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Docs::Site_SVD::Tie_Gzip



Title Page

 Software Version Description
 for
 Tie::Gzip - gzip with a small memory footprint
 Revision: E
 Version: 0.06
 Date: 2004/04/16
 Prepared for: General Public
 Prepared by:  SoftwareDiamonds.com E<lt>support@SoftwareDiamonds.comE<gt>
 Copyright: copyright  2003 Software Diamonds
 Classification: NONE


1.0 SCOPE

This paragraph identifies and provides an overview of the released files.

1.1 Identification

This release, identified in 3.2, is a collection of Perl modules that extend the capabilities of the Perl language.

1.2 System overview

The 'Tie::Gzip' module provides a file handle Tie for compressing and uncompressing files using the gzip format.

By tieing a filehandle to 'Tie::Gzip' subsequent uses of the file subroutines with the tied filehandle will compress data written to an opened file using gzip compression and decompress data read from an opened file using gzip compression.

If the 'Tie::Gzip' tie receives a filename or mode filename after completing the tie, 'Tie::Gzip' will open filename.

During the tie, Tie::Gzip will first try to load the 'Compress::Zlib' module and package. If successful, 'Tie::Gzip' uses the 'Compress::Zlib' for compressing and decompressing the file data.

If unsuccessful, 'Tie::Gzip' setups up the following pipes to an anticipated GNU 'gzip' site command for compressing and decompressing the file data:

 gzip --decompress --stdout {} | # read file data
 | gzip --stdout > {} # write file data

where the string '{}' is a placeholder for the filename.

1.3 Document overview.

This document releases Tie::Gzip version 0.06 providing a description of the inventory, installation instructions and other information necessary to utilize and track this release.


3.0 VERSION DESCRIPTION

All file specifications in this SVD use the Unix operating system file specification.

3.1 Inventory of materials released.

This document releases the file

 Tie-Gzip-0.06.tar.gz

found at the following repository(s):

  http://www.softwarediamonds/packages/
  http://www.perl.com/CPAN/authors/id/S/SO/SOFTDIA/

Restrictions regarding duplication and license provisions are as follows:

Copyright.

copyright 2003 Software Diamonds

Copyright holder contact.
 603 882-0846 E<lt>support@SoftwareDiamonds.comE<gt>
License.

Software Diamonds permits the redistribution and use in source and binary forms, with or without modification, provided that the following conditions are met:

  1. Redistributions of source code, modified or unmodified must retain the above copyright notice, this list of conditions and the following disclaimer.

  2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.

SOFTWARE DIAMONDS, http://www.SoftwareDiamonds.com, PROVIDES THIS SOFTWARE 'AS IS' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL SOFTWARE DIAMONDS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING USE OF THIS SOFTWARE, EVEN IF ADVISED OF NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE POSSIBILITY OF SUCH DAMAGE.

3.2 Inventory of software contents

The content of the released, compressed, archieve file, consists of the following files:

 file                                                         version date       comment
 ------------------------------------------------------------ ------- ---------- ------------------------
 lib/Docs/Site_SVD/Tie_Gzip.pm                                0.06    2004/04/16 revised 0.05
 MANIFEST                                                     0.06    2004/04/16 generated, replaces 0.05
 Makefile.PL                                                  0.06    2004/04/16 generated, replaces 0.05
 README                                                       0.06    2004/04/16 generated, replaces 0.05
 lib/Tie/Gzip.pm                                              1.15    2004/04/16 revised 1.14
 t/Tie/Gzip.pm                                                0.05    2004/04/16 revised 0.04
 t/Tie/Gzip.t                                                 0.04    2004/04/16 revised 0.03
 t/Tie/Gzip.d                                                 0.04    2004/04/16 revised 0.03
 t/Tie/File/Package.pm                                        1.16    2004/04/16 unchanged
 t/Tie/File/SmartNL.pm                                        1.13    2004/04/16 unchanged
 t/Tie/Test/Tech.pm                                           1.2     2004/04/16 revised 1.19
 t/Tie/Data/Secs2.pm                                          1.17    2004/04/16 revised 1.16
 t/Tie/Data/SecsPack.pm                                       0.02    2004/04/16 unchanged
 t/Tie/gzip0.htm                                              0.06    2004/04/16 unchanged

