Application: gvSIG desktop

package com.iver.utiles.console.jedit;

/*

 * 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.BadLocationException;

import javax.swing.text.Document;

/**

 * Class with several utility functions used by the text area component.

 * @author Slava Pestov

 * @version $Id$

 */

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;

        }

}