| |
| package IO::Uncompress::Gunzip ; |
| |
| require 5.006 ; |
| |
| # for RFC1952 |
| |
| use strict ; |
| use warnings; |
| use bytes; |
| |
| use IO::Uncompress::RawInflate 2.048 ; |
| |
| use Compress::Raw::Zlib 2.048 () ; |
| use IO::Compress::Base::Common 2.048 qw(:Status createSelfTiedObject); |
| use IO::Compress::Gzip::Constants 2.048 ; |
| use IO::Compress::Zlib::Extra 2.048 ; |
| |
| require Exporter ; |
| |
| our ($VERSION, @ISA, @EXPORT_OK, %EXPORT_TAGS, $GunzipError); |
| |
| @ISA = qw( Exporter IO::Uncompress::RawInflate ); |
| @EXPORT_OK = qw( $GunzipError gunzip ); |
| %EXPORT_TAGS = %IO::Uncompress::RawInflate::DEFLATE_CONSTANTS ; |
| push @{ $EXPORT_TAGS{all} }, @EXPORT_OK ; |
| Exporter::export_ok_tags('all'); |
| |
| $GunzipError = ''; |
| |
| $VERSION = '2.048'; |
| |
| sub new |
| { |
| my $class = shift ; |
| $GunzipError = ''; |
| my $obj = createSelfTiedObject($class, \$GunzipError); |
| |
| $obj->_create(undef, 0, @_); |
| } |
| |
| sub gunzip |
| { |
| my $obj = createSelfTiedObject(undef, \$GunzipError); |
| return $obj->_inf(@_) ; |
| } |
| |
| sub getExtraParams |
| { |
| use IO::Compress::Base::Common 2.048 qw(:Parse); |
| return ( 'ParseExtra' => [1, 1, Parse_boolean, 0] ) ; |
| } |
| |
| sub ckParams |
| { |
| my $self = shift ; |
| my $got = shift ; |
| |
| # gunzip always needs crc32 |
| $got->value('CRC32' => 1); |
| |
| return 1; |
| } |
| |
| sub ckMagic |
| { |
| my $self = shift; |
| |
| my $magic ; |
| $self->smartReadExact(\$magic, GZIP_ID_SIZE); |
| |
| *$self->{HeaderPending} = $magic ; |
| |
| return $self->HeaderError("Minimum header size is " . |
| GZIP_MIN_HEADER_SIZE . " bytes") |
| if length $magic != GZIP_ID_SIZE ; |
| |
| return $self->HeaderError("Bad Magic") |
| if ! isGzipMagic($magic) ; |
| |
| *$self->{Type} = 'rfc1952'; |
| |
| return $magic ; |
| } |
| |
| sub readHeader |
| { |
| my $self = shift; |
| my $magic = shift; |
| |
| return $self->_readGzipHeader($magic); |
| } |
| |
| sub chkTrailer |
| { |
| my $self = shift; |
| my $trailer = shift; |
| |
| # Check CRC & ISIZE |
| my ($CRC32, $ISIZE) = unpack("V V", $trailer) ; |
| *$self->{Info}{CRC32} = $CRC32; |
| *$self->{Info}{ISIZE} = $ISIZE; |
| |
| if (*$self->{Strict}) { |
| return $self->TrailerError("CRC mismatch") |
| if $CRC32 != *$self->{Uncomp}->crc32() ; |
| |
| my $exp_isize = *$self->{UnCompSize}->get32bit(); |
| return $self->TrailerError("ISIZE mismatch. Got $ISIZE" |
| . ", expected $exp_isize") |
| if $ISIZE != $exp_isize ; |
| } |
| |
| return STATUS_OK; |
| } |
| |
| sub isGzipMagic |
| { |
| my $buffer = shift ; |
| return 0 if length $buffer < GZIP_ID_SIZE ; |
| my ($id1, $id2) = unpack("C C", $buffer) ; |
| return $id1 == GZIP_ID1 && $id2 == GZIP_ID2 ; |
| } |
| |
| sub _readFullGzipHeader($) |
| { |
| my ($self) = @_ ; |
| my $magic = '' ; |
| |
| $self->smartReadExact(\$magic, GZIP_ID_SIZE); |
| |
| *$self->{HeaderPending} = $magic ; |
| |
| return $self->HeaderError("Minimum header size is " . |
| GZIP_MIN_HEADER_SIZE . " bytes") |
| if length $magic != GZIP_ID_SIZE ; |
| |
| |
| return $self->HeaderError("Bad Magic") |
| if ! isGzipMagic($magic) ; |
| |
| my $status = $self->_readGzipHeader($magic); |
| delete *$self->{Transparent} if ! defined $status ; |
| return $status ; |
| } |
| |
| sub _readGzipHeader($) |
| { |
| my ($self, $magic) = @_ ; |
| my ($HeaderCRC) ; |
| my ($buffer) = '' ; |
| |
| $self->smartReadExact(\$buffer, GZIP_MIN_HEADER_SIZE - GZIP_ID_SIZE) |
| or return $self->HeaderError("Minimum header size is " . |
| GZIP_MIN_HEADER_SIZE . " bytes") ; |
| |
| my $keep = $magic . $buffer ; |
| *$self->{HeaderPending} = $keep ; |
| |
| # now split out the various parts |
| my ($cm, $flag, $mtime, $xfl, $os) = unpack("C C V C C", $buffer) ; |
| |
| $cm == GZIP_CM_DEFLATED |
| or return $self->HeaderError("Not Deflate (CM is $cm)") ; |
| |
| # check for use of reserved bits |
| return $self->HeaderError("Use of Reserved Bits in FLG field.") |
| if $flag & GZIP_FLG_RESERVED ; |
| |
| my $EXTRA ; |
| my @EXTRA = () ; |
| if ($flag & GZIP_FLG_FEXTRA) { |
