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Java > Open Source Codes > org > gjt > sp > jedit > buffer > IndentFoldHandler


1 /*
2  * IndentFoldHandler.java - Indent-based fold handler
3  * :tabSize=8:indentSize=8:noTabs=false:
4  * :folding=explicit:collapseFolds=1:
5  *
6  * Copyright (C) 2001, 2002 Slava Pestov
7  *
8  * This program is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU General Public License
10  * as published by the Free Software Foundation; either version 2
11  * of the License, or any later version.
12  *
13  * This program is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16  * GNU General Public License for more details.
17  *
18  * You should have received a copy of the GNU General Public License
19  * along with this program; if not, write to the Free Software
20  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
21  */
22
23 package org.gjt.sp.jedit.buffer;
24
25 import javax.swing.text.Segment JavaDoc;
26
27 /**
28  * A fold handler that folds lines based on their indent level.
29  * @author Slava Pestov
30  * @version $Id: IndentFoldHandler.java 5339 2006-01-25 23:12:07Z spestov $
31  * @since jEdit 4.0pre1
32  */
33 public class IndentFoldHandler extends FoldHandler
34 {
35     public IndentFoldHandler()
36     {
37         super("indent");
38     }
39
40     //{{{ getFoldLevel() method
41 /**
42      * Returns the fold level of the specified line.
43      * @param buffer The buffer in question
44      * @param lineIndex The line index
45      * @param seg A segment the fold handler can use to obtain any
46      * text from the buffer, if necessary
47      * @return The fold level of the specified line
48      * @since jEdit 4.0pre1
49      */
50     public int getFoldLevel(JEditBuffer buffer, int lineIndex, Segment JavaDoc seg)
51     {
52         int tabSize = buffer.getTabSize();
53
54         buffer.getLineText(lineIndex,seg);
55
56         int offset = seg.offset;
57         int count = seg.count;
58
59         int whitespace = 0;
60
61         boolean seenNonWhiteSpace = false;
62
63 loop: for(int i = 0; i < count; i++)
64         {
65             switch(seg.array[offset + i])
66             {
67             case ' ':
68                 whitespace++;
69                 break;
70             case '\t':
71                 whitespace += (tabSize - whitespace % tabSize);
72                 break;
73             default:
74                 seenNonWhiteSpace = true;
75                 break loop;
76             }
77         }
78
79         if(!seenNonWhiteSpace)
80         {
81             // empty line. inherit previous line's fold level
82 if(lineIndex != 0)
83                 return buffer.getFoldLevel(lineIndex - 1);
84             else
85                 return 0;
86         }
87             return whitespace;
88     } //}}}
89 }
90
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