2 package IO::Uncompress::Gunzip ;
12 use IO::Uncompress::RawInflate 2.048 ;
14 use Compress::Raw::Zlib 2.048 () ;
15 use IO::Compress::Base::Common 2.048 qw(:Status createSelfTiedObject);
16 use IO::Compress::Gzip::Constants 2.048 ;
17 use IO::Compress::Zlib::Extra 2.048 ;
21 our ($VERSION, @ISA, @EXPORT_OK, %EXPORT_TAGS, $GunzipError);
23 @ISA = qw( Exporter IO::Uncompress::RawInflate );
24 @EXPORT_OK = qw( $GunzipError gunzip );
25 %EXPORT_TAGS = %IO::Uncompress::RawInflate::DEFLATE_CONSTANTS ;
26 push @{ $EXPORT_TAGS{all} }, @EXPORT_OK ;
27 Exporter::export_ok_tags('all');
37 my $obj = createSelfTiedObject($class, \$GunzipError);
39 $obj->_create(undef, 0, @_);
44 my $obj = createSelfTiedObject(undef, \$GunzipError);
45 return $obj->_inf(@_) ;
50 use IO::Compress::Base::Common 2.048 qw(:Parse);
51 return ( 'ParseExtra' => [1, 1, Parse_boolean, 0] ) ;
59 # gunzip always needs crc32
60 $got->value('CRC32' => 1);
70 $self->smartReadExact(\$magic, GZIP_ID_SIZE);
72 *$self->{HeaderPending} = $magic ;
74 return $self->HeaderError("Minimum header size is " .
75 GZIP_MIN_HEADER_SIZE . " bytes")
76 if length $magic != GZIP_ID_SIZE ;
78 return $self->HeaderError("Bad Magic")
79 if ! isGzipMagic($magic) ;
81 *$self->{Type} = 'rfc1952';
91 return $self->_readGzipHeader($magic);
100 my ($CRC32, $ISIZE) = unpack("V V", $trailer) ;
101 *$self->{Info}{CRC32} = $CRC32;
102 *$self->{Info}{ISIZE} = $ISIZE;
104 if (*$self->{Strict}) {
105 return $self->TrailerError("CRC mismatch")
106 if $CRC32 != *$self->{Uncomp}->crc32() ;
108 my $exp_isize = *$self->{UnCompSize}->get32bit();
109 return $self->TrailerError("ISIZE mismatch. Got $ISIZE"
110 . ", expected $exp_isize")
111 if $ISIZE != $exp_isize ;
120 return 0 if length $buffer < GZIP_ID_SIZE ;
121 my ($id1, $id2) = unpack("C C", $buffer) ;
122 return $id1 == GZIP_ID1 && $id2 == GZIP_ID2 ;
125 sub _readFullGzipHeader($)
130 $self->smartReadExact(\$magic, GZIP_ID_SIZE);
132 *$self->{HeaderPending} = $magic ;
134 return $self->HeaderError("Minimum header size is " .
135 GZIP_MIN_HEADER_SIZE . " bytes")
136 if length $magic != GZIP_ID_SIZE ;
139 return $self->HeaderError("Bad Magic")
140 if ! isGzipMagic($magic) ;
142 my $status = $self->_readGzipHeader($magic);
143 delete *$self->{Transparent} if ! defined $status ;
147 sub _readGzipHeader($)
149 my ($self, $magic) = @_ ;
153 $self->smartReadExact(\$buffer, GZIP_MIN_HEADER_SIZE - GZIP_ID_SIZE)
154 or return $self->HeaderError("Minimum header size is " .
155 GZIP_MIN_HEADER_SIZE . " bytes") ;
157 my $keep = $magic . $buffer ;
158 *$self->{HeaderPending} = $keep ;
160 # now split out the various parts
161 my ($cm, $flag, $mtime, $xfl, $os) = unpack("C C V C C", $buffer) ;
163 $cm == GZIP_CM_DEFLATED
164 or return $self->HeaderError("Not Deflate (CM is $cm)") ;
166 # check for use of reserved bits
167 return $self->HeaderError("Use of Reserved Bits in FLG field.")
