Description David Cok 2005-09-24 14:17:37 EDT

The class org.eclipse.jdt.core.dom.CompilationUnit gets a copy of the table of 
line-ending positions from the scanner and allows one to convert from a 
character position to a line number.  For non-GUI tools, however, this is not
sufficient.  One also needs to be able to get the start and end character 
positions of a given line (as is available for instance in PublicScanner).

I suggest adding the following methods to 
org.eclipse.jdt.core.dom.CompilationUnit
(sorry I don't have a means of either compiling or testing the following code).

[Adapted from org.eclipse.jdt.internal.core.util.PublicScanner ]
/*
 *
 * Line numbers are 1-based. 
 * Character positions are 0-based.
 *
 * In case the given line number is inconsistent, answers -1.
 * @param lineNumber a 1-based line number
 * @return the character position of the end of that line
 */
public final int getLineEnd(int lineNumber) {

	if (lineEndTable == null) 
		return -1;
	if (lineNumber > lineEndTable.length) 
		return -1;
	if (lineNumber <= 0) 
		return -1;
	return lineEndTable[lineNumber-1]; // next line start one character 
behind the lineEnd of the previous line
}

public final int[] getLineEnds() {
	//return a live copy of the lineEndTable
	return lineEndTable;
}

/**
 *
 * Line numbers are 1-based. 
 * Character positions are 0-based.
 *
 * e.g.	getLineStart(1) --> 0	indicates that the first line starts at 
character 0.
 *
 * In case the given line number is inconsistent, answers -1.
 * 
 * @param lineNumber a 1-based line number
 * @return the character position of the beginning of that line
 */
public final int getLineStart(int lineNumber) {

	if (lineEndTable == null) 
		return -1;
	if (lineNumber > lineEndTable.length) 
		return -1;
	if (lineNumber <= 0) 
		return -1;
	
	if (lineNumber == 1) 
		return 0;
	return lineEndTable[lineNumber-2]+1; // next line starts one character 
beyond the lineEnd of the previous line
}