org.eclipse.jdt.core/dom/org/eclipse/jdt/internal/core/dom/rewrite/Indents.java - jdt/eclipse.jdt.core - Git at Google

 /*******************************************************************************
  * Copyright (c) 2000, 2005 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  *     IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.jdt.internal.core.dom.rewrite;

 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Map;

 import org.eclipse.jdt.core.JavaCore;
 import org.eclipse.jdt.core.formatter.DefaultCodeFormatterConstants;
 import org.eclipse.jface.text.Assert;
 import org.eclipse.jface.text.BadLocationException;
 import org.eclipse.jface.text.DefaultLineTracker;
 import org.eclipse.jface.text.ILineTracker;
 import org.eclipse.jface.text.IRegion;

 import org.eclipse.text.edits.ReplaceEdit;

 /**
  * Helper class to provide String manipulation functions dealing with indents
  */
 public class Indents {

 	private Indents() {
 		// don't instanciate
 	}

 	/**
 	 * Tests if a character is an indent character. Indent character are all whitespace characters
 	 * except the line delimiter characters.
 	 * @param ch The character to test
 	 * @return Returns <code>true</code> if this the character is a indent character
 	 */
 	public static boolean isIndentChar(char ch) {
 		return Character.isWhitespace(ch) && !isLineDelimiterChar(ch);
 	}

 	/**
 	 * Tests if a character is a line delimiter character.
 	 * @param ch The character to test
 	 * @return Returns <code>true</code> if this the character is a line delimiter character
 	 */
 	public static boolean isLineDelimiterChar(char ch) {
 		return ch == '\n' || ch == '\r';
 	}

 	/**
 	 * Returns the indentation of the given line in indentation units. Odd spaces are
 	 * not counted. This method only analyzes the content of <code>line</code> up to the first
 	 * non-whitespace character.
 	 *
 	 * @param line the string to measure the indent of
 	 * @param tabWidth the width of one tab character in space equivalents
 	 * @param indentWidth the width of one indentation unit in space equivalents
 	 * @return the number of indentation units that line is indented by
 	 */
 	public static int measureIndentUnits(CharSequence line, int tabWidth, int indentWidth) {
 		if (indentWidth <= 0 || tabWidth < 0 || line == null) {
 			throw new IllegalArgumentException();
 		}

 		int visualLength= measureIndentInSpaces(line, tabWidth);
 		return visualLength / indentWidth;
 	}

 	/**
 	 * Returns the indentation of the given line in space equivalents.
 	 * Tab characters are counted using the given <code>tabWidth</code> and every other indent
 	 * character as one. This method analyzes the content of <code>line</code> up to the first
 	 * non-whitespace character.
 	 *
 	 * @param line the string to measure the indent of
 	 * @param tabWidth the width of one tab in space equivalents
 	 * @return the measured indent width in space equivalents
 	 */
 	public static int measureIndentInSpaces(CharSequence line, int tabWidth) {
 		if (tabWidth < 0 || line == null) {
 			throw new IllegalArgumentException();
 		}

 		int length= 0;
 		int max= line.length();
 		for (int i= 0; i < max; i++) {
 			char ch= line.charAt(i);
 			if (ch == '\t') {
 				int reminder= length % tabWidth;
 				length += tabWidth - reminder;
 			} else if (isIndentChar(ch)) {
 				length++;
 			} else {
 				return length;
 			}
 		}
 		return length;
 	}

 	/**
 	 * Returns the leading indentation string of the given line. Note that the returned string
 	 * need not be equal to the leading whitespace as odd spaces are not considered part of the
 	 * indentation.
 	 *
 	 * @param line the line to scan
 	 * @param tabWidth the size of one tab in space equivalents
 	 * @param indentWidth the width of one indentation unit in space equivalents
 	 * @return the indent part of <code>line</code>, but no odd spaces
 	 */
 	public static String extractIndentString(String line, int tabWidth, int indentWidth) {
 		if (tabWidth < 0 || indentWidth <= 0 || line == null) {
 			throw new IllegalArgumentException();
 		}

 		int size= line.length();
 		int end= 0;

 		int spaceEquivs= 0;
 		int characters= 0;
 		for (int i= 0; i < size; i++) {
 			char c= line.charAt(i);
 			if (c == '\t') {
 				int remainder= spaceEquivs % tabWidth;
 				spaceEquivs += tabWidth - remainder;
 				characters++;
 			} else if (isIndentChar(c)) {
 				spaceEquivs++;
 				characters++;
 			} else {
 				break;
 			}
 			if (spaceEquivs >= indentWidth) {
 				end += characters;
 				characters= 0;
 				spaceEquivs= spaceEquivs % indentWidth;
 			}
 		}
 		if (end == 0)
 			return ""; //$NON-NLS-1$
 		else if (end == size)
 			return line;
 		else
 			return line.substring(0, end);
 	}


