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package IO::Compress::RawDeflate ;
# create RFC1951
#
use strict ;
use warnings;
use bytes;
use IO::Compress::Base 2.081 ;
use IO::Compress::Base::Common 2.081 qw(:Status );
use IO::Compress::Adapter::Deflate 2.081 ;
require Exporter ;
our ($VERSION, @ISA, @EXPORT_OK, %DEFLATE_CONSTANTS, %EXPORT_TAGS, $RawDeflateError);
$VERSION = '2.081';
$RawDeflateError = '';
@ISA = qw(IO::Compress::Base Exporter);
@EXPORT_OK = qw( $RawDeflateError rawdeflate ) ;
push @EXPORT_OK, @IO::Compress::Adapter::Deflate::EXPORT_OK ;
%EXPORT_TAGS = %IO::Compress::Adapter::Deflate::DEFLATE_CONSTANTS;
{
my %seen;
foreach (keys %EXPORT_TAGS )
{
push @{$EXPORT_TAGS{constants}},
grep { !$seen{$_}++ }
@{ $EXPORT_TAGS{$_} }
}
$EXPORT_TAGS{all} = $EXPORT_TAGS{constants} ;
}
%DEFLATE_CONSTANTS = %EXPORT_TAGS;
#push @{ $EXPORT_TAGS{all} }, @EXPORT_OK ;
Exporter::export_ok_tags('all');
sub new
{
my $class = shift ;
my $obj = IO::Compress::Base::Common::createSelfTiedObject($class, \$RawDeflateError);
return $obj->_create(undef, @_);
}
sub rawdeflate
{
my $obj = IO::Compress::Base::Common::createSelfTiedObject(undef, \$RawDeflateError);
return $obj->_def(@_);
}
sub ckParams
{
my $self = shift ;
my $got = shift;
return 1 ;
}
sub mkComp
{
my $self = shift ;
my $got = shift ;
my ($obj, $errstr, $errno) = IO::Compress::Adapter::Deflate::mkCompObject(
$got->getValue('crc32'),
$got->getValue('adler32'),
$got->getValue('level'),
$got->getValue('strategy')
);
return $self->saveErrorString(undef, $errstr, $errno)
if ! defined $obj;
return $obj;
}
sub mkHeader
{
my $self = shift ;
return '';
}
sub mkTrailer
{
my $self = shift ;
return '';
}
sub mkFinalTrailer
{
return '';
}
#sub newHeader
#{
# my $self = shift ;
# return '';
#}
sub getExtraParams
{
my $self = shift ;
return getZlibParams();
}
use IO::Compress::Base::Common 2.081 qw(:Parse);
use Compress::Raw::Zlib 2.081 qw(Z_DEFLATED Z_DEFAULT_COMPRESSION Z_DEFAULT_STRATEGY);
our %PARAMS = (
#'method' => [IO::Compress::Base::Common::Parse_unsigned, Z_DEFLATED],
'level' => [IO::Compress::Base::Common::Parse_signed, Z_DEFAULT_COMPRESSION],
'strategy' => [IO::Compress::Base::Common::Parse_signed, Z_DEFAULT_STRATEGY],
'crc32' => [IO::Compress::Base::Common::Parse_boolean, 0],
'adler32' => [IO::Compress::Base::Common::Parse_boolean, 0],
'merge' => [IO::Compress::Base::Common::Parse_boolean, 0],
);
sub getZlibParams
{
return %PARAMS;
}
sub getInverseClass
{
return ('IO::Uncompress::RawInflate',
\$IO::Uncompress::RawInflate::RawInflateError);
}
sub getFileInfo
{
my $self = shift ;
my $params = shift;
my $file = shift ;
}
use Fcntl qw(SEEK_SET);
sub createMerge
{
my $self = shift ;
my $outValue = shift ;
my $outType = shift ;
my ($invClass, $error_ref) = $self->getInverseClass();
eval "require $invClass"
or die "aaaahhhh" ;
my $inf = $invClass->new( $outValue,
Transparent => 0,
#Strict => 1,
AutoClose => 0,
Scan => 1)
or return $self->saveErrorString(undef, "Cannot create InflateScan object: $$error_ref" ) ;
my $end_offset = 0;
$inf->scan()
or return $self->saveErrorString(undef, "Error Scanning: $$error_ref", $inf->errorNo) ;
$inf->zap($end_offset)
or return $self->saveErrorString(undef, "Error Zapping: $$error_ref", $inf->errorNo) ;
my $def = *$self->{Compress} = $inf->createDeflate();
*$self->{Header} = *$inf->{Info}{Header};
*$self->{UnCompSize} = *$inf->{UnCompSize}->clone();
*$self->{CompSize} = *$inf->{CompSize}->clone();
# TODO -- fix this
#*$self->{CompSize} = new U64(0, *$self->{UnCompSize_32bit});
