1IO::Uncompress::Inflate(P3eprml)Programmers Reference GIuOi:d:eUncompress::Inflate(3pm)
2
6 IO::Uncompress::Inflate - Read RFC 1950 files/buffers
7
9 use IO::Uncompress::Inflate qw(inflate $InflateError) ;
10 my $status = inflate $input => $output [,OPTS]
12 or die "inflate failed: $InflateError\n";
13 my $z = new IO::Uncompress::Inflate $input [OPTS]
15 or die "inflate failed: $InflateError\n";
16 $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 $status = $z->inflateSync()
26 $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 $InflateError ;
38 # IO::File mode
40 <$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
53 This module provides a Perl interface that allows the reading of
54 files/buffers that conform to RFC 1950.
55 For writing RFC 1950 files/buffers, see the companion module
57 IO::Compress::Deflate.
58
60 A top-level function, "inflate", 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 use IO::Uncompress::Inflate qw(inflate $InflateError) ;
65 inflate $input => $output [,OPTS]
67 or die "inflate failed: $InflateError\n";
68 The functional interface needs Perl5.005 or better.
70 inflate $input => $output [, OPTS]
72 "inflate" expects at least two parameters, $input and $output.
73 The $input parameter
75 The parameter, $input, is used to define the source of the compressed
77 data.
78 It can take one of the following forms:
80 A filename
82 If the $input parameter is a simple scalar, it is assumed to be a
83 filename. This file will be opened for reading and the input data
84 will be read from it.
85 A filehandle
87 If the $input parameter is a filehandle, the input data will be
88 read from it. The string '-' can be used as an alias for standard
89 input.
90 A scalar reference
92 If $input is a scalar reference, the input data will be read from
93 $$input.
94 An array reference
96 If $input is an array reference, each element in the array must be
97 a filename.
98 The input data will be read from each file in turn.
100 The complete array will be walked to ensure that it only contains
102 valid filenames before any data is uncompressed.
103 An Input FileGlob string
105 If $input is a string that is delimited by the characters "<" and
106 ">" "inflate" will assume that it is an input fileglob string. The
107 input is the list of files that match the fileglob.
108 If the fileglob does not match any files ...
110 See File::GlobMapper for more details.
112 If the $input parameter is any other type, "undef" will be returned.
114 The $output parameter
116 The parameter $output is used to control the destination of the
118 uncompressed data. This parameter can take one of these forms.
119 A filename
121 If the $output parameter is a simple scalar, it is assumed to be a
122 filename. This file will be opened for writing and the
123 uncompressed data will be written to it.
124 A filehandle
126 If the $output parameter is a filehandle, the uncompressed data
127 will be written to it. The string '-' can be used as an alias for
128 standard output.
129 A scalar reference
131 If $output is a scalar reference, the uncompressed data will be
132 stored in $$output.
133 An Array Reference
135 If $output is an array reference, the uncompressed data will be
136 pushed onto the array.
137 An Output FileGlob
139 If $output is a string that is delimited by the characters "<" and
140 ">" "inflate" will assume that it is an output fileglob string.
141 The output is the list of files that match the fileglob.
142 When $output is an fileglob string, $input must also be a fileglob
144 string. Anything else is an error.
145 If the $output parameter is any other type, "undef" will be returned.
147 Notes
149 When $input maps to multiple compressed files/buffers and $output is a
150 single file/buffer, after uncompression $output will contain a
151 concatenation of all the uncompressed data from each of the input
152 files/buffers.
153 Optional Parameters
155 Unless specified below, the optional parameters for "inflate", "OPTS",
156 are the same as those used with the OO interface defined in the
157 "Constructor Options" section below.
158 "AutoClose => 0|1"
160 This option applies to any input or output data streams to
161 "inflate" that are filehandles.
162 If "AutoClose" is specified, and the value is true, it will result
164 in all input and/or output filehandles being closed once "inflate"
165 has completed.
166 This parameter defaults to 0.
168 "BinModeOut => 0|1"
170 When writing to a file or filehandle, set "binmode" before writing
171 to the file.
172 Defaults to 0.
174 "Append => 0|1"
176 TODO
177 "MultiStream => 0|1"
179 If the input file/buffer contains multiple compressed data
180 streams, this option will uncompress the whole lot as a single
181 data stream.
182 Defaults to 0.
184 "TrailingData => $scalar"
186 Returns the data, if any, that is present immediately after the
187 compressed data stream once uncompression is complete.
188 This option can be used when there is useful information
190 immediately following the compressed data stream, and you don't
191 know the length of the compressed data stream.
192 If the input is a buffer, "trailingData" will return everything
194 from the end of the compressed data stream to the end of the
195 buffer.
