ReadableArFile.java

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

import static org.codehaus.mojo.deb.jdpkg.ar.ArUtil.*;

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

/**
 * @author <a href="mailto:trygvis@codehaus.org">Trygve Laugstøl</a>
 * @version $Id$
 */
public class ReadableArFile extends ArFile {
    private InputStream inputStream;
    private ArFileInputStream fileInputStream;
    private long left;

    public ReadableArFile(InputStream inputStream) {
        this.inputStream = inputStream;
    }

    public InputStream open() {
        if (inputStream == null) {
            throw new RuntimeException("This file has already been read");
        }

        return fileInputStream = new ArFileInputStream();
    }

    void close() {
        // If the file havent been opened, skip the bytes
        if (fileInputStream == null) {
            fileInputStream = new ArFileInputStream();
        }

        closeSilent(fileInputStream);
    }

    private class ArFileInputStream extends InputStream {
        private InputStream inputStream;

        public ArFileInputStream() {
            this.inputStream = ReadableArFile.this.inputStream;
            ReadableArFile.this.inputStream = null;
            left = size;
        }

        public int read() throws IOException {
            if (left <= 0) {
                return -1;
            }

            int i = inputStream.read();

            if (i == -1) {
                return -1;
            }

            left--;
            return i;
        }

        public int read(byte b[], int off, int len) throws IOException {
            if (left <= 0) {
                return -1;
            }

            if (len > left) {
                len = (int) left;
            }

            int i = inputStream.read(b, off, len);

            left -= i;

            return i;
        }

        public long skip(long n) throws IOException {
            throw new IOException("Not supported");
        }

        public int available() throws IOException {
            return (int) left;
        }

        public void close() throws IOException {
            // TODO: Make sure that we read out all the bytes from the underlying input stream
            if (left != 0) {
                skipBytes(inputStream, left);
            }

            // Read the extra pad byte if size is odd
            if (size % 2 == 1) {
                skipBytes(inputStream, 1);
            }
        }

        public synchronized void mark(int readlimit) {
            throw new RuntimeException("Not supported");
        }

        public synchronized void reset() throws IOException {
            throw new RuntimeException("Not supported");
        }

        public boolean markSupported() {
            return false;
        }
    }
}