Merge branch 'vincent/rvalue_stmt_given' into blead
[p5sagit/p5-mst-13.2.git] / cpan / IO-Compress / lib / IO / Uncompress / Inflate.pm
CommitLineData
642e522c 1package IO::Uncompress::Inflate ;
2# for RFC1950
3
4use strict ;
5use warnings;
a02d0f6f 6use bytes;
642e522c 7
9b5fd1d4 8use IO::Compress::Base::Common 2.024 qw(:Status createSelfTiedObject);
9use IO::Compress::Zlib::Constants 2.024 ;
1a6a8453 10
9b5fd1d4 11use IO::Uncompress::RawInflate 2.024 ;
642e522c 12
13require Exporter ;
14our ($VERSION, @ISA, @EXPORT_OK, %EXPORT_TAGS, $InflateError);
15
9b5fd1d4 16$VERSION = '2.024';
642e522c 17$InflateError = '';
18
1a6a8453 19@ISA = qw( Exporter IO::Uncompress::RawInflate );
642e522c 20@EXPORT_OK = qw( $InflateError inflate ) ;
1a6a8453 21%EXPORT_TAGS = %IO::Uncompress::RawInflate::DEFLATE_CONSTANTS ;
642e522c 22push @{ $EXPORT_TAGS{all} }, @EXPORT_OK ;
23Exporter::export_ok_tags('all');
24
25
26sub new
27{
1a6a8453 28 my $class = shift ;
29 my $obj = createSelfTiedObject($class, \$InflateError);
30
31 $obj->_create(undef, 0, @_);
642e522c 32}
33
34sub inflate
35{
1a6a8453 36 my $obj = 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->value('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
258133d1 69 #return $self->HeaderError("CRC mismatch.")
70 return undef
71 if ! $self->isZlibMagic($magic) ;
1a6a8453 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
a02d0f6f 95 return STATUS_OK;
1a6a8453 96}
97
98
99
100sub isZlibMagic
101{
258133d1 102 my $self = shift;
1a6a8453 103 my $buffer = shift ;
258133d1 104
105 return 0
106 if length $buffer < ZLIB_HEADER_SIZE ;
107
1a6a8453 108 my $hdr = unpack("n", $buffer) ;
258133d1 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;
642e522c 127}
128
1a6a8453 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
642e522c 1951 ;
196
197__END__
198
199
200=head1 NAME
201
cb7abd7f 202IO::Uncompress::Inflate - Read RFC 1950 files/buffers
203
642e522c 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 = new IO::Uncompress::Inflate $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()
a02d0f6f 220 $char = $z->opened()
221
642e522c 222 $status = $z->inflateSync()
a02d0f6f 223
e7d45986 224 $data = $z->trailingData()
225 $status = $z->nextStream()
642e522c 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
642e522c 249=head1 DESCRIPTION
250
1a6a8453 251This module provides a Perl interface that allows the reading of
642e522c 252files/buffers that conform to RFC 1950.
253
1a6a8453 254For writing RFC 1950 files/buffers, see the companion module IO::Compress::Deflate.
642e522c 255
642e522c 256=head1 Functional Interface
257
1a6a8453 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.
642e522c 262
263 use IO::Uncompress::Inflate qw(inflate $InflateError) ;
264
265 inflate $input => $output [,OPTS]
266 or die "inflate failed: $InflateError\n";
267
642e522c 268The functional interface needs Perl5.005 or better.
269
642e522c 270=head2 inflate $input => $output [, OPTS]
271
1a6a8453 272C<inflate> expects at least two parameters, C<$input> and C<$output>.
642e522c 273
274=head3 The C<$input> parameter
275
276The parameter, C<$input>, is used to define the source of
277the compressed data.
278
279It can take one of the following forms:
280
281=over 5
282
283=item A filename
284
285If the C<$input> parameter is a simple scalar, it is assumed to be a
286filename. This file will be opened for reading and the input data
287will be read from it.
288
289=item A filehandle
290
291If the C<$input> parameter is a filehandle, the input data will be
292read from it.
293The string '-' can be used as an alias for standard input.
294
295=item A scalar reference
296
297If C<$input> is a scalar reference, the input data will be read
298from C<$$input>.
299
300=item An array reference
301
1a6a8453 302If C<$input> is an array reference, each element in the array must be a
303filename.
304
305The input data will be read from each file in turn.
306
642e522c 307The complete array will be walked to ensure that it only
1a6a8453 308contains valid filenames before any data is uncompressed.
