IO::Uncompress::RawInflate(3pm)

1IO::Uncompress::RawInflUasteer(3C)ontributed Perl DocumeInOt:a:tUinocnompress::RawInflate(3)
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NAME

6       IO::Uncompress::RawInflate - Read RFC 1951 files/buffers
7

SYNOPSIS

9           use IO::Uncompress::RawInflate qw(rawinflate $RawInflateError) ;
10
11           my $status = rawinflate $input => $output [,OPTS]
12               or die "rawinflate failed: $RawInflateError\n";
13
14           my $z = IO::Uncompress::RawInflate->new( $input [OPTS] )
15               or die "rawinflate failed: $RawInflateError\n";
16
17           $status = $z->read($buffer)
18           $status = $z->read($buffer, $length)
19           $status = $z->read($buffer, $length, $offset)
20           $line = $z->getline()
21           $char = $z->getc()
22           $char = $z->ungetc()
23           $char = $z->opened()
24
25           $status = $z->inflateSync()
26
27           $data = $z->trailingData()
28           $status = $z->nextStream()
29           $data = $z->getHeaderInfo()
30           $z->tell()
31           $z->seek($position, $whence)
32           $z->binmode()
33           $z->fileno()
34           $z->eof()
35           $z->close()
36
37           $RawInflateError ;
38
39           # IO::File mode
40
41           <$z>
42           read($z, $buffer);
43           read($z, $buffer, $length);
44           read($z, $buffer, $length, $offset);
45           tell($z)
46           seek($z, $position, $whence)
47           binmode($z)
48           fileno($z)
49           eof($z)
50           close($z)
51

DESCRIPTION

53       This module provides a Perl interface that allows the reading of
54       files/buffers that conform to RFC 1951.
55
56       For writing RFC 1951 files/buffers, see the companion module
57       IO::Compress::RawDeflate.
58