 	/**
 	 * Removes the given number of indentation units from a given line. If the line
 	 * does not have the given indent, all the available indentation is removed.
 	 * If <code>indentsToRemove <= 0</code> the line is returned.
 	 *
 	 * 	@param line the line to trim
 	 * @param tabWidth the width of one tab in space equivalents
 	 * @param indentWidth the width of one indentation unit in space equivalents
 	 * @return the trimmed string
 	 */
 	public static String trimIndent(String line, int indentUnitsToRemove, int tabWidth, int indentWidth) {
 		if (tabWidth < 0 || indentWidth <= 0 || line == null) {
 			throw new IllegalArgumentException();
 		}

 		if (indentUnitsToRemove <= 0)
 			return line;

 		final int spaceEquivalentsToRemove= indentUnitsToRemove * indentWidth;

 		int start= 0;
 		int spaceEquivalents= 0;
 		int size= line.length();
 		String prefix= null;
 		for (int i= 0; i < size; i++) {
 			char c= line.charAt(i);
 			if (c == '\t') {
 				int remainder= spaceEquivalents % tabWidth;
 				spaceEquivalents += tabWidth - remainder;
 			} else if (isIndentChar(c)) {
 				spaceEquivalents++;
 			} else {
 				// Assert.isTrue(false, "Line does not have requested number of indents");
 				start= i;
 				break;
 			}
 			if (spaceEquivalents == spaceEquivalentsToRemove) {
 				start= i + 1;
 				break;
 			}
 			if (spaceEquivalents > spaceEquivalentsToRemove) {
 				// can happen if tabSize > indentSize, e.g tabsize==8, indent==4, indentsToRemove==1, line prefixed with one tab
 				// this implements the third option
 				start= i + 1; // remove the tab
 				// and add the missing spaces
 				char[] missing= new char[spaceEquivalents - spaceEquivalentsToRemove];
 				Arrays.fill(missing, ' ');
 				prefix= new String(missing);
 				break;
 			}
 		}
 		String trimmed;
 		if (start == size)
 			trimmed= ""; //$NON-NLS-1$
 		else
 			trimmed= line.substring(start);

 		if (prefix == null)
 			return trimmed;
 		return prefix + trimmed;
 	}

 	/**
 	 * Change the indent of a, possible muti-line, code string. The given number of indent units is removed,
 	 * and a new indent string is added.
 	 * The first line of the code will not be changed (It is considered to have no indent as it might start in
 	 * the middle of a line).
 	 *
 	 * 	@param code the code to change the indent of
 	 * 	@param indentUnitsToRemove the number of indent units to remove from each line (except the first) of the given code
 	 * @param tabWidth the size of one tab in space equivalents
 	 * @param indentWidth the width of one indentation unit in space equivalents
 	 * 	@param newIndentString the new indent string to be added to all lines (except the first)
 	 * 	@param lineDelim the new line delimiter to be used. The returned code will contain only this line delimiter.
 	 * @return the newly indent code, containing only the given line delimiters.
 	 */
 	public static String changeIndent(String code, int indentUnitsToRemove, int tabWidth, int indentWidth, String newIndentString, String lineDelim) {
 		if (tabWidth < 0 || indentWidth <= 0 || code == null || indentUnitsToRemove < 0 || newIndentString == null || lineDelim == null) {
 			throw new IllegalArgumentException();
 		}

 		try {
 			ILineTracker tracker= new DefaultLineTracker();
 			tracker.set(code);
 			int nLines= tracker.getNumberOfLines();
 			if (nLines == 1) {
 				return code;
 			}

 			StringBuffer buf= new StringBuffer();

 			for (int i= 0; i < nLines; i++) {
 				IRegion region= tracker.getLineInformation(i);
 				int start= region.getOffset();
 				int end= start + region.getLength();
 				String line= code.substring(start, end);

 				if (i == 0) {  // no indent for first line (contained in the formatted string)
 					buf.append(line);
 				} else { // no new line after last line
 					buf.append(lineDelim);
 					buf.append(newIndentString);
 					buf.append(trimIndent(line, indentUnitsToRemove, tabWidth, indentWidth));
 				}
 			}
 			return buf.toString();
 		} catch (BadLocationException e) {
 			// can not happen
 			return code;
 		}
 	}

