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/*
* 02/24/2004
*
* DocumentReader.java - A reader for javax.swing.text.Document
* objects.
*
* This library is distributed under a modified BSD license. See the included
* RSyntaxTextArea.License.txt file for details.
*/
package org.fife.io;
import java.io.Reader;
import javax.swing.text.BadLocationException;
import javax.swing.text.Document;
import javax.swing.text.Segment;
/**
* A Reader for javax.swing.text.Document objects.
*
* @author Robert Futrell
* @version 1.0
*/
public class DocumentReader extends Reader {
/**
* The stream's position in the document.
*/
private long position;
/**
* A remembered position in the document.
*/
private long mark;
/**
* The document we're working on.
*/
private Document document;
/**
* Used for fast character access.
*/
private Segment segment;
/**
* Constructor.
*
* @param document The document we're 'reading'.
*/
public DocumentReader(Document document) {
position = 0;
mark = -1;
this.document = document;
this.segment = new Segment();
}
/**
* This currently does nothing...
*/
@Override
public void close() {
}
/**
* Marks the present position in the stream. Subsequent calls to
* reset() will reposition the stream to this point.
*
* @param readAheadLimit Ignored.
*/
@Override
public void mark(int readAheadLimit) {
mark = position;
}
/**
* Tells whether this reader supports the mark operation.
* This always returns true for DocumentReader.
*/
@Override
public boolean markSupported() {
return true;
}
/**
* Reads the single character at the current position in the document.
*/
@Override
public int read() {
if(position>=document.getLength()) {
return -1; // Read past end of document.
}
try {
document.getText((int)position,1, segment);
position++;
return segment.array[segment.offset];
} catch (BadLocationException ble) {
/* Should never happen?? */
ble.printStackTrace();
return -1;
}
}
/**
* Read array.length characters from the beginning
* of the document into array.
*
* @param array The array to read characters into.
* @return The number of characters read.
*/
@Override
public int read(char array[]) {
return read(array, 0, array.length);
}
/**
* Reads characters into a portion of an array.
*
* @param cbuf The destination buffer.
* @param off Offset at which to start storing characters.
* @param len Maximum number of characters to read.
* @return The number of characters read, or -1 if the
* end of the stream (document) has been reached.
*/
@Override
public int read(char cbuf[], int off, int len) {
int k;
if(position>=document.getLength()) {
return -1; // Read past end of document.
}
k = len;
if((position+k)>=document.getLength())
k = document.getLength() - (int)position;
if(off + k >= cbuf.length)
k = cbuf.length - off;
try {
document.getText((int)position, k, segment);
position += k;
System.arraycopy(segment.array,segment.offset,
cbuf,off,
k);
return k;
} catch (BadLocationException ble) {
/* Should never happen ? */
return -1;
}
}
/**
* Tells whether this reader is ready to be read without
* blocking for input. DocumentReader will
* always return true.
*
* @return true if the next read operation will
* return without blocking.
*/
@Override
public boolean ready() {
return true;
}
/**
* Resets the stream. If the stream has been marked, then attempt to
* reposition it at the mark. If the stream has not been marked, then
* move it to the beginning of the document.
*/
@Override
public void reset() {
if(mark==-1) {
position = 0;
}
else {
position = mark;
mark = -1;
}
}
/**
* Skips characters. This will not 'skip' past the end of the document.
*
* @param n The number of characters to skip.
* @return The number of characters actually skipped.
*/
@Override
public long skip(long n) {
if (position+n<=document.getLength()) {
position += n;
return n;
}
long temp = position;
position = document.getLength();
return document.getLength() - temp;
}
/**
* Move to the specified position in the document. If pos
* is greater than the document's length, the stream's position is moved
* to the end of the document.
*
* @param pos The position in the document to move to.
*/
public void seek(long pos) {
position = Math.min(pos, document.getLength());
}
}