/******************************************************************************
 * Copyright © 2013-2016 The Nxt Core Developers.                             *
 *                                                                            *
 * See the AUTHORS.txt, DEVELOPER-AGREEMENT.txt and LICENSE.txt files at      *
 * the top-level directory of this distribution for the individual copyright  *
 * holder information and the developer policies on copyright and licensing.  *
 *                                                                            *
 * Unless otherwise agreed in a custom licensing agreement, no part of the    *
 * Nxt software, including this file, may be copied, modified, propagated,    *
 * or distributed except according to the terms contained in the LICENSE.txt  *
 * file.                                                                      *
 *                                                                            *
 * Removal or modification of this copyright notice is prohibited.            *
 *                                                                            *
 ******************************************************************************/

package nxt.util;

import nxt.NxtException;

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

public class CountingInputStream extends FilterInputStream {

    private long count;
    private final long limit;

    public CountingInputStream(InputStream in, long limit) {
        super(in);
        this.limit = limit;
    }

    @Override
    public int read() throws IOException {
        int read = super.read();
        if (read >= 0) {
            incCount(1);
        }
        return read;
    }

    @Override
    public int read(byte[] b, int off, int len) throws IOException {
        int read = super.read(b, off, len);
        if (read >= 0) {
            incCount(read);
        }
        return read;
    }

    @Override
    public long skip(long n) throws IOException {
        long skipped = super.skip(n);
        if (skipped >= 0) {
            incCount(skipped);
        }
        return skipped;
    }

    public long getCount() {
        return count;
    }

    private void incCount(long n) throws NxtException.NxtIOException {
        count += n;
        if (count > limit) {
            throw new NxtException.NxtIOException("Maximum size exceeded: " + count);
        }
    }
}