| $EXTRA = "" ; |
| $self->smartReadExact(\$buffer, GZIP_FEXTRA_HEADER_SIZE) |
| or return $self->TruncatedHeader("FEXTRA Length") ; |
| |
| my ($XLEN) = unpack("v", $buffer) ; |
| $self->smartReadExact(\$EXTRA, $XLEN) |
| or return $self->TruncatedHeader("FEXTRA Body"); |
| $keep .= $buffer . $EXTRA ; |
| |
| if ($XLEN && *$self->{'ParseExtra'}) { |
| my $bad = IO::Compress::Zlib::Extra::parseRawExtra($EXTRA, |
| \@EXTRA, 1, 1); |
| return $self->HeaderError($bad) |
| if defined $bad; |
| } |
| } |
| |
| my $origname ; |
| if ($flag & GZIP_FLG_FNAME) { |
| $origname = "" ; |
| while (1) { |
| $self->smartReadExact(\$buffer, 1) |
| or return $self->TruncatedHeader("FNAME"); |
| last if $buffer eq GZIP_NULL_BYTE ; |
| $origname .= $buffer |
| } |
| $keep .= $origname . GZIP_NULL_BYTE ; |
| |
| return $self->HeaderError("Non ISO 8859-1 Character found in Name") |
| if *$self->{Strict} && $origname =~ /$GZIP_FNAME_INVALID_CHAR_RE/o ; |
| } |
| |
| my $comment ; |
| if ($flag & GZIP_FLG_FCOMMENT) { |
| $comment = ""; |
| while (1) { |
| $self->smartReadExact(\$buffer, 1) |
| or return $self->TruncatedHeader("FCOMMENT"); |
| last if $buffer eq GZIP_NULL_BYTE ; |
| $comment .= $buffer |
| } |
| $keep .= $comment . GZIP_NULL_BYTE ; |
| |
| return $self->HeaderError("Non ISO 8859-1 Character found in Comment") |
| if *$self->{Strict} && $comment =~ /$GZIP_FCOMMENT_INVALID_CHAR_RE/o ; |
| } |
| |
| if ($flag & GZIP_FLG_FHCRC) { |
| $self->smartReadExact(\$buffer, GZIP_FHCRC_SIZE) |
| or return $self->TruncatedHeader("FHCRC"); |
| |
| $HeaderCRC = unpack("v", $buffer) ; |
| my $crc16 = Compress::Raw::Zlib::crc32($keep) & 0xFF ; |
| |
| return $self->HeaderError("CRC16 mismatch.") |
| if *$self->{Strict} && $crc16 != $HeaderCRC; |
| |
| $keep .= $buffer ; |
| } |
| |
| # Assume compression method is deflated for xfl tests |
| #if ($xfl) { |
| #} |
| |
| *$self->{Type} = 'rfc1952'; |
| |
| return { |
| 'Type' => 'rfc1952', |
| 'FingerprintLength' => 2, |
| 'HeaderLength' => length $keep, |
| 'TrailerLength' => GZIP_TRAILER_SIZE, |
| 'Header' => $keep, |
| 'isMinimalHeader' => $keep eq GZIP_MINIMUM_HEADER ? 1 : 0, |
| |
| 'MethodID' => $cm, |
| 'MethodName' => $cm == GZIP_CM_DEFLATED ? "Deflated" : "Unknown" , |
| 'TextFlag' => $flag & GZIP_FLG_FTEXT ? 1 : 0, |
| 'HeaderCRCFlag' => $flag & GZIP_FLG_FHCRC ? 1 : 0, |
| 'NameFlag' => $flag & GZIP_FLG_FNAME ? 1 : 0, |
| 'CommentFlag' => $flag & GZIP_FLG_FCOMMENT ? 1 : 0, |
| 'ExtraFlag' => $flag & GZIP_FLG_FEXTRA ? 1 : 0, |
| 'Name' => $origname, |
| 'Comment' => $comment, |
| 'Time' => $mtime, |
| 'OsID' => $os, |
| 'OsName' => defined $GZIP_OS_Names{$os} |
| ? $GZIP_OS_Names{$os} : "Unknown", |
| 'HeaderCRC' => $HeaderCRC, |
| 'Flags' => $flag, |
| 'ExtraFlags' => $xfl, |
| 'ExtraFieldRaw' => $EXTRA, |
| 'ExtraField' => [ @EXTRA ], |
| |
| |
| #'CompSize'=> $compsize, |
| #'CRC32'=> $CRC32, |
| #'OrigSize'=> $ISIZE, |
| } |
| } |
| |
| |
| 1; |
| |
| __END__ |
| |
| |
| =head1 NAME |
| |
| IO::Uncompress::Gunzip - Read RFC 1952 files/buffers |
| |
| =head1 SYNOPSIS |
| |
| use IO::Uncompress::Gunzip qw(gunzip $GunzipError) ; |
| |
| my $status = gunzip $input => $output [,OPTS] |
| or die "gunzip failed: $GunzipError\n"; |
| |
| my $z = new IO::Uncompress::Gunzip $input [OPTS] |
| or die "gunzip failed: $GunzipError\n"; |
| |
| $status = $z->read($buffer) |
| $status = $z->read($buffer, $length) |
| $status = $z->read($buffer, $length, $offset) |
| $line = $z->getline() |
| $char = $z->getc() |
| $char = $z->ungetc() |
| $char = $z->opened() |
| |
| $status = $z->inflateSync() |
| |
| $data = $z->trailingData() |
| $status = $z->nextStream() |
| $data = $z->getHeaderInfo() |
| $z->tell() |
| $z->seek($position, $whence) |
| $z->binmode() |
| $z->fileno() |
| $z->eof() |
| $z->close() |
| |
| $GunzipError ; |
| |
| # IO::File mode |
| |
| <$z> |
| read($z, $buffer); |
| read($z, $buffer, $length); |
| read($z, $buffer, $length, $offset); |
| tell($z) |
| seek($z, $position, $whence) |
| binmode($z) |
| fileno($z) |
| eof($z) |
| close($z) |
| |
| =head1 DESCRIPTION |
| |
