mcs/ilasm/scanner/NumberHelper.cs

   1 // NumberHelper.cs\r
   2 // Author: Sergey Chaban (serge@wildwestsoftware.com)\r
   3 \r
   4 using System;\r
   5 using System.Globalization;\r
   6 \r
   7 namespace Mono.ILASM {\r
   8 \r
   9         /// <summary>\r
  10         /// </summary>\r
  11         internal class NumberHelper : StringHelperBase {\r
  12 \r
  13                 private ILToken result;\r
  14 \r
  15                 /// <summary>\r
  16                 /// </summary>\r
  17                 /// <param name="host"></param>\r
  18                 public NumberHelper (ILTokenizer host) : base (host)\r
  19                 {\r
  20                         Reset ();\r
  21                 }\r
  22 \r
  23 \r
  24                 private void Reset ()\r
  25                 {\r
  26                         result = ILToken.Invalid.Clone() as ILToken;\r
  27                 }\r
  28 \r
  29                 /// <summary>\r
  30                 /// </summary>\r
  31                 /// <returns></returns>\r
  32                 public override bool Start (char ch)\r
  33                 {\r
  34                         bool res = (Char.IsDigit (ch) || ch == '-' || (ch == '.' && Char.IsDigit ((char) host.Reader.Peek ())));\r
  35                         Reset ();\r
  36                         return res;\r
  37                 }\r
  38 \r
  39                 /// <summary>\r
  40                 /// </summary>\r
  41                 /// <returns></returns>\r
  42                 public override string Build ()\r
  43                 {\r
  44                         ILReader reader = host.Reader;\r
  45                         reader.MarkLocation ();\r
  46                         string num = reader.ReadToWhitespace ();\r
  47 \r
  48                         NumberStyles nstyles = NumberStyles.AllowExponent | NumberStyles.AllowDecimalPoint;\r
  49 \r
  50                         try {\r
  51                                 if (num.IndexOf ('.') != -1) {\r
  52                                         double d = Double.Parse (num, nstyles, NumberFormatInfo.InvariantInfo);\r
  53                                         result.token = Token.FLOAT64;\r
  54                                         result.val = d;\r
  55                                 } else {\r
  56                                         long i = Int64.Parse (num, nstyles);\r
  57                                         if (i < Int32.MinValue || i > Int32.MaxValue) {\r
  58                                                 result.token = Token.INT64;\r
  59                                                 result.val = i;\r
  60                                         } else {\r
  61                                                 result.token = Token.INT32;\r
  62                                                 result.val = (int) i;\r
  63                                         }\r
  64                                 }\r
  65                         } catch {\r
  66                                 reader.Unread (num.ToCharArray ());\r
  67                                 reader.RestoreLocation ();\r
  68                                 num = String.Empty;\r
  69                                 Reset ();\r
  70                                 throw new ILSyntaxError ("Bad number format!");\r
  71                         }\r
  72                         return num;\r
  73                 }\r
  74 \r
  75 \r
  76                 /// <summary>\r
  77                 /// </summary>\r
  78                 public ILToken ResultToken {\r
  79                         get {\r
  80                                 return result;\r
  81                         }\r
  82                 }\r
  83 \r
  84 \r
  85         }\r
  86 \r
  87 }\r