path: root/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/corext/util/Strings.java

/*******************************************************************************
 * Copyright (c) 2000, 2016 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
 *     Anton Leherbauer (Wind River Systems)
 *     Sergey Prigogin (Google)
 *******************************************************************************/
package org.eclipse.cdt.internal.corext.util;

import org.eclipse.core.runtime.Assert;
import org.eclipse.jface.action.LegacyActionTools;
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.jface.viewers.StyledString;
import org.eclipse.osgi.util.TextProcessor;

import org.eclipse.cdt.core.formatter.IndentManipulation;
import org.eclipse.cdt.core.model.ICProject;

/**
 * Helper class to provide String manipulation functions not available in standard JDK.
 */
public class Strings {

	private Strings() {}
	
	/**
	 * Tells whether we have to use the {@link TextProcessor}
	 * <p>
	 * This is used for performance optimization.
	 * </p>
	 */
	public static final boolean USE_TEXT_PROCESSOR;
	static {
		String testString= "args : String[]"; //$NON-NLS-1$
		USE_TEXT_PROCESSOR= testString != TextProcessor.process(testString);
	}

	private static final String C_ELEMENT_DELIMITERS= TextProcessor.getDefaultDelimiters() + "<>(),?{} "; //$NON-NLS-1$

	public static boolean startsWithIgnoreCase(CharSequence text, CharSequence prefix) {
		int textLength= text.length();
		int prefixLength= prefix.length();
		if (textLength < prefixLength)
			return false;
		for (int i= prefixLength - 1; i >= 0; i--) {
			if (Character.toLowerCase(prefix.charAt(i)) != Character.toLowerCase(text.charAt(i)))
				return false;
		}
		return true;
	}

	public static boolean endsWith(CharSequence containing, CharSequence contained) {
		int start = containing.length() - contained.length();
		if (start < 0)
			return false;
		for (int i = start, j = 0; i < containing.length(); i++, j++) {
			if (containing.charAt(i) != contained.charAt(j))
				return false;
		}
		return true;
	}

	public static String removeNewLine(String message) {
		StringBuffer result= new StringBuffer();
		int current= 0;
		int index= message.indexOf('\n', 0);
		while (index != -1) {
			result.append(message.substring(current, index));
			if (current < index && index != 0)
				result.append(' ');
			current= index + 1;
			index= message.indexOf('\n', current);
		}
		result.append(message.substring(current));
		return result.toString();
	}

	/**
	 * Converts the given string into an array of lines. The lines 
	 * don't contain any line delimiter characters.
	 *
	 * @return the string converted into an array of strings. Returns <code>
	 * 	null</code> if the input string can't be converted in an array of lines.
	 */
	public static String[] convertIntoLines(String input) {
		try {
			ILineTracker tracker= new DefaultLineTracker();
			tracker.set(input);
			int size= tracker.getNumberOfLines();
			String result[]= new String[size];
			for (int i= 0; i < size; i++) {
				IRegion region= tracker.getLineInformation(i);
				int offset= region.getOffset();
				result[i]= input.substring(offset, offset + region.getLength());
			}
			return result;
		} catch (BadLocationException e) {
			return null;
		}
	}

	/**
	 * Returns <code>true</code> if the given string only consists of
	 * white spaces according to C. If the string is empty, <code>true
	 * </code> is returned.
	 * 
	 * @return <code>true</code> if the string only consists of white
	 * 	spaces; otherwise <code>false</code> is returned
	 * 
	 * @see java.lang.Character#isWhitespace(char)
	 */
	public static boolean containsOnlyWhitespaces(String s) {
		int size= s.length();
		for (int i= 0; i < size; i++) {
			if (!Character.isWhitespace(s.charAt(i)))
				return false;
		}
		return true;
	}
	