| This module provides a Perl interface that allows the reading of |
| files/buffers that conform to RFC 1952. |
| |
| For writing RFC 1952 files/buffers, see the companion module IO::Compress::Gzip. |
| |
| =head1 Functional Interface |
| |
| A top-level function, C<gunzip>, is provided to carry out |
| "one-shot" uncompression between buffers and/or files. For finer |
| control over the uncompression process, see the L</"OO Interface"> |
| section. |
| |
| use IO::Uncompress::Gunzip qw(gunzip $GunzipError) ; |
| |
| gunzip $input => $output [,OPTS] |
| or die "gunzip failed: $GunzipError\n"; |
| |
| The functional interface needs Perl5.005 or better. |
| |
| =head2 gunzip $input => $output [, OPTS] |
| |
| C<gunzip> expects at least two parameters, C<$input> and C<$output>. |
| |
| =head3 The C<$input> parameter |
| |
| The parameter, C<$input>, is used to define the source of |
| the compressed data. |
| |
| It can take one of the following forms: |
| |
| =over 5 |
| |
| =item A filename |
| |
| If the C<$input> parameter is a simple scalar, it is assumed to be a |
| filename. This file will be opened for reading and the input data |
| will be read from it. |
| |
| =item A filehandle |
| |
| If the C<$input> parameter is a filehandle, the input data will be |
| read from it. |
| The string '-' can be used as an alias for standard input. |
| |
| =item A scalar reference |
| |
| If C<$input> is a scalar reference, the input data will be read |
| from C<$$input>. |
| |
| =item An array reference |
| |
| If C<$input> is an array reference, each element in the array must be a |
| filename. |
| |
| The input data will be read from each file in turn. |
| |
| The complete array will be walked to ensure that it only |
| contains valid filenames before any data is uncompressed. |
| |
| =item An Input FileGlob string |
| |
| If C<$input> is a string that is delimited by the characters "<" and ">" |
| C<gunzip> will assume that it is an I<input fileglob string>. The |
| input is the list of files that match the fileglob. |
| |
| See L<File::GlobMapper|File::GlobMapper> for more details. |
| |
| =back |
| |
| If the C<$input> parameter is any other type, C<undef> will be returned. |
| |
| =head3 The C<$output> parameter |
| |
| The parameter C<$output> is used to control the destination of the |
| uncompressed data. This parameter can take one of these forms. |
| |
| =over 5 |
| |
| =item A filename |
| |
| If the C<$output> parameter is a simple scalar, it is assumed to be a |
| filename. This file will be opened for writing and the uncompressed |
| data will be written to it. |
| |
| =item A filehandle |
| |
| If the C<$output> parameter is a filehandle, the uncompressed data |
| will be written to it. |
| The string '-' can be used as an alias for standard output. |
| |
| =item A scalar reference |
| |
| If C<$output> is a scalar reference, the uncompressed data will be |
| stored in C<$$output>. |
| |
| =item An Array Reference |
| |
| If C<$output> is an array reference, the uncompressed data will be |
| pushed onto the array. |
| |
| =item An Output FileGlob |
| |
| If C<$output> is a string that is delimited by the characters "<" and ">" |
| C<gunzip> will assume that it is an I<output fileglob string>. The |
| output is the list of files that match the fileglob. |
| |
| When C<$output> is an fileglob string, C<$input> must also be a fileglob |
| string. Anything else is an error. |
| |
| See L<File::GlobMapper|File::GlobMapper> for more details. |
| |
| =back |
| |
| If the C<$output> parameter is any other type, C<undef> will be returned. |
| |
| =head2 Notes |
| |
| When C<$input> maps to multiple compressed files/buffers and C<$output> is |
| a single file/buffer, after uncompression C<$output> will contain a |
| concatenation of all the uncompressed data from each of the input |
| files/buffers. |
| |
| =head2 Optional Parameters |
| |
| Unless specified below, the optional parameters for C<gunzip>, |
| C<OPTS>, are the same as those used with the OO interface defined in the |
| L</"Constructor Options"> section below. |