=head2 3.3 Changes

Changes are as follows

Tie::Gzip-0.01

Originated

Tie::Gzip-0.02

Installed Mark Scarton's engineering change request per below e-mail:

From: Mark.Scarton@FranklinCovey.com Date: Thu, 19 Feb 2004 17:23:37 -0700

In the 'lib/Tie/Gzip.pm' module of the Tie-Gzip-0.01 package, the open of the pipe (``gzip --decompress --stdout |'') is failing due to the reference to $! in the conditional. As a test, I cleared $! before issuing the open call as follows:

 Line 124:
             ###############
             # Some perls will return a glob and a warning
             # for certain pipe errors such as the command
             # not a recognized command
             #
             $! = 0;    ### MAS ###
             my $success = open PIPE, $pipe;
             if($! || !$success) {
                 warn "Could not pipe $pipe: $!\n";
                 $self->CLOSE;
                 return undef;
             }
 Line 167:
             ###############
             # Some perls will return a glob and a warning
             # for certain pipe errors such as the command
             # not a recognized command
             #
             $! = 0;    ### MAS ###
             my $success = open PIPE, $pipe;
             if($! || !$success) {
                 warn "Could not pipe $pipe: $!\n";
                 $self->CLOSE;
                 return undef;
             }

This works. Prior to making this change, test 6 of Gzip.t would fail.

According to the Learning Perl O'Reilly book,

``But if you use die to indicate an error that is not the failure of a system request, don't include $!, since it will generally hold an unrelated message left over from something Perl did internally. It will hold a useful value only immediately after a failed system request. A successful request won't leave anything useful there.''

So $! is only sourced when a system error occurs and it is not cleared prior to the call. If no error occurs, the value is indeterminate.

Tie::Gzip-0.03

prerequisite program because loaded the Data::Secs2 test modules to tlib\Test instead of tlib\Data.

Tie::Gzip-0.04

The lastest build of Test::STDmaker expects the test library in the same directory as the test script. Coordiated with the lastest Test::STDmaker by moving the test library from tlib to t/Tie, the same directory as the test script and deleting the test library File::TestPath program module.


http://ppm.activestate.com/BuildStatus/5.8-linux/linux-5.8/Tie-Gzip-0.03.txt

has the following failures:

 PERL_DL_NONLAZY=1 /home/cpanrun/tmp/5.8.0/bin/perl "-MExtUtils::Command::MM" "-e" "test_harness(0, 'blib/lib', 'blib/arch')" t/Tie/Gzip.t
 t/Tie/Gzip....Could not pipe | gzip --stdout > Gzip1.htm.gz: Illegal seek
 Could not pipe gzip --decompress --stdout Gzip1.htm.gz |: Illegal seek
 Could not pipe gzip --decompress --stdout Gzip1.htm.gz |: Illegal seek
 # Cannot open <Gzip1.htm
 # Test 9 got: '' (t/Tie/Gzip.t at line 319)
 #   Expected: '<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
 <html>
 [snip]
 FAILED test 9
        Failed 1/11 tests, 90.91% okay (less 5 skipped tests: 5 okay, 45.45%)
 Failed 1/1 test scripts, 0.00% okay. 1/11 subtests failed, 90.91% okay.
 Failed Test  Stat Wstat Total Fail  Failed  List of Failed
 -------------------------------------------------------------------------------
 t/Tie/Gzip.t               11    1   9.09%  9
 5 subtests skipped.

The test script is not right and this is a false failure. 
The test script uses the <Test:Tech> 
features to force the C<ok> and C<skip> to perform a skip. 
However, this does not work for Perl code outside the C<ok> and C<skip>
subroutines.  Added test code to skip outside the C<ok> and C<skip> 
subroutines.
Tie::Gzip-0.05

The distribution Tie::Gzip-0.04 failed acrossed many systems. Very strange since it passes as follows:

 PASSED:
 # Running under perl version 5.006001 for MSWin32
 # Win32::BuildNumber 635
 FAILED:
  t/Tie/Gzip....Bareword "gz_package" not allowed while "strict subs" in use at t/Tie/Gzip.t line 265.