	/**
	 * Removes leading tabs and spaces from the given string. If the string
	 * doesn't contain any leading tabs or spaces then the string itself is 
	 * returned.
	 */
	public static String trimLeadingTabsAndSpaces(String line) {
		int size= line.length();
		int start= size;
		for (int i= 0; i < size; i++) {
			char c= line.charAt(i);
			if (!IndentManipulation.isIndentChar(c)) {
				start= i;
				break;
			}
		}
		if (start == 0)
			return line;
		else if (start == size)
			return ""; //$NON-NLS-1$
		else
			return line.substring(start);
	}
	
	public static String trimTrailingTabsAndSpaces(String line) {
		int size= line.length();
		int end= size;
		for (int i= size - 1; i >= 0; i--) {
			char c= line.charAt(i);
			if (IndentManipulation.isIndentChar(c)) {
				end= i;
			} else {
				break;
			}
		}
		if (end == size)
			return line;
		else if (end == 0)
			return ""; //$NON-NLS-1$
		else
			return line.substring(0, end);
	}
		
	/**
	 * Returns the indent of the given string in indentation units. Odd spaces
	 * are not counted.
	 * 
	 * @param line the text line
	 * @param project the project from which to get the formatter
	 *        preferences, or <code>null</code> for global preferences
	 * @since 5.0
	 */
	public static int computeIndentUnits(String line, ICProject project) {
		return IndentManipulation.measureIndentUnits(line, CodeFormatterUtil.getTabWidth(project), CodeFormatterUtil.getIndentWidth(project));
	}
	
	/**
	 * Returns the indent of the given string in indentation units. Odd spaces
	 * are not counted.
	 * 
	 * @param line the text line
	 * @param tabWidth the width of the '\t' character in space equivalents
	 * @param indentWidth the width of one indentation unit in space equivalents
	 * @since 5.0
	 */
	public static int computeIndentUnits(String line, int tabWidth, int indentWidth) {
		return IndentManipulation.measureIndentUnits(line, tabWidth, indentWidth);
	}
	
	/**
	 * Computes the visual length of the indentation of a
	 * <code>CharSequence</code>, counting a tab character as the size until
	 * the next tab stop and every other whitespace character as one.
	 * 
	 * @param line the string to measure the indent of
	 * @param tabSize the visual size of a tab in space equivalents
	 * @return the visual length of the indentation of <code>line</code>
	 * @since 5.0
	 */
	public static int measureIndentLength(CharSequence line, int tabSize) {
		return IndentManipulation.measureIndentInSpaces(line, tabSize);
	}

	/**
	 * Removes the given number of indents from the line. Asserts that the given line 
	 * has the requested number of indents. If <code>indentsToRemove <= 0</code>
	 * the line is returned.
	 * 
	 * @param project the project from which to get the formatter
	 *        preferences, or <code>null</code> for global preferences
	 * @since 5.0
	 */
	public static String trimIndent(String line, int indentsToRemove, ICProject project) {
		return IndentManipulation.trimIndent(line, indentsToRemove, CodeFormatterUtil.getTabWidth(project), CodeFormatterUtil.getIndentWidth(project));
	}
	
	/**
	 * Removes the given number of indents from the line. Asserts that the given line 
	 * has the requested number of indents. If <code>indentsToRemove <= 0</code>
	 * the line is returned.
	 * 
	 * @since 5.0
	 */
	public static String trimIndent(String line, int indentsToRemove, int tabWidth, int indentWidth) {
		return IndentManipulation.trimIndent(line, indentsToRemove, tabWidth, indentWidth);
	}
	
	/**
	 * Removes the common number of indents from all lines. If a line
	 * only consists out of white space it is ignored.

