/*******************************************************************************
* Copyright (c) 2000, 2004 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Common Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/cpl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
*******************************************************************************/
package org.eclipse.jface.text;
import java.util.ArrayList;
import java.util.List;
/**
* Abstract implementation of <code>ILineTracker</code>. It lets the
* definition of line delimiters to subclasses. Assuming that '\n' is
* the only line delimiter, this abstract implementation defines the
* following line scheme:
* <ul>
* <li> "" -> [0,0]
* <li> "a" -> [0,1]
* <li> "\n" -> [0,1], [1,0]
* <li> "a\n" -> [0,2], [2,0]
* <li> "a\nb" -> [0,2], [2,1]
* <li> "a\nbc\n" -> [0,2], [2,3], [5,0]
* </ul>
* This class must be subclassed.
*/
public abstract class AbstractLineTracker implements ILineTracker {
/**
* Combines the information of the occurrence of a line delimiter.
* <code>delimiterIndex</code> is the index where a line delimiter
* starts, whereas <code>delimiterLength</code>, indicates the length
* of the delimiter.
*/
protected static class DelimiterInfo {
public int delimiterIndex;
public int delimiterLength;
public String delimiter;
}
/** The line information */
private List fLines= new ArrayList();
/** The length of the tracked text */
private int fTextLength;
/**
* Creates a new line tracker.
*/
protected AbstractLineTracker() {
}
/**
* Binary search for the line at a given offset.
*
* @param offset the offset whose line should be found
* @return the line of the offset
*/
private int findLine(int offset) {
if (fLines.size() == 0)
return -1;
int left= 0;
int right= fLines.size() -1;
int mid= 0;
Line line= null;
while (left < right) {
mid= (left + right) / 2;
line= (Line) fLines.get(mid);
if (offset < line.offset) {
if (left == mid)
right= left;
else
right= mid -1;
} else if (offset > line.offset) {
if (right == mid)
left= right;
else
left= mid +1;
} else if (offset == line.offset) {
left= right= mid;
}
}
line= (Line) fLines.get(left);
if (line.offset > offset)
-- left;
return left;
}
/**
* Returns the number of lines covered by the specified text range.
*
* @param startLine the line where the text range starts
* @param offset the start offset of the text range
* @param length the length of the text range
* @return the number of lines covered by this text range
* @exception BadLocationException if range is undefined in this tracker
*/
private int getNumberOfLines(int startLine, int offset, int length) throws BadLocationException {
if (length == 0)
return 1;
int target= offset + length;
Line l= (Line) fLines.get(startLine);
if (l.delimiter == null)
return 1;
if (l.offset + l.length > target)
return 1;
if (l.offset + l.length == target)
return 2;
return getLineNumberOfOffset(target) - startLine + 1;
}
/*
* @see org.eclipse.jface.text.ILineTracker#getLineLength(int)
*/
public int getLineLength(int line) throws BadLocationException {
int lines= fLines.size();
if (line < 0 || line > lines)
throw new BadLocationException();
if (lines == 0 || lines == line)
return 0;
Line l= (Line) fLines.get(line);
return l.length;
}
/*
* @see org.eclipse.jface.text.ILineTracker#getLineNumberOfOffset(int)
*/
public int getLineNumberOfOffset(int position) throws BadLocationException {
if (position > fTextLength)
throw new BadLocationException();
if (position == fTextLength) {
int lastLine= fLines.size() - 1;
if (lastLine < 0)
return 0;
Line l= (Line) fLines.get(lastLine);
return (l.delimiter != null ? lastLine + 1 : lastLine);
}
return findLine(position);
}
/*
* @see org.eclipse.jface.text.ILineTracker#getLineInformationOfOffset(int)
*/
public IRegion getLineInformationOfOffset(int position) throws BadLocationException {
if (position > fTextLength)
throw new BadLocationException();
if (position == fTextLength) {
int size= fLines.size();
if (size == 0)
return new Region(0, 0);
Line l= (Line) fLines.get(size - 1);
return (l.delimiter != null ? new Line(fTextLength, 0) : new Line(fTextLength - l.length, l.length));
}
return getLineInformation(findLine(position));
}
/*
* @see org.eclipse.jface.text.ILineTracker#getLineInformation(int)
*/
public IRegion getLineInformation(int line) throws BadLocationException {
int lines= fLines.size();
if (line < 0 || line > lines)
throw new BadLocationException();
if (lines == 0)
return new Line(0, 0);
if (line == lines) {
Line l= (Line) fLines.get(line - 1);
return new Line(l.offset + l.length, 0);
}
Line l= (Line) fLines.get(line);
return (l.delimiter != null ? new Line(l.offset, l.length - l.delimiter.length()) : l);
}
/*
* @see org.eclipse.jface.text.ILineTracker#getLineOffset(int)
*/
public int getLineOffset(int line) throws BadLocationException {
int lines= fLines.size();
if (line < 0 || line > lines)
throw new BadLocationException();