309
642e522c 310=item An Input FileGlob string
311
312If C<$input> is a string that is delimited by the characters "<" and ">"
313C<inflate> will assume that it is an I<input fileglob string>. The
314input is the list of files that match the fileglob.
315
316If the fileglob does not match any files ...
317
318See L<File::GlobMapper|File::GlobMapper> for more details.
319
642e522c 320=back
321
322If the C<$input> parameter is any other type, C<undef> will be returned.
323
642e522c 324=head3 The C<$output> parameter
325
326The parameter C<$output> is used to control the destination of the
327uncompressed data. This parameter can take one of these forms.
328
329=over 5
330
331=item A filename
332
1a6a8453 333If the C<$output> parameter is a simple scalar, it is assumed to be a
334filename. This file will be opened for writing and the uncompressed
335data will be written to it.
642e522c 336
337=item A filehandle
338
1a6a8453 339If the C<$output> parameter is a filehandle, the uncompressed data
340will be written to it.
642e522c 341The string '-' can be used as an alias for standard output.
342
642e522c 343=item A scalar reference
344
1a6a8453 345If C<$output> is a scalar reference, the uncompressed data will be
346stored in C<$$output>.
642e522c 347
642e522c 348=item An Array Reference
349
1a6a8453 350If C<$output> is an array reference, the uncompressed data will be
351pushed onto the array.
642e522c 352
353=item An Output FileGlob
354
355If C<$output> is a string that is delimited by the characters "<" and ">"
356C<inflate> will assume that it is an I<output fileglob string>. The
357output is the list of files that match the fileglob.
358
359When C<$output> is an fileglob string, C<$input> must also be a fileglob
360string. Anything else is an error.
361
362=back
363
364If the C<$output> parameter is any other type, C<undef> will be returned.
365
642e522c 366=head2 Notes
367
c70c1701 368When C<$input> maps to multiple compressed files/buffers and C<$output> is
369a single file/buffer, after uncompression C<$output> will contain a
370concatenation of all the uncompressed data from each of the input
371files/buffers.
372
642e522c 373=head2 Optional Parameters
374
375Unless specified below, the optional parameters for C<inflate>,
376C<OPTS>, are the same as those used with the OO interface defined in the
377L</"Constructor Options"> section below.
378
379=over 5
380
e7d45986 381=item C<< AutoClose => 0|1 >>
642e522c 382
1a6a8453 383This option applies to any input or output data streams to
384C<inflate> that are filehandles.
642e522c 385
386If C<AutoClose> is specified, and the value is true, it will result in all
387input and/or output filehandles being closed once C<inflate> has
388completed.
389
390This parameter defaults to 0.
391
e7d45986 392=item C<< BinModeOut => 0|1 >>
1a6a8453 393
394When writing to a file or filehandle, set C<binmode> before writing to the
395file.
396
397Defaults to 0.
398
e7d45986 399=item C<< Append => 0|1 >>
642e522c 400
9b5fd1d4 401The behaviour of this option is dependent on the type of output data
402stream.
403
404=over 5
405
406=item * A Buffer
407
408If C<Append> is enabled, all uncompressed data will be append to the end of
409the output buffer. Otherwise the output buffer will be cleared before any
410uncompressed data is written to it.
411
412=item * A Filename
413
414If C<Append> is enabled, the file will be opened in append mode. Otherwise
415the contents of the file, if any, will be truncated before any uncompressed
416data is written to it.
417
418=item * A Filehandle
419
420If C<Append> is enabled, the filehandle will be positioned to the end of
421the file via a call to C<seek> before any uncompressed data is
422written to it. Otherwise the file pointer will not be moved.
423
424=back
425
426When C<Append> is specified, and set to true, it will I<append> all uncompressed
427data to the output data stream.
428
429So when the output is a filehandle it will carry out a seek to the eof
430before writing any uncompressed data. If the output is a filename, it will be opened for
431appending. If the output is a buffer, all uncompressed data will be appened to
432the existing buffer.
433
434Conversely when C<Append> is not specified, or it is present and is set to
435false, it will operate as follows.
436
437When the output is a filename, it will truncate the contents of the file
438before writing any uncompressed data. If the output is a filehandle
439its position will not be changed. If the output is a buffer, it will be
440wiped before any uncompressed data is output.
441
442Defaults to 0.
