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Diffstat (limited to 'Master/tlpkg/tlperl/lib/IO/Compress/Gzip.pm')
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diff --git a/Master/tlpkg/tlperl/lib/IO/Compress/Gzip.pm b/Master/tlpkg/tlperl/lib/IO/Compress/Gzip.pm new file mode 100755 index 00000000000..1978b91b283 --- /dev/null +++ b/Master/tlpkg/tlperl/lib/IO/Compress/Gzip.pm @@ -0,0 +1,1242 @@ + +package IO::Compress::Gzip ; + +require 5.004 ; + +use strict ; +use warnings; +use bytes; + + +use IO::Compress::RawDeflate 2.024 ; + +use Compress::Raw::Zlib 2.024 ; +use IO::Compress::Base::Common 2.024 qw(:Status :Parse createSelfTiedObject); +use IO::Compress::Gzip::Constants 2.024 ; +use IO::Compress::Zlib::Extra 2.024 ; + +BEGIN +{ + if (defined &utf8::downgrade ) + { *noUTF8 = \&utf8::downgrade } + else + { *noUTF8 = sub {} } +} + +require Exporter ; + +our ($VERSION, @ISA, @EXPORT_OK, %EXPORT_TAGS, $GzipError); + +$VERSION = '2.024'; +$GzipError = '' ; + +@ISA = qw(Exporter IO::Compress::RawDeflate); +@EXPORT_OK = qw( $GzipError gzip ) ; +%EXPORT_TAGS = %IO::Compress::RawDeflate::DEFLATE_CONSTANTS ; +push @{ $EXPORT_TAGS{all} }, @EXPORT_OK ; +Exporter::export_ok_tags('all'); + +sub new +{ + my $class = shift ; + + my $obj = createSelfTiedObject($class, \$GzipError); + + $obj->_create(undef, @_); +} + + +sub gzip +{ + my $obj = createSelfTiedObject(undef, \$GzipError); + return $obj->_def(@_); +} + +#sub newHeader +#{ +# my $self = shift ; +# #return GZIP_MINIMUM_HEADER ; +# return $self->mkHeader(*$self->{Got}); +#} + +sub getExtraParams +{ + my $self = shift ; + + return ( + # zlib behaviour + $self->getZlibParams(), + + # Gzip header fields + 'Minimal' => [0, 1, Parse_boolean, 0], + 'Comment' => [0, 1, Parse_any, undef], + 'Name' => [0, 1, Parse_any, undef], + 'Time' => [0, 1, Parse_any, undef], + 'TextFlag' => [0, 1, Parse_boolean, 0], + 'HeaderCRC' => [0, 1, Parse_boolean, 0], + 'OS_Code' => [0, 1, Parse_unsigned, $Compress::Raw::Zlib::gzip_os_code], + 'ExtraField'=> [0, 1, Parse_any, undef], + 'ExtraFlags'=> [0, 1, Parse_any, undef], + + ); +} + + +sub ckParams +{ + my $self = shift ; + my $got = shift ; + + # gzip always needs crc32 + $got->value('CRC32' => 1); + + return 1 + if $got->value('Merge') ; + + my $strict = $got->value('Strict') ; + + + { + if (! $got->parsed('Time') ) { + # Modification time defaults to now. + $got->value('Time' => time) ; + } + + # Check that the Name & Comment don't have embedded NULLs + # Also check that they only contain ISO 8859-1 chars. + if ($got->parsed('Name') && defined $got->value('Name')) { + my $name = $got->value('Name'); + + return $self->saveErrorString(undef, "Null Character found in Name", + Z_DATA_ERROR) + if $strict && $name =~ /\x00/ ; + + return $self->saveErrorString(undef, "Non ISO 8859-1 Character found in Name", + Z_DATA_ERROR) + if $strict && $name =~ /$GZIP_FNAME_INVALID_CHAR_RE/o ; + } + + if ($got->parsed('Comment') && defined $got->value('Comment')) { + my $comment = $got->value('Comment'); + + return $self->saveErrorString(undef, "Null Character found in Comment", + Z_DATA_ERROR) + if $strict && $comment =~ /\x00/ ; + + return $self->saveErrorString(undef, "Non ISO 8859-1 Character found in Comment", + Z_DATA_ERROR) + if $strict && $comment =~ /$GZIP_FCOMMENT_INVALID_CHAR_RE/o; + } + + if ($got->parsed('OS_Code') ) { + my $value = $got->value('OS_Code'); + + return $self->saveErrorString(undef, "OS_Code must be between 0 and 255, got '$value'") + if $value < 0 || $value > 255 ; + + } + + # gzip only supports Deflate at present + $got->value('Method' => Z_DEFLATED) ; + + if ( ! $got->parsed('ExtraFlags')) { + $got->value('ExtraFlags' => 2) + if $got->value('Level') == Z_BEST_SPEED ; + $got->value('ExtraFlags' => 4) + if $got->value('Level') == Z_BEST_COMPRESSION ; + } + + my $data = $got->value('ExtraField') ; + if (defined $data) { + my $bad = IO::Compress::Zlib::Extra::parseExtraField($data, $strict, 1) ; + return $self->saveErrorString(undef, "Error