1package IO::Uncompress::Inflate ;
2# for RFC1950
3
4use strict ;
5use warnings;
6use bytes;
7
8use IO::Compress::Base::Common  2.204 qw(:Status );
9use IO::Compress::Zlib::Constants 2.204 ;
10
11use IO::Uncompress::RawInflate  2.204 ;
12
13require Exporter ;
14our ($VERSION, @ISA, @EXPORT_OK, %EXPORT_TAGS, $InflateError);
15
16$VERSION = '2.204';
17$InflateError = '';
18
19@ISA    = qw(IO::Uncompress::RawInflate Exporter);
20@EXPORT_OK = qw( $InflateError inflate ) ;
21%EXPORT_TAGS = %IO::Uncompress::RawInflate::DEFLATE_CONSTANTS ;
22push @{ $EXPORT_TAGS{all} }, @EXPORT_OK ;
23Exporter::export_ok_tags('all');
24
25
26sub new
27{
28    my $class = shift ;
29    my $obj = IO::Compress::Base::Common::createSelfTiedObject($class, \$InflateError);
30
31    $obj->_create(undef, 0, @_);
32}
33
34sub inflate
35{
36    my $obj = IO::Compress::Base::Common::createSelfTiedObject(undef, \$InflateError);
37    return $obj->_inf(@_);
38}
39
40sub getExtraParams
41{
42    return ();
43}
44
45sub ckParams
46{
47    my $self = shift ;
48    my $got = shift ;
49
50    # gunzip always needs adler32
51    $got->setValue('adler32' => 1);
52
53    return 1;
54}
55
56sub ckMagic
57{
58    my $self = shift;
59
60    my $magic ;
61    $self->smartReadExact(\$magic, ZLIB_HEADER_SIZE);
62
63    *$self->{HeaderPending} = $magic ;
64
65    return $self->HeaderError("Header size is " .
66                                        ZLIB_HEADER_SIZE . " bytes")
67        if length $magic != ZLIB_HEADER_SIZE;
68
69    #return $self->HeaderError("CRC mismatch.")
70    return undef
71        if ! $self->isZlibMagic($magic) ;
72
73    *$self->{Type} = 'rfc1950';
74    return $magic;
75}
76
77sub readHeader
78{
79    my $self = shift;
80    my $magic = shift ;
81
82    return $self->_readDeflateHeader($magic) ;
83}
84
85sub chkTrailer
86{
87    my $self = shift;
88    my $trailer = shift;
89
90    my $ADLER32 = unpack("N", $trailer) ;
91    *$self->{Info}{ADLER32} = $ADLER32;
92    return $self->TrailerError("CRC mismatch")
93        if *$self->{Strict} && $ADLER32 != *$self->{Uncomp}->adler32() ;
94
95    return STATUS_OK;
96}
97
98
99
100sub isZlibMagic
101{
102    my $self = shift;
103    my $buffer = shift ;
104
105    return 0
106        if length $buffer < ZLIB_HEADER_SIZE ;
107
108    my $hdr = unpack("n", $buffer) ;
109    #return 0 if $hdr % 31 != 0 ;
110    return $self->HeaderError("CRC mismatch.")
111        if $hdr % 31 != 0 ;
112
113    my ($CMF, $FLG) = unpack "C C", $buffer;
114    my $cm =    bits($CMF, ZLIB_CMF_CM_OFFSET,    ZLIB_CMF_CM_BITS) ;
115
116    # Only Deflate supported
117    return $self->HeaderError("Not Deflate (CM is $cm)")
118        if $cm != ZLIB_CMF_CM_DEFLATED ;
119
120    # Max window value is 7 for Deflate.
121    my $cinfo = bits($CMF, ZLIB_CMF_CINFO_OFFSET, ZLIB_CMF_CINFO_BITS) ;
122    return $self->HeaderError("CINFO > " . ZLIB_CMF_CINFO_MAX .
