IO::Uncompress::RawInflate(3pm)

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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 = new IO::Uncompress::RawInflate $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.
75
76       The $input_filename_or_reference parameter
77
78       The parameter, $input_filename_or_reference, is used to define the
79       source of the compressed data.
80
81       It can take one of the following forms:
82
83       A filename
84            If the <$input_filename_or_reference> parameter is a simple
85            scalar, it is assumed to be a filename. This file will be opened
86            for reading and the input data will be read from it.
87
88       A filehandle
89            If the $input_filename_or_reference parameter is a filehandle, the
90            input data will be read from it.  The string '-' can be used as an
91            alias for standard input.
92
93       A scalar reference
94            If $input_filename_or_reference is a scalar reference, the input
95            data will be read from $$input_filename_or_reference.
96
97       An array reference
98            If $input_filename_or_reference is an array reference, each
99            element in the array must be a filename.
100
101            The input data will be read from each file in turn.
102
103            The complete array will be walked to ensure that it only contains
104            valid filenames before any data is uncompressed.
105
106       An Input FileGlob string
107            If $input_filename_or_reference is a string that is delimited by
108            the characters "<" and ">" "rawinflate" will assume that it is an
109            input fileglob string. The input is the list of files that match
110            the fileglob.
111
112            See File::GlobMapper for more details.
113
114       If the $input_filename_or_reference parameter is any other type,
115       "undef" will be returned.
116
117       The $output_filename_or_reference parameter
118
119       The parameter $output_filename_or_reference is used to control the
120       destination of the uncompressed data. This parameter can take one of
121       these forms.
122
123       A filename
124            If the $output_filename_or_reference parameter is a simple scalar,
125            it is assumed to be a filename.  This file will be opened for
126            writing and the uncompressed data will be written to it.
127
128       A filehandle
129            If the $output_filename_or_reference parameter is a filehandle,
130            the uncompressed data will be written to it.  The string '-' can
131            be used as an alias for standard output.
132
133       A scalar reference
134            If $output_filename_or_reference is a scalar reference, the
135            uncompressed data will be stored in
136            $$output_filename_or_reference.
137
138       An Array Reference
139            If $output_filename_or_reference is an array reference, the
140            uncompressed data will be pushed onto the array.
141
142       An Output FileGlob
143            If $output_filename_or_reference is a string that is delimited by
144            the characters "<" and ">" "rawinflate" will assume that it is an
145            output fileglob string. The output is the list of files that match
146            the fileglob.
147
148            When $output_filename_or_reference is an fileglob string,
149            $input_filename_or_reference must also be a fileglob string.
150            Anything else is an error.
151
152            See File::GlobMapper for more details.
153
154       If the $output_filename_or_reference parameter is any other type,
155       "undef" will be returned.
156
157   Notes
158       When $input_filename_or_reference maps to multiple compressed
159       files/buffers and $output_filename_or_reference is a single
160       file/buffer, after uncompression $output_filename_or_reference will
161       contain a concatenation of all the uncompressed data from each of the
162       input files/buffers.
163
164   Optional Parameters
165       Unless specified below, the optional parameters for "rawinflate",
166       "OPTS", are the same as those used with the OO interface defined in the
167       "Constructor Options" section below.
168
169       "AutoClose => 0|1"
170            This option applies to any input or output data streams to
171            "rawinflate" that are filehandles.
172
173            If "AutoClose" is specified, and the value is true, it will result
174            in all input and/or output filehandles being closed once
175            "rawinflate" has completed.
176
177            This parameter defaults to 0.
178
179       "BinModeOut => 0|1"
180            When writing to a file or filehandle, set "binmode" before writing
181            to the file.
182
183            Defaults to 0.
184
185       "Append => 0|1"
186            The behaviour of this option is dependent on the type of output
187            data stream.
188
189            ·    A Buffer
190
