/*

 * Copyright (c) 2006, 2013, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package java.util.zip;

import java.io.FilterOutputStream;

import java.io.IOException;

import java.io.OutputStream;

/**

 * Implements an output stream filter for uncompressing data stored in the

 * "deflate" compression format.

 *

 * @since       1.6

 * @author      David R Tribble (david@tribble.com)

 *

 * @see InflaterInputStream

 * @see DeflaterInputStream

 * @see DeflaterOutputStream

 */

public class InflaterOutputStream extends FilterOutputStream {

    /** Decompressor for this stream. */

    protected final Inflater inf;

    /** Output buffer for writing uncompressed data. */

    protected final byte[] buf;

    /** Temporary write buffer. */

    private final byte[] wbuf = new byte[1];

    /** Default decompressor is used. */

    private boolean usesDefaultInflater = false;

    /** true iff {@link #close()} has been called. */

    private boolean closed = false;

    /**

     * Checks to make sure that this stream has not been closed.

     */

    private void ensureOpen() throws IOException {

        if (closed) {

            throw new IOException("Stream closed");

        }

    }

    /**

     * Creates a new output stream with a default decompressor and buffer

     * size.

     *

     * @param out output stream to write the uncompressed data to

     * @throws NullPointerException if {@code out} is null

     */

    public InflaterOutputStream(OutputStream out) {

        this(out, new Inflater());

        usesDefaultInflater = true;

    }

    /**

     * Creates a new output stream with the specified decompressor and a

     * default buffer size.

     *

     * @param out output stream to write the uncompressed data to

     * @param infl decompressor ("inflater") for this stream

     * @throws NullPointerException if {@code out} or {@code infl} is null

     */

    public InflaterOutputStream(OutputStream out, Inflater infl) {

        this(out, infl, 512);

    }

    /**

     * Creates a new output stream with the specified decompressor and

     * buffer size.

     *

     * @param out output stream to write the uncompressed data to

     * @param infl decompressor ("inflater") for this stream

     * @param bufLen decompression buffer size

     * @throws IllegalArgumentException if {@code bufLen <= 0}

     * @throws NullPointerException if {@code out} or {@code infl} is null

     */

    public InflaterOutputStream(OutputStream out, Inflater infl, int bufLen) {

        super(out);

        // Sanity checks

        if (out == null)

            throw new NullPointerException("Null output");

        if (infl == null)

            throw new NullPointerException("Null inflater");

        if (bufLen <= 0)

            throw new IllegalArgumentException("Buffer size < 1");

        // Initialize

        inf = infl;

        buf = new byte[bufLen];

    }

    /**

     * Writes any remaining uncompressed data to the output stream and closes

     * the underlying output stream.

     *

     * @throws IOException if an I/O error occurs

     */

    public void close() throws IOException {

        if (!closed) {

            // Complete the uncompressed output

            try {

                finish();

            } finally {

                out.close();

                closed = true;

            }

        }

    }

    /**

     * Flushes this output stream, forcing any pending buffered output bytes to be

     * written.

     *

     * @throws IOException if an I/O error occurs or this stream is already

     * closed

     */

    public void flush() throws IOException {

        ensureOpen();

        // Finish decompressing and writing pending output data

        if (!inf.finished()) {

            try {

                while (!inf.finished()  &&  !inf.needsInput()) {

                    int n;

                    // Decompress pending output data

                    n = inf.inflate(buf, 0, buf.length);

                    if (n < 1) {

                        break;

                    }

                    // Write the uncompressed output data block

                    out.write(buf, 0, n);

                }

                super.flush();

            } catch (DataFormatException ex) {

                // Improperly formatted compressed (ZIP) data

                String msg = ex.getMessage();

                if (msg == null) {

                    msg = "Invalid ZLIB data format";

                }

                throw new ZipException(msg);

            }

        }

    }

    /**

     * Finishes writing uncompressed data to the output stream without closing

     * the underlying stream.  Use this method when applying multiple filters in

     * succession to the same output stream.

     *

     * @throws IOException if an I/O error occurs or this stream is already

     * closed

     */

    public void finish() throws IOException {

        ensureOpen();

        // Finish decompressing and writing pending output data

        flush();

        if (usesDefaultInflater) {

            inf.end();

        }

    }

    /**

     * Writes a byte to the uncompressed output stream.

     *

     * @param b a single byte of compressed data to decompress and write to

     * the output stream

     * @throws IOException if an I/O error occurs or this stream is already

     * closed

     * @throws ZipException if a compression (ZIP) format error occurs

     */

    public void write(int b) throws IOException {

        // Write a single byte of data

        wbuf[0] = (byte) b;

        write(wbuf, 0, 1);

    }

    /**

     * Writes an array of bytes to the uncompressed output stream.

     *

     * @param b buffer containing compressed data to decompress and write to

     * the output stream

     * @param off starting offset of the compressed data within {@code b}

     * @param len number of bytes to decompress from {@code b}

     * @throws IndexOutOfBoundsException if {@code off < 0}, or if

     * {@code len < 0}, or if {@code len > b.length - off}

     * @throws IOException if an I/O error occurs or this stream is already

     * closed

     * @throws NullPointerException if {@code b} is null

     * @throws ZipException if a compression (ZIP) format error occurs

     */

    public void write(byte[] b, int off, int len) throws IOException {

        // Sanity checks

        ensureOpen();

        if (b == null) {

            throw new NullPointerException("Null buffer for read");

        } else if (off < 0 || len < 0 || len > b.length - off) {

            throw new IndexOutOfBoundsException();

        } else if (len == 0) {

            return;

        }

        // Write uncompressed data to the output stream

        try {

            for (;;) {

                int n;

                // Fill the decompressor buffer with output data

                if (inf.needsInput()) {

                    int part;

                    if (len < 1) {

                        break;

                    }

                    part = (len < 512 ? len : 512);

                    inf.setInput(b, off, part);

                    off += part;

                    len -= part;

                }

                // Decompress and write blocks of output data

                do {

                    n = inf.inflate(buf, 0, buf.length);

                    if (n > 0) {

                        out.write(buf, 0, n);

                    }

                } while (n > 0);

                // Check the decompressor

                if (inf.finished()) {

                    break;

                }

                if (inf.needsDictionary()) {

                    throw new ZipException("ZLIB dictionary missing");

                }

            }

        } catch (DataFormatException ex) {

            // Improperly formatted compressed (ZIP) data

            String msg = ex.getMessage();

            if (msg == null) {

                msg = "Invalid ZLIB data format";

            }

            throw new ZipException(msg);

        }

    }

}