123                              " (CINFO is $cinfo)")
124        if $cinfo > ZLIB_CMF_CINFO_MAX ;
125
126    return 1;
127}
128
129sub bits
130{
131    my $data   = shift ;
132    my $offset = shift ;
133    my $mask  = shift ;
134
135    ($data >> $offset ) & $mask & 0xFF ;
136}
137
138
139sub _readDeflateHeader
140{
141    my ($self, $buffer) = @_ ;
142
143#    if (! $buffer) {
144#        $self->smartReadExact(\$buffer, ZLIB_HEADER_SIZE);
145#
146#        *$self->{HeaderPending} = $buffer ;
147#
148#        return $self->HeaderError("Header size is " .
149#                                            ZLIB_HEADER_SIZE . " bytes")
150#            if length $buffer != ZLIB_HEADER_SIZE;
151#
152#        return $self->HeaderError("CRC mismatch.")
153#            if ! isZlibMagic($buffer) ;
154#    }
155
156    my ($CMF, $FLG) = unpack "C C", $buffer;
157    my $FDICT = bits($FLG, ZLIB_FLG_FDICT_OFFSET,  ZLIB_FLG_FDICT_BITS ),
158
159    my $cm = bits($CMF, ZLIB_CMF_CM_OFFSET, ZLIB_CMF_CM_BITS) ;
160    $cm == ZLIB_CMF_CM_DEFLATED
161        or return $self->HeaderError("Not Deflate (CM is $cm)") ;
162
163    my $DICTID;
164    if ($FDICT) {
165        $self->smartReadExact(\$buffer, ZLIB_FDICT_SIZE)
166            or return $self->TruncatedHeader("FDICT");
167
168        $DICTID = unpack("N", $buffer) ;
169    }
170
171    *$self->{Type} = 'rfc1950';
172
173    return {
174        'Type'          => 'rfc1950',
175        'FingerprintLength'  => ZLIB_HEADER_SIZE,
176        'HeaderLength'  => ZLIB_HEADER_SIZE,
177        'TrailerLength' => ZLIB_TRAILER_SIZE,
178        'Header'        => $buffer,
179
180        CMF     =>      $CMF                                               ,
181        CM      => bits($CMF, ZLIB_CMF_CM_OFFSET,     ZLIB_CMF_CM_BITS    ),
182        CINFO   => bits($CMF, ZLIB_CMF_CINFO_OFFSET,  ZLIB_CMF_CINFO_BITS ),
183        FLG     =>      $FLG                                               ,
184        FCHECK  => bits($FLG, ZLIB_FLG_FCHECK_OFFSET, ZLIB_FLG_FCHECK_BITS),
185        FDICT   => bits($FLG, ZLIB_FLG_FDICT_OFFSET,  ZLIB_FLG_FDICT_BITS ),
186        FLEVEL  => bits($FLG, ZLIB_FLG_LEVEL_OFFSET,  ZLIB_FLG_LEVEL_BITS ),
187        DICTID  =>      $DICTID                                            ,
188
189    };
190}
191
192
193
194
1951 ;
196
197__END__
198
199
200=head1 NAME
201
202IO::Uncompress::Inflate - Read RFC 1950 files/buffers
203
204=head1 SYNOPSIS
205
206    use IO::Uncompress::Inflate qw(inflate $InflateError) ;
207
208    my $status = inflate $input => $output [,OPTS]
209        or die "inflate failed: $InflateError\n";
210
211    my $z = IO::Uncompress::Inflate->new( $input [OPTS] )
212        or die "inflate failed: $InflateError\n";
213
214    $status = $z->read($buffer)
215    $status = $z->read($buffer, $length)
216    $status = $z->read($buffer, $length, $offset)
217    $line = $z->getline()
218    $char = $z->getc()
219    $char = $z->ungetc()
220    $char = $z->opened()
221
222    $status = $z->inflateSync()
223
224    $data = $z->trailingData()
225    $status = $z->nextStream()
226    $data = $z->getHeaderInfo()
227    $z->tell()
228    $z->seek($position, $whence)
229    $z->binmode()
230    $z->fileno()
231    $z->eof()
232    $z->close()
233
234    $InflateError ;
235
236    # IO::File mode
237
238    <$z>
239    read($z, $buffer);
240    read($z, $buffer, $length);
241    read($z, $buffer, $length, $offset);
242    tell($z)
243    seek($z, $position, $whence)
244    binmode($z)
245    fileno($z)
246    eof($z)
247    close($z)
248
249=head1 DESCRIPTION
250
251This module provides a Perl interface that allows the reading of
252files/buffers that conform to RFC 1950.