191                 If "Append" is enabled, all uncompressed data will be append
192                 to the end of the output buffer. Otherwise the output buffer
193                 will be cleared before any uncompressed data is written to
194                 it.
195
196            ·    A Filename
197
198                 If "Append" is enabled, the file will be opened in append
199                 mode. Otherwise the contents of the file, if any, will be
200                 truncated before any uncompressed data is written to it.
201
202            ·    A Filehandle
203
204                 If "Append" is enabled, the filehandle will be positioned to
205                 the end of the file via a call to "seek" before any
206                 uncompressed data is written to it.  Otherwise the file
207                 pointer will not be moved.
208
209            When "Append" is specified, and set to true, it will append all
210            uncompressed data to the output data stream.
211
212            So when the output is a filehandle it will carry out a seek to the
213            eof before writing any uncompressed data. If the output is a
214            filename, it will be opened for appending. If the output is a
215            buffer, all uncompressed data will be appended to the existing
216            buffer.
217
218            Conversely when "Append" is not specified, or it is present and is
219            set to false, it will operate as follows.
220
221            When the output is a filename, it will truncate the contents of
222            the file before writing any uncompressed data. If the output is a
223            filehandle its position will not be changed. If the output is a
224            buffer, it will be wiped before any uncompressed data is output.
225
226            Defaults to 0.
227
228       "MultiStream => 0|1"
229            This option is a no-op.
230
231       "TrailingData => $scalar"
232            Returns the data, if any, that is present immediately after the
233            compressed data stream once uncompression is complete.
234
235            This option can be used when there is useful information
236            immediately following the compressed data stream, and you don't
237            know the length of the compressed data stream.
238
239            If the input is a buffer, "trailingData" will return everything
240            from the end of the compressed data stream to the end of the
241            buffer.
242
243            If the input is a filehandle, "trailingData" will return the data
244            that is left in the filehandle input buffer once the end of the
245            compressed data stream has been reached. You can then use the
246            filehandle to read the rest of the input file.
247
248            Don't bother using "trailingData" if the input is a filename.
249
250            If you know the length of the compressed data stream before you
251            start uncompressing, you can avoid having to use "trailingData" by
252            setting the "InputLength" option.
253
254   Examples
255       To read the contents of the file "file1.txt.1951" and write the
256       uncompressed data to the file "file1.txt".
257
258           use strict ;
259           use warnings ;
260           use IO::Uncompress::RawInflate qw(rawinflate $RawInflateError) ;
261
262           my $input = "file1.txt.1951";
263           my $output = "file1.txt";
264           rawinflate $input => $output
265               or die "rawinflate failed: $RawInflateError\n";
266
267       To read from an existing Perl filehandle, $input, and write the
268       uncompressed data to a buffer, $buffer.
269
270           use strict ;
271           use warnings ;
272           use IO::Uncompress::RawInflate qw(rawinflate $RawInflateError) ;
273           use IO::File ;
274
275           my $input = new IO::File "<file1.txt.1951"
276               or die "Cannot open 'file1.txt.1951': $!\n" ;
277           my $buffer ;
278           rawinflate $input => \$buffer
279               or die "rawinflate failed: $RawInflateError\n";
280
281       To uncompress all files in the directory "/my/home" that match
282       "*.txt.1951" and store the compressed data in the same directory
283
284           use strict ;
285           use warnings ;
286           use IO::Uncompress::RawInflate qw(rawinflate $RawInflateError) ;
287
288           rawinflate '</my/home/*.txt.1951>' => '</my/home/#1.txt>'
289               or die "rawinflate failed: $RawInflateError\n";
290
291       and if you want to compress each file one at a time, this will do the
292       trick
293
294           use strict ;
295           use warnings ;
296           use IO::Uncompress::RawInflate qw(rawinflate $RawInflateError) ;
297
298           for my $input ( glob "/my/home/*.txt.1951" )
299           {
300               my $output = $input;
301               $output =~ s/.1951// ;
302               rawinflate $input => $output
303                   or die "Error compressing '$input': $RawInflateError\n";
304           }
305