| |
| =over 5 |
| |
| =item C<< AutoClose => 0|1 >> |
| |
| This option applies to any input or output data streams to |
| C<gunzip> that are filehandles. |
| |
| If C<AutoClose> is specified, and the value is true, it will result in all |
| input and/or output filehandles being closed once C<gunzip> has |
| completed. |
| |
| This parameter defaults to 0. |
| |
| =item C<< BinModeOut => 0|1 >> |
| |
| When writing to a file or filehandle, set C<binmode> before writing to the |
| file. |
| |
| Defaults to 0. |
| |
| =item C<< Append => 0|1 >> |
| |
| The behaviour of this option is dependent on the type of output data |
| stream. |
| |
| =over 5 |
| |
| =item * A Buffer |
| |
| If C<Append> is enabled, all uncompressed data will be append to the end of |
| the output buffer. Otherwise the output buffer will be cleared before any |
| uncompressed data is written to it. |
| |
| =item * A Filename |
| |
| If C<Append> is enabled, the file will be opened in append mode. Otherwise |
| the contents of the file, if any, will be truncated before any uncompressed |
| data is written to it. |
| |
| =item * A Filehandle |
| |
| If C<Append> is enabled, the filehandle will be positioned to the end of |
| the file via a call to C<seek> before any uncompressed data is |
| written to it. Otherwise the file pointer will not be moved. |
| |
| =back |
| |
| When C<Append> is specified, and set to true, it will I<append> all uncompressed |
| data to the output data stream. |
| |
| So when the output is a filehandle it will carry out a seek to the eof |
| before writing any uncompressed data. If the output is a filename, it will be opened for |
| appending. If the output is a buffer, all uncompressed data will be |
| appended to the existing buffer. |
| |
| Conversely when C<Append> is not specified, or it is present and is set to |
| false, it will operate as follows. |
| |
| When the output is a filename, it will truncate the contents of the file |
| before writing any uncompressed data. If the output is a filehandle |
| its position will not be changed. If the output is a buffer, it will be |
| wiped before any uncompressed data is output. |
| |
| Defaults to 0. |
| |
| =item C<< MultiStream => 0|1 >> |
| |
| If the input file/buffer contains multiple compressed data streams, this |
| option will uncompress the whole lot as a single data stream. |
| |
| Defaults to 0. |
| |
| =item C<< TrailingData => $scalar >> |
| |
| Returns the data, if any, that is present immediately after the compressed |
| data stream once uncompression is complete. |
| |
| This option can be used when there is useful information immediately |
| following the compressed data stream, and you don't know the length of the |
| compressed data stream. |
| |
| If the input is a buffer, C<trailingData> will return everything from the |
| end of the compressed data stream to the end of the buffer. |
| |
| If the input is a filehandle, C<trailingData> will return the data that is |
| left in the filehandle input buffer once the end of the compressed data |
| stream has been reached. You can then use the filehandle to read the rest |
| of the input file. |
| |
| Don't bother using C<trailingData> if the input is a filename. |
| |
| If you know the length of the compressed data stream before you start |
| uncompressing, you can avoid having to use C<trailingData> by setting the |
| C<InputLength> option. |
| |
| =back |
| |
| =head2 Examples |
| |
| To read the contents of the file C<file1.txt.gz> and write the |
| uncompressed data to the file C<file1.txt>. |
| |
| use strict ; |
| use warnings ; |
| use IO::Uncompress::Gunzip qw(gunzip $GunzipError) ; |
| |
| my $input = "file1.txt.gz"; |
| my $output = "file1.txt"; |
| gunzip $input => $output |
| or die "gunzip failed: $GunzipError\n"; |
| |
| To read from an existing Perl filehandle, C<$input>, and write the |
| uncompressed data to a buffer, C<$buffer>. |
| |
| use strict ; |
| use warnings ; |
| use IO::Uncompress::Gunzip qw(gunzip $GunzipError) ; |
| use IO::File ; |
| |
