/*******************************************************************************
* Copyright (c) 2009 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
* Zend Technologies
*******************************************************************************/
package org.eclipse.php.internal.core.ast.util;
import java.io.Reader;
/**
* A characters array reader that provides reset options.
*
* @author shalom
*
*/
public class RandomAccessCharArrayReader extends Reader {
private char[] input;
private int position;
/**
* Constructs a new RandomAccessCharArrayReader.
*
* @param input
* The characters input array.
*/
public RandomAccessCharArrayReader(char[] input) {
this.input = input;
}
/*
* (non-Javadoc)
*
* @see java.io.Reader#close()
*/
public void close() {
input = null;
}
/**
* Read characters into a portion of an array.
*
* @param cbuf
* 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 has
* been reached
*
* @exception IllegalStateException
* In case this method was called after the reader was
* closed.
*/
public int read(char[] cbuf, int off, int len) {
if (input == null) {
throw new IllegalStateException("The char array reader was closed."); //$NON-NLS-1$
}
int result = len;
if (len + position >= input.length) {
len = input.length - position;
result = len;
}
if (result <= 0) {
return -1;
}
System.arraycopy(input, position, cbuf, off, len);
position += len;
return result;
}
/**
* Reset the char array reader to the given position.
*
* @param position
* The new position to place the reader.
*
* @throws IllegalStateException
* In case that the reader was closed.
* @throws IllegalArgumentException
* In case that the given position is negative of larger then
* the input array.
*/
public void reset(int position) {
if (input == null) {
throw new IllegalStateException("The char array reader was closed."); //$NON-NLS-1$
}
if (position < 0 || position >= input.length) {
throw new IllegalArgumentException(
"Illegal position (got " + position + " for a character array in the length of " + input.length); //$NON-NLS-1$ //$NON-NLS-2$
}
this.position = position;
}
}