         PutBytes ((byte *) &ret, value, startIndex, 8);
 224
 225                         return ret;
 226                 }
 227
 228                 [CLSCompliant (false)]
 229                 unsafe public static ushort ToUInt16 (byte[] value, int startIndex)
 230                 {
 231                         ushort ret;
 232
 233                         PutBytes ((byte *) &ret, value, startIndex, 2);
 234
 235                         return ret;
 236                 }
 237
 238                 [CLSCompliant (false)]
 239                 unsafe public static uint ToUInt32 (byte[] value, int startIndex)
 240                 {
 241                         uint ret;
 242
 243                         PutBytes ((byte *) &ret, value, startIndex, 4);
 244
 245                         return ret;
 246                 }
 247
 248                 [CLSCompliant (false)]
 249                 unsafe public static ulong ToUInt64 (byte[] value, int startIndex)
 250                 {
 251                         ulong ret;
 252
 253                         PutBytes ((byte *) &ret, value, startIndex, 8);
 254
 255                         return ret;
 256                 }
 257
 258                 unsafe public static float ToSingle (byte[] value, int startIndex)
 259                 {
 260                         float ret;
 261
 262                         PutBytes ((byte *) &ret, value, startIndex, 4);
 263
 264                         return ret;
 265                 }
 266
 267                 unsafe public static double ToDouble (byte[] value, int startIndex)
 268                 {
 269                         double ret;
 270
 271                         if (SwappedWordsInDouble) {
 272                                 byte* p = (byte*)&ret;
 273                                 if (value == null)
 274                                         throw new ArgumentNullException ("value");
 275
 276                                 if (startIndex < 0 || (startIndex > value.Length - 1))
 277                                         throw new ArgumentOutOfRangeException ("startIndex", "Index was"
 278                                                 + " out of range. Must be non-negative and less than the"
 279                                                 + " size of the collection.");
 280
 281                                 // avoid integer overflow (with large pos/neg start_index values)
 282                                 if (value.Length - 8 < startIndex)
 283                                         throw new ArgumentException ("Destination array is not long"
 284                                                 + " enough to copy all the items in the collection."
 285                                                 + " Check array index and length.");
 286
 287                                 p [0] = value [startIndex + 4];
 288                                 p [1] = value [startIndex + 5];
 289                                 p [2] = value [startIndex + 6];
 290                                 p [3] = value [startIndex + 7];
 291                                 p [4] = value [startIndex + 0];
 292                                 p [5] = value [startIndex + 1];
 293                                 p [6] = value [startIndex + 2];
 294                                 p [7] = value [startIndex + 3];
 295
 296                                 return ret;
 297                         }
 298
 299                         PutBytes ((byte *) &ret, value, startIndex, 8);
 300
 301                         return ret;
 302                 }
 303
 304                 unsafe internal static double SwappableToDouble (byte[] value, int startIndex)
 305                 {
 306                         double ret;
 307
 308                         if (SwappedWordsInDouble) {
 309                                 byte* p = (byte*)&ret;
 310                                 if (value == null)
 311                                         throw new ArgumentNullException ("value");
 312
 313                                 if (startIndex < 0 || (startIndex > value.Length - 1))
 314                                         throw new ArgumentOutOfRangeException ("startIndex", "Index was"
 315                                                 + " out of range. Must be non-negative and less than the"
 316                                                 + " size of the collection.");
 317
 318                                 // avoid integer overflow (with large pos/neg start_index values)
 319                                 if (value.Length - 8 < startIndex)
 320                                         throw new ArgumentException ("Destination array is not long"
 321                                                 + " enough to copy all the items in the collection."