  Summary of my perl5 (revision 5.0 version 8 subversion 0) configuration:
    Platform:
      osname=linux, osvers=2.4.22-4tr, archname=i586-linux
  Summary of my perl5 (revision 5.0 version 8 subversion 1) configuration:
    Platform:
      osname=solaris, osvers=2.8, archname=sun4-solaris
  Summary of my perl5 (revision 5.0 version 8 subversion 3) configuration:
    Platform:
      osname=solaris, osvers=2.8, archname=sun4-solaris-thread-multi
  Summary of my perl5 (revision 5.0 version 8 subversion 3) configuration:
    Platform:
      osname=darwin, osvers=7.2.0, archname=ppc-darwin-thread-multi
 
The failure is real. Placed the ommitted $ in front of gz_package and try again.

=item Tie::Gzip-0.06

All the Unix machines are failing as follows:

 Use of uninitialized value in string eq at t/Tie/Gzip.t line 243.
 # Cannot open <gzip0.htm
 Use of uninitialized value in string eq at t/Tie/Gzip.t line 296.
 # Cannot open <gzip0.htm
 FAILED tests 9, 11
        Failed 2/11 tests, 81.82% okay

The reason is the the test script uses gzip0.htm while the distribution file is t/Tie/Gzip0.htm. The difference in capitalition causes failures on operation system with case sensitive file specifitions.

Change the distribution file to t/Tie/gzip0.htm. Added steps to the beginning of the test scripts to ensure that t/Tie/Gzip.t can read gzip0.htm so that do not have to spent time analyzing what went work.


=back

3.4 Adaptation data.

This installation requires that the installation site has the Perl programming language installed. There are no other additional requirements or tailoring needed of configurations files, adaptation data or other software needed for this installation particular to any installation site.

3.5 Related documents.

There are no related documents needed for the installation and test of this release.

3.6 Installation instructions.

Instructions for installation, installation tests and installation support are as follows:

Installation Instructions.

To installed the release file, use the CPAN module pr PPM module in the Perl release or the INSTALL.PL script at the following web site:

 http://packages.SoftwareDiamonds.com

Follow the instructions for the the chosen installation software.

If all else fails, the file may be manually installed. Enter one of the following repositories in a web browser:

  http://www.softwarediamonds/packages/
  http://www.perl.com/CPAN/authors/id/S/SO/SOFTDIA/

Right click on 'Tie-Gzip-0.06.tar.gz' and download to a temporary installation directory. Enter the following where $make is 'nmake' for microsoft windows; otherwise 'make'.

 gunzip Tie-Gzip-0.06.tar.gz
 tar -xf Tie-Gzip-0.06.tar
 perl Makefile.PL
 $make test
 $make install

On Microsoft operating system, nmake, tar, and gunzip must be in the exeuction path. If tar and gunzip are not install, download and install unxutils from

 http://packages.softwarediamonds.com
Prerequistes.
 None.

=item Security, privacy, or safety precautions.

None.

Installation Tests.

Most Perl installation software will run the following test script(s) as part of the installation:

 t/Tie/Gzip.t
Installation support.

If there are installation problems or questions with the installation contact

 603 882-0846 E<lt>support@SoftwareDiamonds.comE<gt>

3.7 Possible problems and known errors

There are no known open issues.


4.0 NOTES

The following are useful acronyms:

.d

extension for a Perl demo script file

.pm

extension for a Perl Library Module

.t

extension for a Perl test script file


2.0 SEE ALSO

Docs::US_DOD::SVD
  http://www.softwarediamonds/packages/  Docs-US_DOD-STD2167A-X.XX.tar.gz
  http://www.perl.com/CPAN/authors/id/S/SO/SOFTDIA/  Docs-US_DOD-STD2167A-X.XX.tar.gz