bundles/winterwell.markdown/src/winterwell/markdown/editors/EmphasisRule.java

   1 /**\r
   2  * Copyright winterwell Mathematics Ltd.\r
   3  * @author Daniel Winterstein\r
   4  * 11 Jan 2007\r
   5  */\r
   6 package winterwell.markdown.editors;\r
   7 \r
   8 import org.eclipse.core.runtime.Assert;\r
   9 import org.eclipse.jface.text.rules.ICharacterScanner;\r
  10 import org.eclipse.jface.text.rules.IRule;\r
  11 import org.eclipse.jface.text.rules.IToken;\r
  12 import org.eclipse.jface.text.rules.MultiLineRule;\r
  13 import org.eclipse.jface.text.rules.Token;\r
  14 \r
  15 /**\r
  16  * \r
  17  *\r
  18  * @author Daniel Winterstein\r
  19  */\r
  20 public class EmphasisRule implements IRule {\r
  21         private static char[][] fDelimiters = null;\r
  22         private char[] fSequence;\r
  23         protected IToken fToken;\r
  24 \r
  25 \r
  26         public EmphasisRule(String marker, IToken token) {\r
  27                 assert marker.equals("*") || marker.equals("_") || marker.equals("**")\r
  28                                 || marker.equals("***") || marker.equals("`") || marker.equals("``");\r
  29                 Assert.isNotNull(token);\r
  30                 fSequence = marker.toCharArray();\r
  31                 fToken = token;\r
  32         }\r
  33         \r
  34         // Copied from org.eclipse.jface.text.rules.PatternRule\r
  35         protected boolean sequenceDetected(ICharacterScanner scanner, char[] sequence, boolean eofAllowed) {\r
  36                 for (int i = 1; i < sequence.length; i++) {\r
  37                         int c = scanner.read();\r
  38                         if (c == ICharacterScanner.EOF && eofAllowed) {\r
  39                                 return true;\r
  40                         } else if (c != sequence[i]) {\r
  41                                 // Non-matching character detected, rewind the scanner back to\r
  42                                 // the start.\r
  43                                 // Do not unread the first character.\r
  44                                 for (int j = i; j > 0; j--)\r
  45                                         scanner.unread();\r
  46                                 return false;\r
  47                         }\r
  48                 }\r
  49                 return true;\r
  50         }\r
  51 \r
  52         /*\r
  53          * @see IRule#evaluate(ICharacterScanner)\r
  54          * \r
  55          * @since 2.0\r
  56          */\r
  57         public IToken evaluate(ICharacterScanner scanner) {\r
  58                 // Should be connected only on the right side\r
  59                 scanner.unread();\r
  60                 boolean sawSpaceBefore = Character.isWhitespace(scanner.read());\r
  61                 if (!sawSpaceBefore && scanner.getColumn() != 0) {\r
  62                         return Token.UNDEFINED;\r
  63                 }\r
  64 \r
  65                 int c = scanner.read();\r
  66                 // Should be connected only on right side\r
  67                 if (c != fSequence[0] || !sequenceDetected(scanner, fSequence, false)) {\r
  68                         scanner.unread();\r
  69                         return Token.UNDEFINED;\r
  70                 }\r
  71                 int readCount = fSequence.length;\r
  72                 if (fDelimiters == null) {\r
  73                         fDelimiters = scanner.getLegalLineDelimiters();\r
  74                 }\r
  75                 // Start sequence detected\r
  76                 int delimiterFound = 0;\r
  77                 // Is it a list item marker, or just a floating *?\r
  78                 if (sawSpaceBefore) {\r
  79                         boolean after = Character.isWhitespace(scanner.read());\r
  80                         scanner.unread();\r
  81                         if (after)\r
  82                                 delimiterFound = 2;\r
  83                 }\r
  84 \r
  85                 while (delimiterFound < 2\r
  86                                 && (c = scanner.read()) != ICharacterScanner.EOF) {\r
  87                         readCount++;\r
  88 \r
  89                         if (!sawSpaceBefore && c == fSequence[0]\r
  90                                         && sequenceDetected(scanner, fSequence, false)) {\r
  91                                 return fToken;\r
  92                         }\r
  93 \r
  94                         int i;\r
  95                         for (i = 0; i < fDelimiters.length; i++) {\r
  96                                 if (c == fDelimiters[i][0]\r
  97                                                 && sequenceDetected(scanner, fDelimiters[i], true)) {\r
  98                                         delimiterFound++;\r
  99                                         break;\r
 100                                 }\r
 101                         }\r
 102                         if (i == fDelimiters.length)\r
 103                                 delimiterFound = 0;\r
 104                         sawSpaceBefore = Character.isWhitespace(c);\r
 105                 }\r
 106                 // Reached ICharacterScanner.EOF\r
 107                 for (; readCount > 0; readCount--)\r
 108                         scanner.unread();\r
 109                 return Token.UNDEFINED;\r
 110         }\r
 111         \r
 112 }\r