com.mucommander.file.impl.zip.provider
Class ZipOutputStream

java.lang.Object
  java.io.OutputStream
      com.mucommander.file.impl.zip.provider.ZipOutputStream

All Implemented Interfaces:

ZipConstants, java.io.Closeable, java.io.Flushable

public class ZipOutputStream
extends java.io.OutputStream
implements ZipConstants

Reimplementation of java.util.zip.ZipOutputStream that handles the extended functionality of this package, especially internal/external file attributes and extra fields with different layouts for local file data and central directory entries.

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This class is based off the org.apache.tools.zip package of the Apache Ant project. The Ant code has been modified under the terms of the Apache License which you can find in the bundled muCommander license file. It was forked at version 1.7.0 of Ant.

Author:

Apache Ant, Maxence Bernard

Field Summary

protected java.util.zip.Deflater	deflater Deflater instance that is used to compress DEFLATED entries
protected byte[]	deflaterBuf Buffer used by Deflater to deflate data
protected java.io.OutputStream	out The underlying stream this ZipOutputStream writes zip-compressed data to.

Fields inherited from interface com.mucommander.file.impl.zip.provider.ZipConstants

CFH_SIG, DD_SIG, DEFAULT_DEFLATER_BUFFER_SIZE, DEFAULT_DEFLATER_COMPRESSION, DEFLATED, EOCD_SIG, LFH_SIG, MAX_ZIP32_SIZE, STORED, UTF_8, WRITE_BUFFER_SIZE

Constructor Summary

ZipOutputStream(java.io.OutputStream out)
Creates a new ZipOutputStream that writes Zip-compressed data to the given OutputStream.

Method Summary

protected static long	adjustToLong(int i) Returns a long that is the unsigned intepretation of the given (signed) int.
void	close() Closes this output stream and releases any system resources associated with the stream.
void	closeEntry() Writes all necessary data for this entry.
protected static void	finalizeEntryData(ZipEntry entry, ZipEntryOutputStream zeos, java.io.OutputStream out, boolean useDataDescriptor, ZipBuffer zipBuffer) Writes the size and CRC information of an entry.
void	finish() Finishs writing the contents and closes this as well as the underlying stream.
void	flush() Flushes this output stream and forces any buffered output bytes to be written out to the stream.
protected static byte[]	getBytes(java.lang.String name, java.lang.String encoding) Retrieve the bytes for the given String in the encoding set for this Stream.
java.lang.String	getEncoding() The encoding to use for filenames and the file comment.
boolean	isSeekable() This method indicates whether this archive is writing to a RandomAccessOutputStream.
void	putNextEntry(ZipEntry ze) Start writing the given entry.
void	setComment(java.lang.String comment) Sets the file comment.
void	setEncoding(java.lang.String encoding) The encoding to use for filenames and the file comment.
void	setLevel(int level) Sets the compression level for subsequent entries.
void	setMethod(int method) Sets the default compression method for subsequent entries.
void	write(byte[] b) Writes the given bytes to the current Zip entry opened with putNextEntry(ZipEntry), using the entry's compression method.
void	write(byte[] b, int offset, int length) Writes the given bytes to the current Zip entry opened with putNextEntry(ZipEntry), using the entry's compression method.
void	write(int b) Writes a single byte to the current Zip entry opened with putNextEntry(ZipEntry), using the entry's compression method.
protected static void	writeCentralDirectoryEnd(java.io.OutputStream out, int nbEntries, long cdLength, long cdOffset, java.lang.String comment, java.lang.String encoding, ZipBuffer zipBuffer) Writes the end of the central directory record.
protected static long	writeCentralFileHeader(ZipEntry ze, java.io.OutputStream out, java.lang.String encoding, long localFileHeaderOffset, boolean useDataDescriptor, ZipBuffer zipBuffer) Writes the central file header for the given entry.
protected static long	writeDataDescriptor(ZipEntry ze, java.io.OutputStream out, ZipBuffer zipBuffer) Writes the data descriptor, using the CRC, compressed and uncompressed size attributes contained in the given ZipEntry.
protected static long	writeLocalFileHeader(ZipEntry ze, java.io.OutputStream out, java.lang.String encoding, boolean useDataDescriptor, ZipBuffer zipBuffer) Writes the local file header entry.
protected static long	writeVersionAndGPBF(java.io.OutputStream out, java.lang.String encoding, boolean useDataDescriptor) Writes the 'version needed to extract' (2 bytes) and 'general purpose bit flag' (2 bytes) fields.
protected static long	writeVersionMadeBy(ZipEntry ze, java.io.OutputStream out, ZipBuffer zipBuffer) Writes central file header's 'Version made by' field, using the platform contained in the given ZipEntry.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

deflater

protected java.util.zip.Deflater deflater

Deflater instance that is used to compress DEFLATED entries

deflaterBuf

protected byte[] deflaterBuf

Buffer used by Deflater to deflate data

out

protected java.io.OutputStream out

The underlying stream this ZipOutputStream writes zip-compressed data to.

