Fix for bugzilla bug 24648 - Editor displaying text in reverse on Eclipse 2.1 platform

1 files changed, 140 insertions, 133 deletions

diff --git a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/text/BufferedDocumentScanner.java b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/text/BufferedDocumentScanner.java
index 0797f0ba6fb..5fd9e21dd0e 100644
--- a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/text/BufferedDocumentScanner.java
+++ b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/text/BufferedDocumentScanner.java
@@ -15,138 +15,145 @@ import org.eclipse.jface.util.Assert;
  */
 public final class BufferedDocumentScanner implements ICharacterScanner {
 
-	/** The document being scanned. */
-	private IDocument fDocument;
-	/** The offset of the document range to scan. */
-	private int fRangeOffset;
-	/** The length of the document range to scan. */
-	private int fRangeLength;
-	/** The delimiters of the document. */
-	private char[][] fDelimiters;
-	
-	/** The buffer. */
-	private final char[] fBuffer;
-	/** The offset of the buffer within the document. */
-	private int fBufferOffset;
-	/** The valid length of the buffer for access. */
-	private int fBufferLength;
-	/** The offset of the scanner within the buffer. */
-	private int fOffset;
-	
-	/**
-	 * Creates a new buffered document scanner.
-	 * The buffer size is set to the given number of characters.
-	 *
-	 * @param size the buffer size
-	 */
-	public BufferedDocumentScanner(int size) {
-		Assert.isTrue(size >= 1);
-		fBuffer= new char[size];
-	}
-	
-	/**
-	 * Fills the buffer with the contens of the document starting at the given offset.
-	 *
-	 * @param offset the document offset at which the buffer starts
-	 */
-	private final void updateBuffer(int offset) {
-
-		fBufferOffset= offset;
-
-		if (fBufferOffset + fBuffer.length > fRangeLength)
-			fBufferLength= fRangeLength - fBufferOffset;
-		else
-			fBufferLength= fBuffer.length;
-				
-		try {
-			final String content= fDocument.get(fBufferOffset, fBufferLength);
-			content.getChars(0, fBufferLength, fBuffer, 0);
-			
-		} catch (BadLocationException e) {
-		}
-	}
-	
-	/**
-	 * Configures the scanner by providing access to the document range over which to scan.
-	 *
-	 * @param document the document to scan
-	 * @param offset the offset of the document range to scan
-	 * @param length the length of the document range to scan
-	 */
-	public final void setRange(IDocument document, int offset, int length) {
-
-		fDocument= document;
-		fRangeOffset= offset;
-		fRangeLength= length;
-
-		String[] delimiters= document.getLegalLineDelimiters();
-		fDelimiters= new char[delimiters.length][];
-		for (int i= 0; i < delimiters.length; i++)
-			fDelimiters[i]= delimiters[i].toCharArray();
-
-		updateBuffer(offset);
-		fOffset= 0;
-	}
-	
-	/*
-	 * @see ICharacterScanner#read()
-	 */
-	public final int read() {
-		
-		if (fOffset == fBufferLength) {
-			if (fBufferOffset + fBufferLength == fDocument.getLength())
-				return EOF;
-			else {
-				updateBuffer(fBufferOffset + fBufferLength);
-				fOffset= 0;
-			}
-		}
-					
-		return fBuffer[fOffset++];
-	}
-	
-	/*
-	 * @see ICharacterScanner#unread
-	 */
-	public final void unread() {
-
-		if (fOffset == 0) {
-			if (fBufferOffset == fRangeOffset) {
-				// error: BOF
-			} else {
-				updateBuffer(fBufferOffset - fBuffer.length);
-				fOffset= fBuffer.length - 1;
-			}
-		} else {			
-			--fOffset;
-		}
-	}
-
-	/*
-	 * @see ICharacterScanner#getColumn()
-	 */
-	public final int getColumn() {
-
-		try {
-			final int offset= fBufferOffset + fOffset;
-			final int line= fDocument.getLineOfOffset(offset);
-			final int start= fDocument.getLineOffset(line);
-				
-			return offset - start;
-				
-		} catch (BadLocationException e) {
-		}
-
-		return -1;
-	}
-
-	/*
-	 * @see ICharacterScanner#getLegalLineDelimiters()
-	 */
-	public final char[][] getLegalLineDelimiters() {
-		return fDelimiters;
-	}
+    /** The document being scanned. */
+    private IDocument fDocument;
+    /** The offset of the document range to scan. */
+    private int fRangeOffset;
+    /** The length of the document range to scan. */
