/jEdit/tags/jedit-4-0-pre3/org/gjt/sp/jedit/buffer/ContentManager.java

  1/*
  2 * ContentManager.java - Manages text content
  3 * :tabSize=8:indentSize=8:noTabs=false:
  4 * :folding=explicit:collapseFolds=1:
  5 *
  6 * Copyright (C) 2001 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
 23package org.gjt.sp.jedit.buffer;
 24
 25import javax.swing.text.Segment;
 26
 27/**
 28 * A class internal to jEdit's document model. You should not use it
 29 * directly. To improve performance, none of the methods in this class
 30 * check for out of bounds access, nor are they thread-safe. The
 31 * <code>Buffer</code> class, through which these methods must be
 32 * called through, implements such protection.
 33 *
 34 * @author Slava Pestov
 35 * @version $Id: ContentManager.java 3909 2001-11-24 02:27:08Z spestov $
 36 * @since jEdit 4.0pre1
 37 */
 38public class ContentManager
 39{
 40	//{{{ ContentManager constructor
 41	public ContentManager()
 42	{
 43		text = new char[1024];
 44	} //}}}
 45
 46	//{{{ getLength() method
 47	public final int getLength()
 48	{
 49		return length;
 50	} //}}}
 51
 52	//{{{ getText() method
 53	public String getText(int start, int len)
 54	{
 55		if(start >= gapStart)
 56			return new String(text,start + gapEnd - gapStart,len);
 57		else if(start + len <= gapStart)
 58			return new String(text,start,len);
 59		else
 60		{
 61			return new String(text,start,gapStart - start)
 62				.concat(new String(text,gapEnd,start + len - gapStart));
 63		}
 64	} //}}}
 65
 66	//{{{ getText() method
 67	public void getText(int start, int len, Segment seg)
 68	{
 69		if(start >= gapStart)
 70		{
 71			seg.array = text;
 72			seg.offset = start + gapEnd - gapStart;
 73			seg.count = len;
 74		}
 75		else if(start + len <= gapStart)
 76		{
 77			seg.array = text;
 78			seg.offset = start;
 79			seg.count = len;
 80		}
 81		else
 82		{
 83			seg.array = new char[len];
 84
 85			// copy text before gap
 86			System.arraycopy(text,start,seg.array,0,gapStart - start);
 87
 88			// copy text after gap
 89			System.arraycopy(text,gapEnd,seg.array,gapStart - start,
 90				len + start - gapStart);
 91
 92			seg.offset = 0;
 93			seg.count = len;
 94		}
 95	} //}}}
 96
 97	//{{{ insert() method
 98	public void insert(int start, String str)
 99	{
100		int len = str.length();
101		if(gapStart != start || gapEnd - gapStart < len)
102		{
103			ensureCapacity(length + len + 200);
104			close(start,start + len + 200);
105		}
106		str.getChars(0,len,text,start);
107		gapStart += len;
108		length += len;
109	} //}}}
110
111	//{{{ insert() method
112	public void insert(int start, Segment seg)
113	{
114		if(gapStart != start || gapEnd - gapStart < seg.count)
115		{
116			ensureCapacity(length + seg.count + 200);
117			close(start,start + seg.count + 200);
118		}
119		System.arraycopy(seg.array,seg.offset,text,start,seg.count);
120		gapStart += seg.count;
121		length += seg.count;
122	} //}}}
123
124	//{{{ remove() method
125	public void remove(int start, int len)
126	{
127		close(start,start);
128		gapEnd += len;
129		length -= len;
130	} //}}}
131
132	//{{{ Private members
133	private char[] text;
134	private int gapStart;
135	private int gapEnd;
136	private int length;
137
138	//{{{ close() method
139	private void close(int newStart, int newEnd)
140	{
141		// Optimization
142		if(gapStart == newStart)
143		{
144			System.arraycopy(text,gapEnd,text,newEnd,length - gapStart);
145		}
146		else
147		{
148			if(gapStart != gapEnd && gapStart != length)
149			{
150				System.arraycopy(text,gapEnd,text,gapStart,
151					length - gapStart);
152			}
153
154			if(newStart != newEnd && newStart != length)
155			{
156				System.arraycopy(text,newStart,text,newEnd,
157					length - newStart);
158			}
159		}
160
161		gapStart = newStart;
162		gapEnd = newEnd;
163	} //}}}
164
165	//{{{ ensureCapacity() method
166	private void ensureCapacity(int capacity)
167	{
168		if(capacity >= text.length)
169		{
170			char[] textN = new char[capacity * 2];
171			System.arraycopy(text,0,textN,0,length + (gapEnd - gapStart));
172			text = textN;
173		}
174	} //}}}
175
176	//}}}
177}