package org.jedit.syntax; /* * TextUtilities.java - Utility functions used by the text area classes * Copyright (C) 1999 Slava Pestov * * You may use and modify this package for any purpose. Redistribution is * permitted, in both source and binary form, provided that this notice * remains intact in all source distributions of this package. */ import javax.swing.text.*; /** * Class with several utility functions used by the text area component. * @author Slava Pestov * @version $Id: TextUtilities.java,v 1.4 1999/12/13 03:40:30 sp Exp $ */ public class TextUtilities { /** * Returns the offset of the bracket matching the one at the * specified offset of the document, or -1 if the bracket is * unmatched (or if the character is not a bracket). * @param doc The document * @param offset The offset * @exception BadLocationException If an out-of-bounds access * was attempted on the document text */ public static int findMatchingBracket(Document doc, int offset) throws BadLocationException { if(doc.getLength() == 0) return -1; char c = doc.getText(offset,1).charAt(0); char cprime; // c` - corresponding character boolean direction; // true = back, false = forward switch(c) { case '(': cprime = ')'; direction = false; break; case ')': cprime = '('; direction = true; break; case '[': cprime = ']'; direction = false; break; case ']': cprime = '['; direction = true; break; case '{': cprime = '}'; direction = false; break; case '}': cprime = '{'; direction = true; break; default: return -1; } int count; // How to merge these two cases is left as an exercise // for the reader. // Go back or forward if(direction) { // Count is 1 initially because we have already // `found' one closing bracket count = 1; // Get text[0,offset-1]; String text = doc.getText(0,offset); // Scan backwards for(int i = offset - 1; i >= 0; i--) { // If text[i] == c, we have found another // closing bracket, therefore we will need // two opening brackets to complete the // match. char x = text.charAt(i); if(x == c) count++; // If text[i] == cprime, we have found a // opening bracket, so we return i if // --count == 0 else if(x == cprime) { if(--count == 0) return i; } } } else { // Count is 1 initially because we have already // `found' one opening bracket count = 1; // So we don't have to + 1 in every loop offset++; // Number of characters to check int len = doc.getLength() - offset; // Get text[offset+1,len]; String text = doc.getText(offset,len); // Scan forwards for(int i = 0; i < len; i++) { // If text[i] == c, we have found another // opening bracket, therefore we will need // two closing brackets to complete the // match. char x = text.charAt(i); if(x == c) count++; // If text[i] == cprime, we have found an // closing bracket, so we return i if // --count == 0 else if(x == cprime) { if(--count == 0) return i + offset; } } } // Nothing found return -1; } /** * Locates the start of the word at the specified position. * @param line The text * @param pos The position */ public static int findWordStart(String line, int pos, String noWordSep) { char ch = line.charAt(pos - 1); if(noWordSep == null) noWordSep = ""; boolean selectNoLetter = (!Character.isLetterOrDigit(ch) && noWordSep.indexOf(ch) == -1); int wordStart = 0; for(int i = pos - 1; i >= 0; i--) { ch = line.charAt(i); if(selectNoLetter ^ (!Character.isLetterOrDigit(ch) && noWordSep.indexOf(ch) == -1)) { wordStart = i + 1; break; } } return wordStart; } /** * Locates the end of the word at the specified position. * @param line The text * @param pos The position */ public static int findWordEnd(String line, int pos, String noWordSep) { char ch = line.charAt(pos); if(noWordSep == null) noWordSep = ""; boolean selectNoLetter = (!Character.isLetterOrDigit(ch) && noWordSep.indexOf(ch) == -1); int wordEnd = line.length(); for(int i = pos; i < line.length(); i++) { ch = line.charAt(i); if(selectNoLetter ^ (!Character.isLetterOrDigit(ch) && noWordSep.indexOf(ch) == -1)) { wordEnd = i; break; } } return wordEnd; } }