Functional Interface

60       A top-level function, "rawinflate", is provided to carry out "one-shot"
61       uncompression between buffers and/or files. For finer control over the
62       uncompression process, see the "OO Interface" section.
63
64           use IO::Uncompress::RawInflate qw(rawinflate $RawInflateError) ;
65
66           rawinflate $input_filename_or_reference => $output_filename_or_reference [,OPTS]
67               or die "rawinflate failed: $RawInflateError\n";
68
69       The functional interface needs Perl5.005 or better.
70
71   rawinflate $input_filename_or_reference => $output_filename_or_reference [,
72       OPTS]
73       "rawinflate" expects at least two parameters,
74       $input_filename_or_reference and $output_filename_or_reference and zero
75       or more optional parameters (see "Optional Parameters")
76
77       The $input_filename_or_reference parameter
78
79       The parameter, $input_filename_or_reference, is used to define the
80       source of the compressed data.
81
82       It can take one of the following forms:
83
84       A filename
85            If the $input_filename_or_reference parameter is a simple scalar,
86            it is assumed to be a filename. This file will be opened for
87            reading and the input data will be read from it.
88
89       A filehandle
90            If the $input_filename_or_reference parameter is a filehandle, the
91            input data will be read from it.  The string '-' can be used as an
92            alias for standard input.
93
94       A scalar reference
95            If $input_filename_or_reference is a scalar reference, the input
96            data will be read from $$input_filename_or_reference.
97
98       An array reference
99            If $input_filename_or_reference is an array reference, each
100            element in the array must be a filename.
101
102            The input data will be read from each file in turn.
103
104            The complete array will be walked to ensure that it only contains
105            valid filenames before any data is uncompressed.
106
107       An Input FileGlob string
108            If $input_filename_or_reference is a string that is delimited by
109            the characters "<" and ">" "rawinflate" will assume that it is an
110            input fileglob string. The input is the list of files that match
111            the fileglob.
112
113            See File::GlobMapper for more details.
114
115       If the $input_filename_or_reference parameter is any other type,
116       "undef" will be returned.
117
118       The $output_filename_or_reference parameter
119
120       The parameter $output_filename_or_reference is used to control the
121       destination of the uncompressed data. This parameter can take one of
122       these forms.
123
124       A filename
125            If the $output_filename_or_reference parameter is a simple scalar,
126            it is assumed to be a filename.  This file will be opened for
127            writing and the uncompressed data will be written to it.
128
129       A filehandle
130            If the $output_filename_or_reference parameter is a filehandle,
131            the uncompressed data will be written to it.  The string '-' can
132            be used as an alias for standard output.
133
134       A scalar reference
135            If $output_filename_or_reference is a scalar reference, the
136            uncompressed data will be stored in
137            $$output_filename_or_reference.
138
139       An Array Reference
140            If $output_filename_or_reference is an array reference, the
141            uncompressed data will be pushed onto the array.
142
143       An Output FileGlob
144            If $output_filename_or_reference is a string that is delimited by
145            the characters "<" and ">" "rawinflate" will assume that it is an
146            output fileglob string. The output is the list of files that match
147            the fileglob.
148
149            When $output_filename_or_reference is an fileglob string,
150            $input_filename_or_reference must also be a fileglob string.
151            Anything else is an error.
152
153            See File::GlobMapper for more details.
154
155       If the $output_filename_or_reference parameter is any other type,
156       "undef" will be returned.
157
158   Notes
159       When $input_filename_or_reference maps to multiple compressed
160       files/buffers and $output_filename_or_reference is a single
161       file/buffer, after uncompression $output_filename_or_reference will
162       contain a concatenation of all the uncompressed data from each of the
163       input files/buffers.
164
165   Optional Parameters
166       The optional parameters for the one-shot function "rawinflate" are (for
167       the most part) identical to those used with the OO interface defined in
168       the "Constructor Options" section. The exceptions are listed below
169
170       "AutoClose => 0|1"
171            This option applies to any input or output data streams to
172            "rawinflate" that are filehandles.
173
174            If "AutoClose" is specified, and the value is true, it will result
175            in all input and/or output filehandles being closed once
176            "rawinflate" has completed.
177
178            This parameter defaults to 0.