with ExtraField Parameter: $bad", Z_DATA_ERROR) + if $bad ; + + $got->value('ExtraField', $data) ; + } + } + + return 1; +} + +sub mkTrailer +{ + my $self = shift ; + return pack("V V", *$self->{Compress}->crc32(), + *$self->{UnCompSize}->get32bit()); +} + +sub getInverseClass +{ + return ('IO::Uncompress::Gunzip', + \$IO::Uncompress::Gunzip::GunzipError); +} + +sub getFileInfo +{ + my $self = shift ; + my $params = shift; + my $filename = shift ; + + my $defaultTime = (stat($filename))[9] ; + + $params->value('Name' => $filename) + if ! $params->parsed('Name') ; + + $params->value('Time' => $defaultTime) + if ! $params->parsed('Time') ; +} + + +sub mkHeader +{ + my $self = shift ; + my $param = shift ; + + # stort-circuit if a minimal header is requested. + return GZIP_MINIMUM_HEADER if $param->value('Minimal') ; + + # METHOD + my $method = $param->valueOrDefault('Method', GZIP_CM_DEFLATED) ; + + # FLAGS + my $flags = GZIP_FLG_DEFAULT ; + $flags |= GZIP_FLG_FTEXT if $param->value('TextFlag') ; + $flags |= GZIP_FLG_FHCRC if $param->value('HeaderCRC') ; + $flags |= GZIP_FLG_FEXTRA if $param->wantValue('ExtraField') ; + $flags |= GZIP_FLG_FNAME if $param->wantValue('Name') ; + $flags |= GZIP_FLG_FCOMMENT if $param->wantValue('Comment') ; + + # MTIME + my $time = $param->valueOrDefault('Time', GZIP_MTIME_DEFAULT) ; + + # EXTRA FLAGS + my $extra_flags = $param->valueOrDefault('ExtraFlags', GZIP_XFL_DEFAULT); + + # OS CODE + my $os_code = $param->valueOrDefault('OS_Code', GZIP_OS_DEFAULT) ; + + + my $out = pack("C4 V C C", + GZIP_ID1, # ID1 + GZIP_ID2, # ID2 + $method, # Compression Method + $flags, # Flags + $time, # Modification Time + $extra_flags, # Extra Flags + $os_code, # Operating System Code + ) ; + + # EXTRA + if ($flags & GZIP_FLG_FEXTRA) { + my $extra = $param->value('ExtraField') ; + $out .= pack("v", length $extra) . $extra ; + } + + # NAME + if ($flags & GZIP_FLG_FNAME) { + my $name .= $param->value('Name') ; + $name =~ s/\x00.*$//; + $out .= $name ; + # Terminate the filename with NULL unless it already is + $out .= GZIP_NULL_BYTE + if !length $name or + substr($name, 1, -1) ne GZIP_NULL_BYTE ; + } + + # COMMENT + if ($flags & GZIP_FLG_FCOMMENT) { + my $comment .= $param->value('Comment') ; + $comment =~ s/\x00.*$//; + $out .= $comment ; + # Terminate the comment with NULL unless it already is + $out .= GZIP_NULL_BYTE + if ! length $comment or + substr($comment, 1, -1) ne GZIP_NULL_BYTE; + } + + # HEADER CRC + $out .= pack("v", crc32($out) & 0x00FF ) if $param->value('HeaderCRC') ; + + noUTF8($out); + + return $out ; +} + +sub mkFinalTrailer +{ + return ''; +} + +1; + +__END__ + +=head1 NAME + +IO::Compress::Gzip - Write RFC 1952 files/buffers + + + +=head1 SYNOPSIS + + use IO::Compress::Gzip qw(gzip $GzipError) ; + + my $status = gzip $input => $output [,OPTS] + or die "gzip failed: $GzipError\n"; + + my $z = new IO::Compress::Gzip $output [,OPTS] + or die "gzip failed: $GzipError\n"; + + $z->print($string); + $z->printf($format, $string); + $z->write($string); + $z->syswrite($string [, $length, $offset]); + $z->flush(); + $z->tell(); + $z->eof(); + $z->seek($position, $whence); + $z->binmode(); + $z->fileno(); + $z->opened(); + $z->autoflush(); + $z->input_line_number(); + $z->newStream( [OPTS] ); + + $z->deflateParams(); + + $z->close() ; + + $GzipError ; + + # IO::File mode + + print $z $string; + printf $z $format, $string; + tell $z + eof $z + seek $z, $position, $whence + binmode $z + fileno $z + close $z ; + + +=head1 DESCRIPTION + +This module provides a Perl interface that allows writing compressed +data to files or buffer as defined in RFC 1952. + +All the gzip headers defined in RFC 1952 can be created using +this module. + +For reading RFC 1952 files/buffers, see the companion module +L<IO::Uncompress::Gunzip|IO::Uncompress::Gunzip>. + +=head1 Functional Interface + +A top-level function, C<gzip>, is provided to carry out +"one-shot" compression between buffers and/or files. For finer +control over the