IO::Uncompress::AnyUncompress(3pm)

1IO::Uncompress::AnyUncoUmsperresCso(n3t)ributed Perl DocIuOm:e:nUtnactoimopnress::AnyUncompress(3)
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NAME

6       IO::Uncompress::AnyUncompress - Uncompress gzip, zip, bzip2, zstd, xz,
7       lzma, lzip, lzf or lzop file/buffer
8

SYNOPSIS

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

DESCRIPTION

52       This module provides a Perl interface that allows the reading of
53       files/buffers that have been compressed with a variety of compression
54       libraries.
55
56       The formats supported are:
57
58       RFC 1950
59       RFC 1951 (optionally)
60       gzip (RFC 1952)
61       zip
62       zstd (Zstandard)
63       bzip2
64       lzop
65       lzf
66       lzma
67       lzip
68       xz
69
70       The module will auto-detect which, if any, of the supported compression
71       formats is being used.
72

Functional Interface

74       A top-level function, "anyuncompress", is provided to carry out "one-
75       shot" uncompression between buffers and/or files. For finer control
76       over the uncompression process, see the "OO Interface" section.
77
78           use IO::Uncompress::AnyUncompress qw(anyuncompress $AnyUncompressError) ;
79
80           anyuncompress $input_filename_or_reference => $output_filename_or_reference [,OPTS]
81               or die "anyuncompress failed: $AnyUncompressError\n";
82
83       The functional interface needs Perl5.005 or better.
84
85   anyuncompress $input_filename_or_reference => $output_filename_or_reference
86       [, OPTS]
87       "anyuncompress" expects at least two parameters,
88       $input_filename_or_reference and $output_filename_or_reference and zero
89       or more optional parameters (see "Optional Parameters")
90
91       The $input_filename_or_reference parameter
92
93       The parameter, $input_filename_or_reference, is used to define the
94       source of the compressed data.
95
96       It can take one of the following forms:
97
98       A filename
99            If the $input_filename_or_reference parameter is a simple scalar,
100            it is assumed to be a filename. This file will be opened for
101            reading and the input data will be read from it.
102
103       A filehandle
104            If the $input_filename_or_reference parameter is a filehandle, the
105            input data will be read from it.  The string '-' can be used as an
106            alias for standard input.
107
108       A scalar reference
109            If $input_filename_or_reference is a scalar reference, the input
110            data will be read from $$input_filename_or_reference.
111
112       An array reference
113            If $input_filename_or_reference is an array reference, each
114            element in the array must be a filename.
115
116            The input data will be read from each file in turn.
117
118            The complete array will be walked to ensure that it only contains
119            valid filenames before any data is uncompressed.
120
121       An Input FileGlob string
122            If $input_filename_or_reference is a string that is delimited by
123            the characters "<" and ">" "anyuncompress" will assume that it is
124            an input fileglob string. The input is the list of files that
125            match the fileglob.
126
127            See File::GlobMapper for more details.
128
129       If the $input_filename_or_reference parameter is any other type,
130       "undef" will be returned.
131
132       The $output_filename_or_reference parameter
133
134       The parameter $output_filename_or_reference is used to control the
135       destination of the uncompressed data. This parameter can take one of
136       these forms.
137
138       A filename
139            If the $output_filename_or_reference parameter is a simple scalar,
140            it is assumed to be a filename.  This file will be opened for
141            writing and the uncompressed data will be written to it.
142
143       A filehandle
144            If the $output_filename_or_reference parameter is a filehandle,
145            the uncompressed data will be written to it.  The string '-' can
146            be used as an alias for standard output.
147
148       A scalar reference
149            If $output_filename_or_reference is a scalar reference, the
150            uncompressed data will be stored in
151            $$output_filename_or_reference.
152
153       An Array Reference
154            If $output_filename_or_reference is an array reference, the
155            uncompressed data will be pushed onto the array.
156
157       An Output FileGlob
158            If $output_filename_or_reference is a string that is delimited by
159            the characters "<" and ">" "anyuncompress" will assume that it is
160            an output fileglob string. The output is the list of files that
161            match the fileglob.
162
163            When $output_filename_or_reference is an fileglob string,
164            $input_filename_or_reference must also be a fileglob string.
165            Anything else is an error.
166
167            See File::GlobMapper for more details.
168
169       If the $output_filename_or_reference parameter is any other type,
170       "undef" will be returned.
171
172   Notes
173       When $input_filename_or_reference maps to multiple compressed
174       files/buffers and $output_filename_or_reference is a single
175       file/buffer, after uncompression $output_filename_or_reference will
176       contain a concatenation of all the uncompressed data from each of the
177       input files/buffers.
178
179   Optional Parameters
180       The optional parameters for the one-shot function "anyuncompress" are
181       (for the most part) identical to those used with the OO interface
182       defined in the "Constructor Options" section. The exceptions are listed
183       below
184
185       "AutoClose => 0|1"
