IO::Compress::Lzma(3pm)

1IO::Compress::Lzma(3) User Contributed Perl DocumentationIO::Compress::Lzma(3)
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NAME

6       IO::Compress::Lzma - Write lzma files/buffers
7

SYNOPSIS

9           use IO::Compress::Lzma qw(lzma $LzmaError) ;
10
11           my $status = lzma $input => $output [,OPTS]
12               or die "lzma failed: $LzmaError\n";
13
14           my $z = new IO::Compress::Lzma $output [,OPTS]
15               or die "lzma failed: $LzmaError\n";
16
17           $z->print($string);
18           $z->printf($format, $string);
19           $z->write($string);
20           $z->syswrite($string [, $length, $offset]);
21           $z->flush();
22           $z->tell();
23           $z->eof();
24           $z->seek($position, $whence);
25           $z->binmode();
26           $z->fileno();
27           $z->opened();
28           $z->autoflush();
29           $z->input_line_number();
30           $z->newStream( [OPTS] );
31
32           $z->close() ;
33
34           $LzmaError ;
35
36           # IO::File mode
37
38           print $z $string;
39           printf $z $format, $string;
40           tell $z
41           eof $z
42           seek $z, $position, $whence
43           binmode $z
44           fileno $z
45           close $z ;
46

DESCRIPTION

48       WARNING -- This is a Beta release.
49
50       ·    DO NOT use in production code.
51
52       ·    The documentation is incomplete in places.
53
54       ·    Parts of the interface defined here are tentative.
55
56       ·    Please report any problems you find.
57
58       This module provides a Perl interface that allows writing lzma
59       compressed data to files or buffer.
60
61       For reading lzma files/buffers, see the companion module
62       IO::Uncompress::UnLzma.
63