179
180       "BinModeOut => 0|1"
181            This option is now a no-op. All files will be written  in binmode.
182
183       "Append => 0|1"
184            The behaviour of this option is dependent on the type of output
185            data stream.
186
187            •    A Buffer
188
189                 If "Append" is enabled, all uncompressed data will be append
190                 to the end of the output buffer. Otherwise the output buffer
191                 will be cleared before any uncompressed data is written to
192                 it.
193
194            •    A Filename
195
196                 If "Append" is enabled, the file will be opened in append
197                 mode. Otherwise the contents of the file, if any, will be
198                 truncated before any uncompressed data is written to it.
199
200            •    A Filehandle
201
202                 If "Append" is enabled, the filehandle will be positioned to
203                 the end of the file via a call to "seek" before any
204                 uncompressed data is written to it.  Otherwise the file
205                 pointer will not be moved.
206
207            When "Append" is specified, and set to true, it will append all
208            uncompressed data to the output data stream.
209
210            So when the output is a filehandle it will carry out a seek to the
211            eof before writing any uncompressed data. If the output is a
212            filename, it will be opened for appending. If the output is a
213            buffer, all uncompressed data will be appended to the existing
214            buffer.
215
216            Conversely when "Append" is not specified, or it is present and is
217            set to false, it will operate as follows.
218
219            When the output is a filename, it will truncate the contents of
220            the file before writing any uncompressed data. If the output is a
221            filehandle its position will not be changed. If the output is a
222            buffer, it will be wiped before any uncompressed data is output.
223
224            Defaults to 0.
225
226       "MultiStream => 0|1"
227            This option is a no-op.
228
229       "TrailingData => $scalar"
230            Returns the data, if any, that is present immediately after the
231            compressed data stream once uncompression is complete.
232
233            This option can be used when there is useful information
234            immediately following the compressed data stream, and you don't
235            know the length of the compressed data stream.
236
237            If the input is a buffer, "trailingData" will return everything
238            from the end of the compressed data stream to the end of the
239            buffer.
240
241            If the input is a filehandle, "trailingData" will return the data
242            that is left in the filehandle input buffer once the end of the
243            compressed data stream has been reached. You can then use the
244            filehandle to read the rest of the input file.
245
246            Don't bother using "trailingData" if the input is a filename.
247
248            If you know the length of the compressed data stream before you
249            start uncompressing, you can avoid having to use "trailingData" by
250            setting the "InputLength" option.
251
252   Examples
253       To read the contents of the file "file1.txt.1951" and write the
254       uncompressed data to the file "file1.txt".
255
256           use strict ;
257           use warnings ;
258           use IO::Uncompress::RawInflate qw(rawinflate $RawInflateError) ;
259
260           my $input = "file1.txt.1951";
261           my $output = "file1.txt";
262           rawinflate $input => $output
263               or die "rawinflate failed: $RawInflateError\n";
264
265       To read from an existing Perl filehandle, $input, and write the
266       uncompressed data to a buffer, $buffer.
267
268           use strict ;
269           use warnings ;
270           use IO::Uncompress::RawInflate qw(rawinflate $RawInflateError) ;
271           use IO::File ;
272
273           my $input = IO::File->new( "<file1.txt.1951" )
274               or die "Cannot open 'file1.txt.1951': $!\n" ;
275           my $buffer ;
276           rawinflate $input => \$buffer
277               or die "rawinflate failed: $RawInflateError\n";
278
279       To uncompress all files in the directory "/my/home" that match
280       "*.txt.1951" and store the compressed data in the same directory
281
282           use strict ;
283           use warnings ;
284           use IO::Uncompress::RawInflate qw(rawinflate $RawInflateError) ;
285
286           rawinflate '</my/home/*.txt.1951>' => '</my/home/#1.txt>'
287               or die "rawinflate failed: $RawInflateError\n";
288
289       and if you want to compress each file one at a time, this will do the
290       trick
291
292           use strict ;
293           use warnings ;
294           use IO::Uncompress::RawInflate qw(rawinflate $RawInflateError) ;
295
296           for my $input ( glob "/my/home/*.txt.1951" )
297           {
298               my $output = $input;
299               $output =~ s/.1951// ;
300               rawinflate $input => $output
301                   or die "Error compressing '$input': $RawInflateError\n";
302           }
303