| my $input = new IO::File "<file1.txt.gz" |
| or die "Cannot open 'file1.txt.gz': $!\n" ; |
| my $buffer ; |
| gunzip $input => \$buffer |
| or die "gunzip failed: $GunzipError\n"; |
| |
| To uncompress all files in the directory "/my/home" that match "*.txt.gz" and store the compressed data in the same directory |
| |
| use strict ; |
| use warnings ; |
| use IO::Uncompress::Gunzip qw(gunzip $GunzipError) ; |
| |
| gunzip '</my/home/*.txt.gz>' => '</my/home/#1.txt>' |
| or die "gunzip failed: $GunzipError\n"; |
| |
| and if you want to compress each file one at a time, this will do the trick |
| |
| use strict ; |
| use warnings ; |
| use IO::Uncompress::Gunzip qw(gunzip $GunzipError) ; |
| |
| for my $input ( glob "/my/home/*.txt.gz" ) |
| { |
| my $output = $input; |
| $output =~ s/.gz// ; |
| gunzip $input => $output |
| or die "Error compressing '$input': $GunzipError\n"; |
| } |
| |
| =head1 OO Interface |
| |
| =head2 Constructor |
| |
| The format of the constructor for IO::Uncompress::Gunzip is shown below |
| |
| my $z = new IO::Uncompress::Gunzip $input [OPTS] |
| or die "IO::Uncompress::Gunzip failed: $GunzipError\n"; |
| |
| Returns an C<IO::Uncompress::Gunzip> object on success and undef on failure. |
| The variable C<$GunzipError> will contain an error message on failure. |
| |
| If you are running Perl 5.005 or better the object, C<$z>, returned from |
| IO::Uncompress::Gunzip can be used exactly like an L<IO::File|IO::File> filehandle. |
| This means that all normal input file operations can be carried out with |
| C<$z>. For example, to read a line from a compressed file/buffer you can |
| use either of these forms |
| |
| $line = $z->getline(); |
| $line = <$z>; |
| |
| The mandatory parameter C<$input> is used to determine the source of the |
| compressed data. This parameter can take one of three forms. |
| |
| =over 5 |
| |
| =item A filename |
| |
| If the C<$input> parameter is a scalar, it is assumed to be a filename. This |
| file will be opened for reading and the compressed data will be read from it. |
| |
| =item A filehandle |
| |
| If the C<$input> parameter is a filehandle, the compressed data will be |
| read from it. |
| The string '-' can be used as an alias for standard input. |
| |
| =item A scalar reference |
| |
| If C<$input> is a scalar reference, the compressed data will be read from |
| C<$$output>. |
| |
| =back |
| |
| =head2 Constructor Options |
| |
| The option names defined below are case insensitive and can be optionally |
| prefixed by a '-'. So all of the following are valid |
| |
| -AutoClose |
| -autoclose |
| AUTOCLOSE |
| autoclose |
| |
| OPTS is a combination of the following options: |
| |
| =over 5 |
| |
| =item C<< AutoClose => 0|1 >> |
| |
| This option is only valid when the C<$input> parameter is a filehandle. If |
| specified, and the value is true, it will result in the file being closed once |
| either the C<close> method is called or the IO::Uncompress::Gunzip object is |
| destroyed. |
| |
| This parameter defaults to 0. |
| |
| =item C<< MultiStream => 0|1 >> |
| |
| Allows multiple concatenated compressed streams to be treated as a single |
| compressed stream. Decompression will stop once either the end of the |
| file/buffer is reached, an error is encountered (premature eof, corrupt |
| compressed data) or the end of a stream is not immediately followed by the |
| start of another stream. |
| |
| This parameter defaults to 0. |
| |
| =item C<< Prime => $string >> |
| |
| This option will uncompress the contents of C<$string> before processing the |
| input file/buffer. |
| |
| This option can be useful when the compressed data is embedded in another |
| file/data structure and it is not possible to work out where the compressed |
| data begins without having to read the first few bytes. If this is the |
| case, the uncompression can be I<primed> with these bytes using this |
| option. |
| |
| =item C<< Transparent => 0|1 >> |
| |
| If this option is set and the input file/buffer is not compressed data, |
| the module will allow reading of it anyway. |