168 if $flag & GZIP_FLG_RESERVED ;
172 if ($flag & GZIP_FLG_FEXTRA) {
174 $self->smartReadExact(\$buffer, GZIP_FEXTRA_HEADER_SIZE)
175 or return $self->TruncatedHeader("FEXTRA Length") ;
177 my ($XLEN) = unpack("v", $buffer) ;
178 $self->smartReadExact(\$EXTRA, $XLEN)
179 or return $self->TruncatedHeader("FEXTRA Body");
180 $keep .= $buffer . $EXTRA ;
182 if ($XLEN && *$self->{'ParseExtra'}) {
183 my $bad = IO::Compress::Zlib::Extra::parseRawExtra($EXTRA,
185 return $self->HeaderError($bad)
191 if ($flag & GZIP_FLG_FNAME) {
194 $self->smartReadExact(\$buffer, 1)
195 or return $self->TruncatedHeader("FNAME");
196 last if $buffer eq GZIP_NULL_BYTE ;
199 $keep .= $origname . GZIP_NULL_BYTE ;
201 return $self->HeaderError("Non ISO 8859-1 Character found in Name")
202 if *$self->{Strict} && $origname =~ /$GZIP_FNAME_INVALID_CHAR_RE/o ;
206 if ($flag & GZIP_FLG_FCOMMENT) {
209 $self->smartReadExact(\$buffer, 1)
210 or return $self->TruncatedHeader("FCOMMENT");
211 last if $buffer eq GZIP_NULL_BYTE ;
214 $keep .= $comment . GZIP_NULL_BYTE ;
216 return $self->HeaderError("Non ISO 8859-1 Character found in Comment")
217 if *$self->{Strict} && $comment =~ /$GZIP_FCOMMENT_INVALID_CHAR_RE/o ;
220 if ($flag & GZIP_FLG_FHCRC) {
221 $self->smartReadExact(\$buffer, GZIP_FHCRC_SIZE)
222 or return $self->TruncatedHeader("FHCRC");
224 $HeaderCRC = unpack("v", $buffer) ;
225 my $crc16 = Compress::Raw::Zlib::crc32($keep) & 0xFF ;
227 return $self->HeaderError("CRC16 mismatch.")
228 if *$self->{Strict} && $crc16 != $HeaderCRC;
233 # Assume compression method is deflated for xfl tests
237 *$self->{Type} = 'rfc1952';
241 'FingerprintLength' => 2,
242 'HeaderLength' => length $keep,
243 'TrailerLength' => GZIP_TRAILER_SIZE,
245 'isMinimalHeader' => $keep eq GZIP_MINIMUM_HEADER ? 1 : 0,
248 'MethodName' => $cm == GZIP_CM_DEFLATED ? "Deflated" : "Unknown" ,
249 'TextFlag' => $flag & GZIP_FLG_FTEXT ? 1 : 0,
250 'HeaderCRCFlag' => $flag & GZIP_FLG_FHCRC ? 1 : 0,
251 'NameFlag' => $flag & GZIP_FLG_FNAME ? 1 : 0,
252 'CommentFlag' => $flag & GZIP_FLG_FCOMMENT ? 1 : 0,
253 'ExtraFlag' => $flag & GZIP_FLG_FEXTRA ? 1 : 0,
255 'Comment' => $comment,
258 'OsName' => defined $GZIP_OS_Names{$os}
259 ? $GZIP_OS_Names{$os} : "Unknown",
260 'HeaderCRC' => $HeaderCRC,
262 'ExtraFlags' => $xfl,
263 'ExtraFieldRaw' => $EXTRA,
264 'ExtraField' => [ @EXTRA ],
267 #'CompSize'=> $compsize,
269 #'OrigSize'=> $ISIZE,
281 IO::Uncompress::Gunzip - Read RFC 1952 files/buffers
285 use IO::Uncompress::Gunzip qw(gunzip $GunzipError) ;
287 my $status = gunzip $input => $output [,OPTS]
288 or die "gunzip failed: $GunzipError\n";
290 my $z = new IO::Uncompress::Gunzip $input [OPTS]
291 or die "gunzip failed: $GunzipError\n";
293 $status = $z->read($buffer)
294 $status = $z->read($buffer, $length)
295 $status = $z->read($buffer, $length, $offset)
296 $line = $z->getline()
301 $status = $z->inflateSync()
303 $data = $z->trailingData()
304 $status = $z->nextStream()
305 $data = $z->getHeaderInfo()
307 $z->seek($position, $whence)
319 read($z, $buffer, $length);
320 read($z, $buffer, $length, $offset);
322 seek($z, $position, $whence)
330 This module provides a Perl interface that allows the reading of
331 files/buffers that conform to RFC 1952.
