gunzip.pm

视频监控网络部分的协议ddns,的模块的实现代码,请大家大胆指正.

package IO::Uncompress::Gunzip ;

require 5.004 ;

# for RFC1952

use strict ;
use warnings;
use bytes;

use IO::Uncompress::RawInflate 2.008 ;

use Compress::Raw::Zlib 2.008 qw( crc32 ) ;
use IO::Compress::Base::Common 2.008 qw(:Status createSelfTiedObject);
use IO::Compress::Gzip::Constants 2.008 ;
use IO::Compress::Zlib::Extra 2.008 ;

require Exporter ;

our ($VERSION, @ISA, @EXPORT_OK, %EXPORT_TAGS, $GunzipError);

@ISA = qw( Exporter IO::Uncompress::RawInflate );
@EXPORT_OK = qw( $GunzipError gunzip );
%EXPORT_TAGS = %IO::Uncompress::RawInflate::DEFLATE_CONSTANTS ;
push @{ $EXPORT_TAGS{all} }, @EXPORT_OK ;
Exporter::export_ok_tags('all');

$GunzipError = '';

$VERSION = '2.008';

sub new
{
    my $class = shift ;
    $GunzipError = '';
    my $obj = createSelfTiedObject($class, \$GunzipError);

    $obj->_create(undef, 0, @_);
}

sub gunzip
{
    my $obj = createSelfTiedObject(undef, \$GunzipError);
    return $obj->_inf(@_) ;
}

sub getExtraParams
{
    use IO::Compress::Base::Common  2.008 qw(:Parse);
    return ( 'ParseExtra' => [1, 1, Parse_boolean,  0] ) ;
}

sub ckParams
{
    my $self = shift ;
    my $got = shift ;

    # gunzip always needs crc32
    $got->value('CRC32' => 1);

    return 1;
}

sub ckMagic
{
    my $self = shift;

    my $magic ;
    $self->smartReadExact(\$magic, GZIP_ID_SIZE);

    *$self->{HeaderPending} = $magic ;

    return $self->HeaderError("Minimum header size is " . 
                              GZIP_MIN_HEADER_SIZE . " bytes") 
        if length $magic != GZIP_ID_SIZE ;                                    

    return $self->HeaderError("Bad Magic")
        if ! isGzipMagic($magic) ;

    *$self->{Type} = 'rfc1952';

    return $magic ;
}

sub readHeader
{
    my $self = shift;
    my $magic = shift;

    return $self->_readGzipHeader($magic);
}

sub chkTrailer
{
    my $self = shift;
    my $trailer = shift;

    # Check CRC & ISIZE 
    my ($CRC32, $ISIZE) = unpack("V V", $trailer) ;
    *$self->{Info}{CRC32} = $CRC32;    
    *$self->{Info}{ISIZE} = $ISIZE;    

    if (*$self->{Strict}) {
        return $self->TrailerError("CRC mismatch")
            if $CRC32 != *$self->{Uncomp}->crc32() ;

        my $exp_isize = *$self->{UnCompSize}->get32bit();
        return $self->TrailerError("ISIZE mismatch. Got $ISIZE"
                                  . ", expected $exp_isize")
            if $ISIZE != $exp_isize ;
    }

    return STATUS_OK;
}

sub isGzipMagic
{
    my $buffer = shift ;
    return 0 if length $buffer < GZIP_ID_SIZE ;
    my ($id1, $id2) = unpack("C C", $buffer) ;
    return $id1 == GZIP_ID1 && $id2 == GZIP_ID2 ;
}

sub _readFullGzipHeader($)
{
    my ($self) = @_ ;
    my $magic = '' ;

    $self->smartReadExact(\$magic, GZIP_ID_SIZE);

    *$self->{HeaderPending} = $magic ;

    return $self->HeaderError("Minimum header size is " . 
                              GZIP_MIN_HEADER_SIZE . " bytes") 
        if length $magic != GZIP_ID_SIZE ;                                    


    return $self->HeaderError("Bad Magic")
        if ! isGzipMagic($magic) ;

    my $status = $self->_readGzipHeader($magic);
    delete *$self->{Transparent} if ! defined $status ;
    return $status ;
}

sub _readGzipHeader($)
{
    my ($self, $magic) = @_ ;
    my ($HeaderCRC) ;
    my ($buffer) = '' ;

    $self->smartReadExact(\$buffer, GZIP_MIN_HEADER_SIZE - GZIP_ID_SIZE)
        or return $self->HeaderError("Minimum header size is " . 
                                     GZIP_MIN_HEADER_SIZE . " bytes") ;

    my $keep = $magic . $buffer ;
    *$self->{HeaderPending} = $keep ;

    # now split out the various parts
    my ($cm, $flag, $mtime, $xfl, $os) = unpack("C C V C C", $buffer) ;

    $cm == GZIP_CM_DEFLATED 
        or return $self->HeaderError("Not Deflate (CM is $cm)") ;