 	/**
 	 * Change the indent of a, possible muti-line, code string. The given number of indent units is removed,
 	 * and a new indent string is added.
 	 * The first line of the code will not be changed (It is considered to have no indent as it might start in
 	 * the middle of a line).
 	 * @param source The code to change the indent of
 	 * 	@param indentUnitsToRemove the number of indent units to remove from each line (except the first) of the given code
 	 * @param tabWidth the size of one tab in space equivalents
 	 * @param indentWidth the width of one indentation unit in space equivalents
 	 * 	@param newIndentString the new indent string to be added to all lines (except the first)
 	 * @return returns the resulting text edits
 	 */
 	public static ReplaceEdit[] getChangeIndentEdits(String source, int indentUnitsToRemove, int tabWidth, int indentWidth, String newIndentString) {
 		if (tabWidth < 0 || indentWidth <= 0 || source == null || indentUnitsToRemove < 0 || newIndentString == null) {
 			throw new IllegalArgumentException();
 		}

 		ArrayList result= new ArrayList();
 		try {
 			ILineTracker tracker= new DefaultLineTracker();
 			tracker.set(source);
 			int nLines= tracker.getNumberOfLines();
 			if (nLines == 1)
 				return (ReplaceEdit[])result.toArray(new ReplaceEdit[result.size()]);
 			for (int i= 1; i < nLines; i++) {
 				IRegion region= tracker.getLineInformation(i);
 				int offset= region.getOffset();
 				String line= source.substring(offset, offset + region.getLength());
 				int length= indexOfIndent(line, indentUnitsToRemove, tabWidth, indentWidth);
 				if (length >= 0) {
 					result.add(new ReplaceEdit(offset, length, newIndentString));
 				} else {
 					length= measureIndentUnits(line, tabWidth, indentWidth);
 					result.add(new ReplaceEdit(offset, length, "")); //$NON-NLS-1$
 				}
 			}
 		} catch (BadLocationException cannotHappen) {
 			// can not happen
 		}
 		return (ReplaceEdit[])result.toArray(new ReplaceEdit[result.size()]);
 	}

 	/*
 	 * Returns the index where the indent of the given size ends.
 	 * Returns <code>-1<code> if the line isn't prefixed with an indent of
 	 * the given number of indents.
 	 */
 	private static int indexOfIndent(CharSequence line, int numberOfIndentUnits, int tabWidth, int indentWidth) {

 		int spaceEquivalents= numberOfIndentUnits * indentWidth;

 		int size= line.length();
 		int result= -1;
 		int blanks= 0;
 		for (int i= 0; i < size && blanks < spaceEquivalents; i++) {
 			char c= line.charAt(i);
 			if (c == '\t') {
 				int remainder= blanks % tabWidth;
 				blanks += tabWidth - remainder;
 			} else if (isIndentChar(c)) {
 				blanks++;
 			} else {
 				break;
 			}
 			result= i;
 		}
 		if (blanks < spaceEquivalents)
 			return -1;
 		return result + 1;
 	}

 	/**
 	 * Returns the tab width as configured in the given map.
 	 * @param options the map to get the formatter settings from. Use {@link org.eclipse.jdt.core.IJavaProject#getOptions(boolean)} to
 	 * get the most current project options.
 	 * @return the tab width
 	 */
 	public static int getTabWidth(Map options) {
 		if (options == null) {
 			throw new IllegalArgumentException();
 		}
 		return getIntValue(options, DefaultCodeFormatterConstants.FORMATTER_TAB_SIZE, 4);
 	}

 	/**
 	 * Returns the tab width as configured in the given map.
 	 * @param options the map to get the formatter settings from. Use {@link org.eclipse.jdt.core.IJavaProject#getOptions(boolean)} to
 	 * get the most current project options.
 	 * @return the indent width
 	 */
 	public static int getIndentWidth(Map options) {
 		if (options == null) {
 			throw new IllegalArgumentException();
 		}
 		int tabWidth=getTabWidth(options);
 		boolean isMixedMode= DefaultCodeFormatterConstants.MIXED.equals(options.get(DefaultCodeFormatterConstants.FORMATTER_TAB_CHAR));
 		if (isMixedMode) {
 			return getIntValue(options, DefaultCodeFormatterConstants.FORMATTER_INDENTATION_SIZE, tabWidth);
 		}
 		return tabWidth;
 	}