253
254For writing RFC 1950 files/buffers, see the companion module IO::Compress::Deflate.
255
256=head1 Functional Interface
257
258A top-level function, C<inflate>, is provided to carry out
259"one-shot" uncompression between buffers and/or files. For finer
260control over the uncompression process, see the L</"OO Interface">
261section.
262
263    use IO::Uncompress::Inflate qw(inflate $InflateError) ;
264
265    inflate $input_filename_or_reference => $output_filename_or_reference [,OPTS]
266        or die "inflate failed: $InflateError\n";
267
268The functional interface needs Perl5.005 or better.
269
270=head2 inflate $input_filename_or_reference => $output_filename_or_reference [, OPTS]
271
272C<inflate> expects at least two parameters,
273C<$input_filename_or_reference> and C<$output_filename_or_reference>
274and zero or more optional parameters (see L</Optional Parameters>)
275
276=head3 The C<$input_filename_or_reference> parameter
277
278The parameter, C<$input_filename_or_reference>, is used to define the
279source of the compressed data.
280
281It can take one of the following forms:
282
283=over 5
284
285=item A filename
286
287If the C<$input_filename_or_reference> parameter is a simple scalar, it is
288assumed to be a filename. This file will be opened for reading and the
289input data will be read from it.
290
291=item A filehandle
292
293If the C<$input_filename_or_reference> parameter is a filehandle, the input
294data will be read from it.  The string '-' can be used as an alias for
295standard input.
296
297=item A scalar reference
298
299If C<$input_filename_or_reference> is a scalar reference, the input data
300will be read from C<$$input_filename_or_reference>.
301
302=item An array reference
303
304If C<$input_filename_or_reference> is an array reference, each element in
305the array must be a filename.
306
307The input data will be read from each file in turn.
308
309The complete array will be walked to ensure that it only
310contains valid filenames before any data is uncompressed.
311
312=item An Input FileGlob string
313
314If C<$input_filename_or_reference> is a string that is delimited by the
315characters "<" and ">" C<inflate> will assume that it is an
316I<input fileglob string>. The input is the list of files that match the
317fileglob.
318
319See L<File::GlobMapper|File::GlobMapper> for more details.
320
321=back
322
323If the C<$input_filename_or_reference> parameter is any other type,
324C<undef> will be returned.
325
326=head3 The C<$output_filename_or_reference> parameter
327
328The parameter C<$output_filename_or_reference> is used to control the
329destination of the uncompressed data. This parameter can take one of
330these forms.
331
332=over 5
333
334=item A filename
335
336If the C<$output_filename_or_reference> parameter is a simple scalar, it is
337assumed to be a filename.  This file will be opened for writing and the
338uncompressed data will be written to it.
339
340=item A filehandle
341
342If the C<$output_filename_or_reference> parameter is a filehandle, the
343uncompressed data will be written to it.  The string '-' can be used as
344an alias for standard output.
345
346=item A scalar reference
347
348If C<$output_filename_or_reference> is a scalar reference, the
349uncompressed data will be stored in C<$$output_filename_or_reference>.
350
351=item An Array Reference
352
353If C<$output_filename_or_reference> is an array reference,
354the uncompressed data will be pushed onto the array.
355
356=item An Output FileGlob
357
358If C<$output_filename_or_reference> is a string that is delimited by the
359characters "<" and ">" C<inflate> will assume that it is an
360I<output fileglob string>. The output is the list of files that match the
361fileglob.
