defaultcontent.java

源码为Eclipse开源开发平台桌面开发工具SWT的源代码,

/*******************************************************************************
 * Copyright (c) 2000, 2004 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.custom;

import org.eclipse.swt.*;
import org.eclipse.swt.internal.Compatibility;
import org.eclipse.swt.widgets.*;
import java.util.Vector;

class DefaultContent implements StyledTextContent {
	private final static String LineDelimiter = System.getProperty("line.separator");

	Vector textListeners = new Vector(); // stores text listeners for event sending
	char[] textStore = new char[0];	// stores the actual text
	int gapStart = -1;	// the character position start of the gap
	int gapEnd = -1;	// the character position after the end of the gap
	int gapLine = -1;	// the line on which the gap exists, the gap will always be associated
				// with one line
	int highWatermark = 300;	
	int lowWatermark = 50;		
	
	int[][] lines = new int[50][2];	// array of character positions and lengths representing
							// the lines of text
	int lineCount = 0;	// the number of lines of text	
	int expandExp = 1; 	// the expansion exponent, used to increase the lines array exponentially
	int replaceExpandExp = 1; 	// the expansion exponent, used to increase the lines array exponentially

/** 
 * Creates a new DefaultContent and initializes it.  A <code>StyledTextContent</> will always have
 * at least one empty line.
 */
DefaultContent() {
	super();
	setText("");
}
/** 
 * Adds a line to the end of the line indexes array.  Increases the size of the array if necessary.
 * <code>lineCount</code> is updated to reflect the new entry.
 * <p>
 *
 * @param start the start of the line
 * @param length the length of the line
 */
void addLineIndex(int start, int length) {
	int size = lines.length;
	if (lineCount == size) {
		// expand the lines by powers of 2
		int[][] newLines = new int[size+Compatibility.pow2(expandExp)][2];
		System.arraycopy(lines, 0, newLines, 0, size);
		lines = newLines;
		expandExp++;
	}
	int[] range = new int[] {start, length};
	lines[lineCount] = range;
	lineCount++;
}
/** 
 * Adds a line index to the end of <code>linesArray</code>.  Increases the 
 * size of the array if necessary and returns a new array.
 * <p>
 *
 * @param start the start of the line
 * @param length the length of the line
 * @param linesArray the array to which to add the line index
 * @param count the position at which to add the line
 * @return a new array of line indexes
 */
int[][] addLineIndex(int start, int length, int[][] linesArray, int count) {
	int size = linesArray.length;
	int[][] newLines = linesArray;
	if (count == size) {
		newLines = new int[size+Compatibility.pow2(replaceExpandExp)][2];
		replaceExpandExp++;
		System.arraycopy(linesArray, 0, newLines, 0, size);
	}
	int[] range = new int[] {start, length};
	newLines[count] = range;
	return newLines;
}
/**
 * Adds a <code>TextChangeListener</code> listening for 
 * <code>TextChangingEvent</code> and <code>TextChangedEvent</code>. A 
 * <code>TextChangingEvent</code> is sent before changes to the text occur.
 * A <code>TextChangedEvent</code> is sent after changes to the text 
 * occured.
 * <p>
 *
 * @param listener the listener
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT when listener is null</li>
 * </ul>
 */
public void addTextChangeListener(TextChangeListener listener) {
	if (listener == null) error(SWT.ERROR_NULL_ARGUMENT);
	StyledTextListener typedListener = new StyledTextListener(listener);
	textListeners.addElement(typedListener);	
}	
/**
 * Adjusts the gap to accomodate a text change that is occurring.
 * <p>
 *
 * @param position the position at which a change is occurring
 * @param sizeHint the size of the change
 * @param line the line where the gap will go
 */
void adjustGap(int position, int sizeHint, int line) {
	if (position == gapStart) {
		// text is being inserted at the gap position
		int size = (gapEnd - gapStart) - sizeHint;
		if (lowWatermark <= size && size <= highWatermark)
			return;
	} else if ((position + sizeHint == gapStart) && (sizeHint < 0)) {
		// text is being deleted at the gap position
		int size = (gapEnd - gapStart) - sizeHint;
		if (lowWatermark <= size && size <= highWatermark)
			return;
	}
	moveAndResizeGap(position, sizeHint, line);
}
/**
 * Calculates the indexes of each line in the text store.  Assumes no gap exists.  
 * Optimized to do less checking.
 */
void indexLines(){
	int start = 0;
	lineCount = 0;
	int textLength = textStore.length;
	int i;
	for (i=start; i<textLength; i++) { 
		char ch = textStore[i];					
		if (ch == SWT.CR) {
			// see if the next character is a LF
			if (i + 1 < textLength) {
				ch = textStore[i+1];
				if (ch == SWT.LF) {
					i++;
				}
			}
			addLineIndex(start, i - start + 1);