186            This option applies to any input or output data streams to
187            "anyuncompress" that are filehandles.
188
189            If "AutoClose" is specified, and the value is true, it will result
190            in all input and/or output filehandles being closed once
191            "anyuncompress" has completed.
192
193            This parameter defaults to 0.
194
195       "BinModeOut => 0|1"
196            This option is now a no-op. All files will be written  in binmode.
197
198       "Append => 0|1"
199            The behaviour of this option is dependent on the type of output
200            data stream.
201
202            •    A Buffer
203
204                 If "Append" is enabled, all uncompressed data will be append
205                 to the end of the output buffer. Otherwise the output buffer
206                 will be cleared before any uncompressed data is written to
207                 it.
208
209            •    A Filename
210
211                 If "Append" is enabled, the file will be opened in append
212                 mode. Otherwise the contents of the file, if any, will be
213                 truncated before any uncompressed data is written to it.
214
215            •    A Filehandle
216
217                 If "Append" is enabled, the filehandle will be positioned to
218                 the end of the file via a call to "seek" before any
219                 uncompressed data is written to it.  Otherwise the file
220                 pointer will not be moved.
221
222            When "Append" is specified, and set to true, it will append all
223            uncompressed data to the output data stream.
224
225            So when the output is a filehandle it will carry out a seek to the
226            eof before writing any uncompressed data. If the output is a
227            filename, it will be opened for appending. If the output is a
228            buffer, all uncompressed data will be appended to the existing
229            buffer.
230
231            Conversely when "Append" is not specified, or it is present and is
232            set to false, it will operate as follows.
233
234            When the output is a filename, it will truncate the contents of
235            the file before writing any uncompressed data. If the output is a
236            filehandle its position will not be changed. If the output is a
237            buffer, it will be wiped before any uncompressed data is output.
238
239            Defaults to 0.
240
241       "MultiStream => 0|1"
242            If the input file/buffer contains multiple compressed data
243            streams, this option will uncompress the whole lot as a single
244            data stream.
245
246            Defaults to 0.
247
248       "TrailingData => $scalar"
249            Returns the data, if any, that is present immediately after the
250            compressed data stream once uncompression is complete.
251
252            This option can be used when there is useful information
253            immediately following the compressed data stream, and you don't
254            know the length of the compressed data stream.
255
256            If the input is a buffer, "trailingData" will return everything
257            from the end of the compressed data stream to the end of the
258            buffer.
259
260            If the input is a filehandle, "trailingData" will return the data
261            that is left in the filehandle input buffer once the end of the
262            compressed data stream has been reached. You can then use the
263            filehandle to read the rest of the input file.
264
265            Don't bother using "trailingData" if the input is a filename.
266
267            If you know the length of the compressed data stream before you
268            start uncompressing, you can avoid having to use "trailingData" by
269            setting the "InputLength" option.
270
271   OneShot Examples
272       To read the contents of the file "file1.txt.Compressed" and write the
273       uncompressed data to the file "file1.txt".
274
275           use strict ;
276           use warnings ;
277           use IO::Uncompress::AnyUncompress qw(anyuncompress $AnyUncompressError) ;
278
279           my $input = "file1.txt.Compressed";
280           my $output = "file1.txt";
281           anyuncompress $input => $output
282               or die "anyuncompress failed: $AnyUncompressError\n";
283
284       To read from an existing Perl filehandle, $input, and write the
285       uncompressed data to a buffer, $buffer.
286
287           use strict ;
288           use warnings ;
289           use IO::Uncompress::AnyUncompress qw(anyuncompress $AnyUncompressError) ;
290           use IO::File ;
291
292           my $input = IO::File->new( "<file1.txt.Compressed" )
293               or die "Cannot open 'file1.txt.Compressed': $!\n" ;
294           my $buffer ;
295           anyuncompress $input => \$buffer
296               or die "anyuncompress failed: $AnyUncompressError\n";
297
298       To uncompress all files in the directory "/my/home" that match
299       "*.txt.Compressed" and store the compressed data in the same directory
300
301           use strict ;
302           use warnings ;
303           use IO::Uncompress::AnyUncompress qw(anyuncompress $AnyUncompressError) ;
304
305           anyuncompress '</my/home/*.txt.Compressed>' => '</my/home/#1.txt>'
306               or die "anyuncompress failed: $AnyUncompressError\n";
307
308       and if you want to compress each file one at a time, this will do the
309       trick
310
311           use strict ;
312           use warnings ;
313           use IO::Uncompress::AnyUncompress qw(anyuncompress $AnyUncompressError) ;
314
315           for my $input ( glob "/my/home/*.txt.Compressed" )
316           {
317               my $output = $input;
318               $output =~ s/.Compressed// ;
319               anyuncompress $input => $output
320                   or die "Error compressing '$input': $AnyUncompressError\n";
321           }
322

