zlib.pm

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    _inflateInit($flags, $got->value('WindowBits'), $got->value('Bufsize'), 
                 $got->value('Dictionary')) ;
}

sub Compress::Raw::Zlib::InflateScan::new
{
    my $pkg = shift ;
    my ($got) = ParseParameters(0,
                    {
                        'CRC32'         => [1, 1, Parse_boolean,  0],
                        'ADLER32'       => [1, 1, Parse_boolean,  0],
                        'Bufsize'       => [1, 1, Parse_unsigned, 4096],
                 
                        'WindowBits'    => [1, 1, Parse_signed,   -MAX_WBITS()],
                        'Dictionary'    => [1, 1, Parse_any,      ""],
            }, @_) ;


    croak "Compress::Raw::Zlib::InflateScan::new: Bufsize must be >= 1, you specified " . 
            $got->value('Bufsize')
        unless $got->value('Bufsize') >= 1;

    my $flags = 0 ;
    #$flags |= FLAG_APPEND if $got->value('AppendOutput') ;
    $flags |= FLAG_CRC    if $got->value('CRC32') ;
    $flags |= FLAG_ADLER  if $got->value('ADLER32') ;
    #$flags |= FLAG_CONSUME_INPUT if $got->value('ConsumeInput') ;

    _inflateScanInit($flags, $got->value('WindowBits'), $got->value('Bufsize'), 
                 '') ;
}

sub Compress::Raw::Zlib::inflateScanStream::createDeflateStream
{
    my $pkg = shift ;
    my ($got) = ParseParameters(0,
            {
                'AppendOutput'  => [1, 1, Parse_boolean,  0],
                'CRC32'         => [1, 1, Parse_boolean,  0],
                'ADLER32'       => [1, 1, Parse_boolean,  0],
                'Bufsize'       => [1, 1, Parse_unsigned, 4096],
 
                'Level'         => [1, 1, Parse_signed,   Z_DEFAULT_COMPRESSION()],
                'Method'        => [1, 1, Parse_unsigned, Z_DEFLATED()],
                'WindowBits'    => [1, 1, Parse_signed,   - MAX_WBITS()],
                'MemLevel'      => [1, 1, Parse_unsigned, MAX_MEM_LEVEL()],
                'Strategy'      => [1, 1, Parse_unsigned, Z_DEFAULT_STRATEGY()],
            }, @_) ;

    croak "Compress::Raw::Zlib::InflateScan::createDeflateStream: Bufsize must be >= 1, you specified " . 
            $got->value('Bufsize')
        unless $got->value('Bufsize') >= 1;

    my $flags = 0 ;
    $flags |= FLAG_APPEND if $got->value('AppendOutput') ;
    $flags |= FLAG_CRC    if $got->value('CRC32') ;
    $flags |= FLAG_ADLER  if $got->value('ADLER32') ;

    $pkg->_createDeflateStream($flags,
                $got->value('Level'), 
                $got->value('Method'), 
                $got->value('WindowBits'), 
                $got->value('MemLevel'), 
                $got->value('Strategy'), 
                $got->value('Bufsize'),
                ) ;

}

sub Compress::Raw::Zlib::inflateScanStream::inflate
{
    my $self = shift ;
    my $buffer = $_[1];
    my $eof = $_[2];

    my $status = $self->scan(@_);

    if ($status == Z_OK() && $_[2]) {
        my $byte = ' ';
        
        $status = $self->scan(\$byte, $_[1]) ;
    }
    
    return $status ;
}

sub Compress::Raw::Zlib::deflateStream::deflateParams
{
    my $self = shift ;
    my ($got) = ParseParameters(0, {
                'Level'      => [1, 1, Parse_signed,   undef],
                'Strategy'   => [1, 1, Parse_unsigned, undef],
                'Bufsize'    => [1, 1, Parse_unsigned, undef],
                }, 
                @_) ;

    croak "Compress::Raw::Zlib::deflateParams needs Level and/or Strategy"
        unless $got->parsed('Level') + $got->parsed('Strategy') +
            $got->parsed('Bufsize');

    croak "Compress::Raw::Zlib::Inflate::deflateParams: Bufsize must be >= 1, you specified " . 
            $got->value('Bufsize')
        if $got->parsed('Bufsize') && $got->value('Bufsize') <= 1;

    my $flags = 0;
    $flags |= 1 if $got->parsed('Level') ;
    $flags |= 2 if $got->parsed('Strategy') ;
    $flags |= 4 if $got->parsed('Bufsize') ;