+    private int fRangeLength;
+    /** The delimiters of the document. */
+    private char[][] fDelimiters;
+    
+    /** The buffer. */
+    private final char[] fBuffer;
+    /** The offset of the buffer within the document. */
+    private int fBufferOffset;
+    /** The valid length of the buffer for access. */
+    private int fBufferLength;
+    /** The offset of the scanner within the buffer. */
+    private int fOffset;
+    
+    /**
+     * Creates a new buffered document scanner.
+     * The buffer size is set to the given number of characters.
+     *
+     * @param size the buffer size
+     */
+    public BufferedDocumentScanner(int size) {
+        Assert.isTrue(size >= 1);
+        fBuffer= new char[size];
+    }
+    
+    /**
+     * Fills the buffer with the contents of the document starting at the given offset.
+     *
+     * @param offset the document offset at which the buffer starts
+     */
+    private final void updateBuffer(int offset) {
+        
+        // Clamp at start of the file document range
+        if (offset < 0)
+            offset = 0;
+
+        fBufferOffset= offset;
+        fBufferLength= fBuffer.length;
+        
+        // assert(offset >= fRangeOffset && offset < fRangeOffset + fRangeLength);
+
+        if (fBufferOffset + fBufferLength > fRangeOffset + fRangeLength)
+            fBufferLength= fRangeOffset + fRangeLength - fBufferOffset;
+                
+        try {
+            final String content= fDocument.get(fBufferOffset, fBufferLength);
+            content.getChars(0, fBufferLength, fBuffer, 0);
+            
+        } catch (BadLocationException e) {
+        }
+    }
+    
+    /**
+     * Configures the scanner by providing access to the document range over which to scan.
+     *
+     * @param document the document to scan
+     * @param offset the offset of the document range to scan
+     * @param length the length of the document range to scan
+     */
+    public final void setRange(IDocument document, int offset, int length) {
+
+        fDocument= document;
+        fRangeOffset= offset;
+        fRangeLength= length;
+        
+        // Clamp at end of the real document
+        if (fRangeLength > fDocument.getLength())
+           fRangeLength = fDocument.getLength();
+
+        String[] delimiters= document.getLegalLineDelimiters();
+        fDelimiters= new char[delimiters.length][];
+        for (int i= 0; i < delimiters.length; i++)
+            fDelimiters[i]= delimiters[i].toCharArray();
+
+        updateBuffer(offset);
+        fOffset= 0;
+    }
+    
+    /*
+     * @see ICharacterScanner#read()
+     */
+    public final int read() {
+        
+        if (fOffset >= fBufferLength) {
+            if (fBufferOffset + fBufferLength >= fRangeOffset + fRangeLength)
+                return EOF;
+            else {
+                updateBuffer(fBufferOffset + fBufferLength);
+                fOffset= 0;
+            }
+        }
+                    
+        return fBuffer[fOffset++];
+    }
+    
+    /*
+     * @see ICharacterScanner#unread
+     */
+    public final void unread() {
+
+        if (fOffset <= 0) {
+            if (fBufferOffset <= fRangeOffset) {
+                // error: BOF
+            } else {
+                updateBuffer(fBufferOffset - fBuffer.length);
+                fOffset = fBuffer.length - 1; // should always be a valid place
+            }
+        } else {            
+            --fOffset;
+        }
+    }
+
+    /*
+     * @see ICharacterScanner#getColumn()
+     */
+    public final int getColumn() {
+
+        try {
+            final int offset= fBufferOffset + fOffset;
+            final int line= fDocument.getLineOfOffset(offset);
+            final int start= fDocument.getLineOffset(line);
+                
+            return offset - start;
+                
+        } catch (BadLocationException e) {
+        }
+
+        return -1;
+    }
+
+    /*
+     * @see ICharacterScanner#getLegalLineDelimiters()
+     */
+    public final char[][] getLegalLineDelimiters() {
+        return fDelimiters;
+    }
 
 }
-
-