ilasm/scanner/ILReader.cs

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