642e522c 443
e7d45986 444=item C<< MultiStream => 0|1 >>
1a6a8453 445
e7d45986 446If the input file/buffer contains multiple compressed data streams, this
447option will uncompress the whole lot as a single data stream.
1a6a8453 448
e7d45986 449Defaults to 0.
1a6a8453 450
258133d1 451=item C<< TrailingData => $scalar >>
452
453Returns the data, if any, that is present immediately after the compressed
454data stream once uncompression is complete.
455
456This option can be used when there is useful information immediately
457following the compressed data stream, and you don't know the length of the
458compressed data stream.
459
460If the input is a buffer, C<trailingData> will return everything from the
461end of the compressed data stream to the end of the buffer.
462
463If the input is a filehandle, C<trailingData> will return the data that is
464left in the filehandle input buffer once the end of the compressed data
465stream has been reached. You can then use the filehandle to read the rest
466of the input file.
467
468Don't bother using C<trailingData> if the input is a filename.
469
258133d1 470If you know the length of the compressed data stream before you start
471uncompressing, you can avoid having to use C<trailingData> by setting the
472C<InputLength> option.
473
642e522c 474=back
475
642e522c 476=head2 Examples
477
478To read the contents of the file C<file1.txt.1950> and write the
10c2b2bb 479uncompressed data to the file C<file1.txt>.
642e522c 480
481 use strict ;
482 use warnings ;
483 use IO::Uncompress::Inflate qw(inflate $InflateError) ;
484
485 my $input = "file1.txt.1950";
486 my $output = "file1.txt";
487 inflate $input => $output
488 or die "inflate failed: $InflateError\n";
489
642e522c 490To read from an existing Perl filehandle, C<$input>, and write the
491uncompressed data to a buffer, C<$buffer>.
492
493 use strict ;
494 use warnings ;
495 use IO::Uncompress::Inflate qw(inflate $InflateError) ;
496 use IO::File ;
497
498 my $input = new IO::File "<file1.txt.1950"
499 or die "Cannot open 'file1.txt.1950': $!\n" ;
500 my $buffer ;
501 inflate $input => \$buffer
502 or die "inflate failed: $InflateError\n";
503
504To uncompress all files in the directory "/my/home" that match "*.txt.1950" and store the compressed data in the same directory
505
506 use strict ;
507 use warnings ;
508 use IO::Uncompress::Inflate qw(inflate $InflateError) ;
509
510 inflate '</my/home/*.txt.1950>' => '</my/home/#1.txt>'
511 or die "inflate failed: $InflateError\n";
512
513and if you want to compress each file one at a time, this will do the trick
514
515 use strict ;
516 use warnings ;
517 use IO::Uncompress::Inflate qw(inflate $InflateError) ;
518
519 for my $input ( glob "/my/home/*.txt.1950" )
520 {
521 my $output = $input;
522 $output =~ s/.1950// ;
523 inflate $input => $output
524 or die "Error compressing '$input': $InflateError\n";
525 }
526
527=head1 OO Interface
528
529=head2 Constructor
530
531The format of the constructor for IO::Uncompress::Inflate is shown below
532
642e522c 533 my $z = new IO::Uncompress::Inflate $input [OPTS]
534 or die "IO::Uncompress::Inflate failed: $InflateError\n";
535
536Returns an C<IO::Uncompress::Inflate> object on success and undef on failure.
537The variable C<$InflateError> will contain an error message on failure.
538
1a6a8453 539If you are running Perl 5.005 or better the object, C<$z>, returned from
540IO::Uncompress::Inflate can be used exactly like an L<IO::File|IO::File> filehandle.
541This means that all normal input file operations can be carried out with
542C<$z>. For example, to read a line from a compressed file/buffer you can
543use either of these forms
642e522c 544
545 $line = $z->getline();
546 $line = <$z>;
547
548The mandatory parameter C<$input> is used to determine the source of the
549compressed data. This parameter can take one of three forms.
550
551=over 5
552
553=item A filename
554
555If the C<$input> parameter is a scalar, it is assumed to be a filename. This
556file will be opened for reading and the compressed data will be read from it.
557
558=item A filehandle
559
560If the C<$input> parameter is a filehandle, the compressed data will be
561read from it.
562The string '-' can be used as an alias for standard input.
563
642e522c 564=item A scalar reference
565
566If C<$input> is a scalar reference, the compressed data will be read from
567C<$$output>.