    $self->_deflateParams($flags, $got->value('Level'), 
                          $got->value('Strategy'), $got->value('Bufsize'));

}


# Autoload methods go after __END__, and are processed by the autosplit program.

1;
__END__


=head1 NAME

Compress::Raw::Zlib - Low-Level Interface to zlib compression library

=head1 SYNOPSIS

    use Compress::Raw::Zlib ;

    ($d, $status) = new Compress::Raw::Zlib::Deflate( [OPT] ) ;
    $status = $d->deflate($input, $output) ;
    $status = $d->flush($output [, $flush_type]) ;
    $d->deflateParams(OPTS) ;
    $d->deflateTune(OPTS) ;
    $d->dict_adler() ;
    $d->crc32() ;
    $d->adler32() ;
    $d->total_in() ;
    $d->total_out() ;
    $d->msg() ;
    $d->get_Strategy();
    $d->get_Level();
    $d->get_BufSize();

    ($i, $status) = new Compress::Raw::Zlib::Inflate( [OPT] ) ;
    $status = $i->inflate($input, $output [, $eof]) ;
    $status = $i->inflateSync($input) ;
    $i->dict_adler() ;
    $d->crc32() ;
    $d->adler32() ;
    $i->total_in() ;
    $i->total_out() ;
    $i->msg() ;
    $d->get_BufSize();

    $crc = adler32($buffer [,$crc]) ;
    $crc = crc32($buffer [,$crc]) ;

    $crc = adler32_combine($crc1, $crc2, $len2)l
    $crc = crc32_combine($adler1, $adler2, $len2)

    ZLIB_VERSION
    ZLIB_VERNUM

=head1 DESCRIPTION

The I<Compress::Raw::Zlib> module provides a Perl interface to the I<zlib>
compression library (see L</AUTHOR> for details about where to get
I<zlib>). 



=head1 Compress::Raw::Zlib::Deflate

This section defines an interface that allows in-memory compression using
the I<deflate> interface provided by zlib.

Here is a definition of the interface available:


=head2 B<($d, $status) = new Compress::Raw::Zlib::Deflate( [OPT] ) >

Initialises a deflation object. 

If you are familiar with the I<zlib> library, it combines the
features of the I<zlib> functions C<deflateInit>, C<deflateInit2>
and C<deflateSetDictionary>.

If successful, it will return the initialised deflation object, C<$d>
and a C<$status> of C<Z_OK> in a list context. In scalar context it
returns the deflation object, C<$d>, only.

If not successful, the returned deflation object, C<$d>, will be
I<undef> and C<$status> will hold the a I<zlib> error code.

The function optionally takes a number of named options specified as
C<< Name => value >> pairs. This allows individual options to be
tailored without having to specify them all in the parameter list.

For backward compatibility, it is also possible to pass the parameters
as a reference to a hash containing the name=>value pairs.

Below is a list of the valid options:

=over 5

=item B<-Level>

Defines the compression level. Valid values are 0 through 9,
C<Z_NO_COMPRESSION>, C<Z_BEST_SPEED>, C<Z_BEST_COMPRESSION>, and
C<Z_DEFAULT_COMPRESSION>.

The default is Z_DEFAULT_COMPRESSION.

=item B<-Method>

Defines the compression method. The only valid value at present (and
the default) is Z_DEFLATED.

=item B<-WindowBits>

For a definition of the meaning and valid values for C<WindowBits>
refer to the I<zlib> documentation for I<deflateInit2>.

Defaults to MAX_WBITS.

=item B<-MemLevel>

For a definition of the meaning and valid values for C<MemLevel>
refer to the I<zlib> documentation for I<deflateInit2>.

Defaults to MAX_MEM_LEVEL.

=item B<-Strategy>

Defines the strategy used to tune the compression. The valid values are
C<Z_DEFAULT_STRATEGY>, C<Z_FILTERED>, C<Z_RLE>, C<Z_FIXED> and
C<Z_HUFFMAN_ONLY>.

The default is Z_DEFAULT_STRATEGY.

=item B<-Dictionary>

When a dictionary is specified I<Compress::Raw::Zlib> will automatically
call C<deflateSetDictionary> directly after calling C<deflateInit>. The
Adler32 value for the dictionary can be obtained by calling the method 
C<$d-E<gt>dict_adler()>.

The default is no dictionary.

=item B<-Bufsize>

Sets the initial size for the output buffer used by the C<$d-E<gt>deflate>
and C<$d-E<gt>flush> methods. If the buffer has to be
reallocated to increase the size, it will grow in increments of
C<Bufsize>.

The default buffer size is 4096.