compression process, see the L</"OO Interface"> +section. + + use IO::Compress::Gzip qw(gzip $GzipError) ; + + gzip $input => $output [,OPTS] + or die "gzip failed: $GzipError\n"; + +The functional interface needs Perl5.005 or better. + +=head2 gzip $input => $output [, OPTS] + +C<gzip> expects at least two parameters, C<$input> and C<$output>. + +=head3 The C<$input> parameter + +The parameter, C<$input>, is used to define the source of +the uncompressed data. + +It can take one of the following forms: + +=over 5 + +=item A filename + +If the C<$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<$$input>. + +=item An array reference + +If C<$input> is an array reference, each element in the array must be a +filename. + +The input data will be read from each file in turn. + +The complete array will be walked to ensure that it only +contains valid filenames before any data is compressed. + +=item An Input FileGlob string + +If C<$input> is a string that is delimited by the characters "<" and ">" +C<gzip> will assume that it is an I<input fileglob string>. The +input is the list of files that match the fileglob. + +If the fileglob does not match any files ... + +See L<File::GlobMapper|File::GlobMapper> for more details. + +=back + +If the C<$input> parameter is any other type, C<undef> will be returned. + +In addition, if C<$input> is a simple filename, the default values for +the C<Name> and C<Time> options will be sourced from that file. + +If you do not want to use these defaults they can be overridden by +explicitly setting the C<Name> and C<Time> options or by setting the +C<Minimal> parameter. + +=head3 The C<$output> parameter + +The parameter C<$output> is used to control the destination of the +compressed data. This parameter can take one of these forms. + +=over 5 + +=item A filename + +If the C<$output> parameter is a simple scalar, it is assumed to be a +filename. This file will be opened for writing and the compressed +data will be written to it. + +=item A filehandle + +If the C<$output> parameter is a filehandle, the compressed data +will be written to it. +The string '-' can be used as an alias for standard output. + +=item A scalar reference + +If C<$output> is a scalar reference, the compressed data will be +stored in C<$$output>. + +=item An Array Reference + +If C<$output> is an array reference, the compressed data will be +pushed onto the array. + +=item An Output FileGlob + +If C<$output> is a string that is delimited by the characters "<" and ">" +C<gzip> 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. + +=back + +If the C<$output> parameter is any other type, C<undef> will be returned. + +=head2 Notes + +When C<$input> maps to multiple files/buffers and C<$output> is a single +file/buffer the input files/buffers will be stored +in C<$output> as a concatenated series of compressed data streams. + +=head2 Optional Parameters + +Unless specified below, the optional parameters for C<gzip>, +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<gzip> 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<gzip> has +completed. + +This parameter defaults to 0. + +=item C<< BinModeIn => 0|1 >> + +When reading from a file or filehandle, set C<binmode> before reading. + +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 compressed data will be append to the end of +the output buffer. Otherwise the output buffer will be cleared before any +compressed 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 compressed +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 compressed 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 compressed +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 compressed data. If the output is a filename, it will be opened for +appending. If the output is a buffer, all compressed data will be appened 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 compressed 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 compressed data is output. + +Defaults to 0. + +=back + +=head2 Examples + +To read the contents of the file C<file1.txt> and write the compressed +data to the file C<file1.txt.gz>. + + use strict ; + use warnings ; + use IO::Compress::Gzip qw(gzip $GzipError) ; + + my $input = "file1.txt"; + gzip $input => "$input.gz" + or die "gzip failed: $GzipError\n"; + +To read from an existing Perl filehandle, C<$input>, and write the +compressed data to a buffer, C<$buffer>. + + use strict ; + use warnings ; + use IO::Compress::Gzip qw(gzip $GzipError) ; + use IO::File ; + + my $input = new IO::File "<file1.txt" + or die "Cannot open 'file1.txt': $!