568
569=back
570
571=head2 Constructor Options
572
642e522c 573The option names defined below are case insensitive and can be optionally
574prefixed by a '-'. So all of the following are valid
575
576 -AutoClose
577 -autoclose
578 AUTOCLOSE
579 autoclose
580
581OPTS is a combination of the following options:
582
583=over 5
584
e7d45986 585=item C<< AutoClose => 0|1 >>
642e522c 586
587This option is only valid when the C<$input> parameter is a filehandle. If
588specified, and the value is true, it will result in the file being closed once
589either the C<close> method is called or the IO::Uncompress::Inflate object is
590destroyed.
591
592This parameter defaults to 0.
593
e7d45986 594=item C<< MultiStream => 0|1 >>
642e522c 595
642e522c 596Allows multiple concatenated compressed streams to be treated as a single
597compressed stream. Decompression will stop once either the end of the
598file/buffer is reached, an error is encountered (premature eof, corrupt
599compressed data) or the end of a stream is not immediately followed by the
600start of another stream.
601
602This parameter defaults to 0.
603
e7d45986 604=item C<< Prime => $string >>
642e522c 605
606This option will uncompress the contents of C<$string> before processing the
607input file/buffer.
608
609This option can be useful when the compressed data is embedded in another
610file/data structure and it is not possible to work out where the compressed
1a6a8453 611data begins without having to read the first few bytes. If this is the
612case, the uncompression can be I<primed> with these bytes using this
613option.
642e522c 614
e7d45986 615=item C<< Transparent => 0|1 >>
642e522c 616
f6fd7794 617If this option is set and the input file/buffer is not compressed data,
642e522c 618the module will allow reading of it anyway.
619
f6fd7794 620In addition, if the input file/buffer does contain compressed data and
621there is non-compressed data immediately following it, setting this option
622will make this module treat the whole file/bufffer as a single data stream.
623
642e522c 624This option defaults to 1.
625
e7d45986 626=item C<< BlockSize => $num >>
642e522c 627
1a6a8453 628When reading the compressed input data, IO::Uncompress::Inflate will read it in
629blocks of C<$num> bytes.
642e522c 630
631This option defaults to 4096.
632
e7d45986 633=item C<< InputLength => $size >>
642e522c 634
1a6a8453 635When present this option will limit the number of compressed bytes read
636from the input file/buffer to C<$size>. This option can be used in the
637situation where there is useful data directly after the compressed data
638stream and you know beforehand the exact length of the compressed data
639stream.
642e522c 640
1a6a8453 641This option is mostly used when reading from a filehandle, in which case
642the file pointer will be left pointing to the first byte directly after the
642e522c 643compressed data stream.
644
642e522c 645This option defaults to off.
646
e7d45986 647=item C<< Append => 0|1 >>
642e522c 648
649This option controls what the C<read> method does with uncompressed data.
650
1a6a8453 651If set to 1, all uncompressed data will be appended to the output parameter
652of the C<read> method.
642e522c 653
1a6a8453 654If set to 0, the contents of the output parameter of the C<read> method
655will be overwritten by the uncompressed data.
642e522c 656
657Defaults to 0.
658
e7d45986 659=item C<< Strict => 0|1 >>
642e522c 660
642e522c 661This option controls whether the extra checks defined below are used when
1a6a8453 662carrying out the decompression. When Strict is on, the extra tests are
663carried out, when Strict is off they are not.
642e522c 664
665The default for this option is off.
666
642e522c 667=over 5
668
669=item 1
670
671The ADLER32 checksum field must be present.
672
673=item 2
674
675The value of the ADLER32 field read must match the adler32 value of the
676uncompressed data actually contained in the file.
677
678=back
679
642e522c 680=back
681
682=head2 Examples
683
684TODO
685
686=head1 Methods
687
688=head2 read
689
690Usage is
691
692 $status = $z->read($buffer)
693
694Reads a block of compressed data (the size the the compressed block is
695determined by the C<Buffer> option in the constructor), uncompresses it and
1a6a8453 696writes any uncompressed data into C<$buffer>. If the C<Append> parameter is
697set in the constructor, the uncompressed data will be appended to the
698C<$buffer> parameter. Otherwise C<$buffer> will be overwritten.
642e522c 699
1a6a8453 700Returns the number of uncompressed bytes written to C<$buffer>, zero if eof
701or a negative number on error.