OO Interface

324   Constructor
325       The format of the constructor for IO::Uncompress::AnyUncompress is
326       shown below
327
328           my $z = IO::Uncompress::AnyUncompress->new( $input [OPTS] )
329               or die "IO::Uncompress::AnyUncompress failed: $AnyUncompressError\n";
330
331       The constructor takes one mandatory parameter, $input, defined below,
332       and zero or more "OPTS", defined in "Constructor Options".
333
334       Returns an "IO::Uncompress::AnyUncompress" object on success and undef
335       on failure.  The variable $AnyUncompressError will contain an error
336       message on failure.
337
338       If you are running Perl 5.005 or better the object, $z, returned from
339       IO::Uncompress::AnyUncompress can be used exactly like an IO::File
340       filehandle.  This means that all normal input file operations can be
341       carried out with $z.  For example, to read a line from a compressed
342       file/buffer you can use either of these forms
343
344           $line = $z->getline();
345           $line = <$z>;
346
347       Below is a simple exaple of using the OO interface to read the
348       compressed file "myfile.Compressed" and write its contents to stdout.
349
350           my $filename = "myfile.Compressed";
351           my $z = IO::Uncompress::AnyUncompress->new($filename)
352               or die "IO::Uncompress::AnyUncompress failed: $AnyUncompressError\n";
353
354           while (<$z>) {
355               print $_;
356           }
357           $z->close();
358
359       See "EXAMPLES" for further examples
360
361       The mandatory parameter $input is used to determine the source of the
362       compressed data. This parameter can take one of three forms.
363
364       A filename
365            If the $input parameter is a scalar, it is assumed to be a
366            filename. This file will be opened for reading and the compressed
367            data will be read from it.
368
369       A filehandle
370            If the $input parameter is a filehandle, the compressed data will
371            be read from it.  The string '-' can be used as an alias for
372            standard input.
373
374       A scalar reference
375            If $input is a scalar reference, the compressed data will be read
376            from $$input.
377
378   Constructor Options
379       The option names defined below are case insensitive and can be
380       optionally prefixed by a '-'.  So all of the following are valid
381
382           -AutoClose
383           -autoclose
384           AUTOCLOSE
385           autoclose
386
387       OPTS is a combination of the following options:
388
389       "AutoClose => 0|1"
390            This option is only valid when the $input parameter is a
391            filehandle. If specified, and the value is true, it will result in
392            the file being closed once either the "close" method is called or
393            the IO::Uncompress::AnyUncompress object is destroyed.
394
395            This parameter defaults to 0.
396
397       "MultiStream => 0|1"
398            Allows multiple concatenated compressed streams to be treated as a
399            single compressed stream. Decompression will stop once either the
400            end of the file/buffer is reached, an error is encountered
401            (premature eof, corrupt compressed data) or the end of a stream is
402            not immediately followed by the start of another stream.
403
404            This parameter defaults to 0.
405
406       "Prime => $string"
407            This option will uncompress the contents of $string before
408            processing the input file/buffer.
409
410            This option can be useful when the compressed data is embedded in
411            another file/data structure and it is not possible to work out
412            where the compressed data begins without having to read the first
413            few bytes. If this is the case, the uncompression can be primed
414            with these bytes using this option.
415
416       "Transparent => 0|1"
417            If this option is set and the input file/buffer is not compressed
418            data, the module will allow reading of it anyway.
419
420            In addition, if the input file/buffer does contain compressed data
421            and there is non-compressed data immediately following it, setting
422            this option will make this module treat the whole file/buffer as a
423            single data stream.
424
425            This option defaults to 1.
426
427       "BlockSize => $num"
428            When reading the compressed input data,
429            IO::Uncompress::AnyUncompress will read it in blocks of $num
430            bytes.
431
432            This option defaults to 4096.
433
434       "InputLength => $size"
435            When present this option will limit the number of compressed bytes
436            read from the input file/buffer to $size. This option can be used
437            in the situation where there is useful data directly after the
438            compressed data stream and you know beforehand the exact length of
439            the compressed data stream.
440
441            This option is mostly used when reading from a filehandle, in
442            which case the file pointer will be left pointing to the first
443            byte directly after the compressed data stream.
444
445            This option defaults to off.
446
447       "Append => 0|1"
448            This option controls what the "read" method does with uncompressed
449            data.
450
451            If set to 1, all uncompressed data will be appended to the output
452            parameter of the "read" method.
453
454            If set to 0, the contents of the output parameter of the "read"
455            method will be overwritten by the uncompressed data.
456
457            Defaults to 0.
458
459       "Strict => 0|1"
460            This option controls whether the extra checks defined below are
461            used when carrying out the decompression. When Strict is on, the
462            extra tests are carried out, when Strict is off they are not.
463
464            The default for this option is off.
465
466       "RawInflate => 0|1"
467            When auto-detecting the compressed format, try to test for raw-
468            deflate (RFC 1951) content using the "IO::Uncompress::RawInflate"
469            module.
470
471            The reason this is not default behaviour is because RFC 1951
472            content can only be detected by attempting to uncompress it. This
473            process is error prone and can result is false positives.
474
475            Defaults to 0.
476
477       "UnLzma => 0|1"
478            When auto-detecting the compressed format, try to test for
479            lzma_alone content using the "IO::Uncompress::UnLzma" module.
480
481            The reason this is not default behaviour is because lzma_alone
482            content can only be detected by attempting to uncompress it. This
483            process is error prone and can result is false positives.
484
485            Defaults to 0.
486