333 For writing RFC 1952 files/buffers, see the companion module IO::Compress::Gzip.
335 =head1 Functional Interface
337 A top-level function, C<gunzip>, is provided to carry out
338 "one-shot" uncompression between buffers and/or files. For finer
339 control over the uncompression process, see the L</"OO Interface">
342 use IO::Uncompress::Gunzip qw(gunzip $GunzipError) ;
344 gunzip $input => $output [,OPTS]
345 or die "gunzip failed: $GunzipError\n";
347 The functional interface needs Perl5.005 or better.
349 =head2 gunzip $input => $output [, OPTS]
351 C<gunzip> expects at least two parameters, C<$input> and C<$output>.
353 =head3 The C<$input> parameter
355 The parameter, C<$input>, is used to define the source of
358 It can take one of the following forms:
364 If the C<$input> parameter is a simple scalar, it is assumed to be a
365 filename. This file will be opened for reading and the input data
366 will be read from it.
370 If the C<$input> parameter is a filehandle, the input data will be
372 The string '-' can be used as an alias for standard input.
374 =item A scalar reference
376 If C<$input> is a scalar reference, the input data will be read
379 =item An array reference
381 If C<$input> is an array reference, each element in the array must be a
384 The input data will be read from each file in turn.
386 The complete array will be walked to ensure that it only
387 contains valid filenames before any data is uncompressed.
389 =item An Input FileGlob string
391 If C<$input> is a string that is delimited by the characters "<" and ">"
392 C<gunzip> will assume that it is an I<input fileglob string>. The
393 input is the list of files that match the fileglob.
395 See L<File::GlobMapper|File::GlobMapper> for more details.
399 If the C<$input> parameter is any other type, C<undef> will be returned.
401 =head3 The C<$output> parameter
403 The parameter C<$output> is used to control the destination of the
404 uncompressed data. This parameter can take one of these forms.
410 If the C<$output> parameter is a simple scalar, it is assumed to be a
411 filename. This file will be opened for writing and the uncompressed
412 data will be written to it.
416 If the C<$output> parameter is a filehandle, the uncompressed data
417 will be written to it.
418 The string '-' can be used as an alias for standard output.
420 =item A scalar reference
422 If C<$output> is a scalar reference, the uncompressed data will be
423 stored in C<$$output>.
425 =item An Array Reference
427 If C<$output> is an array reference, the uncompressed data will be
428 pushed onto the array.
430 =item An Output FileGlob
432 If C<$output> is a string that is delimited by the characters "<" and ">"
433 C<gunzip> will assume that it is an I<output fileglob string>. The
434 output is the list of files that match the fileglob.
436 When C<$output> is an fileglob string, C<$input> must also be a fileglob
437 string. Anything else is an error.
439 See L<File::GlobMapper|File::GlobMapper> for more details.
443 If the C<$output> parameter is any other type, C<undef> will be returned.
447 When C<$input> maps to multiple compressed files/buffers and C<$output> is
448 a single file/buffer, after uncompression C<$output> will contain a
449 concatenation of all the uncompressed data from each of the input
452 =head2 Optional Parameters
454 Unless specified below, the optional parameters for C<gunzip>,
455 C<OPTS>, are the same as those used with the OO interface defined in the
456 L</"Constructor Options"> section below.
460 =item C<< AutoClose => 0|1 >>
462 This option applies to any input or output data streams to
463 C<gunzip> that are filehandles.
465 If C<AutoClose> is specified, and the value is true, it will result in all
466 input and/or output filehandles being closed once C<gunzip> has
469 This parameter defaults to 0.
471 =item C<< BinModeOut => 0|1 >>
473 When writing to a file or filehandle, set C<binmode> before writing to the
478 =item C<< Append => 0|1 >>
480 The behaviour of this option is dependent on the type of output data
487 If C<Append> is enabled, all uncompressed data will be append to the end of
488 the output buffer. Otherwise the output buffer will be cleared before any
489 uncompressed data is written to it.
