mcs/ilasm/scanner/ILReader.cs

   1 // ILReader.cs\r
   2 // Author: Sergey Chaban (serge@wildwestsoftware.com)\r
   3 \r
   4 using System;\r
   5 using System.IO;\r
   6 using System.Text;\r
   7 using System.Collections;\r
   8 \r
   9 namespace Mono.ILASM {\r
  10 \r
  11 \r
  12         /// <summary>\r
  13         /// </summary>\r
  14         public class ILReader {\r
  15                 \r
  16                 private StreamReader reader;\r
  17                 private Stack putback_stack;\r
  18                 private Location location;\r
  19                 private Location markedLocation;\r
  20                 \r
  21                 public ILReader (StreamReader reader)\r
  22                 {\r
  23                         this.reader = reader;\r
  24                         putback_stack = new Stack ();\r
  25                         \r
  26                         location = new Location ();\r
  27                         markedLocation = Location.Unknown;\r
  28                 }\r
  29 \r
  30 \r
  31 \r
  32                 /// <summary>\r
  33                 /// </summary>\r
  34                 public Location Location {\r
  35                         get {\r
  36                                 return location;\r
  37                         }\r
  38                 }\r
  39 \r
  40 \r
  41                 /// <summary>\r
  42                 /// Provides access to underlying StreamReader.\r
  43                 /// </summary>\r
  44                 public StreamReader BaseReader {\r
  45                         get {\r
  46                                 return reader;\r
  47                         }\r
  48                 }\r
  49 \r
  50                 private int DoRead ()\r
  51                 {\r
  52                         if (putback_stack.Count > 0) \r
  53                                 return (char) putback_stack.Pop ();\r
  54                         \r
  55                         return reader.Read ();\r
  56                 }\r
  57 \r
  58                 private int DoPeek ()\r
  59                 {\r
  60                         if (putback_stack.Count > 0)\r
  61                                 return (char) putback_stack.Peek ();\r
  62                         \r
  63                         return reader.Peek ();\r
  64                 }\r
  65 \r
  66                 /// <summary>\r
  67                 /// </summary>\r
  68                 /// <returns></returns>\r
  69                 public int Read ()\r
  70                 {\r
  71                         int read = DoRead ();\r
  72                         if (read == '\n')\r
  73                                 location.NewLine ();\r
  74                         else\r
  75                                 location.NextColumn ();\r
  76                         return read;\r
  77                 }\r
  78 \r
  79                 /// <summary>\r
  80                 /// </summary>\r
  81                 /// <returns></returns>\r
  82                 public int Peek ()\r
  83                 {\r
  84                         return DoPeek ();\r
  85                 }\r
  86 \r
  87 \r
  88                 /// <summary>\r
  89                 /// </summary>\r
  90                 public void Unread (char c)\r
  91                 {\r
  92                         putback_stack.Push (c);\r
  93 \r
  94                         if ('\n' == c)\r
  95                                 location.PreviousLine ();\r
  96 \r
  97                         location.PreviousColumn ();\r
  98                 }\r
  99 \r
 100 \r
 101                 /// <summary>\r
 102                 /// </summary>\r
 103                 /// <param name="chars"></param>\r
 104                 public void Unread (char [] chars)\r
 105                 {\r
 106                         for (int i=chars.Length-1; i>=0; i--)\r
 107                                 Unread (chars[i]);                                      \r
 108                 }\r
 109 \r
 110                 /// <summary>\r
 111                 /// </summary>\r
 112                 /// <param name="c"></param>\r
 113                 public void Unread (int c)\r
 114                 {\r
 115                         Unread ((char)c);\r
 116                 }\r
 117 \r
 118 \r
 119                 /// <summary>\r
 120                 /// </summary>\r
 121                 public void SkipWhitespace ()\r
 122                 {\r
 123                         int ch = Read ();\r
 124                         for (; ch != -1 && Char.IsWhiteSpace((char) ch); ch = Read ());\r
 125                         if (ch != -1) Unread (ch);\r
 126                 }\r
 127 \r
 128 \r
 129                 /// <summary>\r
 130                 /// </summary>\r
 131                 /// <returns></returns>\r
 132                 public string ReadToWhitespace ()\r
 133                 {\r
 134                         StringBuilder sb = new StringBuilder ();\r
 135                         int ch = Read ();\r
 136                         for (; ch != -1 && !Char.IsWhiteSpace((char) ch); sb.Append ((char) ch), ch = Read ());\r
 137                         if (ch != -1) Unread (ch);\r
 138                         return sb.ToString ();\r
 139                 }\r
 140 \r
 141 \r
 142                 /// <summary>\r
 143                 /// </summary>\r
 144                 public void MarkLocation ()\r
 145                 {\r
 146                         if (markedLocation == Location.Unknown) {\r
 147                                 markedLocation = new Location (location);\r
 148                         } else {\r
 149                                 markedLocation.CopyFrom (location);\r
 150                         }\r
 151                 }\r
 152 \r
 153 \r
 154                 /// <summary>\r
 155                 /// </summary>\r
 156                 public void RestoreLocation ()\r
 157                 {\r
 158                         if (markedLocation != Location.Unknown) {\r
 159                                 location.CopyFrom (markedLocation);\r
 160                         }\r
 161                 }\r
 162 \r
 163         }\r
 164 \r
 165 }\r
 166 \r