ArUtil.java

package org.codehaus.mojo.deb.jdpkg.ar;

import java.io.Closeable;
import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;

/**
 * @author <a href="mailto:trygve.laugstol@arktekk.no">Trygve Laugstøl</a>
 * @version $Id$
 */
public class ArUtil {
    public static final String LF = "\n";
    public static final String AR_ARCHIVE_MAGIC = "!<arch>" + LF;
    public static final String AR_FILE_MAGIC = "`\n";
    public static final String US_ASCII = "US-ASCII";

    public static void close(Closeable closeable) {
        closeSilent(closeable);
    }

    public static void closeSilent(Closeable closeable) {
        try {
            if (closeable != null) {
                closeable.close();
            }
        } catch (IOException e) {
            // ignore
        }
    }

    public static String convertString(byte[] bytes, int start, int count) throws UnsupportedEncodingException {
        String s = new String(bytes, start, count, ArUtil.US_ASCII);

        int index = s.indexOf(' ');

        if (index == -1) {
            return s;
        }

        s = s.substring(0, index);

        return s;
    }

    public static byte[] readBytes(InputStream is, long count) throws IOException {
        byte[] bytes = new byte[(int) count];

        int start = 0;

        do {
            int read = is.read(bytes, start, (int) count);

            // If we're at EOF, but trying to read the first set of bytes, return null
            if (read == -1) {
                if (start > 0) {
                    throw new EOFException();
                }

                return null;
            }

            start += read;
            count -= read;
        } while (count > 0);

        return bytes;
    }

    public static void skipBytes(InputStream is, long count) throws IOException {
        long left = count;

        do {
            long read = is.skip(left);

            left -= read;
        } while (left > 0);
    }

    public static void copy(InputStream input, OutputStream output, int bufferSize) throws IOException {
        final byte[] buffer = new byte[bufferSize];
        int n = 0;
        while (-1 != (n = input.read(buffer))) {
            output.write(buffer, 0, n);
        }
    }
}