362
363When C<$output_filename_or_reference> is an fileglob string,
364C<$input_filename_or_reference> must also be a fileglob string. Anything
365else is an error.
366
367See L<File::GlobMapper|File::GlobMapper> for more details.
368
369=back
370
371If the C<$output_filename_or_reference> parameter is any other type,
372C<undef> will be returned.
373
374=head2 Notes
375
376When C<$input_filename_or_reference> maps to multiple compressed
377files/buffers and C<$output_filename_or_reference> is
378a single file/buffer, after uncompression C<$output_filename_or_reference> will contain a
379concatenation of all the uncompressed data from each of the input
380files/buffers.
381
382=head2 Optional Parameters
383
384The optional parameters for the one-shot function C<inflate>
385are (for the most part) identical to those used with the OO interface defined in the
386L</"Constructor Options"> section. The exceptions are listed below
387
388=over 5
389
390=item C<< AutoClose => 0|1 >>
391
392This option applies to any input or output data streams to
393C<inflate> that are filehandles.
394
395If C<AutoClose> is specified, and the value is true, it will result in all
396input and/or output filehandles being closed once C<inflate> has
397completed.
398
399This parameter defaults to 0.
400
401=item C<< BinModeOut => 0|1 >>
402
403This option is now a no-op. All files will be written  in binmode.
404
405=item C<< Append => 0|1 >>
406
407The behaviour of this option is dependent on the type of output data
408stream.
409
410=over 5
411
412=item * A Buffer
413
414If C<Append> is enabled, all uncompressed data will be append to the end of
415the output buffer. Otherwise the output buffer will be cleared before any
416uncompressed data is written to it.
417
418=item * A Filename
419
420If C<Append> is enabled, the file will be opened in append mode. Otherwise
421the contents of the file, if any, will be truncated before any uncompressed
422data is written to it.
423
424=item * A Filehandle
425
426If C<Append> is enabled, the filehandle will be positioned to the end of
427the file via a call to C<seek> before any uncompressed data is
428written to it.  Otherwise the file pointer will not be moved.
429
430=back
431
432When C<Append> is specified, and set to true, it will I<append> all uncompressed
433data to the output data stream.
434
435So when the output is a filehandle it will carry out a seek to the eof
436before writing any uncompressed data. If the output is a filename, it will be opened for
437appending. If the output is a buffer, all uncompressed data will be
438appended to the existing buffer.
439
440Conversely when C<Append> is not specified, or it is present and is set to
441false, it will operate as follows.
442
443When the output is a filename, it will truncate the contents of the file
444before writing any uncompressed data. If the output is a filehandle
445its position will not be changed. If the output is a buffer, it will be
446wiped before any uncompressed data is output.
447
448Defaults to 0.
449
450=item C<< MultiStream => 0|1 >>
451
452If the input file/buffer contains multiple compressed data streams, this
453option will uncompress the whole lot as a single data stream.
454
455Defaults to 0.
456
457=item C<< TrailingData => $scalar >>
458
459Returns the data, if any, that is present immediately after the compressed
460data stream once uncompression is complete.
461
462This option can be used when there is useful information immediately
463following the compressed data stream, and you don't know the length of the
464compressed data stream.
465
466If the input is a buffer, C<trailingData> will return everything from the
467end of the compressed data stream to the end of the buffer.
468
469If the input is a filehandle, C<trailingData> will return the data that is
470left in the filehandle input buffer once the end of the compressed data
471stream has been reached. You can then use the filehandle to read the rest
472of the input file.
473
474Don't bother using C<trailingData> if the input is a filename.
475
476If you know the length of the compressed data stream before you start
477uncompressing, you can avoid having to use C<trailingData> by setting the
478C<InputLength> option.
479
480=back
481
482=head2 Examples
483
484To read the contents of the file C<file1.txt.1950> and write the
485uncompressed data to the file C<file1.txt>.
