mcs/class/corlib/ReferenceSources/ParseNumbers.cs

   1 //
   2 // ParseNumbers.cs
   3 //
   4 // Authors:
   5 //      Marek Safar  <marek.safar@gmail.com>
   6 //
   7 // Copyright (C) 2015 Xamarin Inc (http://www.xamarin.com)
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28
  29 using System.Globalization;
  30 using System.Text;
  31
  32 namespace System {
  33
  34     static class ParseNumbers
  35     {
  36         internal const int PrintAsI1=0x40;
  37         internal const int PrintAsI2=0x80;
  38 //        internal const int PrintAsI4=0x100;
  39         internal const int TreatAsUnsigned=0x200;
  40         internal const int TreatAsI1=0x400;
  41         internal const int TreatAsI2=0x800;
  42         internal const int IsTight=0x1000;
  43 //        internal const int NoSpace=0x2000;
  44
  45         public  static int StringToInt (string value, int fromBase, int flags)
  46                 {
  47                         if ((flags & IsTight) == 0)
  48                                 throw new NotImplementedException ();
  49
  50                         if (value == null)
  51                                 return 0;
  52
  53                         int chars = 0;
  54                         uint result = 0;
  55                         int digitValue;
  56
  57                         int i = 0;
  58                         int len = value.Length;
  59                         bool negative = false;
  60
  61                         if (len == 0) {
  62                                 // Mimic broken .net behaviour
  63                                 throw new ArgumentOutOfRangeException ("Empty string");
  64                         }
  65
  66                         //Check for a sign
  67                         if (value [i] == '-') {
  68                                 if (fromBase != 10)
  69                                         throw new ArgumentException ("String cannot contain a minus sign if the base is not 10.");
  70
  71                                 if ((flags & TreatAsUnsigned) != 0)
  72                                         throw new OverflowException ("Negative number");
  73
  74                                 negative = true;
  75                                 i++;
  76                         } else if (value [i] == '+') {
  77                                 i++;
  78                         }
  79
  80                         if (fromBase == 16 && i + 1 < len && value [i] =='0' && (value [i + 1] == 'x' || value [i + 1] == 'X')) {
  81                                 i += 2;
  82                         }
  83
  84                         uint max_value;
  85                         if ((flags & TreatAsI1) != 0) {
  86                                 max_value = Byte.MaxValue;
  87                         } else if ((flags & TreatAsI2) != 0) {
  88                                 max_value = UInt16.MaxValue;
  89                         } else {
  90                                 max_value = UInt32.MaxValue;
  91                         }
  92
  93                         while (i < len) {
  94                                 char c = value [i++];
  95                                 if (Char.IsNumber (c)) {
  96                                         digitValue = c - '0';
  97                                 } else if (Char.IsLetter (c)) {
  98                                         digitValue = Char.ToLowerInvariant (c) - 'a' + 10;
  99                                 } else {
 100                                         if (chars > 0) {
 101                                                 throw new FormatException ("Additional unparsable characters are at the end of the string.");
 102                                         }
 103
 104                                         throw new FormatException ("Could not find any parsable digits.");
 105                                 }
 106
 107                                 if (digitValue >= fromBase) {
 108                                         if (chars > 0) {
 109                                                 throw new FormatException ("Additional unparsable characters are at the end of the string.");
 110                                         }
 111
 112                                         throw new FormatException ("Could not find any parsable digits.");
 113                                 }
 114
 115                                 var res = (uint) fromBase * result + (uint) digitValue;
 116                                 if (res < result || res > max_value)
 117                                         throw new OverflowException ();
 118
 119                                 result = res;
 120                                 chars++;
 121                         }
 122
 123                         if (chars == 0)
 124                                 throw new FormatException ("Could not find any parsable digits.");
 125
 126                         return negative ? -(int)result : (int)result;
 127                 }
 128
 129                 public static string LongToString (long value, int toBase, int width, char paddingChar, int flags)
 130         {
 131                         if (value == 0)
 132                                 return "0";
 133                         if (toBase == 10)
 134                                 return value.ToString ();
 135
 136                         byte[] val = BitConverter.GetBytes (value);
 137
 138                         switch (toBase) {
 139                         case 2:
 140                                 return ConvertToBase2 (val);
 141                         case 8:
 142                                 return ConvertToBase8 (val);
 143                         case 16:
 144                                 return ConvertToBase16 (val);
 145                         default:
 146                                 throw new NotImplementedException ();
 147                         }
 148         }
 149
 150                 public static long StringToLong (string value, int fromBase, int flags)
 151                 {
 152                         if ((flags & IsTight) == 0)
 153                                 throw new NotImplementedException ();
 154
 155                         if (value == null)
 156                                 return 0;
 157
 158                         int chars = 0;
 159                         int digitValue = -1;
 160                         long result = 0;
 161
 162                         int i = 0;
 163                         int len = value.Length;
 164                         bool negative = false;
 165
 166                         if (len == 0) {
 167                                 // Mimic broken .net behaviour
 168                                 throw new ArgumentOutOfRangeException ("Empty string");
 169                         }
 170
 171                         //Check for a sign
 172                         if (value [i] == '-') {
 173                                 if (fromBase != 10)
 174                                         throw new ArgumentException ("String cannot contain a minus sign if the base is not 10.");
 175
 176                                 if ((flags & TreatAsUnsigned) != 0)
 177                                         throw new OverflowException ("Negative number");
 178
 179                                 negative = true;
 180                                 i++;
 181                         } else if (value [i] == '+') {
 182                                 i++;
 183                         }
 184
 185                         if (fromBase == 16 && i + 1 < len && value [i] =='0' && (value [i + 1] == 'x' || value [i + 1] == 'X')) {
 186                                 i += 2;
 187                         }
 188
 189                         while (i < len) {
 190                                 char c = value[i++];
 191                                 if (Char.IsNumber (c)) {
 192                                         digitValue = c - '0';
