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/*
 * Copyright (c) 1996, 2006, 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
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 * questions.
 */

package java.util.zip;

import java.io.OutputStream;
import java.io.IOException;
import java.util.Vector;
import java.util.HashSet;


This class implements an output stream filter for writing files in the
ZIP file format. Includes support for both compressed and uncompressed
entries.

Author:     David Connelly
/**
 * This class implements an output stream filter for writing files in the
 * ZIP file format. Includes support for both compressed and uncompressed
 * entries.
 *
 * @author      David Connelly
 */
public
class ZipOutputStream extends DeflaterOutputStream implements ZipConstants {

    private static class XEntry {
        public final ZipEntry entry;
        public final long offset;
        public final int flag;
        public XEntry(ZipEntry entry, long offset) {
            this.entry = entry;
            this.offset = offset;
            this.flag = (entry.method == DEFLATED &&
                         (entry.size  == -1 ||
                          entry.csize == -1 ||
                          entry.crc   == -1))
                // store size, compressed size, and crc-32 in data descriptor
                // immediately following the compressed entry data
                ? 8
                // store size, compressed size, and crc-32 in LOC header
                : 0;
        }
    }

    private XEntry current;
    private Vector<XEntry> xentries = new Vector<XEntry>();
    private HashSet<String> names = new HashSet<String>();
    private CRC32 crc = new CRC32();
    private long written = 0;
    private long locoff = 0;
    private String comment;
    private int method = DEFLATED;
    private boolean finished;

    private boolean closed = false;

    private static int version(ZipEntry e) throws ZipException {
        switch (e.method) {
        case DEFLATED: return 20;
        case STORED:   return 10;
        default: throw new ZipException("unsupported compression method");
        }
    }

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

/**
     * Checks to make sure that this stream has not been closed.
     */
    private void ensureOpen() throws IOException {
        if (closed) {
            throw new IOException("Stream closed");
        }
    }
    
Compression method for uncompressed (STORED) entries.

/**
     * Compression method for uncompressed (STORED) entries.
     */
    public static final int STORED = ZipEntry.STORED;

    
Compression method for compressed (DEFLATED) entries.

/**
     * Compression method for compressed (DEFLATED) entries.
     */
    public static final int DEFLATED = ZipEntry.DEFLATED;

    
Creates a new ZIP output stream.

Params:
  • out – the actual output stream
/**
     * Creates a new ZIP output stream.
     * @param out the actual output stream
     */
    public ZipOutputStream(OutputStream out) {
        super(out, new Deflater(Deflater.DEFAULT_COMPRESSION, true));
        usesDefaultDeflater = true;
    }

    
Sets the ZIP file comment.

Params:
  • comment – the comment string
Throws:
/**
     * Sets the ZIP file comment.
     * @param comment the comment string
     * @exception IllegalArgumentException if the length of the specified
     *            ZIP file comment is greater than 0xFFFF bytes
     */
    public void setComment(String comment) {
        if (comment != null && comment.length() > 0xffff/3
                                           && getUTF8Length(comment) > 0xffff) {
            throw new IllegalArgumentException("ZIP file comment too long.");
        }
        this.comment = comment;
    }

    
Sets the default compression method for subsequent entries. This
default will be used whenever the compression method is not specified
for an individual ZIP file entry, and is initially set to DEFLATED.

Params:
  • method – the default compression method
Throws:
/**
     * Sets the default compression method for subsequent entries. This
     * default will be used whenever the compression method is not specified
     * for an individual ZIP file entry, and is initially set to DEFLATED.
     * @param method the default compression method
     * @exception IllegalArgumentException if the specified compression method
     *            is invalid
     */
    public void setMethod(int method) {
        if (method != DEFLATED && method != STORED) {
            throw new IllegalArgumentException("invalid compression method");
        }
        this.method = method;
    }

    
Sets the compression level for subsequent entries which are DEFLATED.
The default setting is DEFAULT_COMPRESSION.

Params:
  • level – the compression level (0-9)
Throws:
/**
     * Sets the compression level for subsequent entries which are DEFLATED.
     * The default setting is DEFAULT_COMPRESSION.
     * @param level the compression level (0-9)
     * @exception IllegalArgumentException if the compression level is invalid
     */
    public void setLevel(int level) {
        def.setLevel(level);
    }

    
Begins writing a new ZIP file entry and positions the stream to the
start of the entry data. Closes the current entry if still active.
The default compression method will be used if no compression method
was specified for the entry, and the current time will be used if
the entry has no set modification time.