Constructor Detail

ZipOutputStream

public ZipOutputStream(java.io.OutputStream out)

Creates a new ZipOutputStream that writes Zip-compressed data to the given OutputStream. If a RandomAccessOutputStream is supplied, the Zip entries will be written without data descriptor, which will yield a slightly smaller file.

Parameters:

out - the underlying OutputStream stream where compressed data is written to

Method Detail

isSeekable

public boolean isSeekable()

This method indicates whether this archive is writing to a RandomAccessOutputStream.

Returns:

true if seekable

setEncoding

public void setEncoding(java.lang.String encoding)

The encoding to use for filenames and the file comment.

For a list of possible values see http://java.sun.com/j2se/1.5.0/docs/guide/intl/encoding.doc.html. Defaults to the platform's default character encoding.

Parameters:

encoding - the encoding value

getEncoding

public java.lang.String getEncoding()

The encoding to use for filenames and the file comment.

Returns:

null if using the platform's default character encoding.

finish

public void finish()
            throws java.io.IOException

Finishs writing the contents and closes this as well as the underlying stream.

Throws:

java.io.IOException - on error

closeEntry

public void closeEntry()
                throws java.io.IOException

Writes all necessary data for this entry. This method must be called after an entry opened by putNextEntry(ZipEntry) has finished being written.

Throws:

java.io.IOException - on error

finalizeEntryData

protected static void finalizeEntryData(ZipEntry entry,
                                        ZipEntryOutputStream zeos,
                                        java.io.OutputStream out,
                                        boolean useDataDescriptor,
                                        ZipBuffer zipBuffer)
                                 throws java.io.IOException

Writes the size and CRC information of an entry. This method is to be called right after a file entry's data has been written.

The size and CRC information is written to the given OutputStream, either as a data descriptor or in the entry's local file header, and is set in the given ZipEntry instance.

Parameters:

entry - the entry

zeos - the Zip entry's output stream

out - the

useDataDescriptor - if true, a data descriptor will be written to out. If false, size and CRC information will be written in the local file header (requires out to be a RandomAccessOutputStream).

zipBuffer - a ZipBuffer instance used to convert integer values to Zip variants

Throws:

java.io.IOException - if an I/O error occurred

putNextEntry

public void putNextEntry(ZipEntry ze)
                  throws java.io.IOException

Start writing the given entry. The entry is written by calling the write() of this class. When the entry has finished being written, closeEntry() must be called.

Parameters:

ze - the entry to write

Throws:

java.io.IOException - on error

setComment

public void setComment(java.lang.String comment)

Sets the file comment.

Parameters:

comment - the comment

setLevel

public void setLevel(int level)

Sets the compression level for subsequent entries.

Default is Deflater.DEFAULT_COMPRESSION.

Parameters:

level - the compression level.

Throws:

java.lang.IllegalArgumentException - if an invalid compression level is specified.

setMethod

public void setMethod(int method)

Sets the default compression method for subsequent entries.

Default is DEFLATED.

Parameters:

method - an int from java.util.zip.ZipEntry

writeLocalFileHeader

protected static long writeLocalFileHeader(ZipEntry ze,
                                           java.io.OutputStream out,
                                           java.lang.String encoding,
                                           boolean useDataDescriptor,
                                           ZipBuffer zipBuffer)
                                    throws java.io.IOException

Writes the local file header entry.

Parameters:

ze - the entry to write

out - the OutputStream to write the header to

encoding - the encoding to use for writing the entry's filename. If UTF-8 is used, the general purpose bit flag will be set accordingly.

useDataDescriptor - indicates whether a data descriptor will follow the file entry's data. The general purpose bit flag will be set accordingly.

zipBuffer - a ZipBuffer instance used to convert integer values to Zip variants

Returns:

the size (number of bytes) of the written local file header

Throws:

java.io.IOException - if an I/O error occurred

writeDataDescriptor

protected static long writeDataDescriptor(ZipEntry ze,
                                          java.io.OutputStream out,
                                          ZipBuffer zipBuffer)
                                   throws java.io.IOException

Writes the data descriptor, using the CRC, compressed and uncompressed size attributes contained in the given ZipEntry. The length of the field is returned, it is always 16 bytes.

Parameters:

ze - the entry for which to write the data descriptor

out - the OutputStream where to write the data descriptor to

zipBuffer - a ZipBuffer instance used to convert integer values to Zip variants

Returns:

the number of bytes that were written, i.e. the size of the data descriptor (16 bytes)

Throws:

java.io.IOException - if an I/O error occurred

writeVersionMadeBy

protected static long writeVersionMadeBy(ZipEntry ze,
                                         java.io.OutputStream out,
                                         ZipBuffer zipBuffer)
                                  throws java.io.IOException

Writes central file header's 'Version made by' field, using the platform contained in the given ZipEntry. The length of the field is returned, it is always 2 bytes.