if (lines == 0)
return 0;
if (line == lines) {
Line l= (Line) fLines.get(line - 1);
return l.offset + l.length;
}
Line l= (Line) fLines.get(line);
return l.offset;
}
/*
* @see org.eclipse.jface.text.ILineTracker#getNumberOfLines()
*/
public int getNumberOfLines() {
int lines= fLines.size();
if (lines == 0)
return 1;
Line l= (Line) fLines.get(lines - 1);
return (l.delimiter != null ? lines + 1 : lines);
}
/*
* @see org.eclipse.jface.text.ILineTracker#getNumberOfLines(int, int)
*/
public int getNumberOfLines(int position, int length) throws BadLocationException {
if (position < 0 || position + length > fTextLength)
throw new BadLocationException();
if (length == 0) // optimization
return 1;
return getNumberOfLines(getLineNumberOfOffset(position), position, length);
}
/*
* @see org.eclipse.jface.text.ILineTracker#computeNumberOfLines(java.lang.String)
*/
public int computeNumberOfLines(String text) {
int count= 0;
int start= 0;
DelimiterInfo delimiterInfo= nextDelimiterInfo(text, start);
while (delimiterInfo != null && delimiterInfo.delimiterIndex > -1) {
++count;
start= delimiterInfo.delimiterIndex + delimiterInfo.delimiterLength;
delimiterInfo= nextDelimiterInfo(text, start);
}
return count;
}
/* ----------------- manipulation ------------------------------ */
/**
* Returns the information about the first delimiter found in the given
* text starting at the given offset.
*
* @param text the text to be searched
* @param offset the offset in the given text
* @return the information of the first found delimiter or <code>null</code>
*/
protected abstract DelimiterInfo nextDelimiterInfo(String text, int offset);
/**
* Creates the line structure for the given text. Newly created lines
* are inserted into the line structure starting at the given
* position. Returns the number of newly created lines.
*
* @param text the text for which to create a line structure
* @param insertPosition the position at which the newly created lines are inserted
* into the tracker's line structure
* @param offset the offset of all newly created lines
* @return the number of newly created lines
*/
private int createLines(String text, int insertPosition, int offset) {
int count= 0;
int start= 0;
DelimiterInfo delimiterInfo= nextDelimiterInfo(text, 0);
while (delimiterInfo != null && delimiterInfo.delimiterIndex > -1) {
int index= delimiterInfo.delimiterIndex + (delimiterInfo.delimiterLength - 1);
if (insertPosition + count >= fLines.size())
fLines.add(new Line(offset + start, offset + index, delimiterInfo.delimiter));
else
fLines.add(insertPosition + count, new Line(offset + start, offset + index, delimiterInfo.delimiter));
++count;
start= index + 1;
delimiterInfo= nextDelimiterInfo(text, start);
}
if (start < text.length()) {
if (insertPosition + count < fLines.size()) {
// there is a line below the current
Line l= (Line) fLines.get(insertPosition + count);
int delta= text.length() - start;
l.offset -= delta;
l.length += delta;
} else {
fLines.add(new Line(offset + start, offset + text.length() - 1, null));
++count;
}
}
return count;
}
/**
* Keeps track of the line information when text is inserted.
* Returns the number of inserted lines.
*
* @param lineNumber the line at which the insert happens
* @param offset at which the insert happens
* @param text the inserted text
* @return the number of inserted lines
* @exception BadLocationException if offset is invalid in this tracker
*/
private int insert(int lineNumber, int offset, String text) throws BadLocationException {
if (text == null || text.length() == 0)
return 0;
fTextLength += text.length();
int size= fLines.size();
if (size == 0 || lineNumber >= size)
return createLines(text, size, offset);
Line line= (Line) fLines.get(lineNumber);
DelimiterInfo delimiterInfo= nextDelimiterInfo(text, 0);
if (delimiterInfo == null || delimiterInfo.delimiterIndex == -1) {
line.length += text.length();
return 0;
}
// as there is a line break, split line but do so only if rest of line is not of length 0
int restLength= line.offset + line.length - offset;
if (restLength > 0) {
// determine start and end of the second half of the splitted line
Line lineRest= new Line(offset, restLength);
lineRest.delimiter= line.delimiter;
// shift it by the inserted text
lineRest.offset += text.length();
// and insert in line structure
fLines.add(lineNumber + 1, lineRest);
}
// adapt the beginning of the splitted line
line.delimiter= delimiterInfo.delimiter;
int nextStart= offset + delimiterInfo.delimiterIndex + delimiterInfo.delimiterLength;
line.length= nextStart - line.offset;
// insert lines for the remaining text
text= text.substring(delimiterInfo.delimiterIndex + delimiterInfo.delimiterLength);
return createLines(text, lineNumber + 1, nextStart) + 1;
}
/**
* Keeps track of the line information when text is removed. Returns
* whether the line at which the deletion start will thereby be deleted.