\n" ; + my $buffer ; + gzip $input => \$buffer + or die "gzip failed: $GzipError\n"; + +To compress all files in the directory "/my/home" that match "*.txt" +and store the compressed data in the same directory + + use strict ; + use warnings ; + use IO::Compress::Gzip qw(gzip $GzipError) ; + + gzip '</my/home/*.txt>' => '<*.gz>' + or die "gzip failed: $GzipError\n"; + +and if you want to compress each file one at a time, this will do the trick + + use strict ; + use warnings ; + use IO::Compress::Gzip qw(gzip $GzipError) ; + + for my $input ( glob "/my/home/*.txt" ) + { + my $output = "$input.gz" ; + gzip $input => $output + or die "Error compressing '$input': $GzipError\n"; + } + +=head1 OO Interface + +=head2 Constructor + +The format of the constructor for C<IO::Compress::Gzip> is shown below + + my $z = new IO::Compress::Gzip $output [,OPTS] + or die "IO::Compress::Gzip failed: $GzipError\n"; + +It returns an C<IO::Compress::Gzip> object on success and undef on failure. +The variable C<$GzipError> will contain an error message on failure. + +If you are running Perl 5.005 or better the object, C<$z>, returned from +IO::Compress::Gzip can be used exactly like an L<IO::File|IO::File> filehandle. +This means that all normal output file operations can be carried out +with C<$z>. +For example, to write to a compressed file/buffer you can use either of +these forms + + $z->print("hello world\n"); + print $z "hello world\n"; + +The mandatory parameter C<$output> is used to control the destination +of the compressed data. This parameter can take one of these forms. + +=over 5 + +=item A filename + +If the C<$output> parameter is a simple scalar, it is assumed to be a +filename. This file will be opened for writing and the compressed data +will be written to it. + +=item A filehandle + +If the C<$output> parameter is a filehandle, the compressed 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 compressed data will be stored +in C<$$output>. + +=back + +If the C<$output> parameter is any other type, C<IO::Compress::Gzip>::new will +return undef. + +=head2 Constructor Options + +C<OPTS> is any combination of the following options: + +=over 5 + +=item C<< AutoClose => 0|1 >> + +This option is only valid when the C<$output> parameter is a filehandle. If +specified, and the value is true, it will result in the C<$output> being +closed once either the C<close> method is called or the C<IO::Compress::Gzip> +object is destroyed. + +This parameter defaults to 0. + +=item C<< Append => 0|1 >> + +Opens C<$output> in append mode. + +The behaviour of this option is dependent on the type of C<$output>. + +=over 5 + +=item * A Buffer + +If C<$output> is a buffer and C<Append> is enabled, all compressed data +will be append to the end of C<$output>. Otherwise C<$output> will be +cleared before any data is written to it. + +=item * A Filename + +If C<$output> is a filename and C<Append> is enabled, the file will be +opened in append mode. Otherwise the contents of the file, if any, will be +truncated before any compressed data is written to it. + +=item * A Filehandle + +If C<$output> is a filehandle, the file pointer will be positioned to the +end of the file via a call to C<seek> before any compressed data is written +to it. Otherwise the file pointer will not be moved. + +=back + +This parameter defaults to 0. + +=item C<< Merge => 0|1 >> + +This option is used to