493 If C<Append> is enabled, the file will be opened in append mode. Otherwise
494 the contents of the file, if any, will be truncated before any uncompressed
495 data is written to it.
499 If C<Append> is enabled, the filehandle will be positioned to the end of
500 the file via a call to C<seek> before any uncompressed data is
501 written to it. Otherwise the file pointer will not be moved.
505 When C<Append> is specified, and set to true, it will I<append> all uncompressed
506 data to the output data stream.
508 So when the output is a filehandle it will carry out a seek to the eof
509 before writing any uncompressed data. If the output is a filename, it will be opened for
510 appending. If the output is a buffer, all uncompressed data will be
511 appended to the existing buffer.
513 Conversely when C<Append> is not specified, or it is present and is set to
514 false, it will operate as follows.
516 When the output is a filename, it will truncate the contents of the file
517 before writing any uncompressed data. If the output is a filehandle
518 its position will not be changed. If the output is a buffer, it will be
519 wiped before any uncompressed data is output.
523 =item C<< MultiStream => 0|1 >>
525 If the input file/buffer contains multiple compressed data streams, this
526 option will uncompress the whole lot as a single data stream.
530 =item C<< TrailingData => $scalar >>
532 Returns the data, if any, that is present immediately after the compressed
533 data stream once uncompression is complete.
535 This option can be used when there is useful information immediately
536 following the compressed data stream, and you don't know the length of the
537 compressed data stream.
539 If the input is a buffer, C<trailingData> will return everything from the
540 end of the compressed data stream to the end of the buffer.
542 If the input is a filehandle, C<trailingData> will return the data that is
543 left in the filehandle input buffer once the end of the compressed data
544 stream has been reached. You can then use the filehandle to read the rest
547 Don't bother using C<trailingData> if the input is a filename.
549 If you know the length of the compressed data stream before you start
550 uncompressing, you can avoid having to use C<trailingData> by setting the
551 C<InputLength> option.
557 To read the contents of the file C<file1.txt.gz> and write the
558 uncompressed data to the file C<file1.txt>.
562 use IO::Uncompress::Gunzip qw(gunzip $GunzipError) ;
564 my $input = "file1.txt.gz";
565 my $output = "file1.txt";
566 gunzip $input => $output
567 or die "gunzip failed: $GunzipError\n";
569 To read from an existing Perl filehandle, C<$input>, and write the
570 uncompressed data to a buffer, C<$buffer>.
574 use IO::Uncompress::Gunzip qw(gunzip $GunzipError) ;
577 my $input = new IO::File "<file1.txt.gz"
578 or die "Cannot open 'file1.txt.gz': $!\n" ;
580 gunzip $input => \$buffer
581 or die "gunzip failed: $GunzipError\n";
583 To uncompress all files in the directory "/my/home" that match "*.txt.gz" and store the compressed data in the same directory
587 use IO::Uncompress::Gunzip qw(gunzip $GunzipError) ;
589 gunzip '</my/home/*.txt.gz>' => '</my/home/#1.txt>'
590 or die "gunzip failed: $GunzipError\n";
592 and if you want to compress each file one at a time, this will do the trick
596 use IO::Uncompress::Gunzip qw(gunzip $GunzipError) ;
598 for my $input ( glob "/my/home/*.txt.gz" )
602 gunzip $input => $output
603 or die "Error compressing '$input': $GunzipError\n";
610 The format of the constructor for IO::Uncompress::Gunzip is shown below
612 my $z = new IO::Uncompress::Gunzip $input [OPTS]
613 or die "IO::Uncompress::Gunzip failed: $GunzipError\n";
615 Returns an C<IO::Uncompress::Gunzip> object on success and undef on failure.
616 The variable C<$GunzipError> will contain an error message on failure.
618 If you are running Perl 5.005 or better the object, C<$z>, returned from
619 IO::Uncompress::Gunzip can be used exactly like an L<IO::File|IO::File> filehandle.
620 This means that all normal input file operations can be carried out with
621 C<$z>. For example, to read a line from a compressed file/buffer you can
622 use either of these forms
624 $line = $z->getline();
627 The mandatory parameter C<$input> is used to determine the source of the
628 compressed data. This parameter can take one of three forms.