 193                                 } else if (Char.IsLetter (c)) {
 194                                         digitValue = Char.ToLowerInvariant (c) - 'a' + 10;
 195                                 } else {
 196                                         if (chars > 0) {
 197                                                 throw new FormatException ("Additional unparsable "
 198                                                         + "characters are at the end of the string.");
 199                                         } else {
 200                                                 throw new FormatException ("Could not find any parsable"
 201                                                         + " digits.");
 202                                         }
 203                                 }
 204
 205                                 if (digitValue >= fromBase) {
 206                                         if (chars > 0) {
 207                                                 throw new FormatException ("Additional unparsable "
 208                                                         + "characters are at the end of the string.");
 209                                         } else {
 210                                                 throw new FormatException ("Could not find any parsable"
 211                                                         + " digits.");
 212                                         }
 213                                 }
 214
 215                                 result = fromBase * result + digitValue;
 216                                 chars++;
 217                         }
 218
 219                         if (chars == 0)
 220                                 throw new FormatException ("Could not find any parsable digits.");
 221
 222                         return negative ? -result : result;
 223                 }
 224
 225                 public static string IntToString (int value, int toBase, int width, char paddingChar, int flags)
 226                 {
 227                         if (value == 0)
 228                                 return "0";
 229
 230                         if (toBase == 10)
 231                                 return value.ToString ();
 232
 233                         byte[] val;
 234                         if ((flags & PrintAsI1) != 0) {
 235                                 val = BitConverter.GetBytes ((byte) value);
 236                         } else if ((flags & PrintAsI2) != 0) {
 237                                 val = BitConverter.GetBytes ((short) value);
 238                         } else {
 239                                 val = BitConverter.GetBytes (value);
 240                         }
 241
 242                         switch (toBase) {
 243                         case 2:
 244                                 return ConvertToBase2 (val);
 245                         case 8:
 246                                 return ConvertToBase8 (val);
 247                         case 16:
 248                                 return ConvertToBase16 (val);
 249                         default:
 250                                 throw new NotImplementedException ();
 251                         }
 252                 }
 253
 254                 static void EndianSwap (ref byte[] value)
 255                 {
 256                         byte[] buf = new byte[value.Length];
 257                         for (int i = 0; i < value.Length; i++)
 258                                 buf[i] = value[value.Length-1-i];
 259                         value = buf;
 260                 }
 261
 262                 static string ConvertToBase2 (byte[] value)
 263                 {
 264                         if (!BitConverter.IsLittleEndian)
 265                                 EndianSwap (ref value);
 266                         StringBuilder sb = new StringBuilder ();
 267                         for (int i = value.Length - 1; i >= 0; i--) {
 268                                 byte b = value [i];
 269                                 for (int j = 0; j < 8; j++) {
 270                                         if ((b & 0x80) == 0x80) {
 271                                                 sb.Append ('1');
 272                                         }
 273                                         else {
 274                                                 if (sb.Length > 0)
 275                                                         sb.Append ('0');
 276                                         }
 277                                         b <<= 1;
 278                                 }
 279                         }
 280                         return sb.ToString ();
 281                 }
 282
 283                 static string ConvertToBase8 (byte[] value)
 284                 {
 285                         ulong l = 0;
 286                         switch (value.Length) {
 287                         case 1:
 288                                 l = (ulong) value [0];
 289                                 break;
 290                         case 2:
 291                                 l = (ulong) BitConverter.ToUInt16 (value, 0);
 292                                 break;
 293                         case 4:
 294                                 l = (ulong) BitConverter.ToUInt32 (value, 0);
 295                                 break;
 296                         case 8:
 297                                 l = BitConverter.ToUInt64 (value, 0);
 298                                 break;
 299                         default:
 300                                 throw new ArgumentException ("value");
 301                         }
 302
 303                         StringBuilder sb = new StringBuilder ();
 304                         for (int i = 21; i >= 0; i--) {
 305                                 // 3 bits at the time
 306                                 char val = (char) ((l >> i * 3) & 0x7);
 307                                 if ((val != 0) || (sb.Length > 0)) {
 308                                         val += '0';
 309                                         sb.Append (val);
 310                                 }
 311                         }
 312                         return sb.ToString ();
 313                 }
 314
 315                 static string ConvertToBase16 (byte[] value)
 316                 {
 317                         if (!BitConverter.IsLittleEndian)
 318                                 EndianSwap (ref value);
 319                         StringBuilder sb = new StringBuilder ();
 320                         for (int i = value.Length - 1; i >= 0; i--) {
 321                                 char high = (char)((value[i] >> 4) & 0x0f);
 322                                 if ((high != 0) || (sb.Length > 0)) {
 323                                         if (high < 10)
 324                                                 high += '0';
 325                                         else {
 326                                                 high -= (char) 10;
 327                                                 high += 'a';
 328                                         }
 329                                         sb.Append (high);
 330                                 }
 331
 332                                 char low = (char)(value[i] & 0x0f);
 333                                 if ((low != 0) || (sb.Length > 0)) {
 334                                         if (low < 10)
 335                                                 low += '0';
 336                                         else {
 337                                                 low -= (char) 10;
 338                                                 low += 'a';
 339                                         }
 340                                         sb.Append (low);
 341                                 }
 342                         }
 343                         return sb.ToString ();
 344                 }
 345
 346     }
 347 }