if ( $outType eq 'buffer')
{ substr( ${ *$self->{Buffer} }, $end_offset) = '' }
elsif ($outType eq 'handle' || $outType eq 'filename') {
*$self->{FH} = *$inf->{FH} ;
delete *$inf->{FH};
*$self->{FH}->flush() ;
*$self->{Handle} = 1 if $outType eq 'handle';
#seek(*$self->{FH}, $end_offset, SEEK_SET)
*$self->{FH}->seek($end_offset, SEEK_SET)
or return $self->saveErrorString(undef, $!, $!) ;
}
return $def ;
}
#### zlib specific methods
sub deflateParams
{
my $self = shift ;
my $level = shift ;
my $strategy = shift ;
my $status = *$self->{Compress}->deflateParams(Level => $level, Strategy => $strategy) ;
return $self->saveErrorString(0, *$self->{Compress}{Error}, *$self->{Compress}{ErrorNo})
if $status == STATUS_ERROR;
return 1;
}
1;
__END__
=head1 NAME
IO::Compress::RawDeflate - Write RFC 1951 files/buffers
=head1 SYNOPSIS
use IO::Compress::RawDeflate qw(rawdeflate $RawDeflateError) ;
my $status = rawdeflate $input => $output [,OPTS]
or die "rawdeflate failed: $RawDeflateError\n";
my $z = new IO::Compress::RawDeflate $output [,OPTS]
or die "rawdeflate failed: $RawDeflateError\n";
$z->print($string);
$z->printf($format, $string);
$z->write($string);
$z->syswrite($string [, $length, $offset]);
$z->flush();
$z->tell();
$z->eof();
$z->seek($position, $whence);
$z->binmode();
$z->fileno();
$z->opened();
$z->autoflush();
$z->input_line_number();
$z->newStream( [OPTS] );
$z->deflateParams();
$z->close() ;
$RawDeflateError ;
# IO::File mode
print $z $string;
printf $z $format, $string;
tell $z
eof $z
seek $z, $position, $whence
binmode $z
fileno $z
close $z ;
=head1 DESCRIPTION
This module provides a Perl interface that allows writing compressed
data to files or buffer as defined in RFC 1951.
Note that RFC 1951 data is not a good choice of compression format
to use in isolation, especially if you want to auto-detect it.
For reading RFC 1951 files/buffers, see the companion module
L<IO::Uncompress::RawInflate|IO::Uncompress::RawInflate>.
=head1 Functional Interface
A top-level function, C<rawdeflate>, is provided to carry out
"one-shot" compression between buffers and/or files. For finer
control over the compression process, see the L</"OO Interface">
section.
use IO::Compress::RawDeflate qw(rawdeflate $RawDeflateError) ;
rawdeflate $input_filename_or_reference => $output_filename_or_reference [,OPTS]
or die "rawdeflate failed: $RawDeflateError\n";
The functional interface needs Perl5.005 or better.
=head2 rawdeflate $input_filename_or_reference => $output_filename_or_reference [, OPTS]
C<rawdeflate> expects at least two parameters,
C<$input_filename_or_reference> and C<$output_filename_or_reference>.
=head3 The C<$input_filename_or_reference> parameter
The parameter, C<$input_filename_or_reference>, is used to define the
source of the uncompressed data.
It can take one of the following forms:
=over 5
=item A filename
If the <$input_filename_or_reference> parameter is a simple scalar, it is
assumed to be a filename. This file will be opened for reading and the
input data will be read from it.
=item A filehandle
If the C<$input_filename_or_reference> parameter is a filehandle, the input
data will be read from it. The string '-' can be used as an alias for
standard input.
=item A scalar reference
If C<$input_filename_or_reference> is a scalar reference, the input data
will be read from C<$$input_filename_or_reference>.
=item An array reference
If C<$input_filename_or_reference> is an array reference, each element in
the array must be a filename.