Params:
  • e – the ZIP entry to be written
Throws:
/**
     * Begins writing a new ZIP file entry and positions the stream to the
     * start of the entry data. Closes the current entry if still active.
     * The default compression method will be used if no compression method
     * was specified for the entry, and the current time will be used if
     * the entry has no set modification time.
     * @param e the ZIP entry to be written
     * @exception ZipException if a ZIP format error has occurred
     * @exception IOException if an I/O error has occurred
     */
    public void putNextEntry(ZipEntry e) throws IOException {
        ensureOpen();
        if (current != null) {
            closeEntry();       // close previous entry
        }
        if (e.time == -1) {
            e.setTime(System.currentTimeMillis());
        }
        if (e.method == -1) {
            e.method = method;  // use default method
        }
        switch (e.method) {
        case DEFLATED:
            break;
        case STORED:
            // compressed size, uncompressed size, and crc-32 must all be
            // set for entries using STORED compression method
            if (e.size == -1) {
                e.size = e.csize;
            } else if (e.csize == -1) {
                e.csize = e.size;
            } else if (e.size != e.csize) {
                throw new ZipException(
                    "STORED entry where compressed != uncompressed size");
            }
            if (e.size == -1 || e.crc == -1) {
                throw new ZipException(
                    "STORED entry missing size, compressed size, or crc-32");
            }
            break;
        default:
            throw new ZipException("unsupported compression method");
        }
        if (! names.add(e.name)) {
            throw new ZipException("duplicate entry: " + e.name);
        }
        current = new XEntry(e, written);
        xentries.add(current);
        writeLOC(current);
    }

    
Closes the current ZIP entry and positions the stream for writing
the next entry.

Throws:
  • ZipException – if a ZIP format error has occurred
  • IOException – if an I/O error has occurred
/**
     * Closes the current ZIP entry and positions the stream for writing
     * the next entry.
     * @exception ZipException if a ZIP format error has occurred
     * @exception IOException if an I/O error has occurred
     */
    public void closeEntry() throws IOException {
        ensureOpen();
        if (current != null) {
            ZipEntry e = current.entry;
            switch (e.method) {
            case DEFLATED:
                def.finish();
                while (!def.finished()) {
                    deflate();
                }
                if ((current.flag & 8) == 0) {
                    // verify size, compressed size, and crc-32 settings
                    if (e.size != def.getBytesRead()) {
                        throw new ZipException(
                            "invalid entry size (expected " + e.size +
                            " but got " + def.getBytesRead() + " bytes)");
                    }
                    if (e.csize != def.getBytesWritten()) {
                        throw new ZipException(
                            "invalid entry compressed size (expected " +
                            e.csize + " but got " + def.getBytesWritten() + " bytes)");
                    }
                    if (e.crc != crc.getValue()) {
                        throw new ZipException(
                            "invalid entry CRC-32 (expected 0x" +
                            Long.toHexString(e.crc) + " but got 0x" +
                            Long.toHexString(crc.getValue()) + ")");
                    }
                } else {
                    e.size  = def.getBytesRead();
                    e.csize = def.getBytesWritten();
                    e.crc = crc.getValue();
                    writeEXT(e);
                }
                def.reset();
                written += e.csize;
                break;
            case STORED:
                // we already know that both e.size and e.csize are the same
                if (e.size != written - locoff) {
                    throw new ZipException(
                        "invalid entry size (expected " + e.size +
                        " but got " + (written - locoff) + " bytes)");
                }
                if (e.crc != crc.getValue()) {
                    throw new ZipException(
                         "invalid entry crc-32 (expected 0x" +
                         Long.toHexString(e.crc) + " but got 0x" +
                         Long.toHexString(crc.getValue()) + ")");
                }
                break;
            default:
                throw new ZipException("invalid compression method");
            }
            crc.reset();
            current = null;
        }
    }

    
Writes an array of bytes to the current ZIP entry data. This method
will block until all the bytes are written.

