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