	 * @param project the project from which to get the formatter
	 *        preferences, or <code>null</code> for global preferences
	 * @since 5.0
	 */
	public static void trimIndentation(String[] lines, ICProject project) {
		trimIndentation(lines, CodeFormatterUtil.getTabWidth(project), CodeFormatterUtil.getIndentWidth(project), true);
	}
	/**
	 * Removes the common number of indents from all lines. If a line
	 * only consists out of white space it is ignored.
	 * 
	 * @since 5.0
	 */
	public static void trimIndentation(String[] lines, int tabWidth, int indentWidth) {
		trimIndentation(lines, tabWidth, indentWidth, true);
	}
	
	/**
	 * Removes the common number of indents from all lines. If a line
	 * only consists out of white space it is ignored. If <code>
	 * considerFirstLine</code> is false the first line will be ignored.
	 * 
	 * @param project the project from which to get the formatter
	 *        preferences, or <code>null</code> for global preferences
	 * @since 5.0
	 */
	public static void trimIndentation(String[] lines, ICProject project, boolean considerFirstLine) {
		trimIndentation(lines, CodeFormatterUtil.getTabWidth(project), CodeFormatterUtil.getIndentWidth(project), considerFirstLine);
	}
	
	/**
	 * Removes the common number of indents from all lines. If a line
	 * only consists out of white space it is ignored. If <code>
	 * considerFirstLine</code> is false the first line will be ignored.
	 * @since 5.0
	 */
	public static void trimIndentation(String[] lines, int tabWidth, int indentWidth, boolean considerFirstLine) {
		String[] toDo= new String[lines.length];
		// find indentation common to all lines
		int minIndent= Integer.MAX_VALUE; // very large
		for (int i= considerFirstLine ? 0 : 1; i < lines.length; i++) {
			String line= lines[i];
			if (containsOnlyWhitespaces(line))
				continue;
			toDo[i]= line;
			int indent= computeIndentUnits(line, tabWidth, indentWidth);
			if (indent < minIndent) {
				minIndent= indent;
			}
		}
		
		if (minIndent > 0) {
			// remove this indent from all lines
			for (int i= considerFirstLine ? 0 : 1; i < toDo.length; i++) {
				String s= toDo[i];
				if (s != null)
					lines[i]= trimIndent(s, minIndent, tabWidth, indentWidth);
				else {
					String line= lines[i];
					int indent= computeIndentUnits(line, tabWidth, indentWidth);
					if (indent > minIndent)
						lines[i]= trimIndent(line, minIndent, tabWidth, indentWidth);
					else
						lines[i]= trimLeadingTabsAndSpaces(line);
				}
			}
		}
	}
		
	/**
	 * Returns that part of the indentation of <code>line</code> that makes up
	 * a multiple of indentation units.
	 * 
	 * @param line the line to scan
	 * @param project the project from which to get the formatter
	 *        preferences, or <code>null</code> for global preferences
	 * @return the indent part of <code>line</code>, but no odd spaces
	 * @since 5.0
	 */
	public static String getIndentString(String line, ICProject project) {
		return IndentManipulation.extractIndentString(line, CodeFormatterUtil.getTabWidth(project), CodeFormatterUtil.getIndentWidth(project));
	}
	
	/**
	 * Returns that part of the indentation of <code>line</code> that makes up
	 * a multiple of indentation units.
	 * 
	 * @param line the line to scan
	 * @param tabWidth the size of one tab in space equivalents
	 * @param indentWidth the size of the indent in space equivalents
	 * @return the indent part of <code>line</code>, but no odd spaces
	 * @since 5.0
	 */
	public static String getIndentString(String line, int tabWidth, int indentWidth) {
		return IndentManipulation.extractIndentString(line, tabWidth, indentWidth);
	}
		
	public static String[] removeTrailingEmptyLines(String[] sourceLines) {
		int lastNonEmpty= findLastNonEmptyLineIndex(sourceLines);
		String[] result= new String[lastNonEmpty + 1];
		for (int i= 0; i < result.length; i++) {
			result[i]= sourceLines[i];
		}
		return result;
	}

	private static int findLastNonEmptyLineIndex(String[] sourceLines) {
		for (int i= sourceLines.length - 1; i >= 0; i--) {
			if (! sourceLines[i].trim().isEmpty())
				return i;
		}
		return -1;
	}
	