Methods

488   read
489       Usage is
490
491           $status = $z->read($buffer)
492
493       Reads a block of compressed data (the size of the compressed block is
494       determined by the "Buffer" option in the constructor), uncompresses it
495       and writes any uncompressed data into $buffer. If the "Append"
496       parameter is set in the constructor, the uncompressed data will be
497       appended to the $buffer parameter. Otherwise $buffer will be
498       overwritten.
499
500       Returns the number of uncompressed bytes written to $buffer, zero if
501       eof or a negative number on error.
502
503   read
504       Usage is
505
506           $status = $z->read($buffer, $length)
507           $status = $z->read($buffer, $length, $offset)
508
509           $status = read($z, $buffer, $length)
510           $status = read($z, $buffer, $length, $offset)
511
512       Attempt to read $length bytes of uncompressed data into $buffer.
513
514       The main difference between this form of the "read" method and the
515       previous one, is that this one will attempt to return exactly $length
516       bytes. The only circumstances that this function will not is if end-of-
517       file or an IO error is encountered.
518
519       Returns the number of uncompressed bytes written to $buffer, zero if
520       eof or a negative number on error.
521
522   getline
523       Usage is
524
525           $line = $z->getline()
526           $line = <$z>
527
528       Reads a single line.
529
530       This method fully supports the use of the variable $/ (or
531       $INPUT_RECORD_SEPARATOR or $RS when "English" is in use) to determine
532       what constitutes an end of line. Paragraph mode, record mode and file
533       slurp mode are all supported.
534
535   getc
536       Usage is
537
538           $char = $z->getc()
539
540       Read a single character.
541
542   ungetc
543       Usage is
544
545           $char = $z->ungetc($string)
546
547   getHeaderInfo
548       Usage is
549
550           $hdr  = $z->getHeaderInfo();
551           @hdrs = $z->getHeaderInfo();
552
553       This method returns either a hash reference (in scalar context) or a
554       list or hash references (in array context) that contains information
555       about each of the header fields in the compressed data stream(s).
556
557   tell
558       Usage is
559
560           $z->tell()
561           tell $z
562
563       Returns the uncompressed file offset.
564
565   eof
566       Usage is
567
568           $z->eof();
569           eof($z);
570
571       Returns true if the end of the compressed input stream has been
572       reached.
573
574   seek
575           $z->seek($position, $whence);
576           seek($z, $position, $whence);
577
578       Provides a sub-set of the "seek" functionality, with the restriction
579       that it is only legal to seek forward in the input file/buffer.  It is
580       a fatal error to attempt to seek backward.
581
582       Note that the implementation of "seek" in this module does not provide
583       true random access to a compressed file/buffer. It  works by
584       uncompressing data from the current offset in the file/buffer until it
585       reaches the uncompressed offset specified in the parameters to "seek".
586       For very small files this may be acceptable behaviour. For large files
587       it may cause an unacceptable delay.
588
589       The $whence parameter takes one the usual values, namely SEEK_SET,
590       SEEK_CUR or SEEK_END.
591
592       Returns 1 on success, 0 on failure.
593
594   binmode
595       Usage is
596
597           $z->binmode
598           binmode $z ;
599
600       This is a noop provided for completeness.
601
602   opened
603           $z->opened()
604
605       Returns true if the object currently refers to a opened file/buffer.
606
607   autoflush
608           my $prev = $z->autoflush()
609           my $prev = $z->autoflush(EXPR)
610
611       If the $z object is associated with a file or a filehandle, this method
612       returns the current autoflush setting for the underlying filehandle. If
613       "EXPR" is present, and is non-zero, it will enable flushing after every
614       write/print operation.
615
616       If $z is associated with a buffer, this method has no effect and always
617       returns "undef".
618
619       Note that the special variable $| cannot be used to set or retrieve the
620       autoflush setting.
621
622   input_line_number
623           $z->input_line_number()
