Compress::Zlib

Compress::Zlib

Version 1.07

27th November 1999

Copyright (c) 1995-1999 Paul Marquess. All rights reserved.
This program is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.

DESCRIPTION
-----------

This module provides a Perl interface to part of the info-zip zlib
compression library. For more details see the pod documentation
embedded in the file Zlib.pm.

PREREQUISITES
-------------

Before you can build Compress::Zlib you need to have the following
installed on your system:

* Perl 5.004 or better.
* Info-zip zlib 1.0.2 or better (note that this module is NOT
compatable with versions of zlib <= 1.0.1).

The zlib compression library is available at
http://www.cdrom.com/pub/infozip/zlib/

When building Compress::Zlib, you can optionally build the zlib
library at the same time. If you are running Windows 95/98/NT, this
seems to be the most straightforward option.

If you want Compress::Zlib to build zlib, fetch a copy of the zlib
distribution from the site mentioned above and unpack it into the
Compress::ZLib source directory. If you have fetched zlib 1.1.3, it will
create a directory called zlib-1.1.3.

Now, whether you are building zlib or not, edit the file config.in
and follow the instructions given in it.

BUILDING THE MODULE
-------------------

Assuming you have met all the prerequisites, the module can now be built
using this sequence of commands:

perl Makefile.PL
make
make test

INSTALLATION
------------

To install Compress::ZLib, run the command below:

make install

TROUBLESHOOTING
---------------

HP-UX
-----

I've had a report that when building Compress::Zlib under HP-UX that it is
necessary to have first built the zlib library with the -fpic option.

FEEDBACK
--------

How to report a problem with Compress::Zlib.

To help me help you, I need of the following information:

1. The version of Perl and the operating system name and version you
are running. The full output from running "perl -V" will tell me all
I need to know. If your perl doesn't understand the -V flag, then it's
too old to build this module -- you need to have Perl 5.004 or better.

2. The version of Compress::Zlib you have.
If you have successfully installed Compress::Zlib, this one-liner
will tell you:

perl -e 'use Compress::Zlib; print "ver $Compress::Zlib::VERSION\n"'

If you haven't installed Compress::Zlib then search Compress::Zlib.pm
for a line like this:

$VERSION = "1.05" ;

3. The version of zlib you have installed.
If you don't know look at the beginning of the file zlib.h.

4. If you are having problems building Compress::Zlib, send me a
complete log of what happened.

CHANGES
-------

0.1 - first alpha release. 2nd October 1995
0.2 - Fixed a minor allocation problem in Zlib.xs
0.3 - Added prototype specification.
0.4 - Upgrade to support zlib 0.99

Added dictionary interface.

Fixed bug in gzreadline - previously it would keep returning
the same buffer. This bug was reported by Helmut Jarausch

Removed dependancy to zutil.h and so dropped support for

DEF_MEM_LEVEL (use MAX_MEM_LEVEL instead)
DEF_WBITS (use MAX_WBITS instead)

0.5 - Confirmed that no changes were necessary for zlib 1.0.3, or 1.0.4.

The optional parameters for deflateInit and inflateInit can now
be specified as an associative array in addition to a reference
to an associative array. They can also accept the -Name
syntax.

gzopen can now optionally take a reference to an open
filehandle in place of a filename. In this case it will call
gzdopen.

Added gzstream example script.

1.00 - 14 Nov 1997

* Fixed crc32 & adler32. They were very broken.

* The following functions can now take a scalar reference in
place of a scalar for their buffer parameters:

compress
uncompress
deflate
inflate
crc32
adler32

This should mean applications that make use of the module don't
have to copy large buffers around.

* Normally the inflate method consumes I<all> of the input buffer
before returning. The exception to this is when inflate detects
the end of the stream (Z_STREAM_END). In this case the input
buffer need not be completely consumed. To allow processing of
file formats that embed a deflation stream (e.g. zip, gzip),
the inflate method now sets the buffer parameter to be what
remains after inflation.

When the return status is Z_STREAM_END, it will be what remains
of the buffer (if any) after deflation. When the status is Z_OK
it will be an empty string.

This change means that the buffer parameter must be a lvalue.

* Fixed crc32 and adler32. They were both very broken.

* Added the Compress::Zlib::memGzip function.

1.01 - 23 Nov 1997

* A number of fixes to the test suite and the example scripts to
allow them to work under win32. All courtesy of Gurusamy
Sarathy.

1.02 - 31 Jan 1999

* The return codes for gzread, gzreadline and gzwrite were
documented incorrectly as returning a status code.

* The test harness was missing a "gzclose". This caused problem
showed up on an amiga. Thanks to Erik van Roode for reporting
this one.

* Patched zlib.t for OS/2. Thanks to Ilya Zakharevich for the patch.

1.03 - 17 Mar 1999

* Updated to use the new PL_ symbols.
Means the module can be built with Perl 5.005_5*

1.04 - 27 May 1999

* Bug 19990527.001: compress(undef) core dumps -- Fixed.

1.05 - 3 June 1999

* Previous release used newSVpvn, which doesn't exist in 5.004_04
or earlier. Changed to use newSVpv instead.

* The module needs Perl 5.004 or better, so updated the version
checking in Zlib.pm and Makefile.PL

1.06 - 20 Sep 1999

* Fixed a nasty problem where inflate could truncate the data
returned. Thanks to Douglas Thomson <[email protected]>
for both spotting the problem and fixing the bug.

* Added a note about the undocumented features in zlib that are
required when accessing zip files.

* gzclose will now get called automaticallly when the gzip object is
destroyed.

1.07 - 27 Nov 1999

* ANSI-ified the static functions in Zlib.xs

* Added the ability to build zlib along with the module.
This feature is 90% based on a Makefile provided by Gurusamy
Sarathy.

Paul Marquess <[email protected]>