	/**
	 * Change the indent of, possible muti-line, code range. The current indent is removed, a new indent 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 project the project from which to get the formatter
	 *        preferences, or <code>null</code> for global preferences
	 * @since 5.0
	 */
	public static String changeIndent(String code, int codeIndentLevel, ICProject project, String newIndent, String lineDelim) {
		return IndentManipulation.changeIndent(code, codeIndentLevel, CodeFormatterUtil.getTabWidth(project), CodeFormatterUtil.getIndentWidth(project), newIndent, lineDelim);
	}
	
	/**
	 * Change the indent of, possible muti-line, code range. The current indent is removed, a new indent 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)
	 * @since 5.0
	 */
	public static String changeIndent(String code, int codeIndentLevel, int tabWidth, int indentWidth, String newIndent, String lineDelim) {
		return IndentManipulation.changeIndent(code, codeIndentLevel, tabWidth, indentWidth, newIndent, lineDelim);
	}
	
	public static String trimIndentation(String source, ICProject project, boolean considerFirstLine) {
		return trimIndentation(source, CodeFormatterUtil.getTabWidth(project), CodeFormatterUtil.getIndentWidth(project), considerFirstLine);
	}
	
	public static String trimIndentation(String source, int tabWidth, int indentWidth, boolean considerFirstLine) {
		try {
			ILineTracker tracker= new DefaultLineTracker();
			tracker.set(source);
			int size= tracker.getNumberOfLines();
			if (size == 1)
				return source;
			String lines[]= new String[size];
			for (int i= 0; i < size; i++) {
				IRegion region= tracker.getLineInformation(i);
				int offset= region.getOffset();
				lines[i]= source.substring(offset, offset + region.getLength());
			}
			Strings.trimIndentation(lines, tabWidth, indentWidth, considerFirstLine);
			StringBuffer result= new StringBuffer();
			int last= size - 1;
			for (int i= 0; i < size; i++) {
				result.append(lines[i]);
				if (i < last)
					result.append(tracker.getLineDelimiter(i));
			}
			return result.toString();
		} catch (BadLocationException e) {
			Assert.isTrue(false,"Can not happend"); //$NON-NLS-1$
			return null;
		}
	}
		
	/**
	 * Concatenate the given strings into one strings using the passed line delimiter as a
	 * delimiter. No delimiter is added to the last line.
	 */
	public static String concatenate(String[] lines, String delimiter) {
		StringBuffer buffer= new StringBuffer();
		for (int i= 0; i < lines.length; i++) {
			if (i > 0)
				buffer.append(delimiter);
			buffer.append(lines[i]);
		}
		return buffer.toString();
	}
	
	public static boolean equals(String s, char[] c) {
		if (s.length() != c.length)
			return false;

		for (int i = c.length; --i >= 0;) {
			if (s.charAt(i) != c[i])
				return false;
		}
		return true;
	}
		
	public static String removeTrailingCharacters(String text, char toRemove) {
		int size= text.length();
		int end= size;
		for (int i= size - 1; i >= 0; i--) {
			char c= text.charAt(i);
			if (c == toRemove) {
				end= i;
			} else {
				break;
			}
		}
		if (end == size)
			return text;
		else if (end == 0)
			return ""; //$NON-NLS-1$
		else
			return text.substring(0, end);
	}

	/**
	 * Converts tabs to spaces in a line of text.
	 * @param line The line of text.
	 * @param tabWidth Tabulation size.
	 * @return The line with tab characters replaced by spaces.
	 */
	public static String convertTabsToSpaces(String line, int tabWidth) {
		StringBuilder buf = null;
		for (int i = 0; i < line.length(); i++) {
			char c = line.charAt(i);
			if (c == '\t') {
				if (buf == null) {
					buf = new StringBuilder(line.length() * tabWidth);
					buf.append(line.subSequence(0, i));
				}
				for (int k = tabWidth - i % tabWidth; --k >= 0;) {
					buf.append(' ');
				}
			} else if (buf != null) {
				buf.append(c);
			}
		}
		return buf != null ? buf.toString() : line;
	}

	public static String removeMnemonicIndicator(String string) {
		return LegacyActionTools.removeMnemonics(string);
	}