    # check for use of reserved bits
    return $self->HeaderError("Use of Reserved Bits in FLG field.")
        if $flag & GZIP_FLG_RESERVED ; 

    my $EXTRA ;
    my @EXTRA = () ;
    if ($flag & GZIP_FLG_FEXTRA) {
        $EXTRA = "" ;
        $self->smartReadExact(\$buffer, GZIP_FEXTRA_HEADER_SIZE) 
            or return $self->TruncatedHeader("FEXTRA Length") ;

        my ($XLEN) = unpack("v", $buffer) ;
        $self->smartReadExact(\$EXTRA, $XLEN) 
            or return $self->TruncatedHeader("FEXTRA Body");
        $keep .= $buffer . $EXTRA ;

        if ($XLEN && *$self->{'ParseExtra'}) {
            my $bad = IO::Compress::Zlib::Extra::parseRawExtra($EXTRA,
                                                \@EXTRA, 1, 1);
            return $self->HeaderError($bad)
                if defined $bad;
        }
    }

    my $origname ;
    if ($flag & GZIP_FLG_FNAME) {
        $origname = "" ;
        while (1) {
            $self->smartReadExact(\$buffer, 1) 
                or return $self->TruncatedHeader("FNAME");
            last if $buffer eq GZIP_NULL_BYTE ;
            $origname .= $buffer 
        }
        $keep .= $origname . GZIP_NULL_BYTE ;

        return $self->HeaderError("Non ISO 8859-1 Character found in Name")
            if *$self->{Strict} && $origname =~ /$GZIP_FNAME_INVALID_CHAR_RE/o ;
    }

    my $comment ;
    if ($flag & GZIP_FLG_FCOMMENT) {
        $comment = "";
        while (1) {
            $self->smartReadExact(\$buffer, 1) 
                or return $self->TruncatedHeader("FCOMMENT");
            last if $buffer eq GZIP_NULL_BYTE ;
            $comment .= $buffer 
        }
        $keep .= $comment . GZIP_NULL_BYTE ;

        return $self->HeaderError("Non ISO 8859-1 Character found in Comment")
            if *$self->{Strict} && $comment =~ /$GZIP_FCOMMENT_INVALID_CHAR_RE/o ;
    }

    if ($flag & GZIP_FLG_FHCRC) {
        $self->smartReadExact(\$buffer, GZIP_FHCRC_SIZE) 
            or return $self->TruncatedHeader("FHCRC");

        $HeaderCRC = unpack("v", $buffer) ;
        my $crc16 = crc32($keep) & 0xFF ;

        return $self->HeaderError("CRC16 mismatch.")
            if *$self->{Strict} && $crc16 != $HeaderCRC;

        $keep .= $buffer ;
    }

    # Assume compression method is deflated for xfl tests
    #if ($xfl) {
    #}

    *$self->{Type} = 'rfc1952';

    return {
        'Type'          => 'rfc1952',
        'FingerprintLength'  => 2,
        'HeaderLength'  => length $keep,
        'TrailerLength' => GZIP_TRAILER_SIZE,
        'Header'        => $keep,
        'isMinimalHeader' => $keep eq GZIP_MINIMUM_HEADER ? 1 : 0,

        'MethodID'      => $cm,
        'MethodName'    => $cm == GZIP_CM_DEFLATED ? "Deflated" : "Unknown" ,
        'TextFlag'      => $flag & GZIP_FLG_FTEXT ? 1 : 0,
        'HeaderCRCFlag' => $flag & GZIP_FLG_FHCRC ? 1 : 0,
        'NameFlag'      => $flag & GZIP_FLG_FNAME ? 1 : 0,
        'CommentFlag'   => $flag & GZIP_FLG_FCOMMENT ? 1 : 0,
        'ExtraFlag'     => $flag & GZIP_FLG_FEXTRA ? 1 : 0,
        'Name'          => $origname,
        'Comment'       => $comment,
        'Time'          => $mtime,
        'OsID'          => $os,
        'OsName'        => defined $GZIP_OS_Names{$os} 
                                 ? $GZIP_OS_Names{$os} : "Unknown",
        'HeaderCRC'     => $HeaderCRC,
        'Flags'         => $flag,
        'ExtraFlags'    => $xfl,
        'ExtraFieldRaw' => $EXTRA,
        'ExtraField'    => [ @EXTRA ],


        #'CompSize'=> $compsize,
        #'CRC32'=> $CRC32,
        #'OrigSize'=> $ISIZE,
      }
}


1;

__END__


=head1 NAME



IO::Uncompress::Gunzip - Read RFC 1952 files/buffers



=head1 SYNOPSIS

    use IO::Uncompress::Gunzip qw(gunzip $GunzipError) ;

    my $status = gunzip $input => $output [,OPTS]
        or die "gunzip failed: $GunzipError\n";

    my $z = new IO::Uncompress::Gunzip $input [OPTS] 
        or die "gunzip failed: $GunzipError\n";

    $status = $z->read($buffer)
    $status = $z->read($buffer, $length)
    $status = $z->read($buffer, $length, $offset)
    $line = $z->getline()
    $char = $z->getc()
    $char = $z->ungetc()
    $char = $z->opened()

    $status = $z->inflateSync()

    $data = $z->trailingData()
    $status = $z->nextStream()
    $data = $z->getHeaderInfo()
    $z->tell()
    $z->seek($position, $whence)
    $z->binmode()
    $z->fileno()
    $z->eof()
    $z->close()

    $GunzipError ;

    # IO::File mode

    <$z>
    read($z, $buffer);
    read($z, $buffer, $length);
    read($z, $buffer, $length, $offset);
    tell($z)
    seek($z, $position, $whence)
    binmode($z)
    fileno($z)
    eof($z)
    close($z)


=head1 DESCRIPTION



This module provides a Perl interface that allows the reading of
files/buffers that conform to RFC 1952.