=item B<-AppendOutput>

This option controls how data is written to the output buffer by the
C<$d-E<gt>deflate> and C<$d-E<gt>flush> methods.

If the C<AppendOutput> option is set to false, the output buffers in the
C<$d-E<gt>deflate> and C<$d-E<gt>flush>  methods will be truncated before
uncompressed data is written to them.

If the option is set to true, uncompressed data will be appended to the
output buffer in the C<$d-E<gt>deflate> and C<$d-E<gt>flush> methods.

This option defaults to false.

=item B<-CRC32>

If set to true, a crc32 checksum of the uncompressed data will be
calculated. Use the C<$d-E<gt>crc32> method to retrieve this value.

This option defaults to false.


=item B<-ADLER32>

If set to true, an adler32 checksum of the uncompressed data will be
calculated. Use the C<$d-E<gt>adler32> method to retrieve this value.

This option defaults to false.


=back

Here is an example of using the C<Compress::Raw::Zlib::Deflate> optional
parameter list to override the default buffer size and compression
level. All other options will take their default values.

    my $d = new Compress::Raw::Zlib::Deflate ( -Bufsize => 300, 
                                               -Level   => Z_BEST_SPEED ) ;


=head2 B<$status = $d-E<gt>deflate($input, $output)>

Deflates the contents of C<$input> and writes the compressed data to
C<$output>.

The C<$input> and C<$output> parameters can be either scalars or scalar
references.

When finished, C<$input> will be completely processed (assuming there
were no errors). If the deflation was successful it writes the deflated
data to C<$output> and returns a status value of C<Z_OK>.

On error, it returns a I<zlib> error code.

If the C<AppendOutput> option is set to true in the constructor for
the C<$d> object, the compressed data will be appended to C<$output>. If
it is false, C<$output> will be truncated before any compressed data is
written to it.

B<Note>: This method will not necessarily write compressed data to
C<$output> every time it is called. So do not assume that there has been
an error if the contents of C<$output> is empty on returning from
this method. As long as the return code from the method is C<Z_OK>,
the deflate has succeeded.

=head2 B<$status = $d-E<gt>flush($output [, $flush_type]) >

Typically used to finish the deflation. Any pending output will be
written to C<$output>.

Returns C<Z_OK> if successful.

Note that flushing can seriously degrade the compression ratio, so it
should only be used to terminate a decompression (using C<Z_FINISH>) or
when you want to create a I<full flush point> (using C<Z_FULL_FLUSH>).

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_PARTIAL_FLUSH>, C<Z_SYNC_FLUSH>
and C<Z_FULL_FLUSH>. It is strongly recommended that you only set the
C<flush_type> parameter if you fully understand the implications of
what it does. See the C<zlib> documentation for details.

If the C<AppendOutput> option is set to true in the constructor for
the C<$d> object, the compressed data will be appended to C<$output>. If
it is false, C<$output> will be truncated before any compressed data is
written to it.

=head2 B<$status = $d-E<gt>deflateParams([OPT])>

Change settings for the deflate object C<$d>.

The list of the valid options is shown below. Options not specified
will remain unchanged.


=over 5

=item B<-Level>

Defines the compression level. Valid values are 0 through 9,
C<Z_NO_COMPRESSION>, C<Z_BEST_SPEED>, C<Z_BEST_COMPRESSION>, and
C<Z_DEFAULT_COMPRESSION>.

=item B<-Strategy>

Defines the strategy used to tune the compression. The valid values are
C<Z_DEFAULT_STRATEGY>, C<Z_FILTERED> and C<Z_HUFFMAN_ONLY>. 

=item B<-BufSize>

Sets the initial size for the output buffer used by the C<$d-E<gt>deflate>
and C<$d-E<gt>flush> methods. If the buffer has to be
reallocated to increase the size, it will grow in increments of
C<Bufsize>.


=back

=head2 B<$status = $d-E<gt>deflateTune($good_length, $max_lazy, $nice_length, $max_chain)>

Tune the internal settings for the deflate object C<$d>. This option is
only available if you are running zlib 1.2.2.3 or better.

Refer to the documentation in zlib.h for instructions on how to fly
C<deflateTune>.

=head2 B<$d-E<gt>dict_adler()>

Returns the adler32 value for the dictionary.

=head2 B<$d-E<gt>crc32()>

Returns the crc32 value for the uncompressed data to date. 

If the C<CRC32> option is not enabled in the constructor for this object,
this method will always return 0;

=head2 B<$d-E<gt>adler32()>

Returns the adler32 value for the uncompressed data to date.