 	/**
 	 * Creates a string that represents the given number of indentation units.
 	 * The returned string can contain tabs and/or spaces depending on the core
 	 * formatter preferences.
 	 *
 	 * @param indentationUnits the number of indentation units to generate
 	 * @param options the options to get the formatter settings from. Use {@link org.eclipse.jdt.core.IJavaProject#getOptions(boolean)} to
 	 * get the most current project options.
 	 * @return the indent string
 	 */
 	public static String createIndentString(int indentationUnits, Map options) {
 		if (options == null || indentationUnits < 0) {
 			throw new IllegalArgumentException();
 		}

 		String tabChar= getStringValue(options, DefaultCodeFormatterConstants.FORMATTER_TAB_CHAR, JavaCore.TAB);

 		final int tabs, spaces;
 		if (JavaCore.SPACE.equals(tabChar)) {
 			tabs= 0;
 			spaces= indentationUnits * getIndentWidth(options);
 		} else if (JavaCore.TAB.equals(tabChar)) {
 			// indentWidth == tabWidth
 			tabs= indentationUnits;
 			spaces= 0;
 		} else if (DefaultCodeFormatterConstants.MIXED.equals(tabChar)){
 			int tabWidth= getTabWidth(options);
 			int spaceEquivalents= indentationUnits * getIndentWidth(options);
 			if (tabWidth > 0) {
 				tabs= spaceEquivalents / tabWidth;
 				spaces= spaceEquivalents % tabWidth;
 			} else {
 				tabs= 0;
 				spaces= spaceEquivalents;
 			}
 		} else {
 			// new indent type not yet handled
 			Assert.isTrue(false);
 			return null;
 		}

 		StringBuffer buffer= new StringBuffer(tabs + spaces);
 		for(int i= 0; i < tabs; i++)
 			buffer.append('\t');
 		for(int i= 0; i < spaces; i++)
 			buffer.append(' ');
 		return buffer.toString();
 	}

 	private static String getStringValue(Map options, String key, String def) {
 		Object value= options.get(key);
 		if (value instanceof String)
 			return (String) value;
 		return def;
 	}

 	private static int getIntValue(Map options, String key, int def) {
 		try {
 			return Integer.parseInt((String) options.get(key));
 		} catch (NumberFormatException e) {
 			return def;
 		}
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2005 IBM Corporation and others.
	* All rights reserved. This program and the accompanying materials
	* are made available under the terms of the Eclipse Public License v1.0
	* which accompanies this distribution, and is available at
	* http://www.eclipse.org/legal/epl-v10.html
	*
	* Contributors:
	* IBM Corporation - initial API and implementation
	*******************************************************************************/
	package org.eclipse.jdt.internal.core.dom.rewrite;

	import java.util.ArrayList;
	import java.util.Arrays;
	import java.util.Map;

	import org.eclipse.jdt.core.JavaCore;
	import org.eclipse.jdt.core.formatter.DefaultCodeFormatterConstants;
	import org.eclipse.jface.text.Assert;
	import org.eclipse.jface.text.BadLocationException;
	import org.eclipse.jface.text.DefaultLineTracker;
	import org.eclipse.jface.text.ILineTracker;
	import org.eclipse.jface.text.IRegion;

	import org.eclipse.text.edits.ReplaceEdit;

	/**
	* Helper class to provide String manipulation functions dealing with indents
	*/
	public class Indents {

	private Indents() {
	// don't instanciate
	}

	/**
	* Tests if a character is an indent character. Indent character are all whitespace characters
	* except the line delimiter characters.
	* @param ch The character to test
	* @return Returns <code>true</code> if this the character is a indent character
	*/
	public static boolean isIndentChar(char ch) {
	return Character.isWhitespace(ch) && !isLineDelimiterChar(ch);
	}

	/**
	* Tests if a character is a line delimiter character.
	* @param ch The character to test
	* @return Returns <code>true</code> if this the character is a line delimiter character
	*/
	public static boolean isLineDelimiterChar(char ch) {
	return ch == '\n' \|\| ch == '\r';
	}