486
487    use strict ;
488    use warnings ;
489    use IO::Uncompress::Inflate qw(inflate $InflateError) ;
490
491    my $input = "file1.txt.1950";
492    my $output = "file1.txt";
493    inflate $input => $output
494        or die "inflate failed: $InflateError\n";
495
496To read from an existing Perl filehandle, C<$input>, and write the
497uncompressed data to a buffer, C<$buffer>.
498
499    use strict ;
500    use warnings ;
501    use IO::Uncompress::Inflate qw(inflate $InflateError) ;
502    use IO::File ;
503
504    my $input = IO::File->new( "<file1.txt.1950" )
505        or die "Cannot open 'file1.txt.1950': $!\n" ;
506    my $buffer ;
507    inflate $input => \$buffer
508        or die "inflate failed: $InflateError\n";
509
510To uncompress all files in the directory "/my/home" that match "*.txt.1950" and store the compressed data in the same directory
511
512    use strict ;
513    use warnings ;
514    use IO::Uncompress::Inflate qw(inflate $InflateError) ;
515
516    inflate '</my/home/*.txt.1950>' => '</my/home/#1.txt>'
517        or die "inflate failed: $InflateError\n";
518
519and if you want to compress each file one at a time, this will do the trick
520
521    use strict ;
522    use warnings ;
523    use IO::Uncompress::Inflate qw(inflate $InflateError) ;
524
525    for my $input ( glob "/my/home/*.txt.1950" )
526    {
527        my $output = $input;
528        $output =~ s/.1950// ;
529        inflate $input => $output
530            or die "Error compressing '$input': $InflateError\n";
531    }
532
533=head1 OO Interface
534
535=head2 Constructor
536
537The format of the constructor for IO::Uncompress::Inflate is shown below
538
539    my $z = IO::Uncompress::Inflate->new( $input [OPTS] )
540        or die "IO::Uncompress::Inflate failed: $InflateError\n";
541
542Returns an C<IO::Uncompress::Inflate> object on success and undef on failure.
543The variable C<$InflateError> will contain an error message on failure.
544
545If you are running Perl 5.005 or better the object, C<$z>, returned from
546IO::Uncompress::Inflate can be used exactly like an L<IO::File|IO::File> filehandle.
547This means that all normal input file operations can be carried out with
548C<$z>.  For example, to read a line from a compressed file/buffer you can
549use either of these forms
550
551    $line = $z->getline();
552    $line = <$z>;
553
554The mandatory parameter C<$input> is used to determine the source of the
555compressed data. This parameter can take one of three forms.
556
557=over 5
558
559=item A filename
560
561If the C<$input> parameter is a scalar, it is assumed to be a filename. This
562file will be opened for reading and the compressed data will be read from it.
563
564=item A filehandle
565
566If the C<$input> parameter is a filehandle, the compressed data will be
567read from it.
568The string '-' can be used as an alias for standard input.
569
570=item A scalar reference
571
572If C<$input> is a scalar reference, the compressed data will be read from
573C<$$input>.
574
575=back
576
577=head2 Constructor Options
578
579The option names defined below are case insensitive and can be optionally
580prefixed by a '-'.  So all of the following are valid
581
582    -AutoClose
583    -autoclose
584    AUTOCLOSE
585    autoclose
586
587OPTS is a combination of the following options:
588
589=over 5
590
591=item C<< AutoClose => 0|1 >>
592
593This option is only valid when the C<$input> parameter is a filehandle. If
594specified, and the value is true, it will result in the file being closed once
595either the C<close> method is called or the IO::Uncompress::Inflate object is
596destroyed.
597
598This parameter defaults to 0.
599
600=item C<< MultiStream => 0|1 >>
601
602Allows multiple concatenated compressed streams to be treated as a single
603compressed stream. Decompression will stop once either the end of the
604file/buffer is reached, an error is encountered (premature eof, corrupt
605compressed data) or the end of a stream is not immediately followed by the
606start of another stream.
607
608This parameter defaults to 0.
609
610=item C<< Prime => $string >>
611
612This option will uncompress the contents of C<$string> before processing the
613input file/buffer.