The input data will be read from each file in turn.
The complete array will be walked to ensure that it only
contains valid filenames before any data is compressed.
=item An Input FileGlob string
If C<$input_filename_or_reference> is a string that is delimited by the
characters "<" and ">" C<rawdeflate> will assume that it is an
I<input fileglob string>. The input is the list of files that match the
fileglob.
See L<File::GlobMapper|File::GlobMapper> for more details.
=back
If the C<$input_filename_or_reference> parameter is any other type,
C<undef> will be returned.
=head3 The C<$output_filename_or_reference> parameter
The parameter C<$output_filename_or_reference> is used to control the
destination of the compressed data. This parameter can take one of
these forms.
=over 5
=item A filename
If the C<$output_filename_or_reference> parameter is a simple scalar, it is
assumed to be a filename. This file will be opened for writing and the
compressed data will be written to it.
=item A filehandle
If the C<$output_filename_or_reference> parameter is a filehandle, the
compressed data will be written to it. The string '-' can be used as
an alias for standard output.
=item A scalar reference
If C<$output_filename_or_reference> is a scalar reference, the
compressed data will be stored in C<$$output_filename_or_reference>.
=item An Array Reference
If C<$output_filename_or_reference> is an array reference,
the compressed data will be pushed onto the array.
=item An Output FileGlob
If C<$output_filename_or_reference> is a string that is delimited by the
characters "<" and ">" C<rawdeflate> will assume that it is an
I<output fileglob string>. The output is the list of files that match the
fileglob.
When C<$output_filename_or_reference> is an fileglob string,
C<$input_filename_or_reference> must also be a fileglob string. Anything
else is an error.
See L<File::GlobMapper|File::GlobMapper> for more details.
=back
If the C<$output_filename_or_reference> parameter is any other type,
C<undef> will be returned.
=head2 Notes
When C<$input_filename_or_reference> maps to multiple files/buffers and
C<$output_filename_or_reference> is a single
file/buffer the input files/buffers will be stored
in C<$output_filename_or_reference> as a concatenated series of compressed data streams.
=head2 Optional Parameters
Unless specified below, the optional parameters for C<rawdeflate>,
C<OPTS>, are the same as those used with the OO interface defined in the
L</"Constructor Options"> section below.
=over 5
=item C<< AutoClose => 0|1 >>
This option applies to any input or output data streams to
C<rawdeflate> that are filehandles.
If C<AutoClose> is specified, and the value is true, it will result in all
input and/or output filehandles being closed once C<rawdeflate> has
completed.
This parameter defaults to 0.
=item C<< BinModeIn => 0|1 >>
When reading from a file or filehandle, set C<binmode> before reading.
Defaults to 0.
=item C<< Append => 0|1 >>
The behaviour of this option is dependent on the type of output data
stream.
=over 5
=item * A Buffer
If C<Append> is enabled, all compressed data will be append to the end of
the output buffer. Otherwise the output buffer will be cleared before any
compressed data is written to it.
=item * A Filename
If C<Append> is enabled, the file will be opened in append mode. Otherwise
the contents of the file, if any, will be truncated before any compressed
data is written to it.
=item * A Filehandle
If C<Append> is enabled, the filehandle will be positioned to the end of
the file via a call to C<seek> before any compressed data is
written to it. Otherwise the file pointer will not be moved.
=back
When C<Append> is specified, and set to true, it will I<append> all compressed
data to the output data stream.
So when the output is a filehandle it will carry out a seek to the eof
before writing any compressed data. If the output is a filename, it will be opened for
appending. If the output is a buffer, all compressed data will be
appended to the existing buffer.
Conversely when C<Append> is not specified, or it is present and is set to
false, it will operate as follows.
When the output is a filename, it will truncate the contents of the file
before writing any compressed data. If the output is a filehandle
its position will not be changed. If the output is a buffer, it will be
wiped before any compressed data is output.
Defaults to 0.
