Method getInputStream

src/gnu/zip/ZipFile.java:412–464

Creates an input stream reading the given zip entry as uncompressed data. Normally zip entry should be an entry returned by getEntry() or entries(). This implementation returns null if the requested entry does not exist. This decision is not obviously correct, however, it does appear to mirror Su

(ZipEntry entry)

   * @exception ZipException if the Zip archive is malformed.  
   */
  public InputStream getInputStream(ZipEntry entry) throws IOException
  {
    checkClosed();

    Hashtable entries = getEntries();
    String name = entry.getName();
    ZipEntry zipEntry = (ZipEntry) entries.get(name);
    if (zipEntry == null)
      return null;

    PartialInputStream inp = new PartialInputStream(rrf, 1024);
    inp.seek(zipEntry.offset);

    if (inp.readLeInt() != LOCSIG)
      throw new ZipException("Wrong Local header signature: " + name);

    inp.skip(4);

    if (zipEntry.getMethod() != inp.readLeShort())
      throw new ZipException("Compression method mismatch: " + name);

    inp.skip(16);

    int nameLen = inp.readLeShort();
    int extraLen = inp.readLeShort();
    inp.skip(nameLen + extraLen);

    inp.setLength(zipEntry.getCompressedSize());

    int method = zipEntry.getMethod();
    switch (method)
      {
      case ZipEntry.STORED:
	return inp;
      case ZipEntry.DEFLATED:
        inp.addDummyByte();
        final Inflater inf = new Inflater(true);
        final int sz = (int) entry.getSize();
        return new InflaterInputStream(inp, inf)
        {
          public int available() throws IOException
          {
            if (sz == -1)
              return super.available();
            if (super.available() != 0)
              return sz - inf.getTotalOut();
            return 0;
          }
        };
      default:
	throw new ZipException("Unknown compression method " + method);
      }
  }
  
  /**
   * Returns the (path) name of this zip file.