OO Interface

307   Constructor
308       The format of the constructor for IO::Uncompress::RawInflate is shown
309       below
310
311           my $z = new IO::Uncompress::RawInflate $input [OPTS]
312               or die "IO::Uncompress::RawInflate failed: $RawInflateError\n";
313
314       Returns an "IO::Uncompress::RawInflate" object on success and undef on
315       failure.  The variable $RawInflateError will contain an error message
316       on failure.
317
318       If you are running Perl 5.005 or better the object, $z, returned from
319       IO::Uncompress::RawInflate can be used exactly like an IO::File
320       filehandle.  This means that all normal input file operations can be
321       carried out with $z.  For example, to read a line from a compressed
322       file/buffer you can use either of these forms
323
324           $line = $z->getline();
325           $line = <$z>;
326
327       The mandatory parameter $input is used to determine the source of the
328       compressed data. This parameter can take one of three forms.
329
330       A filename
331            If the $input parameter is a scalar, it is assumed to be a
332            filename. This file will be opened for reading and the compressed
333            data will be read from it.
334
335       A filehandle
336            If the $input parameter is a filehandle, the compressed data will
337            be read from it.  The string '-' can be used as an alias for
338            standard input.
339
340       A scalar reference
341            If $input is a scalar reference, the compressed data will be read
342            from $$input.
343
344   Constructor Options
345       The option names defined below are case insensitive and can be
346       optionally prefixed by a '-'.  So all of the following are valid
347
348           -AutoClose
349           -autoclose
350           AUTOCLOSE
351           autoclose
352
353       OPTS is a combination of the following options:
354
355       "AutoClose => 0|1"
356            This option is only valid when the $input parameter is a
357            filehandle. If specified, and the value is true, it will result in
358            the file being closed once either the "close" method is called or
359            the IO::Uncompress::RawInflate object is destroyed.
360
361            This parameter defaults to 0.
362
363       "MultiStream => 0|1"
364            Allows multiple concatenated compressed streams to be treated as a
365            single compressed stream. Decompression will stop once either the
366            end of the file/buffer is reached, an error is encountered
367            (premature eof, corrupt compressed data) or the end of a stream is
368            not immediately followed by the start of another stream.
369
370            This parameter defaults to 0.
371
372       "Prime => $string"
373            This option will uncompress the contents of $string before
374            processing the input file/buffer.
375
376            This option can be useful when the compressed data is embedded in
377            another file/data structure and it is not possible to work out
378            where the compressed data begins without having to read the first
379            few bytes. If this is the case, the uncompression can be primed
380            with these bytes using this option.
381
382       "Transparent => 0|1"
383            If this option is set and the input file/buffer is not compressed
384            data, the module will allow reading of it anyway.
385
386            In addition, if the input file/buffer does contain compressed data
387            and there is non-compressed data immediately following it, setting
388            this option will make this module treat the whole file/buffer as a
389            single data stream.
390
391            This option defaults to 1.
392
393       "BlockSize => $num"
394            When reading the compressed input data, IO::Uncompress::RawInflate
395            will read it in blocks of $num bytes.
396
397            This option defaults to 4096.
398
399       "InputLength => $size"
400            When present this option will limit the number of compressed bytes
401            read from the input file/buffer to $size. This option can be used
402            in the situation where there is useful data directly after the
403            compressed data stream and you know beforehand the exact length of
404            the compressed data stream.
405
406            This option is mostly used when reading from a filehandle, in
407            which case the file pointer will be left pointing to the first
408            byte directly after the compressed data stream.
409
410            This option defaults to off.
411
412       "Append => 0|1"
413            This option controls what the "read" method does with uncompressed
414            data.
415
416            If set to 1, all uncompressed data will be appended to the output
417            parameter of the "read" method.
418
419            If set to 0, the contents of the output parameter of the "read"
420            method will be overwritten by the uncompressed data.
421
422            Defaults to 0.
423
424       "Strict => 0|1"
425            This option is a no-op.
426
427   Examples
428       TODO
429