=back
=head2 Examples
To read the contents of the file C<file1.txt> and write the compressed
data to the file C<file1.txt.1951>.
use strict ;
use warnings ;
use IO::Compress::RawDeflate qw(rawdeflate $RawDeflateError) ;
my $input = "file1.txt";
rawdeflate $input => "$input.1951"
or die "rawdeflate failed: $RawDeflateError\n";
To read from an existing Perl filehandle, C<$input>, and write the
compressed data to a buffer, C<$buffer>.
use strict ;
use warnings ;
use IO::Compress::RawDeflate qw(rawdeflate $RawDeflateError) ;
use IO::File ;
my $input = new IO::File "<file1.txt"
or die "Cannot open 'file1.txt': $!\n" ;
my $buffer ;
rawdeflate $input => \$buffer
or die "rawdeflate failed: $RawDeflateError\n";
To compress all files in the directory "/my/home" that match "*.txt"
and store the compressed data in the same directory
use strict ;
use warnings ;
use IO::Compress::RawDeflate qw(rawdeflate $RawDeflateError) ;
rawdeflate '</my/home/*.txt>' => '<*.1951>'
or die "rawdeflate failed: $RawDeflateError\n";
and if you want to compress each file one at a time, this will do the trick
use strict ;
use warnings ;
use IO::Compress::RawDeflate qw(rawdeflate $RawDeflateError) ;
for my $input ( glob "/my/home/*.txt" )
{
my $output = "$input.1951" ;
rawdeflate $input => $output
or die "Error compressing '$input': $RawDeflateError\n";
}
=head1 OO Interface
=head2 Constructor
The format of the constructor for C<IO::Compress::RawDeflate> is shown below
my $z = new IO::Compress::RawDeflate $output [,OPTS]
or die "IO::Compress::RawDeflate failed: $RawDeflateError\n";
It returns an C<IO::Compress::RawDeflate> object on success and undef on failure.
The variable C<$RawDeflateError> will contain an error message on failure.
If you are running Perl 5.005 or better the object, C<$z>, returned from
IO::Compress::RawDeflate can be used exactly like an L<IO::File|IO::File> filehandle.
This means that all normal output file operations can be carried out
with C<$z>.
For example, to write to a compressed file/buffer you can use either of
these forms
$z->print("hello world\n");
print $z "hello world\n";
The mandatory parameter C<$output> is used to control the destination
of the compressed data. This parameter can take one of these forms.
=over 5
=item A filename
If the C<$output> parameter is a simple scalar, it is assumed to be a
filename. This file will be opened for writing and the compressed data
will be written to it.
=item A filehandle
If the C<$output> parameter is a filehandle, the compressed data will be
written to it.
The string '-' can be used as an alias for standard output.
=item A scalar reference
If C<$output> is a scalar reference, the compressed data will be stored
in C<$$output>.
=back
If the C<$output> parameter is any other type, C<IO::Compress::RawDeflate>::new will
return undef.
=head2 Constructor Options
C<OPTS> is any combination of the following options:
=over 5
=item C<< AutoClose => 0|1 >>
This option is only valid when the C<$output> parameter is a filehandle. If
specified, and the value is true, it will result in the C<$output> being
closed once either the C<close> method is called or the C<IO::Compress::RawDeflate>
object is destroyed.
This parameter defaults to 0.
=item C<< Append => 0|1 >>
Opens C<$output> in append mode.
The behaviour of this option is dependent on the type of C<$output>.
=over 5
=item * A Buffer
If C<$output> is a buffer and C<Append> is enabled, all compressed data
will be append to the end of C<$output>. Otherwise C<$output> will be
cleared before any data is written to it.
=item * A Filename
If C<$output> is a filename and C<Append> is enabled, the file will be
opened in append mode. Otherwise the contents of the file, if any, will be
truncated before any compressed data is written to it.
=item * A Filehandle
If C<$output> is a filehandle, the file pointer will be positioned to the
end of the file via a call to C<seek> before any compressed data is written
to it. Otherwise the file pointer will not be moved.
=back
This parameter defaults to 0.
=item C<< Merge => 0|1 >>
This option is used to compress input data and append it to an existing
compressed data stream in C<$output>. The end result is a single compressed
data stream stored in C<$output>.
It is a fatal error to attempt to use this option when C<$output> is not an
RFC 1951 data stream.
There are a number of other limitations with the C<Merge> option:
=over 5
=item 1
This module needs to have been built with zlib 1.2.1 or better to work. A
fatal error will be thrown if C<Merge> is used with an older version of
zlib.
=item 2
If C<$output> is a file or a filehandle, it must be seekable.
=back
This parameter defaults to 0.
=item -Level
Defines the compression level used by zlib. The value should either be
a number between 0 and 9 (0 means no compression and 9 is maximum
compression), or one of the symbolic constants defined below.
