Previously, Deflater.deflate would pass Z_SYNC_FLUSH to zlib
unconditionally, which caused the output to be enormous when setInput
was called repeatedly with very small input buffers. In order to
allow zlib to buffer output and thereby maximize compression, we must
use Z_NO_FLUSH until Deflater.finish is called, at which point we
switch to Z_FINISH. We also modify DeflaterOutputStream.close to call
Deflater.finish and write any remaining output to the wrapped stream.
Note the following excerpt from PNGFileFormat.java in SWT:
/*
* InflaterInputStream does not consume all bytes in the stream
* when it is closed. This may leave unread IDAT chunks. The fix
* is to read all available bytes before closing it.
*/
while (stream.available() > 0) stream.read();
stream.close();
This code relies on the documented behavior of
InflaterInputStream.available, which must return "0 after EOF has been
reached, otherwise always return 1". This is unlike
InputStream.available, which is documented to return "the number of
bytes that can be read (or skipped over) from this input stream
without blocking by the next caller of a method for this input
stream", and says nothing about how many bytes are left until the end
of stream.
This commit modifies InflaterInputStream.available to behave according
to Sun's documentation.
