net.sourceforge.phpeclipse.ui/src/net/sourceforge/phpdt/internal/ui/text/PHPCodeReader.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 net.sourceforge.phpdt.internal.corext.phpdoc.SingleCharReader;
  11
  12 import org.eclipse.jface.text.BadLocationException;
  13 import org.eclipse.jface.text.IDocument;
  14
  15 /**
  16  * Reads from a document either forwards or backwards. May be configured to skip
  17  * comments and strings.
  18  */
  19 public class PHPCodeReader extends SingleCharReader {
  20
  21         /** The EOF character */
  22         public static final int EOF = -1;
  23
  24         private boolean fSkipComments = false;
  25
  26         private boolean fSkipStrings = false;
  27
  28         private boolean fForward = false;
  29
  30         private IDocument fDocument;
  31
  32         private int fOffset;
  33
  34         private int fEnd = -1;
  35
  36         private int fCachedLineNumber = -1;
  37
  38         private int fCachedLineOffset = -1;
  39
  40         public PHPCodeReader() {
  41         }
  42
  43         /**
  44          * Returns the offset of the last read character. Should only be called
  45          * after read has been called.
  46          */
  47         public int getOffset() {
  48                 return fForward ? fOffset - 1 : fOffset;
  49         }
  50
  51         public void configureForwardReader(IDocument document, int offset,
  52                         int length, boolean skipComments, boolean skipStrings)
  53                         throws IOException {
  54                 fDocument = document;
  55                 fOffset = offset;
  56                 fSkipComments = skipComments;
  57                 fSkipStrings = skipStrings;
  58
  59                 fForward = true;
  60                 fEnd = Math.min(fDocument.getLength(), fOffset + length);
  61         }
  62
  63         public void configureBackwardReader(IDocument document, int offset,
  64                         boolean skipComments, boolean skipStrings) throws IOException {
  65                 fDocument = document;
  66                 fOffset = offset;
  67                 fSkipComments = skipComments;
  68                 fSkipStrings = skipStrings;
  69
  70                 fForward = false;
  71                 try {
  72                         fCachedLineNumber = fDocument.getLineOfOffset(fOffset);
  73                 } catch (BadLocationException x) {
  74                         throw new IOException(x.getMessage());
  75                 }
  76         }
  77
  78         /*
  79          * @see Reader#close()
  80          */
  81         public void close() throws IOException {
  82                 fDocument = null;
  83         }
  84
  85         /*
  86          * @see SingleCharReader#read()
  87          */
  88         public int read() throws IOException {
  89                 try {
  90                         return fForward ? readForwards() : readBackwards();
  91                 } catch (BadLocationException x) {
  92                         throw new IOException(x.getMessage());
  93                 }
  94         }
  95
  96         private void gotoCommentEnd() throws BadLocationException {
  97                 while (fOffset < fEnd) {
  98                         char current = fDocument.getChar(fOffset++);
  99                         if (current == '*') {
 100                                 if (fOffset < fEnd && fDocument.getChar(fOffset) == '/') {
 101                                         ++fOffset;
 102                                         return;
 103                                 }
 104                         }
 105                 }
 106         }
 107
 108         private void gotoStringEnd(char delimiter) throws BadLocationException {
 109                 while (fOffset < fEnd) {
 110                         char current = fDocument.getChar(fOffset++);
 111                         if (current == '\\') {
 112                                 // ignore escaped characters
 113                                 ++fOffset;
 114                         } else if (current == delimiter) {
 115                                 return;
 116                         }
 117                 }
 118         }
 119
 120         private void gotoLineEnd() throws BadLocationException {
 121                 int line = fDocument.getLineOfOffset(fOffset);
 122                 fOffset = fDocument.getLineOffset(line + 1);
 123         }
 124
 125         private int readForwards() throws BadLocationException {
 126                 while (fOffset < fEnd) {
 127                         char current = fDocument.getChar(fOffset++);
 128
 129                         switch (current) {
 130                         case '"':
 131                         case '\'':
 132
 133                                 if (fSkipStrings) {
 134                                         gotoStringEnd(current);
 135                                         continue;
 136                                 }
 137
 138                                 return current;
 139                         case '#':
 140
 141                                 if (fSkipComments && fOffset < fEnd) {
 142                                         gotoLineEnd();
 143                                         continue;
 144                                 }
 145
 146                                 return current;
 147
 148                         case '/':
 149
 150                                 if (fSkipComments && fOffset < fEnd) {
 151                                         char next = fDocument.getChar(fOffset);
 152                                         if (next == '*') {
 153                                                 // a comment starts, advance to the comment end
 154                                                 ++fOffset;
 155                                                 gotoCommentEnd();
 156                                                 continue;
 157                                         } else if (next == '/') {
 158                                                 // '//'-comment starts, advance to the line end
 159                                                 gotoLineEnd();
 160                                                 continue;
 161                                         }
 162                                 }
 163
 164                                 return current;
 165
 166                         }
 167
 168                         return current;
 169                 }
 170
 171                 return EOF;
 172         }
 173
 174         private void handleSingleLineComment() throws BadLocationException {
 175                 int line = fDocument.getLineOfOffset(fOffset);
 176                 if (line < fCachedLineNumber) {
 177                         fCachedLineNumber = line;
 178                         fCachedLineOffset = fDocument.getLineOffset(line);
 179                         int offset = fOffset;
 180                         while (fCachedLineOffset < offset) {
 181                                 char current = fDocument.getChar(offset--);
 182
 183                                 if (current == '/' && fCachedLineOffset <= offset
 184                                                 && fDocument.getChar(offset) == '/') {
 185                                         fOffset = offset;
 186                                         return;
 187                                 }
 188
 189                                 if (current == '#' && fCachedLineOffset <= offset) {
 190                                         fOffset = offset;
 191                                         return;
 192                                 }
 193                         }
 194                 }
 195         }
 196
 197         private void gotoCommentStart() throws BadLocationException {
 198                 while (0 < fOffset) {
 199                         char current = fDocument.getChar(fOffset--);
 200                         if (current == '*' && 0 <= fOffset
 201                                         && fDocument.getChar(fOffset) == '/')
 202                                 return;
 203                 }
 204         }
 205
 206         private void gotoStringStart(char delimiter) throws BadLocationException {
 207                 while (0 < fOffset) {
 208                         char current = fDocument.getChar(fOffset);
 209                         if (current == delimiter) {
 210                                 if (!(0 <= fOffset && fDocument.getChar(fOffset - 1) == '\\'))
 211                                         return;
 212                         }
 213                         --fOffset;
 214                 }
 215         }
 216
 217         private int readBackwards() throws BadLocationException {
 218
 219                 while (0 < fOffset) {
 220                         --fOffset;
 221
 222                         handleSingleLineComment();
 223
 224                         char current = fDocument.getChar(fOffset);
 225                         switch (current) {
 226                         case '/':
 227
 228                                 if (fSkipComments && fOffset > 1) {
 229                                         char next = fDocument.getChar(fOffset - 1);
 230                                         if (next == '*') {
 231                                                 // a comment ends, advance to the comment start
 232                                                 fOffset -= 2;
 233                                                 gotoCommentStart();
 234                                                 continue;
 235                                         }
 236                                 }
 237
 238                                 return current;
 239                         case '"':
 240                         case '\'':
 241
 242                                 if (fSkipStrings) {
 243                                         --fOffset;
 244                                         gotoStringStart(current);
 245                                         continue;
 246                                 }
 247
 248                                 return current;
 249                         }
 250
 251                         return current;
 252                 }
 253
 254                 return EOF;
 255         }
 256 }