/*
 * Copyright 1996-2008 Sun Microsystems, Inc.  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.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any 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
 */
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.
     */
    private void ensureOpen() throws IOException {
        if (closed) {
            throw new IOException("Stream closed");
        }
    }
    /**
     * Compression method for uncompressed (STORED) entries.
     */
    public static final int STORED = ZipEntry.STORED;

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

    /**
     * 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.
     * @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.
     * @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.
     * @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.
     * @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.
     * @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.
     * @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.
     * @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();
        }
        // 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.
     * @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;
    }
}