| |
| In addition, if the input file/buffer does contain compressed data and |
| there is non-compressed data immediately following it, setting this option |
| will make this module treat the whole file/buffer as a single data stream. |
| |
| This option defaults to 1. |
| |
| =item C<< BlockSize => $num >> |
| |
| When reading the compressed input data, IO::Uncompress::Gunzip will read it in |
| blocks of C<$num> bytes. |
| |
| This option defaults to 4096. |
| |
| =item C<< InputLength => $size >> |
| |
| When present this option will limit the number of compressed bytes read |
| from the input file/buffer to C<$size>. This option can be used in the |
| situation where there is useful data directly after the compressed data |
| stream and you know beforehand the exact length of the compressed data |
| stream. |
| |
| This option is mostly used when reading from a filehandle, in which case |
| the file pointer will be left pointing to the first byte directly after the |
| compressed data stream. |
| |
| This option defaults to off. |
| |
| =item C<< Append => 0|1 >> |
| |
| This option controls what the C<read> method does with uncompressed data. |
| |
| If set to 1, all uncompressed data will be appended to the output parameter |
| of the C<read> method. |
| |
| If set to 0, the contents of the output parameter of the C<read> method |
| will be overwritten by the uncompressed data. |
| |
| Defaults to 0. |
| |
| =item C<< Strict => 0|1 >> |
| |
| This option controls whether the extra checks defined below are used when |
| carrying out the decompression. When Strict is on, the extra tests are |
| carried out, when Strict is off they are not. |
| |
| The default for this option is off. |
| |
| =over 5 |
| |
| =item 1 |
| |
| If the FHCRC bit is set in the gzip FLG header byte, the CRC16 bytes in the |
| header must match the crc16 value of the gzip header actually read. |
| |
| =item 2 |
| |
| If the gzip header contains a name field (FNAME) it consists solely of ISO |
| 8859-1 characters. |
| |
| =item 3 |
| |
| If the gzip header contains a comment field (FCOMMENT) it consists solely |
| of ISO 8859-1 characters plus line-feed. |
| |
| =item 4 |
| |
| If the gzip FEXTRA header field is present it must conform to the sub-field |
| structure as defined in RFC 1952. |
| |
| =item 5 |
| |
| The CRC32 and ISIZE trailer fields must be present. |
| |
| =item 6 |
| |
| The value of the CRC32 field read must match the crc32 value of the |
| uncompressed data actually contained in the gzip file. |
| |
| =item 7 |
| |
| The value of the ISIZE fields read must match the length of the |
| uncompressed data actually read from the file. |
| |
| =back |
| |
| =item C<< ParseExtra => 0|1 >> |
| If the gzip FEXTRA header field is present and this option is set, it will |
| force the module to check that it conforms to the sub-field structure as |
| defined in RFC 1952. |
| |
| If the C<Strict> is on it will automatically enable this option. |
| |
| Defaults to 0. |
| |
| =back |
| |
| =head2 Examples |
| |
| TODO |
| |
| =head1 Methods |
| |
| =head2 read |
| |
| Usage is |
| |
| $status = $z->read($buffer) |
| |
| Reads a block of compressed data (the size the the compressed block is |
| determined by the C<Buffer> option in the constructor), uncompresses it and |
| writes any uncompressed data into C<$buffer>. If the C<Append> parameter is |
| set in the constructor, the uncompressed data will be appended to the |
| C<$buffer> parameter. Otherwise C<$buffer> will be overwritten. |
| |
| Returns the number of uncompressed bytes written to C<$buffer>, zero if eof |
| or a negative number on error. |
| |
| =head2 read |
| |
| Usage is |
| |
| $status = $z->read($buffer, $length) |
| $status = $z->read($buffer, $length, $offset) |
| |
| $status = read($z, $buffer, $length) |
| $status = read($z, $buffer, $length, $offset) |
| |
| Attempt to read C<$length> bytes of uncompressed data into C<$buffer>. |
| |
| The main difference between this form of the C<read> method and the |