Z_NO_COMPRESSION
Z_BEST_SPEED
Z_BEST_COMPRESSION
Z_DEFAULT_COMPRESSION
The default is Z_DEFAULT_COMPRESSION.
Note, these constants are not imported by C<IO::Compress::RawDeflate> by default.
use IO::Compress::RawDeflate qw(:strategy);
use IO::Compress::RawDeflate qw(:constants);
use IO::Compress::RawDeflate qw(:all);
=item -Strategy
Defines the strategy used to tune the compression. Use one of the symbolic
constants defined below.
Z_FILTERED
Z_HUFFMAN_ONLY
Z_RLE
Z_FIXED
Z_DEFAULT_STRATEGY
The default is Z_DEFAULT_STRATEGY.
=item C<< Strict => 0|1 >>
This is a placeholder option.
=back
=head2 Examples
TODO
=head1 Methods
=head2 print
Usage is
$z->print($data)
print $z $data
Compresses and outputs the contents of the C<$data> parameter. This
has the same behaviour as the C<print> built-in.
Returns true if successful.
=head2 printf
Usage is
$z->printf($format, $data)
printf $z $format, $data
Compresses and outputs the contents of the C<$data> parameter.
Returns true if successful.
=head2 syswrite
Usage is
$z->syswrite $data
$z->syswrite $data, $length
$z->syswrite $data, $length, $offset
Compresses and outputs the contents of the C<$data> parameter.
Returns the number of uncompressed bytes written, or C<undef> if
unsuccessful.
=head2 write
Usage is
$z->write $data
$z->write $data, $length
$z->write $data, $length, $offset
Compresses and outputs the contents of the C<$data> parameter.
Returns the number of uncompressed bytes written, or C<undef> if
unsuccessful.
=head2 flush
Usage is
$z->flush;
$z->flush($flush_type);
Flushes any pending compressed data to the output file/buffer.
This method takes an optional parameter, C<$flush_type>, that controls
how the flushing will be carried out. By default the C<$flush_type>
used is C<Z_FINISH>. Other valid values for C<$flush_type> are
C<Z_NO_FLUSH>, C<Z_SYNC_FLUSH>, C<Z_FULL_FLUSH> and C<Z_BLOCK>. It is
strongly recommended that you only set the C<flush_type> parameter if
you fully understand the implications of what it does - overuse of C<flush>
can seriously degrade the level of compression achieved. See the C<zlib>
documentation for details.
Returns true on success.
=head2 tell
Usage is
$z->tell()
tell $z
Returns the uncompressed file offset.
=head2 eof
Usage is
$z->eof();
eof($z);
Returns true if the C<close> method has been called.
=head2 seek
$z->seek($position, $whence);
seek($z, $position, $whence);
Provides a sub-set of the C<seek> functionality, with the restriction
that it is only legal to seek forward in the output file/buffer.
It is a fatal error to attempt to seek backward.
Empty parts of the file/buffer will have NULL (0x00) bytes written to them.
The C<$whence> parameter takes one the usual values, namely SEEK_SET,
SEEK_CUR or SEEK_END.
Returns 1 on success, 0 on failure.
=head2 binmode
Usage is
$z->binmode
binmode $z ;
This is a noop provided for completeness.
=head2 opened
$z->opened()
Returns true if the object currently refers to a opened file/buffer.
=head2 autoflush
my $prev = $z->autoflush()
my $prev = $z->autoflush(EXPR)
If the C<$z> object is associated with a file or a filehandle, this method
returns the current autoflush setting for the underlying filehandle. If
C<EXPR> is present, and is non-zero, it will enable flushing after every
write/print operation.
If C<$z> is associated with a buffer, this method has no effect and always
returns C<undef>.
B<Note> that the special variable C<$|> B<cannot> be used to set or
retrieve the autoflush setting.
=head2 input_line_number
$z->input_line_number()
$z->input_line_number(EXPR)
This method always returns C<undef> when compressing.
=head2 fileno
$z->fileno()
fileno($z)
If the C<$z> object is associated with a file or a filehandle, C<fileno>
will return the underlying file descriptor. Once the C<close> method is
called C<fileno> will return C<undef>.
If the C<$z> object is associated with a buffer, this method will return
C<undef>.
=head2 close
$z->close() ;
close $z ;
Flushes any pending compressed data and then closes the output file/buffer.