196 If the input is a filehandle, "trailingData" will return the data
198 that is left in the filehandle input buffer once the end of the
199 compressed data stream has been reached. You can then use the
200 filehandle to read the rest of the input file.
201 Don't bother using "trailingData" if the input is a filename.
203 If you know the length of the compressed data stream before you
205 start uncompressing, you can avoid having to use "trailingData" by
206 setting the "InputLength" option.
207 Examples
209 To read the contents of the file "file1.txt.1950" and write the
210 uncompressed data to the file "file1.txt".
211 use strict ;
213 use warnings ;
214 use IO::Uncompress::Inflate qw(inflate $InflateError) ;
215 my $input = "file1.txt.1950";
217 my $output = "file1.txt";
218 inflate $input => $output
219 or die "inflate failed: $InflateError\n";
220 To read from an existing Perl filehandle, $input, and write the
222 uncompressed data to a buffer, $buffer.
223 use strict ;
225 use warnings ;
226 use IO::Uncompress::Inflate qw(inflate $InflateError) ;
227 use IO::File ;
228 my $input = new IO::File "<file1.txt.1950"
230 or die "Cannot open 'file1.txt.1950': $!\n" ;
231 my $buffer ;
232 inflate $input => \$buffer
233 or die "inflate failed: $InflateError\n";
234 To uncompress all files in the directory "/my/home" that match
236 "*.txt.1950" and store the compressed data in the same directory
237 use strict ;
239 use warnings ;
240 use IO::Uncompress::Inflate qw(inflate $InflateError) ;
241 inflate '</my/home/*.txt.1950>' => '</my/home/#1.txt>'
243 or die "inflate failed: $InflateError\n";
244 and if you want to compress each file one at a time, this will do the
246 trick
247 use strict ;
249 use warnings ;
250 use IO::Uncompress::Inflate qw(inflate $InflateError) ;
251 for my $input ( glob "/my/home/*.txt.1950" )
253 {
254 my $output = $input;
255 $output =~ s/.1950// ;
256 inflate $input => $output
257 or die "Error compressing '$input': $InflateError\n";
258 }
259
261 Constructor
262 The format of the constructor for IO::Uncompress::Inflate is shown
263 below
264 my $z = new IO::Uncompress::Inflate $input [OPTS]
266 or die "IO::Uncompress::Inflate failed: $InflateError\n";
267 Returns an "IO::Uncompress::Inflate" object on success and undef on
269 failure. The variable $InflateError will contain an error message on
270 failure.
271 If you are running Perl 5.005 or better the object, $z, returned from
273 IO::Uncompress::Inflate can be used exactly like an IO::File
274 filehandle. This means that all normal input file operations can be
275 carried out with $z. For example, to read a line from a compressed
276 file/buffer you can use either of these forms
277 $line = $z->getline();
279 $line = <$z>;
280 The mandatory parameter $input is used to determine the source of the
282 compressed data. This parameter can take one of three forms.
283 A filename
285 If the $input parameter is a scalar, it is assumed to be a
286 filename. This file will be opened for reading and the compressed
287 data will be read from it.
288 A filehandle
290 If the $input parameter is a filehandle, the compressed data will
291 be read from it. The string '-' can be used as an alias for
292 standard input.
293 A scalar reference
295 If $input is a scalar reference, the compressed data will be read
296 from $$output.
297 Constructor Options
299 The option names defined below are case insensitive and can be
300 optionally prefixed by a '-'. So all of the following are valid
301 -AutoClose
303 -autoclose
304 AUTOCLOSE
305 autoclose
306 OPTS is a combination of the following options:
308 "AutoClose => 0|1"
310 This option is only valid when the $input parameter is a
311 filehandle. If specified, and the value is true, it will result in
312 the file being closed once either the "close" method is called or
313 the IO::Uncompress::Inflate object is destroyed.
314 This parameter defaults to 0.
316 "MultiStream => 0|1"
318 Allows multiple concatenated compressed streams to be treated as a
319 single compressed stream. Decompression will stop once either the
320 end of the file/buffer is reached, an error is encountered
321 (premature eof, corrupt compressed data) or the end of a stream is
322 not immediately followed by the start of another stream.
323 This parameter defaults to 0.
325 "Prime => $string"
327 This option will uncompress the contents of $string before
328 processing the input file/buffer.
329 This option can be useful when the compressed data is embedded in
331 another file/data structure and it is not possible to work out
332 where the compressed data begins without having to read the first
333 few bytes. If this is the case, the uncompression can be primed
334 with these bytes using this option.
335 "Transparent => 0|1"
337 If this option is set and the input file/buffer is not compressed
338 data, the module will allow reading of it anyway.