OO Interface

305   Constructor
306       The format of the constructor for IO::Uncompress::RawInflate is shown
307       below
308
309           my $z = IO::Uncompress::RawInflate->new( $input [OPTS] )
310               or die "IO::Uncompress::RawInflate failed: $RawInflateError\n";
311
312       Returns an "IO::Uncompress::RawInflate" object on success and undef on
313       failure.  The variable $RawInflateError will contain an error message
314       on failure.
315
316       If you are running Perl 5.005 or better the object, $z, returned from
317       IO::Uncompress::RawInflate can be used exactly like an IO::File
318       filehandle.  This means that all normal input file operations can be
319       carried out with $z.  For example, to read a line from a compressed
320       file/buffer you can use either of these forms
321
322           $line = $z->getline();
323           $line = <$z>;
324
325       The mandatory parameter $input is used to determine the source of the
326       compressed data. This parameter can take one of three forms.
327
328       A filename
329            If the $input parameter is a scalar, it is assumed to be a
330            filename. This file will be opened for reading and the compressed
331            data will be read from it.
332
333       A filehandle
334            If the $input parameter is a filehandle, the compressed data will
335            be read from it.  The string '-' can be used as an alias for
336            standard input.
337
338       A scalar reference
339            If $input is a scalar reference, the compressed data will be read
340            from $$input.
341
342   Constructor Options
343       The option names defined below are case insensitive and can be
344       optionally prefixed by a '-'.  So all of the following are valid
345
346           -AutoClose
347           -autoclose
348           AUTOCLOSE
349           autoclose
350
351       OPTS is a combination of the following options:
352
353       "AutoClose => 0|1"
354            This option is only valid when the $input parameter is a
355            filehandle. If specified, and the value is true, it will result in
356            the file being closed once either the "close" method is called or
357            the IO::Uncompress::RawInflate object is destroyed.
358
359            This parameter defaults to 0.
360
361       "MultiStream => 0|1"
362            Allows multiple concatenated compressed streams to be treated as a
363            single compressed stream. Decompression will stop once either the
364            end of the file/buffer is reached, an error is encountered
365            (premature eof, corrupt compressed data) or the end of a stream is
366            not immediately followed by the start of another stream.
367
368            This parameter defaults to 0.
369
370       "Prime => $string"
371            This option will uncompress the contents of $string before
372            processing the input file/buffer.
373
374            This option can be useful when the compressed data is embedded in
375            another file/data structure and it is not possible to work out
376            where the compressed data begins without having to read the first
377            few bytes. If this is the case, the uncompression can be primed
378            with these bytes using this option.
379
380       "Transparent => 0|1"
381            If this option is set and the input file/buffer is not compressed
382            data, the module will allow reading of it anyway.
383
384            In addition, if the input file/buffer does contain compressed data
385            and there is non-compressed data immediately following it, setting
386            this option will make this module treat the whole file/buffer as a
387            single data stream.
388
389            This option defaults to 1.
390
391       "BlockSize => $num"
392            When reading the compressed input data, IO::Uncompress::RawInflate
393            will read it in blocks of $num bytes.
394
395            This option defaults to 4096.
396
397       "InputLength => $size"
398            When present this option will limit the number of compressed bytes
399            read from the input file/buffer to $size. This option can be used
400            in the situation where there is useful data directly after the
401            compressed data stream and you know beforehand the exact length of
402            the compressed data stream.
403
404            This option is mostly used when reading from a filehandle, in
405            which case the file pointer will be left pointing to the first
406            byte directly after the compressed data stream.
407
408            This option defaults to off.
409
410       "Append => 0|1"
411            This option controls what the "read" method does with uncompressed
412            data.
413
414            If set to 1, all uncompressed data will be appended to the output
415            parameter of the "read" method.
416
417            If set to 0, the contents of the output parameter of the "read"
418            method will be overwritten by the uncompressed data.
419
420            Defaults to 0.
421
422       "Strict => 0|1"
423            This option is a no-op.
424
425   Examples
426       TODO
427

