TextUtilities.java :  » IDE » bluej-editor » bluej » editor » moe » Java Open Source

package bluej.editor.moe;

/*
 * 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 4757 2006-12-08 04:41:48Z davmac $
 */
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 = 1;
        int step;
        int texttOffset;
        int len;
        int i;
        if (direction) {
            // search backwards
            step = -1;
            texttOffset = 0;
            len = offset;
            i = len - 1;
        }
        else {
            // search forwards
            step = 1;
            texttOffset = offset + 1;
            len = doc.getLength() - texttOffset;
            i = 0;
        }
        String textt = doc.getText(texttOffset, len);

        while (len > 0) {
            char x = textt.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 + texttOffset;
                }
            }
            
            len--;
            i += step;
            
            if (x == '\"' || x == '\'') {
                char quoteChar = x;
                // A quoted string, need to find the matching quote before matching
                // further brackets...
                while (len > 0) {
                    x = textt.charAt(i);
                    if (x == quoteChar) {
                        // Found the matching quote, as long as it is not \-quoted.
                        if (i == 0 || textt.charAt(i - 1) != '\\') {
                            len--;
                            i += step;
                            break;
                        }
                    }
                    len--;
                    i += step;
                }
            }
        }

    // 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;
  }
}