org.codehaus.plexus.archiver.zip

Class ZipFile

public class ZipFile extends Object

Replacement for java.util.ZipFile.

This class adds support for file name encodings other than UTF-8 (which is required to work on ZIP files created by native zip tools and is able to skip a preamble like the one found in self extracting archives. Furthermore it returns instances of org.apache.tools.zip.ZipEntry instead of java.util.zip.ZipEntry.

It doesn't extend java.util.zip.ZipFile as it would have to reimplement all methods anyway. Like java.util.ZipFile, it uses RandomAccessFile under the covers and supports compressed and uncompressed entries.

The method signatures mimic the ones of java.util.zip.ZipFile, with a couple of exceptions:

Version: $Revision: 2436 $ $Date: 2005-09-01 13:20:41 -0400 (Thu, 01 Sep 2005) $ from org.apache.ant.tools.zip.ZipFile v1.13

Nested Class Summary
classZipFile.BoundedInputStream
InputStream that delegates requests to the underlying RandomAccessFile, making sure that only bytes from a certain range can be read.
Field Summary
RandomAccessFilearchive
The actual data source.
static intCFD_LOCATOR_OFFSET
static intCFH_LEN
HashtabledataOffsets
Maps ZipEntrys to Longs, recording the offsets of the actual file data.
Stringencoding
The encoding to use for filenames and the file comment.
Hashtableentries
Maps ZipEntrys to Longs, recording the offsets of the local file headers.
static longLFH_OFFSET_FOR_FILENAME_LENGTH
Number of bytes in local file header up to the "length of filename" entry.
static intMIN_EOCD_SIZE
HashtablenameMap
Maps String to ZipEntrys, name -> actual entry.
Constructor Summary
ZipFile(File f)
Opens the given file for reading, assuming the platform's native encoding for file names.
ZipFile(String name)
Opens the given file for reading, assuming the platform's native encoding for file names.
ZipFile(String name, String encoding)
Opens the given file for reading, assuming the specified encoding for file names.
ZipFile(File f, String encoding)
Opens the given file for reading, assuming the specified encoding for file names.
Method Summary
voidclose()
Closes the archive.
protected static DatefromDosTime(ZipLong l)
Convert a DOS date/time field to a Date object.
StringgetEncoding()
The encoding to use for filenames and the file comment.
EnumerationgetEntries()
Returns all entries.
ZipEntrygetEntry(String name)
Returns a named entry - or null if no entry by that name exists.
InputStreamgetInputStream(ZipEntry ze)
Returns an InputStream for reading the contents of the given entry.
protected StringgetString(byte[] bytes)
Retrieve a String from the given bytes using the encoding set for this ZipFile.
voidpopulateFromCentralDirectory()
Reads the central directory of the given archive and populates the internal tables with ZipEntry instances.
voidpositionAtCentralDirectory()
Searches for the "End of central dir record", parses it and positions the stream at the first central directory record.
voidresolveLocalFileHeaderData()
Walks through all recorded entries and adds the data available from the local file header.

Field Detail

archive

private RandomAccessFile archive
The actual data source.

CFD_LOCATOR_OFFSET

private static final int CFD_LOCATOR_OFFSET

CFH_LEN

private static final int CFH_LEN

dataOffsets

private Hashtable dataOffsets
Maps ZipEntrys to Longs, recording the offsets of the actual file data.

encoding

private String encoding
The encoding to use for filenames and the file comment.

For a list of possible values see http://java.sun.com/products/jdk/1.2/docs/guide/internat/encoding.doc.html. Defaults to the platform's default character encoding.

entries

private Hashtable entries
Maps ZipEntrys to Longs, recording the offsets of the local file headers.

LFH_OFFSET_FOR_FILENAME_LENGTH

private static final long LFH_OFFSET_FOR_FILENAME_LENGTH
Number of bytes in local file header up to the "length of filename" entry.

MIN_EOCD_SIZE

private static final int MIN_EOCD_SIZE

nameMap

private Hashtable nameMap
Maps String to ZipEntrys, name -> actual entry.

Constructor Detail

ZipFile

public ZipFile(File f)
Opens the given file for reading, assuming the platform's native encoding for file names.

Parameters: f the archive.

Throws: IOException if an error occurs while reading the file.

ZipFile

public ZipFile(String name)
Opens the given file for reading, assuming the platform's native encoding for file names.

Parameters: name name of the archive.

Throws: IOException if an error occurs while reading the file.

ZipFile

public ZipFile(String name, String encoding)
Opens the given file for reading, assuming the specified encoding for file names.

Parameters: name name of the archive. encoding the encoding to use for file names

Throws: IOException if an error occurs while reading the file.

ZipFile

public ZipFile(File f, String encoding)
Opens the given file for reading, assuming the specified encoding for file names.

Parameters: f the archive. encoding the encoding to use for file names

Throws: IOException if an error occurs while reading the file.

Method Detail

close

public void close()
Closes the archive.

Throws: IOException if an error occurs closing the archive.

fromDosTime

protected static Date fromDosTime(ZipLong l)
Convert a DOS date/time field to a Date object.

Parameters: l contains the stored DOS time.

Returns: a Date instance corresponding to the given time.

getEncoding

public String getEncoding()
The encoding to use for filenames and the file comment.

Returns: null if using the platform's default character encoding.

getEntries

public Enumeration getEntries()
Returns all entries.

Returns: all entries as ZipEntry instances

getEntry

public ZipEntry getEntry(String name)
Returns a named entry - or null if no entry by that name exists.

Parameters: name name of the entry.

Returns: the ZipEntry corresponding to the given name - or null if not present.

getInputStream

public InputStream getInputStream(ZipEntry ze)
Returns an InputStream for reading the contents of the given entry.

Parameters: ze the entry to get the stream for.

Returns: a stream to read the entry from.

getString

protected String getString(byte[] bytes)
Retrieve a String from the given bytes using the encoding set for this ZipFile.

Parameters: bytes the byte array to transform

Returns: String obtained by using the given encoding

Throws: ZipException if the encoding cannot be recognized.

populateFromCentralDirectory

private void populateFromCentralDirectory()
Reads the central directory of the given archive and populates the internal tables with ZipEntry instances.

The ZipEntrys will know all data that can be obtained from the central directory alone, but not the data that requires the local file header or additional data to be read.

positionAtCentralDirectory

private void positionAtCentralDirectory()
Searches for the "End of central dir record", parses it and positions the stream at the first central directory record.

resolveLocalFileHeaderData

private void resolveLocalFileHeaderData()
Walks through all recorded entries and adds the data available from the local file header.

Also records the offsets for the data to read from the entries.