Methods

429   read
430       Usage is
431
432           $status = $z->read($buffer)
433
434       Reads a block of compressed data (the size of the compressed block is
435       determined by the "Buffer" option in the constructor), uncompresses it
436       and writes any uncompressed data into $buffer. If the "Append"
437       parameter is set in the constructor, the uncompressed data will be
438       appended to the $buffer parameter. Otherwise $buffer will be
439       overwritten.
440
441       Returns the number of uncompressed bytes written to $buffer, zero if
442       eof or a negative number on error.
443
444   read
445       Usage is
446
447           $status = $z->read($buffer, $length)
448           $status = $z->read($buffer, $length, $offset)
449
450           $status = read($z, $buffer, $length)
451           $status = read($z, $buffer, $length, $offset)
452
453       Attempt to read $length bytes of uncompressed data into $buffer.
454
455       The main difference between this form of the "read" method and the
456       previous one, is that this one will attempt to return exactly $length
457       bytes. The only circumstances that this function will not is if end-of-
458       file or an IO error is encountered.
459
460       Returns the number of uncompressed bytes written to $buffer, zero if
461       eof or a negative number on error.
462
463   getline
464       Usage is
465
466           $line = $z->getline()
467           $line = <$z>
468
469       Reads a single line.
470
471       This method fully supports the use of the variable $/ (or
472       $INPUT_RECORD_SEPARATOR or $RS when "English" is in use) to determine
473       what constitutes an end of line. Paragraph mode, record mode and file
474       slurp mode are all supported.
475
476   getc
477       Usage is
478
479           $char = $z->getc()
480
481       Read a single character.
482
483   ungetc
484       Usage is
485
486           $char = $z->ungetc($string)
487
488   inflateSync
489       Usage is
490
491           $status = $z->inflateSync()
492
493       TODO
494
495   getHeaderInfo
496       Usage is
497
498           $hdr  = $z->getHeaderInfo();
499           @hdrs = $z->getHeaderInfo();
500
501       This method returns either a hash reference (in scalar context) or a
502       list or hash references (in array context) that contains information
503       about each of the header fields in the compressed data stream(s).
504
505   tell
506       Usage is
507
508           $z->tell()
509           tell $z
510
511       Returns the uncompressed file offset.
512
513   eof
514       Usage is
515
516           $z->eof();
517           eof($z);
518
519       Returns true if the end of the compressed input stream has been
520       reached.
521
522   seek
523           $z->seek($position, $whence);
524           seek($z, $position, $whence);
525
526       Provides a sub-set of the "seek" functionality, with the restriction
527       that it is only legal to seek forward in the input file/buffer.  It is
528       a fatal error to attempt to seek backward.
529
530       Note that the implementation of "seek" in this module does not provide
531       true random access to a compressed file/buffer. It  works by
532       uncompressing data from the current offset in the file/buffer until it
533       reaches the uncompressed offset specified in the parameters to "seek".
534       For very small files this may be acceptable behaviour. For large files
535       it may cause an unacceptable delay.
536
537       The $whence parameter takes one the usual values, namely SEEK_SET,
538       SEEK_CUR or SEEK_END.
539
540       Returns 1 on success, 0 on failure.
541
542   binmode
543       Usage is
544
545           $z->binmode
546           binmode $z ;
547
548       This is a noop provided for completeness.
549
550   opened
551           $z->opened()
552
553       Returns true if the object currently refers to a opened file/buffer.
554
555   autoflush
556           my $prev = $z->autoflush()
557           my $prev = $z->autoflush(EXPR)
558
559       If the $z object is associated with a file or a filehandle, this method
560       returns the current autoflush setting for the underlying filehandle. If
561       "EXPR" is present, and is non-zero, it will enable flushing after every
562       write/print operation.
563
564       If $z is associated with a buffer, this method has no effect and always
565       returns "undef".
566
567       Note that the special variable $| cannot be used to set or retrieve the
568       autoflush setting.
569
570   input_line_number
571           $z->input_line_number()
572           $z->input_line_number(EXPR)
573
574       Returns the current uncompressed line number. If "EXPR" is present it
575       has the effect of setting the line number. Note that setting the line
576       number does not change the current position within the file/buffer
577       being read.
578
579       The contents of $/ are used to determine what constitutes a line
580       terminator.
581
582   fileno
583           $z->fileno()
584           fileno($z)
585
586       If the $z object is associated with a file or a filehandle, "fileno"
587       will return the underlying file descriptor. Once the "close" method is
588       called "fileno" will return "undef".
589
590       If the $z object is associated with a buffer, this method will return
591       "undef".
592
593   close
594           $z->close() ;
595           close $z ;
596
597       Closes the output file/buffer.
598
599       For most versions of Perl this method will be automatically invoked if
600       the IO::Uncompress::RawInflate object is destroyed (either explicitly
601       or by the variable with the reference to the object going out of
602       scope). The exceptions are Perl versions 5.005 through 5.00504 and
603       5.8.0. In these cases, the "close" method will be called automatically,
604       but not until global destruction of all live objects when the program
605       is terminating.
606
607       Therefore, if you want your scripts to be able to run on all versions
608       of Perl, you should call "close" explicitly and not rely on automatic
609       closing.
610
611       Returns true on success, otherwise 0.
612
613       If the "AutoClose" option has been enabled when the
614       IO::Uncompress::RawInflate object was created, and the object is
615       associated with a file, the underlying file will also be closed.
616
617   nextStream
618       Usage is
619
620           my $status = $z->nextStream();
621
622       Skips to the next compressed data stream in the input file/buffer. If a
623       new compressed data stream is found, the eof marker will be cleared and
624       $.  will be reset to 0.
625
626       Returns 1 if a new stream was found, 0 if none was found, and -1 if an
627       error was encountered.
628
629   trailingData
630       Usage is
631
632           my $data = $z->trailingData();
633
634       Returns the data, if any, that is present immediately after the
635       compressed data stream once uncompression is complete. It only makes
636       sense to call this method once the end of the compressed data stream
637       has been encountered.
638
639       This option can be used when there is useful information immediately
640       following the compressed data stream, and you don't know the length of
641       the compressed data stream.
642
643       If the input is a buffer, "trailingData" will return everything from
644       the end of the compressed data stream to the end of the buffer.
645
646       If the input is a filehandle, "trailingData" will return the data that
647       is left in the filehandle input buffer once the end of the compressed
648       data stream has been reached. You can then use the filehandle to read
649       the rest of the input file.
650
651       Don't bother using "trailingData" if the input is a filename.
652
653       If you know the length of the compressed data stream before you start
654       uncompressing, you can avoid having to use "trailingData" by setting
655       the "InputLength" option in the constructor.
656

Importing

658       No symbolic constants are required by IO::Uncompress::RawInflate at
659       present.
660
661       :all Imports "rawinflate" and $RawInflateError.  Same as doing this
662
663                use IO::Uncompress::RawInflate qw(rawinflate $RawInflateError) ;
664

EXAMPLES

666   Working with Net::FTP
667       See IO::Compress::FAQ
668

SUPPORT

670       General feedback/questions/bug reports should be sent to
671       <https://github.com/pmqs/IO-Compress/issues> (preferred) or
672       <https://rt.cpan.org/Public/Dist/Display.html?Name=IO-Compress>.
673

AUTHOR

702       This module was written by Paul Marquess, "pmqs@cpan.org".
703

MODIFICATION HISTORY

705       See the Changes file.
706

COPYRIGHT AND LICENSE

708       Copyright (c) 2005-2021 Paul Marquess. All rights reserved.
709
710       This program is free software; you can redistribute it and/or modify it
711       under the same terms as Perl itself.
712
713
714
715perl v5.34.0                      2021-07-22     IO::Uncompress::RawInflate(3)