Functional Interface

65       A top-level function, "lzma", is provided to carry out "one-shot"
66       compression between buffers and/or files. For finer control over the
67       compression process, see the "OO Interface" section.
68
69           use IO::Compress::Lzma qw(lzma $LzmaError) ;
70
71           lzma $input => $output [,OPTS]
72               or die "lzma failed: $LzmaError\n";
73
74       The functional interface needs Perl5.005 or better.
75
76   lzma $input => $output [, OPTS]
77       "lzma" expects at least two parameters, $input and $output.
78
79       The $input parameter
80
81       The parameter, $input, is used to define the source of the uncompressed
82       data.
83
84       It can take one of the following forms:
85
86       A filename
87            If the $input parameter is a simple scalar, it is assumed to be a
88            filename. This file will be opened for reading and the input data
89            will be read from it.
90
91       A filehandle
92            If the $input parameter is a filehandle, the input data will be
93            read from it.  The string '-' can be used as an alias for standard
94            input.
95
96       A scalar reference
97            If $input is a scalar reference, the input data will be read from
98            $$input.
99
100       An array reference
101            If $input is an array reference, each element in the array must be
102            a filename.
103
104            The input data will be read from each file in turn.
105
106            The complete array will be walked to ensure that it only contains
107            valid filenames before any data is compressed.
108
109       An Input FileGlob string
110            If $input is a string that is delimited by the characters "<" and
111            ">" "lzma" will assume that it is an input fileglob string. The
112            input is the list of files that match the fileglob.
113
114            See File::GlobMapper for more details.
115
116       If the $input parameter is any other type, "undef" will be returned.
117
118       The $output parameter
119
120       The parameter $output is used to control the destination of the
121       compressed data. This parameter can take one of these forms.
122
123       A filename
124            If the $output parameter is a simple scalar, it is assumed to be a
125            filename.  This file will be opened for writing and the compressed
126            data will be written to it.
127
128       A filehandle
129            If the $output parameter is a filehandle, the compressed data will
130            be written to it.  The string '-' can be used as an alias for
131            standard output.
132
133       A scalar reference
134            If $output is a scalar reference, the compressed data will be
135            stored in $$output.
136
137       An Array Reference
138            If $output is an array reference, the compressed data will be
139            pushed onto the array.
140
141       An Output FileGlob
142            If $output is a string that is delimited by the characters "<" and
143            ">" "lzma" will assume that it is an output fileglob string. The
144            output is the list of files that match the fileglob.
145
146            When $output is an fileglob string, $input must also be a fileglob
147            string. Anything else is an error.
148
149            See File::GlobMapper for more details.
150
151       If the $output parameter is any other type, "undef" will be returned.
152
153   Notes
154       When $input maps to multiple files/buffers and $output is a single
155       file/buffer the input files/buffers will be stored in $output as a
156       concatenated series of compressed data streams.
157
158   Optional Parameters
159       Unless specified below, the optional parameters for "lzma", "OPTS", are
160       the same as those used with the OO interface defined in the
161       "Constructor Options" section below.
162
163       "AutoClose => 0|1"
164            This option applies to any input or output data streams to "lzma"
165            that are filehandles.
166
167            If "AutoClose" is specified, and the value is true, it will result
168            in all input and/or output filehandles being closed once "lzma"
169            has completed.
170
171            This parameter defaults to 0.
172
173       "BinModeIn => 0|1"
174            When reading from a file or filehandle, set "binmode" before
175            reading.
176
177            Defaults to 0.
178
179       "Append => 0|1"
180            The behaviour of this option is dependent on the type of output
181            data stream.
182
183            ·    A Buffer
184
185                 If "Append" is enabled, all compressed data will be append to
186                 the end of the output buffer. Otherwise the output buffer
187                 will be cleared before any compressed data is written to it.
188
189            ·    A Filename
190
191                 If "Append" is enabled, the file will be opened in append
192                 mode. Otherwise the contents of the file, if any, will be
193                 truncated before any compressed data is written to it.
194
195            ·    A Filehandle
196
197                 If "Append" is enabled, the filehandle will be positioned to
198                 the end of the file via a call to "seek" before any
199                 compressed data is written to it.  Otherwise the file pointer
200                 will not be moved.
201
202            When "Append" is specified, and set to true, it will append all
203            compressed data to the output data stream.
204
205            So when the output is a filehandle it will carry out a seek to the
206            eof before writing any compressed data. If the output is a
207            filename, it will be opened for appending. If the output is a
208            buffer, all compressed data will be appened to the existing
209            buffer.
210
211            Conversely when "Append" is not specified, or it is present and is
212            set to false, it will operate as follows.
213
214            When the output is a filename, it will truncate the contents of
215            the file before writing any compressed data. If the output is a
216            filehandle its position will not be changed. If the output is a
217            buffer, it will be wiped before any compressed data is output.
218
219            Defaults to 0.
220
221   Examples
222       To read the contents of the file "file1.txt" and write the compressed
223       data to the file "file1.txt.lzma".
224
225           use strict ;
226           use warnings ;
227           use IO::Compress::Lzma qw(lzma $LzmaError) ;
228
229           my $input = "file1.txt";
230           lzma $input => "$input.lzma"
231               or die "lzma failed: $LzmaError\n";
232
233       To read from an existing Perl filehandle, $input, and write the
234       compressed data to a buffer, $buffer.
235
236           use strict ;
237           use warnings ;
238           use IO::Compress::Lzma qw(lzma $LzmaError) ;
239           use IO::File ;
240
241           my $input = new IO::File "<file1.txt"
242               or die "Cannot open 'file1.txt': $!\n" ;
243           my $buffer ;
244           lzma $input => \$buffer
245               or die "lzma failed: $LzmaError\n";
246
247       To compress all files in the directory "/my/home" that match "*.txt"
248       and store the compressed data in the same directory
249
250           use strict ;
251           use warnings ;
252           use IO::Compress::Lzma qw(lzma $LzmaError) ;
253
254           lzma '</my/home/*.txt>' => '<*.lzma>'
255               or die "lzma failed: $LzmaError\n";
256
257       and if you want to compress each file one at a time, this will do the
258       trick
259
260           use strict ;
261           use warnings ;
262           use IO::Compress::Lzma qw(lzma $LzmaError) ;
263
264           for my $input ( glob "/my/home/*.txt" )
265           {
266               my $output = "$input.lzma" ;
267               lzma $input => $output
268                   or die "Error compressing '$input': $LzmaError\n";
269           }
270