| previous one, is that this one will attempt to return I<exactly> C<$length> |
| bytes. The only circumstances that this function will not is if end-of-file |
| or an IO error is encountered. |
| |
| Returns the number of uncompressed bytes written to C<$buffer>, zero if eof |
| or a negative number on error. |
| |
| =head2 getline |
| |
| Usage is |
| |
| $line = $z->getline() |
| $line = <$z> |
| |
| Reads a single line. |
| |
| This method fully supports the use of of the variable C<$/> (or |
| C<$INPUT_RECORD_SEPARATOR> or C<$RS> when C<English> is in use) to |
| determine what constitutes an end of line. Paragraph mode, record mode and |
| file slurp mode are all supported. |
| |
| =head2 getc |
| |
| Usage is |
| |
| $char = $z->getc() |
| |
| Read a single character. |
| |
| =head2 ungetc |
| |
| Usage is |
| |
| $char = $z->ungetc($string) |
| |
| =head2 inflateSync |
| |
| Usage is |
| |
| $status = $z->inflateSync() |
| |
| TODO |
| |
| =head2 getHeaderInfo |
| |
| Usage is |
| |
| $hdr = $z->getHeaderInfo(); |
| @hdrs = $z->getHeaderInfo(); |
| |
| This method returns either a hash reference (in scalar context) or a list |
| or hash references (in array context) that contains information about each |
| of the header fields in the compressed data stream(s). |
| |
| =over 5 |
| |
| =item Name |
| |
| The contents of the Name header field, if present. If no name is |
| present, the value will be undef. Note this is different from a zero length |
| name, which will return an empty string. |
| |
| =item Comment |
| |
| The contents of the Comment header field, if present. If no comment is |
| present, the value will be undef. Note this is different from a zero length |
| comment, which will return an empty string. |
| |
| =back |
| |
| =head2 tell |
| |
| Usage is |
| |
| $z->tell() |
| tell $z |
| |
| Returns the uncompressed file offset. |
| |
| =head2 eof |
| |
| Usage is |
| |
| $z->eof(); |
| eof($z); |
| |
| Returns true if the end of the compressed input stream has been reached. |
| |
| =head2 seek |
| |
| $z->seek($position, $whence); |
| seek($z, $position, $whence); |
| |
| Provides a sub-set of the C<seek> functionality, with the restriction |
| that it is only legal to seek forward in the input file/buffer. |
| It is a fatal error to attempt to seek backward. |
| |
| The C<$whence> parameter takes one the usual values, namely SEEK_SET, |
| SEEK_CUR or SEEK_END. |
| |
| Returns 1 on success, 0 on failure. |
| |
| =head2 binmode |
| |
| Usage is |
| |
| $z->binmode |
| binmode $z ; |
| |
| This is a noop provided for completeness. |
| |
| =head2 opened |
| |
| $z->opened() |
| |
| Returns true if the object currently refers to a opened file/buffer. |
| |
| =head2 autoflush |
| |
| my $prev = $z->autoflush() |
| my $prev = $z->autoflush(EXPR) |
| |
| If the C<$z> object is associated with a file or a filehandle, this method |
| returns the current autoflush setting for the underlying filehandle. If |
| C<EXPR> is present, and is non-zero, it will enable flushing after every |
| write/print operation. |
| |
| If C<$z> is associated with a buffer, this method has no effect and always |
| returns C<undef>. |
| |
| B<Note> that the special variable C<$|> B<cannot> be used to set or |
| retrieve the autoflush setting. |
| |
| =head2 input_line_number |
| |
| $z->input_line_number() |
| $z->input_line_number(EXPR) |
| |
| Returns the current uncompressed line number. If C<EXPR> is present it has |
| the effect of setting the line number. Note that setting the line number |
| does not change the current position within the file/buffer being read. |
| |
| The contents of C<$/> are used to to determine what constitutes a line |
| terminator. |
| |
| =head2 fileno |
| |
| $z->fileno() |
| fileno($z) |
| |
| If the C<$z> object is associated with a file or a filehandle, C<fileno> |
| will return the underlying file descriptor. Once the C<close> method is |
| called C<fileno> will return C<undef>. |
| |
| If the C<$z> object is associated with a buffer, this method will return |
| C<undef>. |
| |
| =head2 close |
| |
| $z->close() ; |