			start = i + 1;
		} else if (ch == SWT.LF) {
			addLineIndex(start, i - start + 1);
			start = i + 1;
		} 
	}			
	addLineIndex(start, i - start);
}
/** 
 * Returns whether or not the given character is a line delimiter.  Both CR and LF 
 * are valid line delimiters.
 * <p>
 *
 * @param ch the character to test
 * @return true if ch is a delimiter, false otherwise
 */
boolean isDelimiter(char ch) {
	if (ch == SWT.CR) return true;
	if (ch == SWT.LF) return true;
	return false;
}	
/**
 * Determine whether or not the replace operation is valid.  DefaultContent will not allow
 * the /r/n line delimiter to be split or partially deleted.
 * <p>
 *
 * @param start	start offset of text to replace
 * @param replaceLength start offset of text to replace
 * @param newText start offset of text to replace
 */
protected boolean isValidReplace(int start, int replaceLength, String newText){
	if (replaceLength == 0) {
		// inserting text, see if the \r\n line delimiter is being split
		if (start == 0) return true;
		if (start == getCharCount()) return true;
		char before = getTextRange(start - 1, 1).charAt(0);
		if (before == '\r') {
			char after = getTextRange(start, 1).charAt(0);
			if (after == '\n') return false;
		}
	} else {
		// deleting text, see if part of a \r\n line delimiter is being deleted
		char startChar = getTextRange(start, 1).charAt(0);
		if (startChar == '\n') {
			// see if char before delete position is \r
			if (start != 0) {
				char before = getTextRange(start - 1, 1).charAt(0);
				if (before == '\r') return false;
			}
		}
		char endChar = getTextRange(start + replaceLength - 1, 1).charAt(0);
		if (endChar == '\r') {
			// see if char after delete position is \n
			if (start + replaceLength != getCharCount()) {
				char after = getTextRange(start + replaceLength, 1).charAt(0);
				if (after == '\n') return false;
			}
		}
	} 
	return true;
}
/**
 * Calculates the indexes of each line of text in the given range.
 * <p>
 *
 * @param offset the logical start offset of the text lineate
 * @param length the length of the text to lineate, includes gap
 * @param numLines the number of lines to initially allocate for the line index array,
 *	passed in for efficiency (the exact number of lines may be known)
 * @return a line indexes array where each line is identified by a start offset and 
 * 	a length
 */
int[][] indexLines(int offset, int length, int numLines){
	int[][] indexedLines = new int[numLines][2];
	int start = 0;
	int lineCnt = 0;
	int i;
	replaceExpandExp = 1;
	for (i=start; i<length; i++) {
		int location = i + offset; 
		if ((location >= gapStart) && (location < gapEnd)) {
			// ignore the gap
		} else {
			char ch = textStore[location];				
			if (ch == SWT.CR) {
				// see if the next character is a LF
				if (location+1 < textStore.length) {
					ch = textStore[location+1];
					if (ch == SWT.LF) {
						i++;
					} 
				}
				indexedLines = addLineIndex(start, i - start + 1, indexedLines, lineCnt);
				lineCnt++;
				start = i + 1;
			} else if (ch == SWT.LF) {
				indexedLines = addLineIndex(start, i - start + 1, indexedLines, lineCnt);
				lineCnt++;
				start = i + 1;
			} 
		}
	}
	int[][] newLines = new int[lineCnt+1][2];
	System.arraycopy(indexedLines, 0, newLines, 0, lineCnt);
	int[] range = new int[] {start, i - start};
	newLines[lineCnt]=range;
	return newLines; 
}
/**
 * Inserts text.
 * <p>
 *
 * @param position the position at which to insert the text
 * @param length the text to insert
 */
void insert(int position, String text) {	
	if (text.length() == 0) return;
				
	int startLine = getLineAtOffset(position);
	int change = text.length();
	boolean endInsert = position == getCharCount();
	adjustGap(position, change, startLine);

	// during an insert the gap will be adjusted to start at
	// position and it will be associated with startline, the
	// inserted text will be placed in the gap		
	int startLineOffset = getOffsetAtLine(startLine);
	// at this point, startLineLength will include the start line
	// and all of the newly inserted text
	int	startLineLength = getPhysicalLine(startLine).length();
	
	if (change > 0) {
		// shrink gap 
		gapStart += (change);
		for (int i = 0; i < text.length(); i++)
			textStore[position + i]= text.charAt(i);
	}
		
	// figure out the number of new lines that have been inserted
	int [][] newLines = indexLines(startLineOffset, startLineLength, 10);
	// only insert an empty line if it is the last line in the text
	int numNewLines = newLines.length - 1;
	if (newLines[numNewLines][1] == 0) {
		// last inserted line is a new line
		if (endInsert) {
			// insert happening at end of the text, leave numNewLines as
			// is since the last new line will not be concatenated with another
			// line 
			numNewLines += 1;
		} else {
			numNewLines -= 1;
		}
	}
	