OO Interface

272   Constructor
273       The format of the constructor for "IO::Compress::Lzma" is shown below
274
275           my $z = new IO::Compress::Lzma $output [,OPTS]
276               or die "IO::Compress::Lzma failed: $LzmaError\n";
277
278       It returns an "IO::Compress::Lzma" object on success and undef on
279       failure.  The variable $LzmaError will contain an error message on
280       failure.
281
282       If you are running Perl 5.005 or better the object, $z, returned from
283       IO::Compress::Lzma can be used exactly like an IO::File filehandle.
284       This means that all normal output file operations can be carried out
285       with $z.  For example, to write to a compressed file/buffer you can use
286       either of these forms
287
288           $z->print("hello world\n");
289           print $z "hello world\n";
290
291       The mandatory parameter $output is used to control the destination of
292       the compressed data. This parameter can take one of these forms.
293
294       A filename
295            If the $output parameter is a simple scalar, it is assumed to be a
296            filename. This file will be opened for writing and the compressed
297            data will be written to it.
298
299       A filehandle
300            If the $output parameter is a filehandle, the compressed data will
301            be written to it.  The string '-' can be used as an alias for
302            standard output.
303
304       A scalar reference
305            If $output is a scalar reference, the compressed data will be
306            stored in $$output.
307
308       If the $output parameter is any other type, "IO::Compress::Lzma"::new
309       will return undef.
310
311   Constructor Options
312       "OPTS" is any combination of the following options:
313
314       "AutoClose => 0|1"
315            This option is only valid when the $output parameter is a
316            filehandle. If specified, and the value is true, it will result in
317            the $output being closed once either the "close" method is called
318            or the "IO::Compress::Lzma" object is destroyed.
319
320            This parameter defaults to 0.
321
322       "Append => 0|1"
323            Opens $output in append mode.
324
325            The behaviour of this option is dependent on the type of $output.
326
327            ·    A Buffer
328
329                 If $output is a buffer and "Append" is enabled, all
330                 compressed data will be append to the end of $output.
331                 Otherwise $output will be cleared before any data is written
332                 to it.
333
334            ·    A Filename
335
336                 If $output is a filename and "Append" is enabled, the file
337                 will be opened in append mode. Otherwise the contents of the
338                 file, if any, will be truncated before any compressed data is
339                 written to it.
340
341            ·    A Filehandle
342
343                 If $output is a filehandle, the file pointer will be
344                 positioned to the end of the file via a call to "seek" before
345                 any compressed data is written to it.  Otherwise the file
346                 pointer will not be moved.
347
348            This parameter defaults to 0.
349
350       "Filter => $filter"
351            When present  $filter  option must be an object of type
352            "Lzma::Filter::Lzma1".  See "Lzma::Filter::Lzma" for a definition
353            of "Lzma::Filter::Lzma1".
354
355            If this option is not present an "Lzma::Filter::Lzma1" object with
356            default values will be used.
357
358       "Strict => 0|1"
359            This is a placeholder option.
360
361   Examples
362       TODO
363