614
615This option can be useful when the compressed data is embedded in another
616file/data structure and it is not possible to work out where the compressed
617data begins without having to read the first few bytes. If this is the
618case, the uncompression can be I<primed> with these bytes using this
619option.
620
621=item C<< Transparent => 0|1 >>
622
623If this option is set and the input file/buffer is not compressed data,
624the module will allow reading of it anyway.
625
626In addition, if the input file/buffer does contain compressed data and
627there is non-compressed data immediately following it, setting this option
628will make this module treat the whole file/buffer as a single data stream.
629
630This option defaults to 1.
631
632=item C<< BlockSize => $num >>
633
634When reading the compressed input data, IO::Uncompress::Inflate will read it in
635blocks of C<$num> bytes.
636
637This option defaults to 4096.
638
639=item C<< InputLength => $size >>
640
641When present this option will limit the number of compressed bytes read
642from the input file/buffer to C<$size>. This option can be used in the
643situation where there is useful data directly after the compressed data
644stream and you know beforehand the exact length of the compressed data
645stream.
646
647This option is mostly used when reading from a filehandle, in which case
648the file pointer will be left pointing to the first byte directly after the
649compressed data stream.
650
651This option defaults to off.
652
653=item C<< Append => 0|1 >>
654
655This option controls what the C<read> method does with uncompressed data.
656
657If set to 1, all uncompressed data will be appended to the output parameter
658of the C<read> method.
659
660If set to 0, the contents of the output parameter of the C<read> method
661will be overwritten by the uncompressed data.
662
663Defaults to 0.
664
665=item C<< Strict => 0|1 >>
666
667This option controls whether the extra checks defined below are used when
668carrying out the decompression. When Strict is on, the extra tests are
669carried out, when Strict is off they are not.
670
671The default for this option is off.
672
673=over 5
674
675=item 1
676
677The ADLER32 checksum field must be present.
678
679=item 2
680
681The value of the ADLER32 field read must match the adler32 value of the
682uncompressed data actually contained in the file.
683
684=back
685
686=back
687
688=head2 Examples
689
690TODO
691
692=head1 Methods
693
694=head2 read
695
696Usage is
697
698    $status = $z->read($buffer)
699
700Reads a block of compressed data (the size of the compressed block is
701determined by the C<Buffer> option in the constructor), uncompresses it and
702writes any uncompressed data into C<$buffer>. If the C<Append> parameter is
703set in the constructor, the uncompressed data will be appended to the
704C<$buffer> parameter. Otherwise C<$buffer> will be overwritten.
705
706Returns the number of uncompressed bytes written to C<$buffer>, zero if eof
707or a negative number on error.
708
709=head2 read
710
711Usage is
712
713    $status = $z->read($buffer, $length)
714    $status = $z->read($buffer, $length, $offset)
715
716    $status = read($z, $buffer, $length)
717    $status = read($z, $buffer, $length, $offset)
718
719Attempt to read C<$length> bytes of uncompressed data into C<$buffer>.
720
721The main difference between this form of the C<read> method and the
722previous one, is that this one will attempt to return I<exactly> C<$length>
723bytes. The only circumstances that this function will not is if end-of-file
724or an IO error is encountered.
725
726Returns the number of uncompressed bytes written to C<$buffer>, zero if eof
727or a negative number on error.
728
729=head2 getline
730
731Usage is
732
733    $line = $z->getline()
734    $line = <$z>
735
736Reads a single line.
737
738This method fully supports the use of the variable C<$/> (or
739C<$INPUT_RECORD_SEPARATOR> or C<$RS> when C<English> is in use) to
740determine what constitutes an end of line. Paragraph mode, record mode and
741file slurp mode are all supported.
742
743=head2 getc
744
745Usage is
746
747    $char = $z->getc()
748
749Read a single character.