compress input data and append it to an existing +compressed data stream in C<$output>. The end result is a single compressed +data stream stored in C<$output>. + +It is a fatal error to attempt to use this option when C<$output> is not an +RFC 1952 data stream. + +There are a number of other limitations with the C<Merge> option: + +=over 5 + +=item 1 + +This module needs to have been built with zlib 1.2.1 or better to work. A +fatal error will be thrown if C<Merge> is used with an older version of +zlib. + +=item 2 + +If C<$output> is a file or a filehandle, it must be seekable. + +=back + +This parameter defaults to 0. + +=item -Level + +Defines the compression level used by zlib. The value should either be +a number between 0 and 9 (0 means no compression and 9 is maximum +compression), or one of the symbolic constants defined below. + + Z_NO_COMPRESSION + Z_BEST_SPEED + Z_BEST_COMPRESSION + Z_DEFAULT_COMPRESSION + +The default is Z_DEFAULT_COMPRESSION. + +Note, these constants are not imported by C<IO::Compress::Gzip> by default. + + use IO::Compress::Gzip qw(:strategy); + use IO::Compress::Gzip qw(:constants); + use IO::Compress::Gzip qw(:all); + +=item -Strategy + +Defines the strategy used to tune the compression. Use one of the symbolic +constants defined below. + + Z_FILTERED + Z_HUFFMAN_ONLY + Z_RLE + Z_FIXED + Z_DEFAULT_STRATEGY + +The default is Z_DEFAULT_STRATEGY. + +=item C<< Minimal => 0|1 >> + +If specified, this option will force the creation of the smallest possible +compliant gzip header (which is exactly 10 bytes long) as defined in +RFC 1952. + +See the section titled "Compliance" in RFC 1952 for a definition +of the values used for the fields in the gzip header. + +All other parameters that control the content of the gzip header will +be ignored if this parameter is set to 1. + +This parameter defaults to 0. + +=item C<< Comment => $comment >> + +Stores the contents of C<$comment> in the COMMENT field in +the gzip header. +By default, no comment field is written to the gzip file. + +If the C<-Strict> option is enabled, the comment can only consist of ISO +8859-1 characters plus line feed. + +If the C<-Strict> option is disabled, the comment field can contain any +character except NULL. If any null characters are present, the field +will be truncated at the first NULL. + +=item C<< Name => $string >> + +Stores the contents of C<$string> in the gzip NAME header field. If +C<Name> is not specified, no gzip NAME field will be created. + +If the C<-Strict> option is enabled, C<$string> can only consist of ISO +8859-1 characters. + +If C<-Strict> is disabled, then C<$string> can contain any character +except NULL. If any null characters are present, the field will be +truncated at the first NULL. + +=item C<< Time => $number >> + +Sets the MTIME field in the gzip header to $number. + +This field defaults to the time the C<IO::Compress::Gzip> object was created +if this option is not specified. + +=item C<< TextFlag => 0|1 >> + +This parameter controls the setting of the FLG.FTEXT bit in the gzip +header. It is used to signal that the data stored in the gzip file/buffer +is probably text. + +The default is 0. + +=item C<< HeaderCRC => 0|1 >> + +When true this parameter will set the FLG.FHCRC bit to 1 in the gzip header +and set the CRC16 header field to the CRC of the complete gzip header +except the CRC16 field itself. + +B<Note> that gzip files created with the C<HeaderCRC> flag set to 1 cannot +be read by most, if not all, of the the standard gunzip utilities, most +notably gzip version 1.2.4. You should therefore avoid using this option if +you want to maximize the portability of your gzip files. + +This parameter defaults to 0. + +=item C<< OS_Code => $value >> + +Stores C<$value> in the gzip OS header field. A number between 0 and 255 is +valid. + +If not specified, this parameter defaults to the OS code of the Operating +System this module was built on. The value 3 is used as a catch-all for all +Unix variants and