	/**
	* Returns the indentation of the given line in indentation units. Odd spaces are
	* not counted. This method only analyzes the content of <code>line</code> up to the first
	* non-whitespace character.
	*
	* @param line the string to measure the indent of
	* @param tabWidth the width of one tab character in space equivalents
	* @param indentWidth the width of one indentation unit in space equivalents
	* @return the number of indentation units that line is indented by
	*/
	public static int measureIndentUnits(CharSequence line, int tabWidth, int indentWidth) {
	if (indentWidth <= 0 \|\| tabWidth < 0 \|\| line == null) {
	throw new IllegalArgumentException();
	}

	int visualLength= measureIndentInSpaces(line, tabWidth);
	return visualLength / indentWidth;
	}

	/**
	* Returns the indentation of the given line in space equivalents.
	* Tab characters are counted using the given <code>tabWidth</code> and every other indent
	* character as one. This method analyzes the content of <code>line</code> up to the first
	* non-whitespace character.
	*
	* @param line the string to measure the indent of
	* @param tabWidth the width of one tab in space equivalents
	* @return the measured indent width in space equivalents
	*/
	public static int measureIndentInSpaces(CharSequence line, int tabWidth) {
	if (tabWidth < 0 \|\| line == null) {
	throw new IllegalArgumentException();
	}

	int length= 0;
	int max= line.length();
	for (int i= 0; i < max; i++) {
	char ch= line.charAt(i);
	if (ch == '\t') {
	int reminder= length % tabWidth;
	length += tabWidth - reminder;
	} else if (isIndentChar(ch)) {
	length++;
	} else {
	return length;
	}
	}
	return length;
	}

	/**
	* Returns the leading indentation string of the given line. Note that the returned string
	* need not be equal to the leading whitespace as odd spaces are not considered part of the
	* indentation.
	*
	* @param line the line to scan
	* @param tabWidth the size of one tab in space equivalents
	* @param indentWidth the width of one indentation unit in space equivalents
	* @return the indent part of <code>line</code>, but no odd spaces
	*/
	public static String extractIndentString(String line, int tabWidth, int indentWidth) {
	if (tabWidth < 0 \|\| indentWidth <= 0 \|\| line == null) {
	throw new IllegalArgumentException();
	}

	int size= line.length();
	int end= 0;

	int spaceEquivs= 0;
	int characters= 0;
	for (int i= 0; i < size; i++) {
	char c= line.charAt(i);
	if (c == '\t') {
	int remainder= spaceEquivs % tabWidth;
	spaceEquivs += tabWidth - remainder;
	characters++;
	} else if (isIndentChar(c)) {
	spaceEquivs++;
	characters++;
	} else {
	break;
	}
	if (spaceEquivs >= indentWidth) {
	end += characters;
	characters= 0;
	spaceEquivs= spaceEquivs % indentWidth;
	}
	}
	if (end == 0)
	return ""; //$NON-NLS-1$
	else if (end == size)
	return line;
	else
	return line.substring(0, end);
	}


	/**
	* Removes the given number of indentation units from a given line. If the line
	* does not have the given indent, all the available indentation is removed.
	* If <code>indentsToRemove <= 0</code> the line is returned.
	*
	* @param line the line to trim
	* @param tabWidth the width of one tab in space equivalents
	* @param indentWidth the width of one indentation unit in space equivalents
	* @return the trimmed string
	*/
	public static String trimIndent(String line, int indentUnitsToRemove, int tabWidth, int indentWidth) {
	if (tabWidth < 0 \|\| indentWidth <= 0 \|\| line == null) {
	throw new IllegalArgumentException();
	}

	if (indentUnitsToRemove <= 0)
	return line;

	final int spaceEquivalentsToRemove= indentUnitsToRemove * indentWidth;

	int start= 0;
	int spaceEquivalents= 0;
	int size= line.length();
	String prefix= null;
	for (int i= 0; i < size; i++) {
	char c= line.charAt(i);
	if (c == '\t') {
	int remainder= spaceEquivalents % tabWidth;
	spaceEquivalents += tabWidth - remainder;
	} else if (isIndentChar(c)) {
	spaceEquivalents++;
	} else {
	// Assert.isTrue(false, "Line does not have requested number of indents");
	start= i;
	break;
	}
	if (spaceEquivalents == spaceEquivalentsToRemove) {
	start= i + 1;
	break;
	}
	if (spaceEquivalents > spaceEquivalentsToRemove) {
	// can happen if tabSize > indentSize, e.g tabsize==8, indent==4, indentsToRemove==1, line prefixed with one tab
	// this implements the third option
	start= i + 1; // remove the tab
	// and add the missing spaces
	char[] missing= new char[spaceEquivalents - spaceEquivalentsToRemove];
	Arrays.fill(missing, ' ');
	prefix= new String(missing);
	break;
	}
	}
	String trimmed;
	if (start == size)
	trimmed= ""; //$NON-NLS-1$
	else
	trimmed= line.substring(start);