Methods

365   print
366       Usage is
367
368           $z->print($data)
369           print $z $data
370
371       Compresses and outputs the contents of the $data parameter. This has
372       the same behaviour as the "print" built-in.
373
374       Returns true if successful.
375
376   printf
377       Usage is
378
379           $z->printf($format, $data)
380           printf $z $format, $data
381
382       Compresses and outputs the contents of the $data parameter.
383
384       Returns true if successful.
385
386   syswrite
387       Usage is
388
389           $z->syswrite $data
390           $z->syswrite $data, $length
391           $z->syswrite $data, $length, $offset
392
393       Compresses and outputs the contents of the $data parameter.
394
395       Returns the number of uncompressed bytes written, or "undef" if
396       unsuccessful.
397
398   write
399       Usage is
400
401           $z->write $data
402           $z->write $data, $length
403           $z->write $data, $length, $offset
404
405       Compresses and outputs the contents of the $data parameter.
406
407       Returns the number of uncompressed bytes written, or "undef" if
408       unsuccessful.
409
410   flush
411       Usage is
412
413           $z->flush;
414
415       Flushes any pending compressed data to the output file/buffer.
416
417       Returns true on success.
418
419   tell
420       Usage is
421
422           $z->tell()
423           tell $z
424
425       Returns the uncompressed file offset.
426
427   eof
428       Usage is
429
430           $z->eof();
431           eof($z);
432
433       Returns true if the "close" method has been called.
434
435   seek
436           $z->seek($position, $whence);
437           seek($z, $position, $whence);
438
439       Provides a sub-set of the "seek" functionality, with the restriction
440       that it is only legal to seek forward in the output file/buffer.  It is
441       a fatal error to attempt to seek backward.
442
443       Empty parts of the file/buffer will have NULL (0x00) bytes written to
444       them.
445
446       The $whence parameter takes one the usual values, namely SEEK_SET,
447       SEEK_CUR or SEEK_END.
448
449       Returns 1 on success, 0 on failure.
450
451   binmode
452       Usage is
453
454           $z->binmode
455           binmode $z ;
456
457       This is a noop provided for completeness.
458
459   opened
460           $z->opened()
461
462       Returns true if the object currently refers to a opened file/buffer.
463
464   autoflush
465           my $prev = $z->autoflush()
466           my $prev = $z->autoflush(EXPR)
467
468       If the $z object is associated with a file or a filehandle, this method
469       returns the current autoflush setting for the underlying filehandle. If
470       "EXPR" is present, and is non-zero, it will enable flushing after every
471       write/print operation.
472
473       If $z is associated with a buffer, this method has no effect and always
474       returns "undef".
475
476       Note that the special variable $| cannot be used to set or retrieve the
477       autoflush setting.
478
479   input_line_number
480           $z->input_line_number()
481           $z->input_line_number(EXPR)
482
483       This method always returns "undef" when compressing.
484
485   fileno
486           $z->fileno()
487           fileno($z)
488
489       If the $z object is associated with a file or a filehandle, "fileno"
490       will return the underlying file descriptor. Once the "close" method is
491       called "fileno" will return "undef".
492
493       If the $z object is is associated with a buffer, this method will
494       return "undef".
495
496   close
497           $z->close() ;
498           close $z ;
499
500       Flushes any pending compressed data and then closes the output
501       file/buffer.
502
503       For most versions of Perl this method will be automatically invoked if
504       the IO::Compress::Lzma object is destroyed (either explicitly or by the
505       variable with the reference to the object going out of scope). The
506       exceptions are Perl versions 5.005 through 5.00504 and 5.8.0. In these
507       cases, the "close" method will be called automatically, but not until
508       global destruction of all live objects when the program is terminating.
509
510       Therefore, if you want your scripts to be able to run on all versions
511       of Perl, you should call "close" explicitly and not rely on automatic
512       closing.
513
514       Returns true on success, otherwise 0.
515
516       If the "AutoClose" option has been enabled when the IO::Compress::Lzma
517       object was created, and the object is associated with a file, the
518       underlying file will also be closed.
519
520   newStream([OPTS])
521       Usage is
522
523           $z->newStream( [OPTS] )
524
525       Closes the current compressed data stream and starts a new one.
526
527       OPTS consists of any of the the options that are available when
528       creating the $z object.
529
530       See the "Constructor Options" section for more details.
531

Importing

533       No symbolic constants are required by this IO::Compress::Lzma at
534       present.
535
536       :all Imports "lzma" and $LzmaError.  Same as doing this
537
538                use IO::Compress::Lzma qw(lzma $LzmaError) ;
539

EXAMPLES

541   Apache::GZip Revisited
542       See IO::Compress::Lzma::FAQ
543

AUTHOR

558       This module was written by Paul Marquess, pmqs@cpan.org.
559

MODIFICATION HISTORY

561       See the Changes file.
562

COPYRIGHT AND LICENSE

564       Copyright (c) 2005-2010 Paul Marquess. All rights reserved.
565
566       This program is free software; you can redistribute it and/or modify it
567       under the same terms as Perl itself.
568
569
570
571perl v5.12.1                      2010-07-24             IO::Compress::Lzma(3)