750
751=head2 ungetc
752
753Usage is
754
755    $char = $z->ungetc($string)
756
757=head2 inflateSync
758
759Usage is
760
761    $status = $z->inflateSync()
762
763TODO
764
765=head2 getHeaderInfo
766
767Usage is
768
769    $hdr  = $z->getHeaderInfo();
770    @hdrs = $z->getHeaderInfo();
771
772This method returns either a hash reference (in scalar context) or a list
773or hash references (in array context) that contains information about each
774of the header fields in the compressed data stream(s).
775
776=head2 tell
777
778Usage is
779
780    $z->tell()
781    tell $z
782
783Returns the uncompressed file offset.
784
785=head2 eof
786
787Usage is
788
789    $z->eof();
790    eof($z);
791
792Returns true if the end of the compressed input stream has been reached.
793
794=head2 seek
795
796    $z->seek($position, $whence);
797    seek($z, $position, $whence);
798
799Provides a sub-set of the C<seek> functionality, with the restriction
800that it is only legal to seek forward in the input file/buffer.
801It is a fatal error to attempt to seek backward.
802
803Note that the implementation of C<seek> in this module does not provide
804true random access to a compressed file/buffer. It  works by uncompressing
805data from the current offset in the file/buffer until it reaches the
806uncompressed offset specified in the parameters to C<seek>. For very small
807files this may be acceptable behaviour. For large files it may cause an
808unacceptable delay.
809
810The C<$whence> parameter takes one the usual values, namely SEEK_SET,
811SEEK_CUR or SEEK_END.
812
813Returns 1 on success, 0 on failure.
814
815=head2 binmode
816
817Usage is
818
819    $z->binmode
820    binmode $z ;
821
822This is a noop provided for completeness.
823
824=head2 opened
825
826    $z->opened()
827
828Returns true if the object currently refers to a opened file/buffer.
829
830=head2 autoflush
831
832    my $prev = $z->autoflush()
833    my $prev = $z->autoflush(EXPR)
834
835If the C<$z> object is associated with a file or a filehandle, this method
836returns the current autoflush setting for the underlying filehandle. If
837C<EXPR> is present, and is non-zero, it will enable flushing after every
838write/print operation.
839
840If C<$z> is associated with a buffer, this method has no effect and always
841returns C<undef>.
842
843B<Note> that the special variable C<$|> B<cannot> be used to set or
844retrieve the autoflush setting.
845
846=head2 input_line_number
847
848    $z->input_line_number()
849    $z->input_line_number(EXPR)
850
851Returns the current uncompressed line number. If C<EXPR> is present it has
852the effect of setting the line number. Note that setting the line number
853does not change the current position within the file/buffer being read.
854
855The contents of C<$/> are used to determine what constitutes a line
856terminator.
857
858=head2 fileno
859
860    $z->fileno()
861    fileno($z)
862
863If the C<$z> object is associated with a file or a filehandle, C<fileno>
864will return the underlying file descriptor. Once the C<close> method is
865called C<fileno> will return C<undef>.
866
867If the C<$z> object is associated with a buffer, this method will return
868C<undef>.
869
870=head2 close
871
872    $z->close() ;
873    close $z ;
874
875Closes the output file/buffer.
876
877For most versions of Perl this method will be automatically invoked if
878the IO::Uncompress::Inflate object is destroyed (either explicitly or by the
879variable with the reference to the object going out of scope). The
880exceptions are Perl versions 5.005 through 5.00504 and 5.8.0. In
881these cases, the C<close> method will be called automatically, but
882not until global destruction of all live objects when the program is
883terminating.
884
885Therefore, if you want your scripts to be able to run on all versions
886of Perl, you should call C<close> explicitly and not rely on automatic
887closing.
888
889Returns true on success, otherwise 0.
890
891If the C<AutoClose> option has been enabled when the IO::Uncompress::Inflate
892object was created, and the object is associated with a file, the
893underlying file will also be closed.
894
895=head2 nextStream
896
897Usage is
898
899    my $status = $z->nextStream();
900
901Skips to the next compressed data stream in the input file/buffer. If a new
902compressed data stream is found, the eof marker will be cleared and C<$.>
903will be reset to 0.