634 If the C<$input> parameter is a scalar, it is assumed to be a filename. This
635 file will be opened for reading and the compressed data will be read from it.
639 If the C<$input> parameter is a filehandle, the compressed data will be
641 The string '-' can be used as an alias for standard input.
643 =item A scalar reference
645 If C<$input> is a scalar reference, the compressed data will be read from
650 =head2 Constructor Options
652 The option names defined below are case insensitive and can be optionally
653 prefixed by a '-'. So all of the following are valid
660 OPTS is a combination of the following options:
664 =item C<< AutoClose => 0|1 >>
666 This option is only valid when the C<$input> parameter is a filehandle. If
667 specified, and the value is true, it will result in the file being closed once
668 either the C<close> method is called or the IO::Uncompress::Gunzip object is
671 This parameter defaults to 0.
673 =item C<< MultiStream => 0|1 >>
675 Allows multiple concatenated compressed streams to be treated as a single
676 compressed stream. Decompression will stop once either the end of the
677 file/buffer is reached, an error is encountered (premature eof, corrupt
678 compressed data) or the end of a stream is not immediately followed by the
679 start of another stream.
681 This parameter defaults to 0.
683 =item C<< Prime => $string >>
685 This option will uncompress the contents of C<$string> before processing the
688 This option can be useful when the compressed data is embedded in another
689 file/data structure and it is not possible to work out where the compressed
690 data begins without having to read the first few bytes. If this is the
691 case, the uncompression can be I<primed> with these bytes using this
694 =item C<< Transparent => 0|1 >>
696 If this option is set and the input file/buffer is not compressed data,
697 the module will allow reading of it anyway.
699 In addition, if the input file/buffer does contain compressed data and
700 there is non-compressed data immediately following it, setting this option
701 will make this module treat the whole file/buffer as a single data stream.
703 This option defaults to 1.
705 =item C<< BlockSize => $num >>
707 When reading the compressed input data, IO::Uncompress::Gunzip will read it in
708 blocks of C<$num> bytes.
710 This option defaults to 4096.
712 =item C<< InputLength => $size >>
714 When present this option will limit the number of compressed bytes read
715 from the input file/buffer to C<$size>. This option can be used in the
716 situation where there is useful data directly after the compressed data
717 stream and you know beforehand the exact length of the compressed data
720 This option is mostly used when reading from a filehandle, in which case
721 the file pointer will be left pointing to the first byte directly after the
722 compressed data stream.
724 This option defaults to off.
726 =item C<< Append => 0|1 >>
728 This option controls what the C<read> method does with uncompressed data.
730 If set to 1, all uncompressed data will be appended to the output parameter
731 of the C<read> method.
733 If set to 0, the contents of the output parameter of the C<read> method
734 will be overwritten by the uncompressed data.
738 =item C<< Strict => 0|1 >>
740 This option controls whether the extra checks defined below are used when
741 carrying out the decompression. When Strict is on, the extra tests are
742 carried out, when Strict is off they are not.
744 The default for this option is off.
750 If the FHCRC bit is set in the gzip FLG header byte, the CRC16 bytes in the
751 header must match the crc16 value of the gzip header actually read.
755 If the gzip header contains a name field (FNAME) it consists solely of ISO
760 If the gzip header contains a comment field (FCOMMENT) it consists solely
761 of ISO 8859-1 characters plus line-feed.
765 If the gzip FEXTRA header field is present it must conform to the sub-field
766 structure as defined in RFC 1952.
770 The CRC32 and ISIZE trailer fields must be present.
774 The value of the CRC32 field read must match the crc32 value of the
775 uncompressed data actually contained in the gzip file.
779 The value of the ISIZE fields read must match the length of the
780 uncompressed data actually read from the file.