	// make room for the new lines
	expandLinesBy(numNewLines);
	// shift down the lines after the replace line
	for (int i = lineCount-1; i > startLine; i--) {
		lines[i + numNewLines]=lines[i];
	}
	// insert the new lines
	for (int i=0; i<numNewLines; i++) {
		newLines[i][0] += startLineOffset;
		lines[startLine + i]=newLines[i];
	}
	// update the last inserted line
	if (numNewLines < newLines.length) {
		newLines[numNewLines][0] += startLineOffset;
		lines[startLine + numNewLines] = newLines[numNewLines];
	}
	
	lineCount += numNewLines;
	gapLine = getLineAtPhysicalOffset(gapStart);		
}
/**
 * Moves the gap and adjusts its size in anticipation of a text change.  
 * The gap is resized to actual size + the specified size and moved to the given 
 * position.
 * <p>
 *
 * @param position the position at which a change is occurring
 * @param sizeHint the size of the change
 * @param line the line where the gap should be put
 */
void moveAndResizeGap(int position, int size, int newGapLine) {
	char[] content = null;
	int oldSize = gapEnd - gapStart;
	int newSize;
	if (size > 0) {
		newSize = highWatermark + size;
	} else {
		newSize = lowWatermark - size;
	}
	// remove the old gap from the lines information
	if (gapExists()) {
		// adjust the line length
		lines[gapLine][1] = lines[gapLine][1] - oldSize;
		// adjust the offsets of the lines after the gapLine
		for (int i=gapLine+1; i<lineCount; i++) {
			lines[i][0]=lines[i][0]-oldSize;
		}
	}
	
	if (newSize < 0) {
		if (oldSize > 0) {
			// removing the gap
			content = new char[textStore.length - oldSize];
			System.arraycopy(textStore, 0, content, 0, gapStart);
			System.arraycopy(textStore, gapEnd, content, gapStart, content.length - gapStart);
			textStore= content;
		}
		gapStart = gapEnd= position;
		return;
	}
	content = new char[textStore.length + (newSize - oldSize)];
	int newGapStart = position;
	int newGapEnd = newGapStart + newSize;
	if (oldSize == 0) {		
		System.arraycopy(textStore, 0, content, 0, newGapStart);
		System.arraycopy(textStore, newGapStart, content, newGapEnd, content.length - newGapEnd);	
	} else if (newGapStart < gapStart) {
		int delta = gapStart - newGapStart;
		System.arraycopy(textStore, 0, content, 0, newGapStart);
		System.arraycopy(textStore, newGapStart, content, newGapEnd, delta);
		System.arraycopy(textStore, gapEnd, content, newGapEnd + delta, textStore.length - gapEnd);
	} else {		
		int delta = newGapStart - gapStart;
		System.arraycopy(textStore, 0, content, 0, gapStart);
		System.arraycopy(textStore, gapEnd, content, gapStart, delta);
		System.arraycopy(textStore, gapEnd + delta, content, newGapEnd, content.length - newGapEnd);
	}
	textStore = content;
	gapStart = newGapStart;
	gapEnd = newGapEnd;
	
	// add the new gap to the lines information
	if (gapExists()) {
		gapLine = newGapLine;
		// adjust the line length
		int gapLength = gapEnd - gapStart;
		lines[gapLine][1] = lines[gapLine][1] + (gapLength);
		// adjust the offsets of the lines after the gapLine
		for (int i=gapLine+1; i<lineCount; i++) {
			lines[i][0]=lines[i][0]+gapLength;
		}
	}
}
/** 
 * Returns the number of lines that are in the specified text.
 * <p>
 *
 * @param startOffset the start of the text to lineate
 * @param length the length of the text to lineate
 * @return number of lines
 */
int lineCount(int startOffset, int length){
	if (length == 0) {
		return 0;
	}
	int lineCnt = 0;
	int count = 0;
	int i = startOffset;
	if (i >= gapStart) {
		i += gapEnd - gapStart;
	}
	while (count < length) {
		if ((i >= gapStart) && (i < gapEnd)) {
			// ignore the gap
		} else {
			char ch = textStore[i];			
			if (ch == SWT.CR) {
				// see if the next character is a LF
				if (i + 1 < textStore.length) {
					ch = textStore[i+1];
					if (ch == SWT.LF) {
						i++;
						count++;
					} 
				} 
				lineCnt++;
			} else if (ch == SWT.LF) {
				lineCnt++;
			}
			count++;
		}
		i++;
	}			
	return lineCnt;
}
/** 
 * Returns the number of lines that are in the specified text.
 * <p>
 *
 * @param text the text to lineate
 * @return number of lines in the text