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 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;           // Holds the brace pairs
  21
  22         protected IDocument fDocument;
  23
  24         protected int       fOffset;          // The current text position from which we search
  25         protected int       nPosOpening;      // The position of the opening brace
  26         protected int       nPosClosing;      // The position of the closing brace
  27         protected int       fAnchor;
  28
  29         protected PHPCodeReader fReader = new PHPCodeReader();
  30
  31         /**
  32          *
  33          * @param pairs The array of opening and closing braces we need for searching the brace matching
  34          */
  35
  36         public PHPPairMatcher (char[] pairs) {
  37                 fPairs = pairs;
  38         }
  39
  40         /*
  41          * @see org.eclipse.jface.text.source.ICharacterPairMatcher#clear()
  42          */
  43         public void clear() {
  44                 if (fReader != null) {
  45                         try {
  46                                 fReader.close();
  47                         } catch (IOException x) {
  48                                 // ignore
  49                         }
  50                 }
  51         }
  52
  53         /**
  54          * Try to find a matching pair of opening and closing braces
  55          *
  56          * @return  Returns a region if a matching pair was found.
  57          */
  58
  59         public IRegion match (IDocument document, int offset) {
  60                 fOffset = offset;
  61
  62                 if (fOffset < 0) {
  63                         return null;
  64                 }
  65
  66                 fDocument = document;
  67
  68                 if (matchPairsAt ()) {                                                                          // If we found a pair of opening and closing braces
  69                         return new Region (nPosOpening, nPosClosing - nPosOpening + 1);
  70                 }
  71
  72                 return null;
  73         }
  74
  75         public int getAnchor() {
  76                 return fAnchor;
  77         }
  78
  79         public void dispose() {
  80                 fDocument = null;
  81                 if (fReader != null) {
  82                         try {
  83                                 fReader.close();
  84                         } catch (IOException x) {
  85                                 // ignore
  86                         }
  87                         fReader = null;
  88                 }
  89         }
  90
  91         /**
  92          * Take the character from the current text position, checks for opening or closing braces and search for
  93          * the corresponding opening or closing brace
  94          *
  95          * @return True if a pair was found
  96          */
  97         protected boolean matchPairsAt() {
  98                 int   i;
  99                 int   nIndexOpen  = fPairs.length;        // Opening index
 100                 int   nIndexClose = fPairs.length;
 101                 char  cCurrentChar;                       // The character from the current text position
 102                 char  cPrevChar;                          // The character from the previouis text position, just
 103                                                           // for the case the user pointed the cursor after the opening or closing brace
 104
 105                 nPosOpening = -1;
 106                 nPosClosing = -1;
 107
 108                 // get the chars preceding and following the start position
 109                 try {
 110             cCurrentChar = fDocument.getChar (fOffset);
 111                         cPrevChar    = fDocument.getChar (Math.max (fOffset - 1, 0));
 112
 113                         // search for opening peer character next to the activation point
 114                         for (i = 0; i < fPairs.length; i = i + 2) {     // The opening brace is on even indexes
 115                                 if (cCurrentChar == fPairs[i]) {            // If the current character matches an opening brace
 116                                         nPosOpening  = fOffset;                 // Remember the character position
 117                                         nIndexOpen   = i;                       // and remember the opening brace for which we search the closing one
 118                                 }
 119                                 else if (cPrevChar == fPairs[i]) {          // If the current character is not an opening, but the previous character is an opening brace
 120                                         nPosOpening  = fOffset - 1;             // Remember the character position
 121                                         nIndexOpen   = i;                       // and remember the opening brace for which we search the closing one
 122                                 }
 123                         }
 124
 125                         // search for closing peer character next to the activation point
 126
 127                         if (nPosOpening < 0) {                              // If we didn't find an opening brace
 128                                 for (i = 1; i < fPairs.length; i = i + 2) {     // The closing brace is on odd indexes
 129                                         if (cCurrentChar == fPairs[i]) {            // If the current character matches an closing brace
 130                                                 nPosClosing  = fOffset;                 // Remember the character position
 131                                                 nIndexClose  = i;                       // and remember the opening brace for which we search the closing one
 132                                         }
 133                                         else if (cPrevChar == fPairs[i]) {          // If the current character is not an opening, but the previous character is an opening brace
