tikhomirov@673: /*
tikhomirov@673:  * Copyright (c) 2013 TMate Software Ltd
tikhomirov@673:  *  
tikhomirov@673:  * This program is free software; you can redistribute it and/or modify
tikhomirov@673:  * it under the terms of the GNU General Public License as published by
tikhomirov@673:  * the Free Software Foundation; version 2 of the License.
tikhomirov@673:  *
tikhomirov@673:  * This program is distributed in the hope that it will be useful,
tikhomirov@673:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
tikhomirov@673:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
tikhomirov@673:  * GNU General Public License for more details.
tikhomirov@673:  *
tikhomirov@673:  * For information on how to redistribute this software under
tikhomirov@673:  * the terms of a license other than GNU General Public License
tikhomirov@673:  * contact TMate Software at support@hg4j.com
tikhomirov@673:  */
tikhomirov@673: package org.tmatesoft.hg.internal;
tikhomirov@673: 
tikhomirov@673: import java.io.IOException;
tikhomirov@673: import java.io.InputStream;
tikhomirov@673: 
tikhomirov@673: /**
tikhomirov@673:  * Wrap our internal API into a public one
tikhomirov@673:  * 
tikhomirov@673:  * @author Artem Tikhomirov
tikhomirov@673:  * @author TMate Software Ltd.
tikhomirov@673:  */
tikhomirov@673: public class DataAccessInputStream extends InputStream {
tikhomirov@673: 	
tikhomirov@673: 	private final DataAccess da;
tikhomirov@673: 	private int bytesLeft = -1;
tikhomirov@673: 
tikhomirov@673: 	public DataAccessInputStream(DataAccess dataAccess) {
tikhomirov@673: 		da = dataAccess;
tikhomirov@673: 	}
tikhomirov@673: 	
tikhomirov@673: 	@Override
tikhomirov@673: 	public int available() throws IOException {
tikhomirov@673: 		initAvailable();
tikhomirov@673: 		return bytesLeft;
tikhomirov@673: 	}
tikhomirov@673: 	
tikhomirov@673: 	@Override
tikhomirov@673: 	public int read() throws IOException {
tikhomirov@673: 		initAvailable();
tikhomirov@673: 		if (bytesLeft == 0) {
tikhomirov@673: 			return -1;
tikhomirov@673: 		}
tikhomirov@673: 		int rv = da.readByte();
tikhomirov@673: 		bytesLeft--;
tikhomirov@673: 		return rv;
tikhomirov@673: 	}
tikhomirov@673: 	
tikhomirov@673: 	@Override
tikhomirov@673: 	public int read(byte[] b, int off, int len) throws IOException {
tikhomirov@673: 		initAvailable();
tikhomirov@673: 		if (bytesLeft == 0) {
tikhomirov@673: 			return -1;
tikhomirov@673: 		}
tikhomirov@673: 		if (len == 0) {
tikhomirov@673: 			return 0;
tikhomirov@673: 		}
tikhomirov@673: 		int x = Math.min(len, bytesLeft);
tikhomirov@673: 		da.readBytes(b, off, x);
tikhomirov@673: 		bytesLeft -= x;
tikhomirov@673: 		return x;
tikhomirov@673: 	}
tikhomirov@673: 
tikhomirov@673: 
tikhomirov@673: 	private void initAvailable() throws IOException {
tikhomirov@673: 		da.reset();
tikhomirov@673: 		if (bytesLeft == -1) {
tikhomirov@673: 			bytesLeft = da.length();
tikhomirov@673: 		}
tikhomirov@673: 	}
tikhomirov@673: }