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:
+ *
+ *
org.apache.tools.zip.ZipEntry instances.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.
+ */ + private String encoding = null; + + /** + * The actual data source. + */ + private RandomAccessFile archive; + + /** + * Opens the given file for reading, assuming the platform's + * native encoding for file names. + */ + public ZipFile(File f) throws IOException, ZipException { + this(f, null); + } + + /** + * Opens the given file for reading, assuming the platform's + * native encoding for file names. + */ + public ZipFile(String name) throws IOException, ZipException { + this(new File(name), null); + } + + /** + * Opens the given file for reading, assuming the specified + * encoding for file names. + */ + public ZipFile(String name, String encoding) + throws IOException, ZipException { + this(new File(name), encoding); + } + + /** + * Opens the given file for reading, assuming the specified + * encoding for file names. + */ + public ZipFile(File f, String encoding) + throws IOException, ZipException { + this.encoding = encoding; + archive = new RandomAccessFile(f, "r"); + populateFromCentralDirectory(); + resolveLocalFileHeaderData(); + } + + /** + * The encoding to use for filenames and the file comment. + * + * @return null if using the platform's default character encoding. + */ + public String getEncoding() { + return encoding; + } + + /** + * Closes the archive. + */ + public void close() throws IOException { + archive.close(); + } + + /** + * Returns all entries as {@link org.apache.tools.ant.ZipEntry + * ZipEntry} instances. + */ + public Enumeration getEntries() { + return entries.keys(); + } + + /** + * Returns a named entry - ornull if no entry by
+ * that name exists.
+ */
+ public ZipEntry getEntry(String name) {
+ return (ZipEntry) nameMap.get(name);
+ }
+
+ /**
+ * Returns an InputStream for reading the contents of the given entry.
+ */
+ public InputStream getInputStream(ZipEntry ze)
+ throws IOException, ZipException {
+ return null;
+ }
+
+ private static final int CFH_LEN =
+ /* version made by */ 2 +
+ /* version needed to extract */ 2 +
+ /* general purpose bit flag */ 2 +
+ /* compression method */ 2 +
+ /* last mod file time */ 2 +
+ /* last mod file date */ 2 +
+ /* crc-32 */ 4 +
+ /* compressed size */ 4 +
+ /* uncompressed size */ 4 +
+ /* filename length */ 2 +
+ /* extra field length */ 2 +
+ /* file comment length */ 2 +
+ /* disk number start */ 2 +
+ /* internal file attributes */ 2 +
+ /* external file attributes */ 4 +
+ /* relative offset of local header */ 4;
+
+ /**
+ * Reads the central directory of the given archive and populates
+ * the interal 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.
+ */ + private void populateFromCentralDirectory() + throws IOException, ZipException { + positionAtCentralDirectory(); + + byte[] cfh = new byte[CFH_LEN]; + + byte[] signatureBytes = new byte[4]; + archive.readFully(signatureBytes); + ZipLong sig = new ZipLong(signatureBytes); + while (sig.equals(ZipOutputStream.CFH_SIG)) { + archive.readFully(cfh); + int off = 0; + ZipEntry ze = new ZipEntry(); + + ZipShort versionMadeBy = new ZipShort(cfh, off); + off += 2; + ze.setPlatform((versionMadeBy.getValue() >> 8) & 0x0F); + + off += 4;// skip version info and general purpose byte + + ze.setMethod((new ZipShort(cfh, off)).getValue()); + off += 2; + + ze.setTime(fromDosTime(new ZipLong(cfh, off)).getTime()); + off += 4; + + ze.setCrc((new ZipLong(cfh, off)).getValue()); + off += 4; + + ze.setCompressedSize((new ZipLong(cfh, off)).getValue()); + off += 4; + + ze.setSize((new ZipLong(cfh, off)).getValue()); + off += 4; + + int fileNameLen = (new ZipShort(cfh, off)).getValue(); + off += 2; + + int extraLen = (new ZipShort(cfh, off)).getValue(); + off += 2; + + int commentLen = (new ZipShort(cfh, off)).getValue(); + off += 2; + + off += 2; // disk number + + ze.setInternalAttributes((new ZipShort(cfh, off)).getValue()); + off += 2; + + ze.setExternalAttributes((new ZipLong(cfh, off)).getValue()); + off += 4; + + // LFH offset + entries.put(ze, new Long((new ZipLong(cfh, off)).getValue())); + + byte[] fileName = new byte[fileNameLen]; + archive.readFully(fileName); + ze.setName(getString(fileName)); + + nameMap.put(ze.getName(), ze); + + archive.skipBytes(extraLen); + + byte[] comment = new byte[commentLen]; + archive.readFully(comment); + ze.setComment(getString(comment)); + + archive.readFully(signatureBytes); + sig = new ZipLong(signatureBytes); + } + } + + /** + * Searches for the first occurence of the central file header + * signature. + */ + private void positionAtCentralDirectory() + throws IOException, ZipException { + archive.seek(0); + int off = 0; + byte[] sig = ZipOutputStream.CFH_SIG.getBytes(); + int curr = archive.read(); + boolean found = false; + while (curr != -1) { + if (curr == sig[0]) { + curr = archive.read(); + if (curr == sig[1]) { + curr = archive.read(); + if (curr == sig[2]) { + curr = archive.read(); + if (curr == sig[3]) { + found = true; + break; + } + } + } + archive.seek(++off); + } else { + off++; + } + curr = archive.read(); + } + if (!found) { + throw new ZipException("archive is not a ZIP archive"); + } + archive.seek(off); + } + + /** + * Number of bytes in local file header up to the "length of + * filename" entry. + */ + private static final long LFH_OFFSET_FOR_FILENAME_LENGTH = + /* local file header signature */ 4 + + /* version needed to extract */ 2 + + /* general purpose bit flag */ 2 + + /* compression method */ 2 + + /* last mod file time */ 2 + + /* last mod file date */ 2 + + /* crc-32 */ 4 + + /* compressed size */ 4 + + /* uncompressed size */ 4; + + /** + * 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.
+ */ + private void resolveLocalFileHeaderData() + throws IOException { + Enumeration enum = getEntries(); + while (enum.hasMoreElements()) { + ZipEntry ze = (ZipEntry) enum.nextElement(); + long offset = ((Long) entries.get(ze)).longValue(); + archive.seek(offset + LFH_OFFSET_FOR_FILENAME_LENGTH); + byte[] b = new byte[2]; + archive.readFully(b); + int fileNameLen = (new ZipShort(b)).getValue(); + archive.readFully(b); + int extraFieldLen = (new ZipShort(b)).getValue(); + archive.skipBytes(fileNameLen); + byte[] localExtraData = new byte[extraFieldLen]; + archive.readFully(localExtraData); + ze.setExtra(localExtraData); + dataOffsets.put(ze, + new Long(offset + LFH_OFFSET_FOR_FILENAME_LENGTH + + 2 + 2 + fileNameLen + extraFieldLen)); + } + } + + /** + * Convert a DOS date/time field to a Date object. + */ + protected static Date fromDosTime(ZipLong l) { + long dosTime = l.getValue(); + Calendar cal = Calendar.getInstance(); + cal.set(Calendar.YEAR, (int) ((dosTime >> 25) & 0x7f) + 1980); + cal.set(Calendar.MONTH, (int) ((dosTime >> 21) & 0x0f) - 1); + cal.set(Calendar.DATE, (int) (dosTime >> 16) & 0x1f); + cal.set(Calendar.HOUR, (int) (dosTime >> 11) & 0x1f); + cal.set(Calendar.MINUTE, (int) (dosTime >> 5) & 0x3f); + cal.set(Calendar.SECOND, (int) (dosTime << 1) & 0x3e); + return cal.getTime(); + } + + /** + * Retrieve a String from the given bytes using the encoding set + * for this ZipFile. + */ + protected String getString(byte[] bytes) throws ZipException { + if (encoding == null) { + return new String(bytes); + } else { + try { + return new String(bytes, encoding); + } catch (UnsupportedEncodingException uee) { + throw new ZipException(uee.getMessage()); + } + } + } + +}