642e522c 702
703=head2 read
704
705Usage is
706
707 $status = $z->read($buffer, $length)
708 $status = $z->read($buffer, $length, $offset)
709
710 $status = read($z, $buffer, $length)
711 $status = read($z, $buffer, $length, $offset)
712
713Attempt to read C<$length> bytes of uncompressed data into C<$buffer>.
714
1a6a8453 715The main difference between this form of the C<read> method and the
716previous one, is that this one will attempt to return I<exactly> C<$length>
717bytes. The only circumstances that this function will not is if end-of-file
718or an IO error is encountered.
642e522c 719
1a6a8453 720Returns the number of uncompressed bytes written to C<$buffer>, zero if eof
721or a negative number on error.
642e522c 722
642e522c 723=head2 getline
724
725Usage is
726
727 $line = $z->getline()
728 $line = <$z>
729
730Reads a single line.
731
258133d1 732This method fully supports the use of of the variable C<$/> (or
733C<$INPUT_RECORD_SEPARATOR> or C<$RS> when C<English> is in use) to
734determine what constitutes an end of line. Paragraph mode, record mode and
735file slurp mode are all supported.
642e522c 736
642e522c 737=head2 getc
738
739Usage is
740
741 $char = $z->getc()
742
743Read a single character.
744
745=head2 ungetc
746
747Usage is
748
749 $char = $z->ungetc($string)
750
642e522c 751=head2 inflateSync
752
753Usage is
754
755 $status = $z->inflateSync()
756
757TODO
758
759=head2 getHeaderInfo
760
761Usage is
762
1a6a8453 763 $hdr = $z->getHeaderInfo();
764 @hdrs = $z->getHeaderInfo();
642e522c 765
1a6a8453 766This method returns either a hash reference (in scalar context) or a list
767or hash references (in array context) that contains information about each
768of the header fields in the compressed data stream(s).
642e522c 769
642e522c 770=head2 tell
771
772Usage is
773
774 $z->tell()
775 tell $z
776
777Returns the uncompressed file offset.
778
779=head2 eof
780
781Usage is
782
783 $z->eof();
784 eof($z);
785
642e522c 786Returns true if the end of the compressed input stream has been reached.
787
642e522c 788=head2 seek
789
790 $z->seek($position, $whence);
791 seek($z, $position, $whence);
792
642e522c 793Provides a sub-set of the C<seek> functionality, with the restriction
794that it is only legal to seek forward in the input file/buffer.
795It is a fatal error to attempt to seek backward.
796
642e522c 797The C<$whence> parameter takes one the usual values, namely SEEK_SET,
798SEEK_CUR or SEEK_END.
799
800Returns 1 on success, 0 on failure.
801
802=head2 binmode
803
804Usage is
805
806 $z->binmode
807 binmode $z ;
808
809This is a noop provided for completeness.
810
a02d0f6f 811=head2 opened
812
813 $z->opened()
814
815Returns true if the object currently refers to a opened file/buffer.
816
817=head2 autoflush
818
819 my $prev = $z->autoflush()
820 my $prev = $z->autoflush(EXPR)
821
822If the C<$z> object is associated with a file or a filehandle, this method
823returns the current autoflush setting for the underlying filehandle. If
824C<EXPR> is present, and is non-zero, it will enable flushing after every
825write/print operation.
826
827If C<$z> is associated with a buffer, this method has no effect and always
828returns C<undef>.
829
830B<Note> that the special variable C<$|> B<cannot> be used to set or
831retrieve the autoflush setting.
832
833=head2 input_line_number
834
835 $z->input_line_number()
836 $z->input_line_number(EXPR)
837
a02d0f6f 838Returns the current uncompressed line number. If C<EXPR> is present it has
839the effect of setting the line number. Note that setting the line number
840does not change the current position within the file/buffer being read.
841
842The contents of C<$/> are used to to determine what constitutes a line
843terminator.
844
642e522c 845=head2 fileno
846
847 $z->fileno()
848 fileno($z)
849
d54256af 850If the C<$z> object is associated with a file or a filehandle, C<fileno>
851will return the underlying file descriptor. Once the C<close> method is
852called C<fileno> will return C<undef>.
642e522c 853
d54256af 854If the C<$z> object is is associated with a buffer, this method will return
855C<undef>.
642e522c 856
857=head2 close
858
859 $z->close() ;
860 close $z ;
861
642e522c 862Closes the output file/buffer.