904
905Returns 1 if a new stream was found, 0 if none was found, and -1 if an
906error was encountered.
907
908=head2 trailingData
909
910Usage is
911
912    my $data = $z->trailingData();
913
914Returns the data, if any, that is present immediately after the compressed
915data stream once uncompression is complete. It only makes sense to call
916this method once the end of the compressed data stream has been
917encountered.
918
919This option can be used when there is useful information immediately
920following the compressed data stream, and you don't know the length of the
921compressed data stream.
922
923If the input is a buffer, C<trailingData> will return everything from the
924end of the compressed data stream to the end of the buffer.
925
926If the input is a filehandle, C<trailingData> will return the data that is
927left in the filehandle input buffer once the end of the compressed data
928stream has been reached. You can then use the filehandle to read the rest
929of the input file.
930
931Don't bother using C<trailingData> if the input is a filename.
932
933If you know the length of the compressed data stream before you start
934uncompressing, you can avoid having to use C<trailingData> by setting the
935C<InputLength> option in the constructor.
936
937=head1 Importing
938
939No symbolic constants are required by IO::Uncompress::Inflate at present.
940
941=over 5
942
943=item :all
944
945Imports C<inflate> and C<$InflateError>.
946Same as doing this
947
948    use IO::Uncompress::Inflate qw(inflate $InflateError) ;
949
950=back
951
952=head1 EXAMPLES
953
954=head2 Working with Net::FTP
955
956See L<IO::Compress::FAQ|IO::Compress::FAQ/"Compressed files and Net::FTP">
957
958=head1 SUPPORT
959
960General feedback/questions/bug reports should be sent to
961L<https://github.com/pmqs/IO-Compress/issues> (preferred) or
962L<https://rt.cpan.org/Public/Dist/Display.html?Name=IO-Compress>.
963
964=head1 SEE ALSO
965
966L<Compress::Zlib>, L<IO::Compress::Gzip>, L<IO::Uncompress::Gunzip>, L<IO::Compress::Deflate>, L<IO::Compress::RawDeflate>, 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::Lzip>, L<IO::Uncompress::UnLzip>, L<IO::Compress::Lzop>, L<IO::Uncompress::UnLzop>, L<IO::Compress::Lzf>, L<IO::Uncompress::UnLzf>, L<IO::Compress::Zstd>, L<IO::Uncompress::UnZstd>, L<IO::Uncompress::AnyInflate>, L<IO::Uncompress::AnyUncompress>
967
968L<IO::Compress::FAQ|IO::Compress::FAQ>
969
970L<File::GlobMapper|File::GlobMapper>, L<Archive::Zip|Archive::Zip>,
971L<Archive::Tar|Archive::Tar>,
972L<IO::Zlib|IO::Zlib>
973
974For RFC 1950, 1951 and 1952 see
975L<https://datatracker.ietf.org/doc/html/rfc1950>,
976L<https://datatracker.ietf.org/doc/html/rfc1951> and
977L<https://datatracker.ietf.org/doc/html/rfc1952>
978
979The I<zlib> compression library was written by Jean-loup Gailly
980C<gzip@prep.ai.mit.edu> and Mark Adler C<madler@alumni.caltech.edu>.
981
982The primary site for the I<zlib> compression library is
983L<http://www.zlib.org>.
984
985The primary site for the I<zlib-ng> compression library is
986L<https://github.com/zlib-ng/zlib-ng>.
987
988The primary site for gzip is L<http://www.gzip.org>.
989
990=head1 AUTHOR
991
992This module was written by Paul Marquess, C<pmqs@cpan.org>.
993
994=head1 MODIFICATION HISTORY
995
996See the Changes file.
997
998=head1 COPYRIGHT AND LICENSE
999
1000Copyright (c) 2005-2023 Paul Marquess. All rights reserved.
1001
1002This program is free software; you can redistribute it and/or
1003modify it under the same terms as Perl itself.
1004