*
* @param lineNumber the lineNumber at which the deletion starts
* @param offset the offset of the first deleted character
* @param length the number of deleted characters
* @return <code>true</code> if the start line has been deleted, <code>false</code> otherwise
* @exception BadLocationException if position is unknown to the tracker
*/
private boolean remove(int lineNumber, int offset, int length) throws BadLocationException {
if (length == 0)
return false;
int removedLineEnds= getNumberOfLines(lineNumber, offset, length) - 1;
Line line= (Line) fLines.get(lineNumber);
if ((lineNumber == fLines.size() - 1) && removedLineEnds > 0) {
line.length -= length;
line.delimiter= null;
} else {
++ lineNumber;
for (int i= 1; i <= removedLineEnds; i++) {
if (lineNumber == fLines.size()) {
line.delimiter= null;
break;
}
Line line2= (Line) fLines.get(lineNumber);
line.length += line2.length;
line.delimiter= line2.delimiter;
fLines.remove(lineNumber);
}
line.length -= length;
}
fTextLength -= length;
if (line.length == 0) {
fLines.remove(line);
return true;
}
return false;
}
/**
* Adapts the offset of all lines with line numbers greater than the specified
* one to the given delta.
*
* @param lineNumber the line number after which to start
* @param delta the offset delta to be applied
*/
private void adaptLineOffsets(int lineNumber, int delta) {
int size= fLines.size();
for (int i= lineNumber + 1; i < size; i++) {
Line l= (Line) fLines.get(i);
l.offset += delta;
}
}
/*
* @see org.eclipse.jface.text.ILineTracker#replace(int, int, java.lang.String)
*/
public void replace(int position, int length, String text) throws BadLocationException {
int firstLine= getLineNumberOfOffset(position);
int insertLineNumber= firstLine;
if (remove(firstLine, position, length))
-- firstLine;
int lastLine= firstLine + insert(insertLineNumber, position, text);
// int lines= fLines.size();
// if (lines > 0) {
//
// // try to collapse the first and the second line if second line is empty
// if (0 <= firstLine && firstLine + 1 < lines) {
// Line l2= (Line) fLines.get(firstLine + 1);
// if (l2.delimiter != null && l2.length == l2.delimiter.length()) {
// // line is empty
//
// // append empty line to precessor
// Line l1= (Line) fLines.get(firstLine);
// StringBuffer buffer= new StringBuffer();
// buffer.append(l1.delimiter);
// buffer.append(l2.delimiter);
//
// // test whether this yields just one line rather then two
// DelimiterInfo info= nextDelimiterInfo(buffer.toString(), 0);
// if (info != null && info.delimiterIndex == 0 && info.delimiterLength == buffer.length()) {
// l1.length += l2.length;
// l1.delimiter += l2.delimiter;
// fLines.remove(firstLine + 1);
// -- lastLine;
// }
// }
// }
//
// // try to collapse the last inserted line with the following line
// if (lastLine < lines) {
// Line l2= (Line) fLines.get(lastLine);
// if (l2.delimiter != null && l2.length == l2.delimiter.length()) {
// // line is empty
//
// // append empty line to precessor
// Line l1= (Line) fLines.get(lastLine -1);
// StringBuffer buffer= new StringBuffer();
// buffer.append(l1.delimiter);
// buffer.append(l2.delimiter);
//
// // test whether this yields just one line rather then two
// DelimiterInfo info= nextDelimiterInfo(buffer.toString(), 0);
// if (info != null && info.delimiterIndex == 0 && info.delimiterLength == buffer.length()) {
// l1.length += l2.length;
// l1.delimiter += l2.delimiter;
// fLines.remove(lastLine);
// }
// }
// }
// }
int delta= -length;
if (text != null)
delta= text.length() + delta;
if (delta != 0)
adaptLineOffsets(lastLine, delta);
}
/*
* @see org.eclipse.jface.text.ILineTracker#set(java.lang.String)
*/
public void set(String text) {
fLines.clear();
if (text != null) {
fTextLength= text.length();
createLines(text, 0, 0);
}
}
/*
* @see org.eclipse.jface.text.ILineTracker#getLineDelimiter(int)
*/
public String getLineDelimiter(int line) throws BadLocationException {
int lines= fLines.size();
if (line < 0 || line > lines)
throw new BadLocationException();
if (lines == 0)
return null;
if (line == lines)
return null;
Line l= (Line) fLines.get(line);
return l.delimiter;
}
}