Params:
  • b – the data to be written
  • off – the start offset in the data
  • len – the number of bytes that are written
Throws:
/**
     * Writes an array of bytes to the current ZIP entry data. This method
     * will block until all the bytes are written.
     * @param b the data to be written
     * @param off the start offset in the data
     * @param len the number of bytes that are written
     * @exception ZipException if a ZIP file error has occurred
     * @exception IOException if an I/O error has occurred
     */
    public synchronized void write(byte[] b, int off, int len)
        throws IOException
    {
        ensureOpen();
        if (off < 0 || len < 0 || off > b.length - len) {
            throw new IndexOutOfBoundsException();
        } else if (len == 0) {
            return;
        }

        if (current == null) {
            throw new ZipException("no current ZIP entry");
        }
        ZipEntry entry = current.entry;
        switch (entry.method) {
        case DEFLATED:
            super.write(b, off, len);
            break;
        case STORED:
            written += len;
            if (written - locoff > entry.size) {
                throw new ZipException(
                    "attempt to write past end of STORED entry");
            }
            out.write(b, off, len);
            break;
        default:
            throw new ZipException("invalid compression method");
        }
        crc.update(b, off, len);
    }

    
Finishes writing the contents of the ZIP output stream without closing
the underlying stream. Use this method when applying multiple filters
in succession to the same output stream.

Throws:
  • ZipException – if a ZIP file error has occurred
  • IOException – if an I/O exception has occurred
/**
     * Finishes writing the contents of the ZIP output stream without closing
     * the underlying stream. Use this method when applying multiple filters
     * in succession to the same output stream.
     * @exception ZipException if a ZIP file error has occurred
     * @exception IOException if an I/O exception has occurred
     */
    public void finish() throws IOException {
        ensureOpen();
        if (finished) {
            return;
        }
        if (current != null) {
            closeEntry();
        }
        if (xentries.size() < 1) {
            throw new ZipException("ZIP file must have at least one entry");
        }
        // write central directory
        long off = written;
        for (XEntry xentry : xentries)
            writeCEN(xentry);
        writeEND(off, written - off);
        finished = true;
    }

    
Closes the ZIP output stream as well as the stream being filtered.

Throws:
  • ZipException – if a ZIP file error has occurred
  • IOException – if an I/O error has occurred
/**
     * Closes the ZIP output stream as well as the stream being filtered.
     * @exception ZipException if a ZIP file error has occurred
     * @exception IOException if an I/O error has occurred
     */
    public void close() throws IOException {
        if (!closed) {
            super.close();
            closed = true;
        }
    }

    /*
     * Writes local file (LOC) header for specified entry.
     */
    private void writeLOC(XEntry xentry) throws IOException {
        ZipEntry e = xentry.entry;
        int flag = xentry.flag;
        writeInt(LOCSIG);           // LOC header signature
        writeShort(version(e));     // version needed to extract
        writeShort(flag);           // general purpose bit flag
        writeShort(e.method);       // compression method
        writeInt(e.time);           // last modification time
        if ((flag & 8) == 8) {
            // store size, uncompressed size, and crc-32 in data descriptor
            // immediately following compressed entry data
            writeInt(0);
            writeInt(0);
            writeInt(0);
        } else {
            writeInt(e.crc);        // crc-32
            writeInt(e.csize);      // compressed size
            writeInt(e.size);       // uncompressed size
        }
        byte[] nameBytes = getUTF8Bytes(e.name);
        writeShort(nameBytes.length);
        writeShort(e.extra != null ? e.extra.length : 0);
        writeBytes(nameBytes, 0, nameBytes.length);
        if (e.extra != null) {
            writeBytes(e.extra, 0, e.extra.length);
        }
        locoff = written;
    }

    /*
     * Writes extra data descriptor (EXT) for specified entry.
     */
    private void writeEXT(ZipEntry e) throws IOException {
        writeInt(EXTSIG);           // EXT header signature
        writeInt(e.crc);            // crc-32
        writeInt(e.csize);          // compressed size
        writeInt(e.size);           // uncompressed size
    }

