* FileIO.java
 * Copyright 2008 Zach Scrivena
 * zachscrivena@gmail.com
 * http://zs.freeshell.org/
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * GNU General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.

package org.freeshell.zs.common;

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

 * Perform file input and output operations.
public final class FileIO
    * Private constructor that should never be called.
    private FileIO()

    * Read a specified number of bytes from the given input stream into the given buffer.
    * This method blocks until the specified number of bytes has been read.
    * An IOException is thrown if the end-of-stream is reached prematurely.
    * @param input
    *     input stream to be read from
    * @param buffer
    *     buffer to be populated with the read bytes
    * @param offset
    *     the start offset in array <code>buffer</code> at which the bytes are written
    * @param len
    *     number of bytes to be read
    * @throws java.io.IOException
    *     if the end-of-stream is reached prematurely, or other IO error occurs
    public static void blockingRead(
            final InputStream input,
            final byte[] buffer,
            final int offset,
            final int len)
            throws IOException
        int total = 0;

        while (total < len)
            final int n = input.read(buffer, offset + total, len - total);

            if (n == -1)
                throw new IOException("End-of-stream reached prematurely.");

            total += n;