Methods

431   read
432       Usage is
433
434           $status = $z->read($buffer)
435
436       Reads a block of compressed data (the size the the compressed block is
437       determined by the "Buffer" option in the constructor), uncompresses it
438       and writes any uncompressed data into $buffer. If the "Append"
439       parameter is set in the constructor, the uncompressed data will be
440       appended to the $buffer parameter. Otherwise $buffer will be
441       overwritten.
442
443       Returns the number of uncompressed bytes written to $buffer, zero if
444       eof or a negative number on error.
445
446   read
447       Usage is
448
449           $status = $z->read($buffer, $length)
450           $status = $z->read($buffer, $length, $offset)
451
452           $status = read($z, $buffer, $length)
453           $status = read($z, $buffer, $length, $offset)
454
455       Attempt to read $length bytes of uncompressed data into $buffer.
456
457       The main difference between this form of the "read" method and the
458       previous one, is that this one will attempt to return exactly $length
459       bytes. The only circumstances that this function will not is if end-of-
460       file or an IO error is encountered.
461
462       Returns the number of uncompressed bytes written to $buffer, zero if
463       eof or a negative number on error.
464
465   getline
466       Usage is
467
468           $line = $z->getline()
469           $line = <$z>
470
471       Reads a single line.
472
473       This method fully supports the use of of the variable $/ (or
474       $INPUT_RECORD_SEPARATOR or $RS when "English" is in use) to determine
475       what constitutes an end of line. Paragraph mode, record mode and file
476       slurp mode are all supported.
477
478   getc
479       Usage is
480
481           $char = $z->getc()
482
483       Read a single character.
484
485   ungetc
486       Usage is
487
488           $char = $z->ungetc($string)
489
490   inflateSync
491       Usage is
492
493           $status = $z->inflateSync()
494
495       TODO
496
497   getHeaderInfo
498       Usage is
499
500           $hdr  = $z->getHeaderInfo();
501           @hdrs = $z->getHeaderInfo();
502
503       This method returns either a hash reference (in scalar context) or a
504       list or hash references (in array context) that contains information
505       about each of the header fields in the compressed data stream(s).
506
507   tell
508       Usage is
509
510           $z->tell()
511           tell $z
512
513       Returns the uncompressed file offset.
514
515   eof
516       Usage is
517
518           $z->eof();
519           eof($z);
520
521       Returns true if the end of the compressed input stream has been
522       reached.
523
524   seek
525           $z->seek($position, $whence);
526           seek($z, $position, $whence);
527
528       Provides a sub-set of the "seek" functionality, with the restriction
529       that it is only legal to seek forward in the input file/buffer.  It is
530       a fatal error to attempt to seek backward.
531
532       Note that the implementation of "seek" in this module does not provide
533       true random access to a compressed file/buffer. It  works by
534       uncompressing data from the current offset in the file/buffer until it
535       reaches the ucompressed offset specified in the parameters to "seek".
536       For very small files this may be acceptable behaviour. For large files
537       it may cause an unacceptable delay.
538
539       The $whence parameter takes one the usual values, namely SEEK_SET,
540       SEEK_CUR or SEEK_END.
541
542       Returns 1 on success, 0 on failure.
543
544   binmode
545       Usage is
546
547           $z->binmode
548           binmode $z ;
549
550       This is a noop provided for completeness.
551
552   opened
553           $z->opened()
554
555       Returns true if the object currently refers to a opened file/buffer.
556
557   autoflush
558           my $prev = $z->autoflush()
559           my $prev = $z->autoflush(EXPR)
560
561       If the $z object is associated with a file or a filehandle, this method
562       returns the current autoflush setting for the underlying filehandle. If
563       "EXPR" is present, and is non-zero, it will enable flushing after every
564       write/print operation.
565
566       If $z is associated with a buffer, this method has no effect and always
567       returns "undef".
568