    /*
     * Write central directory (CEN) header for specified entry.
     * REMIND: add support for file attributes
     */
    private void writeCEN(XEntry xentry) throws IOException {
        ZipEntry e  = xentry.entry;
        int flag = xentry.flag;
        int version = version(e);
        writeInt(CENSIG);           // CEN header signature
        writeShort(version);        // version made by
        writeShort(version);        // version needed to extract
        writeShort(flag);           // general purpose bit flag
        writeShort(e.method);       // compression method
        writeInt(e.time);           // last modification time
        writeInt(e.crc);            // crc-32
        writeInt(e.csize);          // compressed size
        writeInt(e.size);           // uncompressed size
        byte[] nameBytes = getUTF8Bytes(e.name);
        writeShort(nameBytes.length);
        writeShort(e.extra != null ? e.extra.length : 0);
        byte[] commentBytes;
        if (e.comment != null) {
            commentBytes = getUTF8Bytes(e.comment);
            writeShort(commentBytes.length);
        } else {
            commentBytes = null;
            writeShort(0);
        }
        writeShort(0);              // starting disk number
        writeShort(0);              // internal file attributes (unused)
        writeInt(0);                // external file attributes (unused)
        writeInt(xentry.offset);    // relative offset of local header
        writeBytes(nameBytes, 0, nameBytes.length);
        if (e.extra != null) {
            writeBytes(e.extra, 0, e.extra.length);
        }
        if (commentBytes != null) {
            writeBytes(commentBytes, 0, commentBytes.length);
        }
    }

    /*
     * Writes end of central directory (END) header.
     */
    private void writeEND(long off, long len) throws IOException {
        int count = xentries.size();
        writeInt(ENDSIG);           // END record signature
        writeShort(0);              // number of this disk
        writeShort(0);              // central directory start disk
        writeShort(count);          // number of directory entries on disk
        writeShort(count);          // total number of directory entries
        writeInt(len);              // length of central directory
        writeInt(off);              // offset of central directory
        if (comment != null) {      // zip file comment
            byte[] b = getUTF8Bytes(comment);
            writeShort(b.length);
            writeBytes(b, 0, b.length);
        } else {
            writeShort(0);
        }
    }

    /*
     * Writes a 16-bit short to the output stream in little-endian byte order.
     */
    private void writeShort(int v) throws IOException {
        OutputStream out = this.out;
        out.write((v >>> 0) & 0xff);
        out.write((v >>> 8) & 0xff);
        written += 2;
    }

    /*
     * Writes a 32-bit int to the output stream in little-endian byte order.
     */
    private void writeInt(long v) throws IOException {
        OutputStream out = this.out;
        out.write((int)((v >>>  0) & 0xff));
        out.write((int)((v >>>  8) & 0xff));
        out.write((int)((v >>> 16) & 0xff));
        out.write((int)((v >>> 24) & 0xff));
        written += 4;
    }

    /*
     * Writes an array of bytes to the output stream.
     */
    private void writeBytes(byte[] b, int off, int len) throws IOException {
        super.out.write(b, off, len);
        written += len;
    }

    /*
     * Returns the length of String's UTF8 encoding.
     */
    static int getUTF8Length(String s) {
        int count = 0;
        for (int i = 0; i < s.length(); i++) {
            char ch = s.charAt(i);
            if (ch <= 0x7f) {
                count++;
            } else if (ch <= 0x7ff) {
                count += 2;
            } else {
                count += 3;
            }
        }
        return count;
    }

    /*
     * Returns an array of bytes representing the UTF8 encoding
     * of the specified String.
     */
    private static byte[] getUTF8Bytes(String s) {
        char[] c = s.toCharArray();
        int len = c.length;
        // Count the number of encoded bytes...
        int count = 0;
        for (int i = 0; i < len; i++) {
            int ch = c[i];
            if (ch <= 0x7f) {
                count++;
            } else if (ch <= 0x7ff) {
                count += 2;
            } else {
                count += 3;
            }
        }
        // Now return the encoded bytes...
        byte[] b = new byte[count];
        int off = 0;
        for (int i = 0; i < len; i++) {
            int ch = c[i];
            if (ch <= 0x7f) {
                b[off++] = (byte)ch;
            } else if (ch <= 0x7ff) {
                b[off++] = (byte)((ch >> 6) | 0xc0);
                b[off++] = (byte)((ch & 0x3f) | 0x80);
            } else {
                b[off++] = (byte)((ch >> 12) | 0xe0);
                b[off++] = (byte)(((ch >> 6) & 0x3f) | 0x80);
                b[off++] = (byte)((ch & 0x3f) | 0x80);
            }
        }
        return b;
    }
}