339 In addition, if the input file/buffer does contain compressed data
341 and there is non-compressed data immediately following it, setting
342 this option will make this module treat the whole file/bufffer as
343 a single data stream.
344 This option defaults to 1.
346 "BlockSize => $num"
348 When reading the compressed input data, IO::Uncompress::Inflate
349 will read it in blocks of $num bytes.
350 This option defaults to 4096.
352 "InputLength => $size"
354 When present this option will limit the number of compressed bytes
355 read from the input file/buffer to $size. This option can be used
356 in the situation where there is useful data directly after the
357 compressed data stream and you know beforehand the exact length of
358 the compressed data stream.
359 This option is mostly used when reading from a filehandle, in
361 which case the file pointer will be left pointing to the first
362 byte directly after the compressed data stream.
363 This option defaults to off.
365 "Append => 0|1"
367 This option controls what the "read" method does with uncompressed
368 data.
369 If set to 1, all uncompressed data will be appended to the output
371 parameter of the "read" method.
372 If set to 0, the contents of the output parameter of the "read"
374 method will be overwritten by the uncompressed data.
375 Defaults to 0.
377 "Strict => 0|1"
379 This option controls whether the extra checks defined below are
380 used when carrying out the decompression. When Strict is on, the
381 extra tests are carried out, when Strict is off they are not.
382 The default for this option is off.
384 1. The ADLER32 checksum field must be present.
386 2. The value of the ADLER32 field read must match the adler32
388 value of the uncompressed data actually contained in the
389 file.
390 Examples
392 TODO
393
395 read
396 Usage is
397 $status = $z->read($buffer)
399 Reads a block of compressed data (the size the the compressed block is
401 determined by the "Buffer" option in the constructor), uncompresses it
402 and writes any uncompressed data into $buffer. If the "Append"
403 parameter is set in the constructor, the uncompressed data will be
404 appended to the $buffer parameter. Otherwise $buffer will be
405 overwritten.
406 Returns the number of uncompressed bytes written to $buffer, zero if
408 eof or a negative number on error.
409 read
411 Usage is
412 $status = $z->read($buffer, $length)
414 $status = $z->read($buffer, $length, $offset)
415 $status = read($z, $buffer, $length)
417 $status = read($z, $buffer, $length, $offset)
418 Attempt to read $length bytes of uncompressed data into $buffer.
420 The main difference between this form of the "read" method and the
422 previous one, is that this one will attempt to return exactly $length
423 bytes. The only circumstances that this function will not is if end-of-
424 file or an IO error is encountered.
425 Returns the number of uncompressed bytes written to $buffer, zero if
427 eof or a negative number on error.
428 getline
430 Usage is
431 $line = $z->getline()
433 $line = <$z>
434 Reads a single line.
436 This method fully supports the use of of the variable $/ (or
438 $INPUT_RECORD_SEPARATOR or $RS when "English" is in use) to determine
439 what constitutes an end of line. Paragraph mode, record mode and file
440 slurp mode are all supported.
441 getc
443 Usage is
444 $char = $z->getc()
446 Read a single character.
448 ungetc
450 Usage is
451 $char = $z->ungetc($string)
453 inflateSync
455 Usage is
456 $status = $z->inflateSync()
458 TODO
460 getHeaderInfo
462 Usage is
463 $hdr = $z->getHeaderInfo();
465 @hdrs = $z->getHeaderInfo();
466 This method returns either a hash reference (in scalar context) or a
468 list or hash references (in array context) that contains information
469 about each of the header fields in the compressed data stream(s).
470 tell
472 Usage is
473 $z->tell()
475 tell $z
476 Returns the uncompressed file offset.
478 eof
480 Usage is
481 $z->eof();
483 eof($z);
484 Returns true if the end of the compressed input stream has been
486 reached.
487 seek
489 $z->seek($position, $whence);
490 seek($z, $position, $whence);
491 Provides a sub-set of the "seek" functionality, with the restriction
493 that it is only legal to seek forward in the input file/buffer. It is
494 a fatal error to attempt to seek backward.
495 The $whence parameter takes one the usual values, namely SEEK_SET,
497 SEEK_CUR or SEEK_END.
498 Returns 1 on success, 0 on failure.
500 binmode
502 Usage is
503 $z->binmode
505 binmode $z ;
506 This is a noop provided for completeness.
508 opened
510 $z->opened()
511 Returns true if the object currently refers to a opened file/buffer.
513 autoflush
515 my $prev = $z->autoflush()
516 my $prev = $z->autoflush(EXPR)
517 If the $z object is associated with a file or a filehandle, this method
519 returns the current autoflush setting for the underlying filehandle. If
520 "EXPR" is present, and is non-zero, it will enable flushing after every
521 write/print operation.