569       Note that the special variable $| cannot be used to set or retrieve the
570       autoflush setting.
571
572   input_line_number
573           $z->input_line_number()
574           $z->input_line_number(EXPR)
575
576       Returns the current uncompressed line number. If "EXPR" is present it
577       has the effect of setting the line number. Note that setting the line
578       number does not change the current position within the file/buffer
579       being read.
580
581       The contents of $/ are used to to determine what constitutes a line
582       terminator.
583
584   fileno
585           $z->fileno()
586           fileno($z)
587
588       If the $z object is associated with a file or a filehandle, "fileno"
589       will return the underlying file descriptor. Once the "close" method is
590       called "fileno" will return "undef".
591
592       If the $z object is associated with a buffer, this method will return
593       "undef".
594
595   close
596           $z->close() ;
597           close $z ;
598
599       Closes the output file/buffer.
600
601       For most versions of Perl this method will be automatically invoked if
602       the IO::Uncompress::RawInflate object is destroyed (either explicitly
603       or by the variable with the reference to the object going out of
604       scope). The exceptions are Perl versions 5.005 through 5.00504 and
605       5.8.0. In these cases, the "close" method will be called automatically,
606       but not until global destruction of all live objects when the program
607       is terminating.
608
609       Therefore, if you want your scripts to be able to run on all versions
610       of Perl, you should call "close" explicitly and not rely on automatic
611       closing.
612
613       Returns true on success, otherwise 0.
614
615       If the "AutoClose" option has been enabled when the
616       IO::Uncompress::RawInflate object was created, and the object is
617       associated with a file, the underlying file will also be closed.
618
619   nextStream
620       Usage is
621
622           my $status = $z->nextStream();
623
624       Skips to the next compressed data stream in the input file/buffer. If a
625       new compressed data stream is found, the eof marker will be cleared and
626       $.  will be reset to 0.
627
628       Returns 1 if a new stream was found, 0 if none was found, and -1 if an
629       error was encountered.
630
631   trailingData
632       Usage is
633
634           my $data = $z->trailingData();
635
636       Returns the data, if any, that is present immediately after the
637       compressed data stream once uncompression is complete. It only makes
638       sense to call this method once the end of the compressed data stream
639       has been encountered.
640
641       This option can be used when there is useful information immediately
642       following the compressed data stream, and you don't know the length of
643       the compressed data stream.
644
645       If the input is a buffer, "trailingData" will return everything from
646       the end of the compressed data stream to the end of the buffer.
647
648       If the input is a filehandle, "trailingData" will return the data that
649       is left in the filehandle input buffer once the end of the compressed
650       data stream has been reached. You can then use the filehandle to read
651       the rest of the input file.
652
653       Don't bother using "trailingData" if the input is a filename.
654
655       If you know the length of the compressed data stream before you start
656       uncompressing, you can avoid having to use "trailingData" by setting
657       the "InputLength" option in the constructor.
658

Importing

660       No symbolic constants are required by this IO::Uncompress::RawInflate
661       at present.
662
663       :all Imports "rawinflate" and $RawInflateError.  Same as doing this
664
665                use IO::Uncompress::RawInflate qw(rawinflate $RawInflateError) ;
666

EXAMPLES

668   Working with Net::FTP
669       See IO::Compress::FAQ
670

AUTHOR

697       This module was written by Paul Marquess, pmqs@cpan.org.
698

MODIFICATION HISTORY

700       See the Changes file.
701

COPYRIGHT AND LICENSE

703       Copyright (c) 2005-2013 Paul Marquess. All rights reserved.
704
705       This program is free software; you can redistribute it and/or modify it
706       under the same terms as Perl itself.
707
708
709
710perl v5.16.3                      2013-05-19     IO::Uncompress::RawInflate(3)