LimitedInputStream.java

/*******************************************************************************
 * Copyright (c) 2012-2017 Codenvy, S.A.
 * 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:
 *   Codenvy, S.A. - initial API and implementation
 *******************************************************************************/
package org.eclipse.che.plugin.docker.client.connection;

import java.io.IOException;
import java.io.InputStream;

/**
* @author andrew00x
*/
public class LimitedInputStream extends InputStream {
    private final InputStream input;
    private final int         limit;

    private int pos;

    LimitedInputStream(InputStream input, int limit) {
        this.input = input;
        this.limit = limit;
    }

    @Override
    public synchronized int read() throws IOException {
        final byte[] b = new byte[1];
        if (doRead(b, 0, 1) == -1) {
            return -1;
        }
        return b[0];
    }

    @Override
    public synchronized int read(byte[] b) throws IOException {
        if (b == null) {
            throw new NullPointerException();
        }
        return doRead(b, 0, b.length);
    }

    @Override
    public synchronized int read(byte[] b, int off, int len) throws IOException {
        if (b == null) {
            throw new NullPointerException();
        }
        if (off < 0 || len < 0 || len > b.length - off) {
            throw new IndexOutOfBoundsException();
        }
        if (len == 0) {
            return 0;
        }

        return doRead(b, 0, len);
    }

    private int doRead(byte[] b, int off, int len) throws IOException {
        if (pos >= limit) {
            return -1;
        }
        int n = input.read(b, 0, Math.min(len - off, limit - pos));
        pos += n;
        return n;
    }
}