522 If $z is associated with a buffer, this method has no effect and always
524 returns "undef".
525 Note that the special variable $| cannot be used to set or retrieve the
527 autoflush setting.
528 input_line_number
530 $z->input_line_number()
531 $z->input_line_number(EXPR)
532 Returns the current uncompressed line number. If "EXPR" is present it
534 has the effect of setting the line number. Note that setting the line
535 number does not change the current position within the file/buffer
536 being read.
537 The contents of $/ are used to to determine what constitutes a line
539 terminator.
540 fileno
542 $z->fileno()
543 fileno($z)
544 If the $z object is associated with a file or a filehandle, "fileno"
546 will return the underlying file descriptor. Once the "close" method is
547 called "fileno" will return "undef".
548 If the $z object is is associated with a buffer, this method will
550 return "undef".
551 close
553 $z->close() ;
554 close $z ;
555 Closes the output file/buffer.
557 For most versions of Perl this method will be automatically invoked if
559 the IO::Uncompress::Inflate object is destroyed (either explicitly or
560 by the variable with the reference to the object going out of scope).
561 The exceptions are Perl versions 5.005 through 5.00504 and 5.8.0. In
562 these cases, the "close" method will be called automatically, but not
563 until global destruction of all live objects when the program is
564 terminating.
565 Therefore, if you want your scripts to be able to run on all versions
567 of Perl, you should call "close" explicitly and not rely on automatic
568 closing.
569 Returns true on success, otherwise 0.
571 If the "AutoClose" option has been enabled when the
573 IO::Uncompress::Inflate object was created, and the object is
574 associated with a file, the underlying file will also be closed.
575 nextStream
577 Usage is
578 my $status = $z->nextStream();
580 Skips to the next compressed data stream in the input file/buffer. If a
582 new compressed data stream is found, the eof marker will be cleared and
583 $. will be reset to 0.
584 Returns 1 if a new stream was found, 0 if none was found, and -1 if an
586 error was encountered.
587 trailingData
589 Usage is
590 my $data = $z->trailingData();
592 Returns the data, if any, that is present immediately after the
594 compressed data stream once uncompression is complete. It only makes
595 sense to call this method once the end of the compressed data stream
596 has been encountered.
597 This option can be used when there is useful information immediately
599 following the compressed data stream, and you don't know the length of
600 the compressed data stream.
601 If the input is a buffer, "trailingData" will return everything from
603 the end of the compressed data stream to the end of the buffer.
604 If the input is a filehandle, "trailingData" will return the data that
606 is left in the filehandle input buffer once the end of the compressed
607 data stream has been reached. You can then use the filehandle to read
608 the rest of the input file.
609 Don't bother using "trailingData" if the input is a filename.
611 If you know the length of the compressed data stream before you start
613 uncompressing, you can avoid having to use "trailingData" by setting
614 the "InputLength" option in the constructor.
615
617 No symbolic constants are required by this IO::Uncompress::Inflate at
618 present.
619 :all Imports "inflate" and $InflateError. Same as doing this
621 use IO::Uncompress::Inflate qw(inflate $InflateError) ;
623
625 Working with Net::FTP
626 See IO::Uncompress::Inflate::FAQ
627
629 Compress::Zlib, IO::Compress::Gzip, IO::Uncompress::Gunzip,
630 IO::Compress::Deflate, IO::Compress::RawDeflate,
631 IO::Uncompress::RawInflate, IO::Compress::Bzip2,
632 IO::Uncompress::Bunzip2, IO::Compress::Lzop, IO::Uncompress::UnLzop,
633 IO::Compress::Lzf, IO::Uncompress::UnLzf, IO::Uncompress::AnyInflate,
634 IO::Uncompress::AnyUncompress
635 Compress::Zlib::FAQ
637 File::GlobMapper, Archive::Zip, Archive::Tar, IO::Zlib
639 For RFC 1950, 1951 and 1952 see http://www.faqs.org/rfcs/rfc1950.html,
641 http://www.faqs.org/rfcs/rfc1951.html and
642 http://www.faqs.org/rfcs/rfc1952.html
643 The zlib compression library was written by Jean-loup Gailly
645 gzip@prep.ai.mit.edu and Mark Adler madler@alumni.caltech.edu.
646 The primary site for the zlib compression library is
648 http://www.zlib.org.
649 The primary site for gzip is http://www.gzip.org.
651
653 This module was written by Paul Marquess, pmqs@cpan.org.
654
656 See the Changes file.
657
659 Copyright (c) 2005-2009 Paul Marquess. All rights reserved.
660 This program is free software; you can redistribute it and/or modify it
662 under the same terms as Perl itself.
663perl v5.10.1 2017-03-22 IO::Uncompress::Inflate(3pm)