unknown Operating Systems. + +=item C<< ExtraField => $data >> + +This parameter allows additional metadata to be stored in the ExtraField in +the gzip header. An RFC 1952 compliant ExtraField consists of zero or more +subfields. Each subfield consists of a two byte header followed by the +subfield data. + +The list of subfields can be supplied in any of the following formats + + -ExtraField => [$id1, $data1, + $id2, $data2, + ... + ] + -ExtraField => [ [$id1 => $data1], + [$id2 => $data2], + ... + ] + -ExtraField => { $id1 => $data1, + $id2 => $data2, + ... + } + +Where C<$id1>, C<$id2> are two byte subfield ID's. The second byte of +the ID cannot be 0, unless the C<Strict> option has been disabled. + +If you use the hash syntax, you have no control over the order in which +the ExtraSubFields are stored, plus you cannot have SubFields with +duplicate ID. + +Alternatively the list of subfields can by supplied as a scalar, thus + + -ExtraField => $rawdata + +If you use the raw format, and the C<Strict> option is enabled, +C<IO::Compress::Gzip> will check that C<$rawdata> consists of zero or more +conformant sub-fields. When C<Strict> is disabled, C<$rawdata> can +consist of any arbitrary byte stream. + +The maximum size of the Extra Field 65535 bytes. + +=item C<< ExtraFlags => $value >> + +Sets the XFL byte in the gzip header to C<$value>. + +If this option is not present, the value stored in XFL field will be +determined by the setting of the C<Level> option. + +If C<< Level => Z_BEST_SPEED >> has been specified then XFL is set to 2. +If C<< Level => Z_BEST_COMPRESSION >> has been specified then XFL is set to 4. +Otherwise XFL is set to 0. + +=item C<< Strict => 0|1 >> + +C<Strict> will optionally police the values supplied with other options +to ensure they are compliant with RFC1952. + +This option is enabled by default. + +If C<Strict> is enabled the following behaviour will be policed: + +=over 5 + +=item * + +The value supplied with the C<Name> option can only contain ISO 8859-1 +characters. + +=item * + +The value supplied with the C<Comment> option can only contain ISO 8859-1 +characters plus line-feed. + +=item * + +The values supplied with the C<-Name> and C<-Comment> options cannot +contain multiple embedded nulls. + +=item * + +If an C<ExtraField> option is specified and it is a simple scalar, +it must conform to the sub-field structure as defined in RFC 1952. + +=item * + +If an C<ExtraField> option is specified the second byte of the ID will be +checked in each subfield to ensure that it does not contain the reserved +value 0x00. + +=back + +When C<Strict> is disabled the following behaviour will be policed: + +=over 5 + +=item * + +The value supplied with C<-Name> option can contain +any character except NULL. + +=item * + +The value supplied with C<-Comment> option can contain any character +except NULL. + +=item * + +The values supplied with the C<-Name> and C<-Comment> options can contain +multiple embedded nulls. The string written to the gzip header will +consist of the characters up to, but not including, the first embedded +NULL. + +=item * + +If an C<ExtraField> option is specified and it is a simple scalar, the +structure will not be checked. The only error is if the length is too big. + +=item * + +The ID header in an C<ExtraField> sub-field can consist of any two bytes. + +=back + +=back + +=head2 Examples + +TODO + +=head1 Methods + +=head2 print + +Usage is + + $z->print($data) + print $z $data + +Compresses and outputs the contents of the C<$data> parameter. This +has the same behaviour as the C<print> built-in. + +Returns true if successful. + +=head2 printf + +Usage is + + $z->printf($format, $data) + printf $z $format, $data + +Compresses and outputs the contents of the C<$data> parameter. + +Returns true if successful. + +=head2 syswrite + +Usage is + + $z->syswrite $data + $z->syswrite $data, $length + $z->syswrite $data, $length, $offset + +Compresses and outputs the contents of the