	if (prefix == null)
	return trimmed;
	return prefix + trimmed;
	}

	/**
	* Change the indent of a, possible muti-line, code string. The given number of indent units is removed,
	* and a new indent string is added.
	* The first line of the code will not be changed (It is considered to have no indent as it might start in
	* the middle of a line).
	*
	* @param code the code to change the indent of
	* @param indentUnitsToRemove the number of indent units to remove from each line (except the first) of the given code
	* @param tabWidth the size of one tab in space equivalents
	* @param indentWidth the width of one indentation unit in space equivalents
	* @param newIndentString the new indent string to be added to all lines (except the first)
	* @param lineDelim the new line delimiter to be used. The returned code will contain only this line delimiter.
	* @return the newly indent code, containing only the given line delimiters.
	*/
	public static String changeIndent(String code, int indentUnitsToRemove, int tabWidth, int indentWidth, String newIndentString, String lineDelim) {
	if (tabWidth < 0 \|\| indentWidth <= 0 \|\| code == null \|\| indentUnitsToRemove < 0 \|\| newIndentString == null \|\| lineDelim == null) {
	throw new IllegalArgumentException();
	}

	try {
	ILineTracker tracker= new DefaultLineTracker();
	tracker.set(code);
	int nLines= tracker.getNumberOfLines();
	if (nLines == 1) {
	return code;
	}

	StringBuffer buf= new StringBuffer();

	for (int i= 0; i < nLines; i++) {
	IRegion region= tracker.getLineInformation(i);
	int start= region.getOffset();
	int end= start + region.getLength();
	String line= code.substring(start, end);

	if (i == 0) { // no indent for first line (contained in the formatted string)
	buf.append(line);
	} else { // no new line after last line
	buf.append(lineDelim);
	buf.append(newIndentString);
	buf.append(trimIndent(line, indentUnitsToRemove, tabWidth, indentWidth));
	}
	}
	return buf.toString();
	} catch (BadLocationException e) {
	// can not happen
	return code;
	}
	}

	/**
	* Change the indent of a, possible muti-line, code string. The given number of indent units is removed,
	* and a new indent string is added.
	* The first line of the code will not be changed (It is considered to have no indent as it might start in
	* the middle of a line).
	* @param source The code to change the indent of
	* @param indentUnitsToRemove the number of indent units to remove from each line (except the first) of the given code
	* @param tabWidth the size of one tab in space equivalents
	* @param indentWidth the width of one indentation unit in space equivalents
	* @param newIndentString the new indent string to be added to all lines (except the first)
	* @return returns the resulting text edits
	*/
	public static ReplaceEdit[] getChangeIndentEdits(String source, int indentUnitsToRemove, int tabWidth, int indentWidth, String newIndentString) {
	if (tabWidth < 0 \|\| indentWidth <= 0 \|\| source == null \|\| indentUnitsToRemove < 0 \|\| newIndentString == null) {
	throw new IllegalArgumentException();
	}

	ArrayList result= new ArrayList();
	try {
	ILineTracker tracker= new DefaultLineTracker();
	tracker.set(source);
	int nLines= tracker.getNumberOfLines();
	if (nLines == 1)
	return (ReplaceEdit[])result.toArray(new ReplaceEdit[result.size()]);
	for (int i= 1; i < nLines; i++) {
	IRegion region= tracker.getLineInformation(i);
	int offset= region.getOffset();
	String line= source.substring(offset, offset + region.getLength());
	int length= indexOfIndent(line, indentUnitsToRemove, tabWidth, indentWidth);
	if (length >= 0) {
	result.add(new ReplaceEdit(offset, length, newIndentString));
	} else {
	length= measureIndentUnits(line, tabWidth, indentWidth);
	result.add(new ReplaceEdit(offset, length, "")); //$NON-NLS-1$
	}
	}
	} catch (BadLocationException cannotHappen) {
	// can not happen
	}
	return (ReplaceEdit[])result.toArray(new ReplaceEdit[result.size()]);
	}