| close $z ; |
| |
| Closes the output file/buffer. |
| |
| For most versions of Perl this method will be automatically invoked if |
| the IO::Uncompress::Gunzip object is destroyed (either explicitly or by the |
| variable with the reference to the object going out of scope). The |
| exceptions are Perl versions 5.005 through 5.00504 and 5.8.0. In |
| these cases, the C<close> method will be called automatically, but |
| not until global destruction of all live objects when the program is |
| terminating. |
| |
| Therefore, if you want your scripts to be able to run on all versions |
| of Perl, you should call C<close> explicitly and not rely on automatic |
| closing. |
| |
| Returns true on success, otherwise 0. |
| |
| If the C<AutoClose> option has been enabled when the IO::Uncompress::Gunzip |
| object was created, and the object is associated with a file, the |
| underlying file will also be closed. |
| |
| =head2 nextStream |
| |
| Usage is |
| |
| my $status = $z->nextStream(); |
| |
| Skips to the next compressed data stream in the input file/buffer. If a new |
| compressed data stream is found, the eof marker will be cleared and C<$.> |
| will be reset to 0. |
| |
| Returns 1 if a new stream was found, 0 if none was found, and -1 if an |
| error was encountered. |
| |
| =head2 trailingData |
| |
| Usage is |
| |
| my $data = $z->trailingData(); |
| |
| Returns the data, if any, that is present immediately after the compressed |
| data stream once uncompression is complete. It only makes sense to call |
| this method once the end of the compressed data stream has been |
| encountered. |
| |
| This option can be used when there is useful information immediately |
| following the compressed data stream, and you don't know the length of the |
| compressed data stream. |
| |
| If the input is a buffer, C<trailingData> will return everything from the |
| end of the compressed data stream to the end of the buffer. |
| |
| If the input is a filehandle, C<trailingData> will return the data that is |
| left in the filehandle input buffer once the end of the compressed data |
| stream has been reached. You can then use the filehandle to read the rest |
| of the input file. |
| |
| Don't bother using C<trailingData> if the input is a filename. |
| |
| If you know the length of the compressed data stream before you start |
| uncompressing, you can avoid having to use C<trailingData> by setting the |
| C<InputLength> option in the constructor. |
| |
| =head1 Importing |
| |
| No symbolic constants are required by this IO::Uncompress::Gunzip at present. |
| |
| =over 5 |
| |
| =item :all |
| |
| Imports C<gunzip> and C<$GunzipError>. |
| Same as doing this |
| |
| use IO::Uncompress::Gunzip qw(gunzip $GunzipError) ; |
| |
| =back |
| |
| =head1 EXAMPLES |
| |
| =head2 Working with Net::FTP |
| |
| See L<IO::Uncompress::Gunzip::FAQ|IO::Uncompress::Gunzip::FAQ/"Compressed files and Net::FTP"> |
| |
| =head1 SEE ALSO |
| |
| 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> |
| |
| L<IO::Compress::FAQ|IO::Compress::FAQ> |
| |
| L<File::GlobMapper|File::GlobMapper>, L<Archive::Zip|Archive::Zip>, |
| L<Archive::Tar|Archive::Tar>, |
| L<IO::Zlib|IO::Zlib> |
| |
| For RFC 1950, 1951 and 1952 see |
| F<http://www.faqs.org/rfcs/rfc1950.html>, |
| F<http://www.faqs.org/rfcs/rfc1951.html> and |
| F<http://www.faqs.org/rfcs/rfc1952.html> |
| |
| The I<zlib> compression library was written by Jean-loup Gailly |
| F<gzip@prep.ai.mit.edu> and Mark Adler F<madler@alumni.caltech.edu>. |
| |
| The primary site for the I<zlib> compression library is |
| F<http://www.zlib.org>. |
| |
| The primary site for gzip is F<http://www.gzip.org>. |
| |
| =head1 AUTHOR |
| |
| This module was written by Paul Marquess, F<pmqs@cpan.org>. |
| |
| =head1 MODIFICATION HISTORY |
| |
| See the Changes file. |
| |
| =head1 COPYRIGHT AND LICENSE |
| |
| Copyright (c) 2005-2012 Paul Marquess. All rights reserved. |
| |
| This program is free software; you can redistribute it and/or |
| modify it under the same terms as Perl itself. |
| |