 134                                                 nPosClosing  = fOffset - 1;             // Remember the character position
 135                                                 nIndexClose  = i;                       // and remember the opening brace for which we search the closing one
 136                                         }
 137                                 }
 138                         }
 139
 140                         if (nPosClosing > -1) {                             // If we found a closing brace on current position (or before)
 141                                 fAnchor     = RIGHT;
 142                                 nPosOpening = searchForOpeningPeer (nPosClosing, fPairs[nIndexClose - 1], fPairs[nIndexClose], fDocument);
 143
 144                                 return (nPosOpening > -1);                      // If we found a opening brace, return true
 145                         }
 146                         else if (nPosOpening > -1) {                        // If we found a opening brace on current position (or before)
 147                                 fAnchor     = LEFT;
 148                                 nPosClosing = searchForClosingPeer (nPosOpening, fPairs[nIndexOpen], fPairs[nIndexOpen + 1], fDocument);
 149
 150                                 return (nPosClosing > -1);                      // If we found an closing brace for this opening brace return true
 151                         }
 152                 }
 153                 catch (BadLocationException x) {
 154                 }
 155                 catch (IOException x) {
 156                 }
 157
 158                 return false;
 159         }
 160
 161         /**
 162          *
 163          * @param offset               The search start position
 164          * @param openingPeer          The opening brace we had found
 165          * @param closingPeer          The closing brace we search for
 166          * @param document             The document we currently are in
 167          *
 168          * @return
 169          *
 170          * @throws IOException
 171          */
 172         protected int searchForClosingPeer (int offset, char openingPeer,
 173                                                     char closingPeer, IDocument document) throws IOException {
 174                 fReader.configureForwardReader (document, offset + 1, document.getLength(), true, true);
 175
 176                 int stack = 1;                                  // As we have already the opening brace
 177                 int c     = fReader.read ();                            // Read character on position one after the opening brace
 178
 179                 while (c != PHPCodeReader.EOF) {                // As long as we are not at the end
 180                         if ((c == openingPeer) &&                   // If character is opening brace again
 181                             (c != closingPeer)) {                   // and not a closing brace (how could it be?)
 182                                 stack++;                                // put it on stack
 183                         }
 184                         else if (c == closingPeer) {                // If it's a closing brace
 185                                 stack--;                                // Decrement level counter
 186                         }
 187
 188                         if (stack == 0) {                           // If we found the matching closing brace
 189                                 return fReader.getOffset ();            // return the position of this closing brace
 190                         }
 191
 192                         c = fReader.read ();                        // Read the next character
 193                 }
 194
 195                 return -1;
 196         }
 197
 198         /**
 199          *
 200          * @param offset               The search start position
 201          * @param openingPeer          The opening brace we search for
 202          * @param closingPeer          The closing brace we search for
 203          * @param document             The document we currently are in
 204          *
 205          * @return
 206          *
 207          * @throws IOException
 208          */
 209         protected int searchForOpeningPeer (int offset, char openingPeer,
 210                                                 char closingPeer, IDocument document) throws IOException {
 211                 fReader.configureBackwardReader (document, offset, true, true);
 212
 213                 int stack = 1;                                  // As we have already the opening brace
 214                 int c     = fReader.read ();                    // Read character on position one before the closing brace
 215
 216                 while (c != PHPCodeReader.EOF) {                // As long as we are not at the start of text
 217                         if ((c == closingPeer) &&                   // If character is closing brace again
 218                             (c != openingPeer)) {                   // and not a opening brace (how could it be?)
 219                                 stack++;                                // put it on stack
 220                         }
 221                         else if (c == openingPeer) {                // If it's a opening brace
 222                                 stack--;                                // Decrement level counter
 223                         }
 224
 225                         if (stack == 0) {                           // If we found the matching closing brace
 226                                 return fReader.getOffset ();            // return the position of this closing brace
 227                         }
 228
 229                         c = fReader.read ();                        // Read the previous character
 230                 }
 231
 232                 return -1;
 233         }
 234 }