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/jEdit/tags/jedit-4-3-pre5/org/gjt/sp/jedit/buffer/ContentManager.java

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Java | 187 lines | 119 code | 21 blank | 47 comment | 15 complexity | 3c089808b76de821e19243133695b2ab MD5 | raw file
  1/*
  2 * ContentManager.java - Manages text content
  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
 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 4524 2003-03-09 19:26:05Z spestov $
 36 * @since jEdit 4.0pre1
 37 */
 38public class ContentManager
 39{
 40	//{{{ getLength() method
 41	public final int getLength()
 42	{
 43		return length;
 44	} //}}}
 45
 46	//{{{ getText() method
 47	public String getText(int start, int len)
 48	{
 49		if(start >= gapStart)
 50			return new String(text,start + gapEnd - gapStart,len);
 51		else if(start + len <= gapStart)
 52			return new String(text,start,len);
 53		else
 54		{
 55			return new String(text,start,gapStart - start)
 56				.concat(new String(text,gapEnd,start + len - gapStart));
 57		}
 58	} //}}}
 59
 60	//{{{ getText() method
 61	public void getText(int start, int len, Segment seg)
 62	{
 63		if(start >= gapStart)
 64		{
 65			seg.array = text;
 66			seg.offset = start + gapEnd - gapStart;
 67			seg.count = len;
 68		}
 69		else if(start + len <= gapStart)
 70		{
 71			seg.array = text;
 72			seg.offset = start;
 73			seg.count = len;
 74		}
 75		else
 76		{
 77			seg.array = new char[len];
 78
 79			// copy text before gap
 80			System.arraycopy(text,start,seg.array,0,gapStart - start);
 81
 82			// copy text after gap
 83			System.arraycopy(text,gapEnd,seg.array,gapStart - start,
 84				len + start - gapStart);
 85
 86			seg.offset = 0;
 87			seg.count = len;
 88		}
 89	} //}}}
 90
 91	//{{{ insert() method
 92	public void insert(int start, String str)
 93	{
 94		int len = str.length();
 95		moveGapStart(start);
 96		if(gapEnd - gapStart < len)
 97		{
 98			ensureCapacity(length + len + 1024);
 99			moveGapEnd(start + len + 1024);
100		}
101
102		str.getChars(0,len,text,start);
103		gapStart += len;
104		length += len;
105	} //}}}
106
107	//{{{ insert() method
108	public void insert(int start, Segment seg)
109	{
110		moveGapStart(start);
111		if(gapEnd - gapStart < seg.count)
112		{
113			ensureCapacity(length + seg.count + 1024);
114			moveGapEnd(start + seg.count + 1024);
115		}
116
117		System.arraycopy(seg.array,seg.offset,text,start,seg.count);
118		gapStart += seg.count;
119		length += seg.count;
120	} //}}}
121
122	//{{{ _setContent() method
123	public void _setContent(char[] text, int length)
124	{
125		this.text = text;
126		this.gapStart = this.gapEnd = 0;
127		this.length = length;
128	} //}}}
129
130	//{{{ remove() method
131	public void remove(int start, int len)
132	{
133		moveGapStart(start);
134		gapEnd += len;
135		length -= len;
136	} //}}}
137
138	//{{{ Private members
139	private char[] text;
140	private int gapStart;
141	private int gapEnd;
142	private int length;
143
144	//{{{ moveGapStart() method
145	private void moveGapStart(int newStart)
146	{
147		int newEnd = gapEnd + (newStart - gapStart);
148
149		if(newStart == gapStart)
150		{
151			// nothing to do
152		}
153		else if(newStart > gapStart)
154		{
155			System.arraycopy(text,gapEnd,text,gapStart,
156				newStart - gapStart);
157		}
158		else if(newStart < gapStart)
159		{
160			System.arraycopy(text,newStart,text,newEnd,
161				gapStart - newStart);
162		}
163
164		gapStart = newStart;
165		gapEnd = newEnd;
166	} //}}}
167
168	//{{{ moveGapEnd() method
169	private void moveGapEnd(int newEnd)
170	{
171		System.arraycopy(text,gapEnd,text,newEnd,length - gapStart);
172		gapEnd = newEnd;
173	} //}}}
174
175	//{{{ ensureCapacity() method
176	private void ensureCapacity(int capacity)
177	{
178		if(capacity >= text.length)
179		{
180			char[] textN = new char[capacity * 2];
181			System.arraycopy(text,0,textN,0,length + (gapEnd - gapStart));
182			text = textN;
183		}
184	} //}}}
185
186	//}}}
187}