	/*
	* Returns the index where the indent of the given size ends.
	* Returns <code>-1<code> if the line isn't prefixed with an indent of
	* the given number of indents.
	*/
	private static int indexOfIndent(CharSequence line, int numberOfIndentUnits, int tabWidth, int indentWidth) {

	int spaceEquivalents= numberOfIndentUnits * indentWidth;

	int size= line.length();
	int result= -1;
	int blanks= 0;
	for (int i= 0; i < size && blanks < spaceEquivalents; i++) {
	char c= line.charAt(i);
	if (c == '\t') {
	int remainder= blanks % tabWidth;
	blanks += tabWidth - remainder;
	} else if (isIndentChar(c)) {
	blanks++;
	} else {
	break;
	}
	result= i;
	}
	if (blanks < spaceEquivalents)
	return -1;
	return result + 1;
	}

	/**
	* Returns the tab width as configured in the given map.
	* @param options the map to get the formatter settings from. Use {@link org.eclipse.jdt.core.IJavaProject#getOptions(boolean)} to
	* get the most current project options.
	* @return the tab width
	*/
	public static int getTabWidth(Map options) {
	if (options == null) {
	throw new IllegalArgumentException();
	}
	return getIntValue(options, DefaultCodeFormatterConstants.FORMATTER_TAB_SIZE, 4);
	}

	/**
	* Returns the tab width as configured in the given map.
	* @param options the map to get the formatter settings from. Use {@link org.eclipse.jdt.core.IJavaProject#getOptions(boolean)} to
	* get the most current project options.
	* @return the indent width
	*/
	public static int getIndentWidth(Map options) {
	if (options == null) {
	throw new IllegalArgumentException();
	}
	int tabWidth=getTabWidth(options);
	boolean isMixedMode= DefaultCodeFormatterConstants.MIXED.equals(options.get(DefaultCodeFormatterConstants.FORMATTER_TAB_CHAR));
	if (isMixedMode) {
	return getIntValue(options, DefaultCodeFormatterConstants.FORMATTER_INDENTATION_SIZE, tabWidth);
	}
	return tabWidth;
	}

	/**
	* Creates a string that represents the given number of indentation units.
	* The returned string can contain tabs and/or spaces depending on the core
	* formatter preferences.
	*
	* @param indentationUnits the number of indentation units to generate
	* @param options the options to get the formatter settings from. Use {@link org.eclipse.jdt.core.IJavaProject#getOptions(boolean)} to
	* get the most current project options.
	* @return the indent string
	*/
	public static String createIndentString(int indentationUnits, Map options) {
	if (options == null \|\| indentationUnits < 0) {
	throw new IllegalArgumentException();
	}

	String tabChar= getStringValue(options, DefaultCodeFormatterConstants.FORMATTER_TAB_CHAR, JavaCore.TAB);

	final int tabs, spaces;
	if (JavaCore.SPACE.equals(tabChar)) {
	tabs= 0;
	spaces= indentationUnits * getIndentWidth(options);
	} else if (JavaCore.TAB.equals(tabChar)) {
	// indentWidth == tabWidth
	tabs= indentationUnits;
	spaces= 0;
	} else if (DefaultCodeFormatterConstants.MIXED.equals(tabChar)){
	int tabWidth= getTabWidth(options);
	int spaceEquivalents= indentationUnits * getIndentWidth(options);
	if (tabWidth > 0) {
	tabs= spaceEquivalents / tabWidth;
	spaces= spaceEquivalents % tabWidth;
	} else {
	tabs= 0;
	spaces= spaceEquivalents;
	}
	} else {
	// new indent type not yet handled
	Assert.isTrue(false);
	return null;
	}

	StringBuffer buffer= new StringBuffer(tabs + spaces);
	for(int i= 0; i < tabs; i++)
	buffer.append('\t');
	for(int i= 0; i < spaces; i++)
	buffer.append(' ');
	return buffer.toString();
	}

	private static String getStringValue(Map options, String key, String def) {
	Object value= options.get(key);
	if (value instanceof String)
	return (String) value;
	return def;
	}

	private static int getIntValue(Map options, String key, int def) {
	try {
	return Integer.parseInt((String) options.get(key));
	} catch (NumberFormatException e) {
	return def;
	}
	}
	}