net.java.truevfs.comp.zip.DummyByteChannelInputStream Maven / Gradle / Ivy

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Provides basic functionality for reading and writing ZIP files.

There is a newer version: 0.14.0

/*
 * Copyright (C) 2005-2015 Schlichtherle IT Services.
 * All rights reserved. Use is subject to license terms.
 */
package net.java.truevfs.comp.zip;

import net.java.truecommons.io.ChannelInputStream;
import edu.umd.cs.findbugs.annotations.CreatesObligation;
import java.io.IOException;
import java.nio.channels.SeekableByteChannel;
import javax.annotation.WillCloseWhenClosed;

/**
 * An adapter from a seekable byte channel to an input stream which adds a
 * dummy zero byte to the end of the input in order to support
 * {@link ZipInflaterInputStream}.
 *
 * @author Christian Schlichtherle
 */
final class DummyByteChannelInputStream extends ChannelInputStream {
    private boolean added;

    @CreatesObligation
    DummyByteChannelInputStream(
            @WillCloseWhenClosed SeekableByteChannel channel) {
        super(channel);
    }

    @Override
    public int read() throws IOException {
        final int read = super.read();
        if (read < 0 && !added) {
            added = true;
            return 0;
        }
        return read;
    }

    @Override
    public int read(final byte[] buf, final int off, int len) throws IOException {
        if (0 == len) return 0;
        final int read = super.read(buf, off, len);
        if (read < len && !added) {
            added = true;
            if (read < 0) {
                buf[0] = 0;
                return 1;
            } else {
                buf[read] = 0;
                return read + 1;
            }
        }
        return read;
    }

    @Override
    public int available() throws IOException {
        final int avl = super.available();
        return added || avl >= Integer.MAX_VALUE ? avl : avl + 1;
    }
}