ZipInputStream.java

package org.amse.ys.zip;

import java.io.*;

class ZipInputStream extends InputStream {
	private final ZipFile myParent;
    private final MyBufferedInputStream myBaseStream;
    private final Decompressor myDecompressor;
	private boolean myIsClosed;

    public ZipInputStream(ZipFile parent, LocalFileHeader header) throws IOException {
		myParent = parent;
        myBaseStream = parent.getBaseStream();
        myBaseStream.setPosition(header.DataOffset);
        myDecompressor = Decompressor.init(myBaseStream, header);
    }

	@Override
    public int available() throws IOException {
        return myDecompressor.available();
    }

	@Override
    public int read(byte b[], int off, int len) throws IOException {
        if (b == null) {
            throw new NullPointerException();
        } else if ((off < 0) || (off > b.length) || (len < 0) ||
                   ((off + len) > b.length) || ((off + len) < 0)) {
            throw new IndexOutOfBoundsException();
        } else if (len == 0) {
            return 0;
        }

        return myDecompressor.read(b, off, len);
    }

	@Override
    public int read() throws IOException {
        return myDecompressor.read();
    }

    public void close() throws IOException {
		if (!myIsClosed) {
			myIsClosed = true;
			myParent.storeBaseStream(myBaseStream);
			Decompressor.storeDecompressor(myDecompressor);
		}
    }
}