For most versions of Perl this method will be automatically invoked if
the IO::Compress::RawDeflate object is destroyed (either explicitly or by the
variable with the reference to the object going out of scope). The
exceptions are Perl versions 5.005 through 5.00504 and 5.8.0. In
these cases, the C<close> method will be called automatically, but
not until global destruction of all live objects when the program is
terminating.
Therefore, if you want your scripts to be able to run on all versions
of Perl, you should call C<close> explicitly and not rely on automatic
closing.
Returns true on success, otherwise 0.
If the C<AutoClose> option has been enabled when the IO::Compress::RawDeflate
object was created, and the object is associated with a file, the
underlying file will also be closed.
=head2 newStream([OPTS])
Usage is
$z->newStream( [OPTS] )
Closes the current compressed data stream and starts a new one.
OPTS consists of any of the options that are available when creating
the C<$z> object.
See the L</"Constructor Options"> section for more details.
=head2 deflateParams
Usage is
$z->deflateParams
TODO
=head1 Importing
A number of symbolic constants are required by some methods in
C<IO::Compress::RawDeflate>. None are imported by default.
=over 5
=item :all
Imports C<rawdeflate>, C<$RawDeflateError> and all symbolic
constants that can be used by C<IO::Compress::RawDeflate>. Same as doing this
use IO::Compress::RawDeflate qw(rawdeflate $RawDeflateError :constants) ;
=item :constants
Import all symbolic constants. Same as doing this
use IO::Compress::RawDeflate qw(:flush :level :strategy) ;
=item :flush
These symbolic constants are used by the C<flush> method.
Z_NO_FLUSH
Z_PARTIAL_FLUSH
Z_SYNC_FLUSH
Z_FULL_FLUSH
Z_FINISH
Z_BLOCK
=item :level
These symbolic constants are used by the C<Level> option in the constructor.
Z_NO_COMPRESSION
Z_BEST_SPEED
Z_BEST_COMPRESSION
Z_DEFAULT_COMPRESSION
=item :strategy
These symbolic constants are used by the C<Strategy> option in the constructor.
Z_FILTERED
Z_HUFFMAN_ONLY
Z_RLE
Z_FIXED
Z_DEFAULT_STRATEGY
=back
=head1 EXAMPLES
=head2 Apache::GZip Revisited
See L<IO::Compress::FAQ|IO::Compress::FAQ/"Apache::GZip Revisited">
=head2 Working with Net::FTP
See L<IO::Compress::FAQ|IO::Compress::FAQ/"Compressed files and Net::FTP">
=head1 SEE ALSO
L<Compress::Zlib>, L<IO::Compress::Gzip>, L<IO::Uncompress::Gunzip>, L<IO::Compress::Deflate>, L<IO::Uncompress::Inflate>, L<IO::Uncompress::RawInflate>, L<IO::Compress::Bzip2>, L<IO::Uncompress::Bunzip2>, L<IO::Compress::Lzma>, L<IO::Uncompress::UnLzma>, L<IO::Compress::Xz>, L<IO::Uncompress::UnXz>, L<IO::Compress::Lzop>, L<IO::Uncompress::UnLzop>, L<IO::Compress::Lzf>, L<IO::Uncompress::UnLzf>, L<IO::Uncompress::AnyInflate>, L<IO::Uncompress::AnyUncompress>
L<IO::Compress::FAQ|IO::Compress::FAQ>
L<File::GlobMapper|File::GlobMapper>, L<Archive::Zip|Archive::Zip>,
L<Archive::Tar|Archive::Tar>,
L<IO::Zlib|IO::Zlib>
For RFC 1950, 1951 and 1952 see
L<http://www.faqs.org/rfcs/rfc1950.html>,
L<http://www.faqs.org/rfcs/rfc1951.html> and
L<http://www.faqs.org/rfcs/rfc1952.html>
The I<zlib> compression library was written by Jean-loup Gailly
C<gzip@prep.ai.mit.edu> and Mark Adler C<madler@alumni.caltech.edu>.
The primary site for the I<zlib> compression library is
L<http://www.zlib.org>.
The primary site for gzip is L<http://www.gzip.org>.
=head1 AUTHOR
This module was written by Paul Marquess, C<pmqs@cpan.org>.
=head1 MODIFICATION HISTORY
See the Changes file.
=head1 COPYRIGHT AND LICENSE
Copyright (c) 2005-2018 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.