C<$data> parameter. + +Returns the number of uncompressed bytes written, or C<undef> if +unsuccessful. + +=head2 write + +Usage is + + $z->write $data + $z->write $data, $length + $z->write $data, $length, $offset + +Compresses and outputs the contents of the C<$data> parameter. + +Returns the number of uncompressed bytes written, or C<undef> if +unsuccessful. + +=head2 flush + +Usage is + + $z->flush; + $z->flush($flush_type); + +Flushes any pending compressed data to the output file/buffer. + +This method takes an optional parameter, C<$flush_type>, that controls +how the flushing will be carried out. By default the C<$flush_type> +used is C<Z_FINISH>. Other valid values for C<$flush_type> are +C<Z_NO_FLUSH>, C<Z_SYNC_FLUSH>, C<Z_FULL_FLUSH> and C<Z_BLOCK>. It is +strongly recommended that you only set the C<flush_type> parameter if +you fully understand the implications of what it does - overuse of C<flush> +can seriously degrade the level of compression achieved. See the C<zlib> +documentation for details. + +Returns true on success. + +=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 C<close> method has been called. + +=head2 seek + + $z->seek($position, $whence); + seek($z, $position, $whence); + +Provides a sub-set of the C<seek> functionality, with the restriction +that it is only legal to seek forward in the output file/buffer. +It is a fatal error to attempt to seek backward. + +Empty parts of the file/buffer will have NULL (0x00) bytes written to them. + +The C<$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) + +This method always returns C<undef> when compressing. + +=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 is associated with a buffer, this method will return +C<undef>. + +=head2 close + + $z->close() ; + close $z ; + +Flushes any pending compressed data and then closes the output file/buffer. + +For most versions of Perl this method will be automatically invoked if +the IO::Compress::Gzip 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::Compress::Gzip +object was created, and the object is associated with a file, the +underlying file will also be closed. + +=head2 newStream([OPTS]) + +Usage is + + $z->newStream( [OPTS] ) + +Closes the current compressed data stream and starts a new one. + +OPTS consists of any of the the options that are available when creating +the C<$z> object. + +See the L</"Constructor Options"> section for more details. + +=head2 deflateParams + +Usage is + + $z->deflateParams + +TODO + +=head1 Importing + +A number of symbolic constants are required by some methods in +C<IO::Compress::Gzip>. None are imported by default. + +=over 5 + +=item :all + +Imports C<gzip>, C<$GzipError> and all symbolic +constants that can be used by C<IO::Compress::Gzip>. Same as doing this + + use IO::Compress::Gzip qw(gzip $GzipError :constants) ; + +=item :constants + +Import all symbolic constants. Same as doing this + + use IO::Compress::Gzip qw(:flush :level :strategy) ; + +=item :flush + +These symbolic constants are used by the C<flush> method. + + Z_NO_FLUSH + Z_PARTIAL_FLUSH + Z_SYNC_FLUSH + Z_FULL_FLUSH + Z_FINISH + Z_BLOCK + +=item :level + +These symbolic constants are used by the C<Level> option in the constructor. + + Z_NO_COMPRESSION + Z_BEST_SPEED + Z_BEST_COMPRESSION + Z_DEFAULT_COMPRESSION + +=item :strategy + +These symbolic constants are used by the C<Strategy> option in the constructor. + + Z_FILTERED + Z_HUFFMAN_ONLY + Z_RLE + Z_FIXED + Z_DEFAULT_STRATEGY + + + + +=back + +=head1 EXAMPLES + +=head2 Apache::GZip Revisited + +See L<IO::Compress::FAQ|IO::Compress::FAQ/"Apache::GZip Revisited"> + + + +=head2 Working with Net::FTP + +See L<IO::Compress::FAQ|IO::Compress::FAQ/"Compressed files and Net::FTP"> + +=head1 SEE ALSO + +L<Compress::Zlib>, L<IO::Uncompress::Gunzip>, 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<Compress::Zlib::FAQ|Compress::Zlib::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) 2005-2010 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. + |