 322                                                 + " Check array index and length.");
 323
 324                                 p [0] = value [startIndex + 4];
 325                                 p [1] = value [startIndex + 5];
 326                                 p [2] = value [startIndex + 6];
 327                                 p [3] = value [startIndex + 7];
 328                                 p [4] = value [startIndex + 0];
 329                                 p [5] = value [startIndex + 1];
 330                                 p [6] = value [startIndex + 2];
 331                                 p [7] = value [startIndex + 3];
 332
 333                                 return ret;
 334                         } else if (!IsLittleEndian) {
 335                                 byte* p = (byte*)&ret;
 336                                 if (value == null)
 337                                         throw new ArgumentNullException ("value");
 338
 339                                 if (startIndex < 0 || (startIndex > value.Length - 1))
 340                                         throw new ArgumentOutOfRangeException ("startIndex", "Index was"
 341                                                 + " out of range. Must be non-negative and less than the"
 342                                                 + " size of the collection.");
 343
 344                                 // avoid integer overflow (with large pos/neg start_index values)
 345                                 if (value.Length - 8 < startIndex)
 346                                         throw new ArgumentException ("Destination array is not long"
 347                                                 + " enough to copy all the items in the collection."
 348                                                 + " Check array index and length.");
 349
 350                                 p [0] = value [startIndex + 7];
 351                                 p [1] = value [startIndex + 6];
 352                                 p [2] = value [startIndex + 5];
 353                                 p [3] = value [startIndex + 4];
 354                                 p [4] = value [startIndex + 3];
 355                                 p [5] = value [startIndex + 2];
 356                                 p [6] = value [startIndex + 1];
 357                                 p [7] = value [startIndex + 0];
 358
 359                                 return ret;
 360                         }
 361
 362                         PutBytes ((byte *) &ret, value, startIndex, 8);
 363
 364                         return ret;
 365                 }
 366
 367                 public static string ToString (byte[] value)
 368                 {
 369                         if (value == null)
 370                                 throw new ArgumentNullException ("value");
 371
 372                         return ToString (value, 0, value.Length);
 373                 }
 374
 375                 public static string ToString (byte[] value, int startIndex)
 376                 {
 377                         if (value == null)
 378                                 throw new ArgumentNullException ("value");
 379
 380                         return ToString (value, startIndex, value.Length - startIndex);
 381                 }
 382
 383                 public static string ToString (byte[] value, int startIndex, int length)
 384                 {
 385                         if (value == null)
 386                                 throw new ArgumentNullException ("byteArray");
 387
 388                         // The 4th and last clause (start_index >= value.Length)
 389                         // was added as a small fix to a very obscure bug.
 390                         // It makes a small difference when start_index is
 391                         // outside the range and length==0.
 392                         if (startIndex < 0 || startIndex >= value.Length) {
 393                                 // special (but valid) case (e.g. new byte [0])
 394                                 if ((startIndex == 0) && (value.Length == 0))
 395                                         return String.Empty;
 396                                 throw new ArgumentOutOfRangeException ("startIndex", "Index was"
 397                                         + " out of range. Must be non-negative and less than the"
 398                                         + " size of the collection.");
 399                         }
 400
 401                         if (length < 0)
 402                                 throw new ArgumentOutOfRangeException ("length",
 403                                         "Value must be positive.");
 404
 405                         // note: re-ordered to avoid possible integer overflow
 406                         if (startIndex > value.Length - length)
 407                                 throw new ArgumentException ("startIndex + length > value.Length");
 408
 409                         if (length == 0)
 410                                 return string.Empty;
 411
 412                         StringBuilder builder = new StringBuilder(length * 3 - 1);
 413                         int end = startIndex + length;
 414
 415                         for (int i = startIndex; i < end; i++) {
 416                                 if (i > startIndex)
 417                                         builder.Append('-');
 418
 419                                 char high = (char)((value[i] >> 4) & 0x0f);
 420                                 char low = (char)(value[i] & 0x0f);
 421
 422                                 if (high < 10)
 423                                         high += '0';
 424                                 else {
 425                                         high -= (char) 10;
 426                                         high += 'A';
 427                                 }
 428
 429                                 if (low < 10)
 430                                         low += '0';
 431                                 else {
 432                                         low -= (char) 10;
 433                                         low += 'A';
 434                                 }
 435                                 builder.Append(high);
 436                                 builder.Append(low);
 437                         }
 438
 439                         return builder.ToString ();
 440                 }
 441         }
 442 }