624           $z->input_line_number(EXPR)
625
626       Returns the current uncompressed line number. If "EXPR" is present it
627       has the effect of setting the line number. Note that setting the line
628       number does not change the current position within the file/buffer
629       being read.
630
631       The contents of $/ are used to determine what constitutes a line
632       terminator.
633
634   fileno
635           $z->fileno()
636           fileno($z)
637
638       If the $z object is associated with a file or a filehandle, "fileno"
639       will return the underlying file descriptor. Once the "close" method is
640       called "fileno" will return "undef".
641
642       If the $z object is associated with a buffer, this method will return
643       "undef".
644
645   close
646           $z->close() ;
647           close $z ;
648
649       Closes the output file/buffer.
650
651       For most versions of Perl this method will be automatically invoked if
652       the IO::Uncompress::AnyUncompress object is destroyed (either
653       explicitly or by the variable with the reference to the object going
654       out of scope). The exceptions are Perl versions 5.005 through 5.00504
655       and 5.8.0. In these cases, the "close" method will be called
656       automatically, but not until global destruction of all live objects
657       when the program is terminating.
658
659       Therefore, if you want your scripts to be able to run on all versions
660       of Perl, you should call "close" explicitly and not rely on automatic
661       closing.
662
663       Returns true on success, otherwise 0.
664
665       If the "AutoClose" option has been enabled when the
666       IO::Uncompress::AnyUncompress object was created, and the object is
667       associated with a file, the underlying file will also be closed.
668
669   nextStream
670       Usage is
671
672           my $status = $z->nextStream();
673
674       Skips to the next compressed data stream in the input file/buffer. If a
675       new compressed data stream is found, the eof marker will be cleared and
676       $.  will be reset to 0.
677
678       Returns 1 if a new stream was found, 0 if none was found, and -1 if an
679       error was encountered.
680
681   trailingData
682       Usage is
683
684           my $data = $z->trailingData();
685
686       Returns the data, if any, that is present immediately after the
687       compressed data stream once uncompression is complete. It only makes
688       sense to call this method once the end of the compressed data stream
689       has been encountered.
690
691       This option can be used when there is useful information immediately
692       following the compressed data stream, and you don't know the length of
693       the compressed data stream.
694
695       If the input is a buffer, "trailingData" will return everything from
696       the end of the compressed data stream to the end of the buffer.
697
698       If the input is a filehandle, "trailingData" will return the data that
699       is left in the filehandle input buffer once the end of the compressed
700       data stream has been reached. You can then use the filehandle to read
701       the rest of the input file.
702
703       Don't bother using "trailingData" if the input is a filename.
704
705       If you know the length of the compressed data stream before you start
706       uncompressing, you can avoid having to use "trailingData" by setting
707       the "InputLength" option in the constructor.
708

Importing

710       No symbolic constants are required by IO::Uncompress::AnyUncompress at
711       present.
712
713       :all Imports "anyuncompress" and $AnyUncompressError.  Same as doing
714            this
715
716                use IO::Uncompress::AnyUncompress qw(anyuncompress $AnyUncompressError) ;
717

EXAMPLES

SUPPORT

720       General feedback/questions/bug reports should be sent to
721       <https://github.com/pmqs/IO-Compress/issues> (preferred) or
722       <https://rt.cpan.org/Public/Dist/Display.html?Name=IO-Compress>.
723

AUTHOR

739       This module was written by Paul Marquess, "pmqs@cpan.org".
740

MODIFICATION HISTORY

742       See the Changes file.
743

COPYRIGHT AND LICENSE

745       Copyright (c) 2005-2023 Paul Marquess. All rights reserved.
746
747       This program is free software; you can redistribute it and/or modify it
748       under the same terms as Perl itself.
749
750
751
752perl v5.38.0                      2023-07-26  IO::Uncompress::AnyUncompress(3)