863
642e522c 864For most versions of Perl this method will be automatically invoked if
865the IO::Uncompress::Inflate object is destroyed (either explicitly or by the
866variable with the reference to the object going out of scope). The
867exceptions are Perl versions 5.005 through 5.00504 and 5.8.0. In
868these cases, the C<close> method will be called automatically, but
869not until global destruction of all live objects when the program is
870terminating.
871
872Therefore, if you want your scripts to be able to run on all versions
873of Perl, you should call C<close> explicitly and not rely on automatic
874closing.
875
876Returns true on success, otherwise 0.
877
878If the C<AutoClose> option has been enabled when the IO::Uncompress::Inflate
879object was created, and the object is associated with a file, the
880underlying file will also be closed.
881
e7d45986 882=head2 nextStream
883
884Usage is
885
886 my $status = $z->nextStream();
887
888Skips to the next compressed data stream in the input file/buffer. If a new
258133d1 889compressed data stream is found, the eof marker will be cleared and C<$.>
890will be reset to 0.
e7d45986 891
892Returns 1 if a new stream was found, 0 if none was found, and -1 if an
893error was encountered.
894
895=head2 trailingData
896
897Usage is
898
899 my $data = $z->trailingData();
900
258133d1 901Returns the data, if any, that is present immediately after the compressed
902data stream once uncompression is complete. It only makes sense to call
903this method once the end of the compressed data stream has been
904encountered.
905
906This option can be used when there is useful information immediately
907following the compressed data stream, and you don't know the length of the
908compressed data stream.
909
910If the input is a buffer, C<trailingData> will return everything from the
911end of the compressed data stream to the end of the buffer.
912
913If the input is a filehandle, C<trailingData> will return the data that is
914left in the filehandle input buffer once the end of the compressed data
915stream has been reached. You can then use the filehandle to read the rest
916of the input file.
917
918Don't bother using C<trailingData> if the input is a filename.
919
258133d1 920If you know the length of the compressed data stream before you start
921uncompressing, you can avoid having to use C<trailingData> by setting the
922C<InputLength> option in the constructor.
e7d45986 923
642e522c 924=head1 Importing
925
926No symbolic constants are required by this IO::Uncompress::Inflate at present.
927
928=over 5
929
930=item :all
931
932Imports C<inflate> and C<$InflateError>.
933Same as doing this
934
935 use IO::Uncompress::Inflate qw(inflate $InflateError) ;
936
937=back
938
939=head1 EXAMPLES
940
d54256af 941=head2 Working with Net::FTP
642e522c 942
d54256af 943See L<IO::Uncompress::Inflate::FAQ|IO::Uncompress::Inflate::FAQ/"Compressed files and Net::FTP">
642e522c 944
945=head1 SEE ALSO
946
9b5fd1d4 947L<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::Lzop>, L<IO::Uncompress::UnLzop>, L<IO::Compress::Lzf>, L<IO::Uncompress::UnLzf>, L<IO::Uncompress::AnyInflate>, L<IO::Uncompress::AnyUncompress>
642e522c 948
949L<Compress::Zlib::FAQ|Compress::Zlib::FAQ>
950
a02d0f6f 951L<File::GlobMapper|File::GlobMapper>, L<Archive::Zip|Archive::Zip>,
952L<Archive::Tar|Archive::Tar>,
642e522c 953L<IO::Zlib|IO::Zlib>
954
955For RFC 1950, 1951 and 1952 see
956F<http://www.faqs.org/rfcs/rfc1950.html>,
957F<http://www.faqs.org/rfcs/rfc1951.html> and
958F<http://www.faqs.org/rfcs/rfc1952.html>
959
a02d0f6f 960The I<zlib> compression library was written by Jean-loup Gailly
961F<gzip@prep.ai.mit.edu> and Mark Adler F<madler@alumni.caltech.edu>.
962
963The primary site for the I<zlib> compression library is
964F<http://www.zlib.org>.
965
966The primary site for gzip is F<http://www.gzip.org>.
967
642e522c 968=head1 AUTHOR
969
cb7abd7f 970This module was written by Paul Marquess, F<pmqs@cpan.org>.
642e522c 971
642e522c 972=head1 MODIFICATION HISTORY
973
974See the Changes file.
975
976=head1 COPYRIGHT AND LICENSE
642e522c 977
9b5fd1d4 978Copyright (c) 2005-2010 Paul Marquess. All rights reserved.
a02d0f6f 979
642e522c 980This program is free software; you can redistribute it and/or
981modify it under the same terms as Perl itself.
982