For writing RFC 1952 files/buffers, see the companion module IO::Compress::Gzip.





=head1 Functional Interface

A top-level function, C<gunzip>, is provided to carry out
"one-shot" uncompression between buffers and/or files. For finer
control over the uncompression process, see the L</"OO Interface">
section.

    use IO::Uncompress::Gunzip qw(gunzip $GunzipError) ;

    gunzip $input => $output [,OPTS] 
        or die "gunzip failed: $GunzipError\n";



The functional interface needs Perl5.005 or better.


=head2 gunzip $input => $output [, OPTS]


C<gunzip> expects at least two parameters, C<$input> and C<$output>.

=head3 The C<$input> parameter

The parameter, C<$input>, is used to define the source of
the compressed data. 

It can take one of the following forms:

=over 5

=item A filename

If the C<$input> 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> 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> is a scalar reference, the input data will be read
from C<$$input>.

=item An array reference 

If C<$input> 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 uncompressed.



=item An Input FileGlob string

If C<$input> is a string that is delimited by the characters "<" and ">"
C<gunzip> will assume that it is an I<input fileglob string>. The
input is the list of files that match the fileglob.

If the fileglob does not match any files ...

See L<File::GlobMapper|File::GlobMapper> for more details.


=back

If the C<$input> parameter is any other type, C<undef> will be returned.



=head3 The C<$output> parameter

The parameter C<$output> is used to control the destination of the
uncompressed 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 uncompressed
data will be written to it.

=item A filehandle

If the C<$output> parameter is a filehandle, the uncompressed 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 uncompressed data will be
stored in C<$$output>.



=item An Array Reference

If C<$output> is an array reference, the uncompressed data will be
pushed onto the array.

=item An Output FileGlob

If C<$output> is a string that is delimited by the characters "<" and ">"
C<gunzip> will assume that it is an I<output fileglob string>. The
output is the list of files that match the fileglob.

When C<$output> is an fileglob string, C<$input> must also be a fileglob
string. Anything else is an error.

=back

If the C<$output> parameter is any other type, C<undef> will be returned.



=head2 Notes


When C<$input> maps to multiple compressed files/buffers and C<$output> is
a single file/buffer, after uncompression C<$output> will contain a
concatenation of all the uncompressed data from each of the input
files/buffers.





=head2 Optional Parameters

Unless specified below, the optional parameters for C<gunzip>,
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<gunzip> 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<gunzip> has
completed.

This parameter defaults to 0.


=item C<< BinModeOut => 0|1 >>

When writing to a file or filehandle, set C<binmode> before writing to the
file.

Defaults to 0.





=item C<< Append => 0|1 >>

TODO

=item C<< MultiStream => 0|1 >>


If the input file/buffer contains multiple compressed data streams, this
option will uncompress the whole lot as a single data stream.

Defaults to 0.





=item C<< TrailingData => $scalar >>

Returns the data, if any, that is present immediately after the compressed
data stream once uncompression is complete. 

This option can be used when there is useful information immediately
following the compressed data stream, and you don't know the length of the
compressed data stream.

If the input is a buffer, C<trailingData> will return everything from the
end of the compressed data stream to the end of the buffer.

If the input is a filehandle, C<trailingData> will return the data that is
left in the filehandle input buffer once the end of the compressed data
stream has been reached. You can then use the filehandle to read the rest
of the input file. 

Don't bother using C<trailingData> if the input is a filename.



If you know the length of the compressed data stream before you start
uncompressing, you can avoid having to use C<trailingData> by setting the
C<InputLength> option.



=back




=head2 Examples

To read the contents of the file C<file1.txt.gz> and write the
compressed data to the file C<file1.txt>.

    use strict ;
    use warnings ;
    use IO::Uncompress::Gunzip qw(gunzip $GunzipError) ;

    my $input = "file1.txt.gz";
    my $output = "file1.txt";
    gunzip $input => $output
        or die "gunzip failed: $GunzipError\n";


To read from an existing Perl filehandle, C<$input>, and write the
uncompressed data to a buffer, C<$buffer>.

    use strict ;
    use warnings ;
    use IO::Uncompress::Gunzip qw(gunzip $GunzipError) ;
    use IO::File ;

    my $input = new IO::File "<file1.txt.gz"
        or die "Cannot open 'file1.txt.gz': $!\n" ;
    my $buffer ;
    gunzip $input => \$buffer 
        or die "gunzip failed: $GunzipError\n";

To uncompress all files in the directory "/my/home" that match "*.txt.gz" and store the compressed data in the same directory