Parameters:

ze - the entry for which to write the 'Version made by' field

out - the OutputStream where to write the field

zipBuffer - a ZipBuffer instance used to convert integer values to Zip variants

Returns:

the number of bytes that were written, i.e. the size of the 'Version made by' field (2 bytes)

Throws:

java.io.IOException - if an I/O error occurred

writeCentralFileHeader

protected static long writeCentralFileHeader(ZipEntry ze,
                                             java.io.OutputStream out,
                                             java.lang.String encoding,
                                             long localFileHeaderOffset,
                                             boolean useDataDescriptor,
                                             ZipBuffer zipBuffer)
                                      throws java.io.IOException

Writes the central file header for the given entry.

Parameters:

ze - the entry for which to write the central file header

out - the OutputStream to write the central file header to

encoding - the encoding to use for writing the filename and optional comment

localFileHeaderOffset - the offset to the local file header start

useDataDescriptor - true if a data descriptor is used for the entry

zipBuffer - a ZipBuffer instance used to convert integer values to Zip variants

Returns:

the number of bytes that were written, i.e. the size of the central file header

Throws:

java.io.IOException - if an I/O error occurred

writeVersionAndGPBF

protected static long writeVersionAndGPBF(java.io.OutputStream out,
                                          java.lang.String encoding,
                                          boolean useDataDescriptor)
                                   throws java.io.IOException

Writes the 'version needed to extract' (2 bytes) and 'general purpose bit flag' (2 bytes) fields.

Parameters:

out - the OutputStream to write the fields to

encoding - the encoding used for writing the filename and optional comment

useDataDescriptor - true if a data descriptor is used for the entry

Returns:

the number of bytes that were written, i.e. 4

Throws:

java.io.IOException - if an I/O error occurred

writeCentralDirectoryEnd

protected static void writeCentralDirectoryEnd(java.io.OutputStream out,
                                               int nbEntries,
                                               long cdLength,
                                               long cdOffset,
                                               java.lang.String comment,
                                               java.lang.String encoding,
                                               ZipBuffer zipBuffer)
                                        throws java.io.IOException

Writes the end of the central directory record.

Parameters:

out - the OutputStream to write the end of the central directory record to

nbEntries - number of entries the Zip file contains

cdLength - length (in bytes) of the central directory record

cdOffset - offset from the beginning of the Zip file to the start of the central directory record

comment - the optional Zip file comment

encoding - the encoding to use for writing the optional Zip comment

zipBuffer - a ZipBuffer instance used to convert integer values to Zip variants

Throws:

java.io.IOException - if an I/O error occurred

getBytes

protected static byte[] getBytes(java.lang.String name,
                                 java.lang.String encoding)
                          throws java.util.zip.ZipException

Retrieve the bytes for the given String in the encoding set for this Stream.

Parameters:

name - the string to get bytes from

encoding - the encoding the string is encoded with

Returns:

the bytes as a byte array

Throws:

java.util.zip.ZipException - on error

adjustToLong

protected static long adjustToLong(int i)

Returns a long that is the unsigned intepretation of the given (signed) int.

Parameters:

i - the value to treat as unsigned int

Returns:

the unsigned int as a long

write

public void write(byte[] b,
                  int offset,
                  int length)
           throws java.io.IOException

Writes the given bytes to the current Zip entry opened with putNextEntry(ZipEntry), using the entry's compression method. If no entry is currently open, the bytes will be written as-is to the underlying OutputStream.

Overrides:

write in class java.io.OutputStream

Parameters:

b - the byte array to write

offset - the start position to write from

length - the number of bytes to write

Throws:

java.io.IOException - on error

write

public void write(byte[] b)
           throws java.io.IOException

Writes the given bytes to the current Zip entry opened with putNextEntry(ZipEntry), using the entry's compression method. If no entry is currently open, the bytes will be written as-is to the underlying OutputStream.

Overrides:

write in class java.io.OutputStream

Parameters:

b - the byte array to write

Throws:

java.io.IOException - on error

write

public void write(int b)
           throws java.io.IOException

Writes a single byte to the current Zip entry opened with putNextEntry(ZipEntry), using the entry's compression method. If no entry is currently open, the bytes will be written as-is to the underlying OutputStream.

Delegates to the three arg method.

Specified by:

write in class java.io.OutputStream

Parameters:

b - the byte to write

Throws:

java.io.IOException - on error

close

public void close()
           throws java.io.IOException

Closes this output stream and releases any system resources associated with the stream.

Specified by:

close in interface java.io.Closeable

Overrides:

close in class java.io.OutputStream

Throws:

java.io.IOException - if an I/O error occurs.

flush

public void flush()
           throws java.io.IOException

Flushes this output stream and forces any buffered output bytes to be written out to the stream.

Specified by:

flush in interface java.io.Flushable

Overrides:

flush in class java.io.OutputStream

Throws:

java.io.IOException - if an I/O error occurs.