784 =item C<< ParseExtra => 0|1 >>
785 If the gzip FEXTRA header field is present and this option is set, it will
786 force the module to check that it conforms to the sub-field structure as
789 If the C<Strict> is on it will automatically enable this option.
805 $status = $z->read($buffer)
807 Reads a block of compressed data (the size the the compressed block is
808 determined by the C<Buffer> option in the constructor), uncompresses it and
809 writes any uncompressed data into C<$buffer>. If the C<Append> parameter is
810 set in the constructor, the uncompressed data will be appended to the
811 C<$buffer> parameter. Otherwise C<$buffer> will be overwritten.
813 Returns the number of uncompressed bytes written to C<$buffer>, zero if eof
814 or a negative number on error.
820 $status = $z->read($buffer, $length)
821 $status = $z->read($buffer, $length, $offset)
823 $status = read($z, $buffer, $length)
824 $status = read($z, $buffer, $length, $offset)
826 Attempt to read C<$length> bytes of uncompressed data into C<$buffer>.
828 The main difference between this form of the C<read> method and the
829 previous one, is that this one will attempt to return I<exactly> C<$length>
830 bytes. The only circumstances that this function will not is if end-of-file
831 or an IO error is encountered.
833 Returns the number of uncompressed bytes written to C<$buffer>, zero if eof
834 or a negative number on error.
840 $line = $z->getline()
845 This method fully supports the use of of the variable C<$/> (or
846 C<$INPUT_RECORD_SEPARATOR> or C<$RS> when C<English> is in use) to
847 determine what constitutes an end of line. Paragraph mode, record mode and
848 file slurp mode are all supported.
856 Read a single character.
862 $char = $z->ungetc($string)
868 $status = $z->inflateSync()
876 $hdr = $z->getHeaderInfo();
877 @hdrs = $z->getHeaderInfo();
879 This method returns either a hash reference (in scalar context) or a list
880 or hash references (in array context) that contains information about each
881 of the header fields in the compressed data stream(s).
887 The contents of the Name header field, if present. If no name is
888 present, the value will be undef. Note this is different from a zero length
889 name, which will return an empty string.
893 The contents of the Comment header field, if present. If no comment is
894 present, the value will be undef. Note this is different from a zero length
895 comment, which will return an empty string.
906 Returns the uncompressed file offset.
915 Returns true if the end of the compressed input stream has been reached.
919 $z->seek($position, $whence);
920 seek($z, $position, $whence);
922 Provides a sub-set of the C<seek> functionality, with the restriction
923 that it is only legal to seek forward in the input file/buffer.
924 It is a fatal error to attempt to seek backward.
926 The C<$whence> parameter takes one the usual values, namely SEEK_SET,
927 SEEK_CUR or SEEK_END.
929 Returns 1 on success, 0 on failure.
938 This is a noop provided for completeness.
944 Returns true if the object currently refers to a opened file/buffer.
948 my $prev = $z->autoflush()
949 my $prev = $z->autoflush(EXPR)
951 If the C<$z> object is associated with a file or a filehandle, this method
952 returns the current autoflush setting for the underlying filehandle. If
953 C<EXPR> is present, and is non-zero, it will enable flushing after every
954 write/print operation.
956 If C<$z> is associated with a buffer, this method has no effect and always
959 B<Note> that the special variable C<$|> B<cannot> be used to set or
960 retrieve the autoflush setting.
962 =head2 input_line_number
964 $z->input_line_number()
965 $z->input_line_number(EXPR)
967 Returns the current uncompressed line number. If C<EXPR> is present it has
968 the effect of setting the line number. Note that setting the line number
969 does not change the current position within the file/buffer being read.
971 The contents of C<$/> are used to to determine what constitutes a line
979 If the C<$z> object is associated with a file or a filehandle, C<fileno>
980 will return the underlying file descriptor. Once the C<close> method is
981 called C<fileno> will return C<undef>.
