net.sourceforge.phpeclipse.ui/src/net/sourceforge/phpdt/internal/ui/text/PHPPairMatcher.java

   1 package net.sourceforge.phpdt.internal.ui.text;
   2
   3 /*
   4  * (c) Copyright IBM Corp. 2000, 2001.
   5  * All Rights Reserved.
   6  */
   7
   8 import java.io.IOException;
   9
  10 import org.eclipse.jface.text.BadLocationException;
  11 import org.eclipse.jface.text.IDocument;
  12 import org.eclipse.jface.text.IRegion;
  13 import org.eclipse.jface.text.Region;
  14 import org.eclipse.jface.text.source.ICharacterPairMatcher;
  15
  16 /**
  17  * Helper class for match pairs of characters.
  18  */
  19 public class PHPPairMatcher implements ICharacterPairMatcher {
  20         protected char[] fPairs;
  21
  22         protected IDocument fDocument;
  23
  24         protected int fOffset;
  25
  26         protected int fStartPos;
  27
  28         protected int fEndPos;
  29
  30         protected int fAnchor;
  31
  32         protected PHPCodeReader fReader = new PHPCodeReader();
  33
  34         public PHPPairMatcher(char[] pairs) {
  35                 fPairs = pairs;
  36         }
  37
  38         /*
  39          * @see org.eclipse.jface.text.source.ICharacterPairMatcher#clear()
  40          */
  41         public void clear() {
  42                 if (fReader != null) {
  43                         try {
  44                                 fReader.close();
  45                         } catch (IOException x) {
  46                                 // ignore
  47                         }
  48                 }
  49         }
  50
  51         public IRegion match(IDocument document, int offset) {
  52
  53                 fOffset = offset;
  54
  55                 if (fOffset < 0)
  56                         return null;
  57
  58                 fDocument = document;
  59
  60                 if (matchPairsAt() && fStartPos != fEndPos)
  61                         return new Region(fStartPos, fEndPos - fStartPos + 1);
  62
  63                 return null;
  64         }
  65
  66         public int getAnchor() {
  67                 return fAnchor;
  68         }
  69
  70         public void dispose() {
  71                 fDocument = null;
  72                 if (fReader != null) {
  73                         try {
  74                                 fReader.close();
  75                         } catch (IOException x) {
  76                                 // ignore
  77                         }
  78                         fReader = null;
  79                 }
  80         }
  81
  82         protected boolean matchPairsAt() {
  83
  84                 int i;
  85                 int pairIndex1 = fPairs.length;
  86                 int pairIndex2 = fPairs.length;
  87
  88                 fStartPos = -1;
  89                 fEndPos = -1;
  90
  91                 // get the chars preceding and following the start position
  92                 try {
  93
  94                         char prevChar = fDocument.getChar(Math.max(fOffset - 1, 0));
  95                         char nextChar = fDocument.getChar(fOffset);
  96
  97                         // search for opening peer character next to the activation point
  98                         for (i = 0; i < fPairs.length; i = i + 2) {
  99                                 if (nextChar == fPairs[i]) {
 100                                         fStartPos = fOffset;
 101                                         pairIndex1 = i;
 102                                 } else if (prevChar == fPairs[i]) {
 103                                         fStartPos = fOffset - 1;
 104                                         pairIndex1 = i;
 105                                 }
 106                         }
 107
 108                         // search for closing peer character next to the activation point
 109                         for (i = 1; i < fPairs.length; i = i + 2) {
 110                                 if (prevChar == fPairs[i]) {
 111                                         fEndPos = fOffset - 1;
 112                                         pairIndex2 = i;
 113                                 } else if (nextChar == fPairs[i]) {
 114                                         fEndPos = fOffset;
 115                                         pairIndex2 = i;
 116                                 }
 117                         }
 118
 119                         if (fEndPos > -1) {
 120                                 fAnchor = RIGHT;
 121                                 fStartPos = searchForOpeningPeer(fEndPos,
 122                                                 fPairs[pairIndex2 - 1], fPairs[pairIndex2], fDocument);
 123                                 if (fStartPos > -1)
 124                                         return true;
 125                                 else
 126                                         fEndPos = -1;
 127                         } else if (fStartPos > -1) {
 128                                 fAnchor = LEFT;
 129                                 fEndPos = searchForClosingPeer(fStartPos, fPairs[pairIndex1],
 130                                                 fPairs[pairIndex1 + 1], fDocument);
 131                                 if (fEndPos > -1)
 132                                         return true;
 133                                 else
 134                                         fStartPos = -1;
 135                         }
 136
 137                 } catch (BadLocationException x) {
 138                 } catch (IOException x) {
 139                 }
 140
 141                 return false;
 142         }
 143
 144         protected int searchForClosingPeer(int offset, int openingPeer,
 145                         int closingPeer, IDocument document) throws IOException {
 146
 147                 fReader.configureForwardReader(document, offset + 1, document
 148                                 .getLength(), true, true);
 149
 150                 int stack = 1;
 151                 int c = fReader.read();
 152                 while (c != PHPCodeReader.EOF) {
 153                         if (c == openingPeer && c != closingPeer)
 154                                 stack++;
 155                         else if (c == closingPeer)
 156                                 stack--;
 157
 158                         if (stack == 0)
 159                                 return fReader.getOffset();
 160
 161                         c = fReader.read();
 162                 }
 163
 164                 return -1;
 165         }
 166
 167         protected int searchForOpeningPeer(int offset, int openingPeer,
 168                         int closingPeer, IDocument document) throws IOException {
 169
 170                 fReader.configureBackwardReader(document, offset, true, true);
 171
 172                 int stack = 1;
 173                 int c = fReader.read();
 174                 while (c != PHPCodeReader.EOF) {
 175                         if (c == closingPeer && c != openingPeer)
 176                                 stack++;
 177                         else if (c == openingPeer)
 178                                 stack--;
 179
 180                         if (stack == 0)
 181                                 return fReader.getOffset();
 182
 183                         c = fReader.read();
 184                 }
 185
 186                 return -1;
 187         }
 188 }