	
	/**
	 * Adds special marks so that that the given styled string is readable in a BiDi environment.
	 * 
	 * @param styledString the styled string
	 * @return the processed styled string
	 */
	public static StyledString markLTR(StyledString styledString) {
		
		/*
		 * NOTE: For performance reasons we do not call  markLTR(styledString, null)
		 */
		
		if (!USE_TEXT_PROCESSOR)
			return styledString;

		String inputString= styledString.getString();
		String string= TextProcessor.process(inputString);
		if (string != inputString)
			insertMarks(styledString, inputString, string);
		return styledString;
	}

	/**
	 * Adds special marks so that that the given styled string is readable in a BiDi environment.
	 * 
	 * @param styledString the styled string
	 * @param delimiters the additional delimiters
	 * @return the processed styled string
	 */
	public static StyledString markLTR(StyledString styledString, String delimiters) {
		if (!USE_TEXT_PROCESSOR)
			return styledString;

		String inputString= styledString.getString();
		String string= TextProcessor.process(inputString, delimiters);
		if (string != inputString)
			insertMarks(styledString, inputString, string);
		return styledString;
	}

	/**
	 * Adds special marks so that that the given string is readable in a BiDi environment.
	 * 
	 * @param string the string
	 * @return the processed styled string
	 * @since 5.3
	 */
	public static String markLTR(String string) {
		if (!USE_TEXT_PROCESSOR)
			return string;

		return TextProcessor.process(string);
	}

	/**
	 * Adds special marks so that that the given string is readable in a BiDi environment.
	 * 
	 * @param string the string
	 * @param delimiters the delimiters
	 * @return the processed styled string
	 * @since 5.3
	 */
	public static String markLTR(String string, String delimiters) {
		if (!USE_TEXT_PROCESSOR)
			return string;

		return TextProcessor.process(string, delimiters);
	}

	/**
	 * Adds special marks so that that the given C element label is readable in a BiDi
	 * environment.
	 * 
	 * @param string the string
	 * @return the processed styled string
	 * @since 5.3
	 */
	public static String markCElementLabelLTR(String string) {
		if (!USE_TEXT_PROCESSOR)
			return string;

		return TextProcessor.process(string, C_ELEMENT_DELIMITERS);
	}

	/**
	 * Adds special marks so that that the given styled C element label is readable in a BiDi
	 * environment.
	 * 
	 * @param styledString the styled string
	 * @return the processed styled string
	 * @since 5.3
	 */
	public static StyledString markCElementLabelLTR(StyledString styledString) {
		if (!USE_TEXT_PROCESSOR)
			return styledString;

		String inputString= styledString.getString();
		String string= TextProcessor.process(inputString, C_ELEMENT_DELIMITERS);
		if (string != inputString)
			insertMarks(styledString, inputString, string);
		return styledString;
	}

	/**
	 * Inserts the marks into the given styled string.
	 * 
	 * @param styledString the styled string
	 * @param originalString the original string
	 * @param processedString the processed string
	 * @since 5.3
	 */
	private static void insertMarks(StyledString styledString, String originalString, String processedString) {
		int originalLength= originalString.length();
		int processedStringLength= processedString.length();
		char orig= originalLength > 0 ? originalString.charAt(0) : '\0';
		for (int o= 0, p= 0; p < processedStringLength; p++) {
			char processed= processedString.charAt(p);
			if (o < originalLength) {
				if (orig == processed) {
					o++;
					if (o < originalLength)
						orig= originalString.charAt(o);
					continue;
				}
			}
			styledString.insert(processed, p);
		}
	}
}