983 If the C<$z> object is associated with a buffer, this method will return
991 Closes the output file/buffer.
993 For most versions of Perl this method will be automatically invoked if
994 the IO::Uncompress::Gunzip object is destroyed (either explicitly or by the
995 variable with the reference to the object going out of scope). The
996 exceptions are Perl versions 5.005 through 5.00504 and 5.8.0. In
997 these cases, the C<close> method will be called automatically, but
998 not until global destruction of all live objects when the program is
1001 Therefore, if you want your scripts to be able to run on all versions
1002 of Perl, you should call C<close> explicitly and not rely on automatic
1005 Returns true on success, otherwise 0.
1007 If the C<AutoClose> option has been enabled when the IO::Uncompress::Gunzip
1008 object was created, and the object is associated with a file, the
1009 underlying file will also be closed.
1015 my $status = $z->nextStream();
1017 Skips to the next compressed data stream in the input file/buffer. If a new
1018 compressed data stream is found, the eof marker will be cleared and C<$.>
1021 Returns 1 if a new stream was found, 0 if none was found, and -1 if an
1022 error was encountered.
1028 my $data = $z->trailingData();
1030 Returns the data, if any, that is present immediately after the compressed
1031 data stream once uncompression is complete. It only makes sense to call
1032 this method once the end of the compressed data stream has been
1035 This option can be used when there is useful information immediately
1036 following the compressed data stream, and you don't know the length of the
1037 compressed data stream.
1039 If the input is a buffer, C<trailingData> will return everything from the
1040 end of the compressed data stream to the end of the buffer.
1042 If the input is a filehandle, C<trailingData> will return the data that is
1043 left in the filehandle input buffer once the end of the compressed data
1044 stream has been reached. You can then use the filehandle to read the rest
1047 Don't bother using C<trailingData> if the input is a filename.
1049 If you know the length of the compressed data stream before you start
1050 uncompressing, you can avoid having to use C<trailingData> by setting the
1051 C<InputLength> option in the constructor.
1055 No symbolic constants are required by this IO::Uncompress::Gunzip at present.
1061 Imports C<gunzip> and C<$GunzipError>.
1064 use IO::Uncompress::Gunzip qw(gunzip $GunzipError) ;
1070 =head2 Working with Net::FTP
1072 See L<IO::Uncompress::Gunzip::FAQ|IO::Uncompress::Gunzip::FAQ/"Compressed files and Net::FTP">
1076 L<Compress::Zlib>, L<IO::Compress::Gzip>, L<IO::Compress::Deflate>, L<IO::Uncompress::Inflate>, L<IO::Compress::RawDeflate>, L<IO::Uncompress::RawInflate>, L<IO::Compress::Bzip2>, L<IO::Uncompress::Bunzip2>, L<IO::Compress::Lzma>, L<IO::Uncompress::UnLzma>, L<IO::Compress::Xz>, L<IO::Uncompress::UnXz>, L<IO::Compress::Lzop>, L<IO::Uncompress::UnLzop>, L<IO::Compress::Lzf>, L<IO::Uncompress::UnLzf>, L<IO::Uncompress::AnyInflate>, L<IO::Uncompress::AnyUncompress>
1078 L<IO::Compress::FAQ|IO::Compress::FAQ>
1080 L<File::GlobMapper|File::GlobMapper>, L<Archive::Zip|Archive::Zip>,
1081 L<Archive::Tar|Archive::Tar>,
1082 L<IO::Zlib|IO::Zlib>
1084 For RFC 1950, 1951 and 1952 see
1085 F<http://www.faqs.org/rfcs/rfc1950.html>,
1086 F<http://www.faqs.org/rfcs/rfc1951.html> and
1087 F<http://www.faqs.org/rfcs/rfc1952.html>
1089 The I<zlib> compression library was written by Jean-loup Gailly
1090 F<gzip@prep.ai.mit.edu> and Mark Adler F<madler@alumni.caltech.edu>.
1092 The primary site for the I<zlib> compression library is
1093 F<http://www.zlib.org>.
1095 The primary site for gzip is F<http://www.gzip.org>.
1099 This module was written by Paul Marquess, F<pmqs@cpan.org>.
1101 =head1 MODIFICATION HISTORY
1103 See the Changes file.
1105 =head1 COPYRIGHT AND LICENSE
1107 Copyright (c) 2005-2012 Paul Marquess. All rights reserved.
1109 This program is free software; you can redistribute it and/or
1110 modify it under the same terms as Perl itself.