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IO::Compress::Zip(3pm) Perl Programmers Reference Guide IO::Compress::Zip(3pm)
NAME
IO::Compress::Zip - Write zip files/buffers
SYNOPSIS
use IO::Compress::Zip qw(zip $ZipError) ;
my $status = zip $input => $output [,OPTS]
or die "zip failed: $ZipError\n";
my $z = new IO::Compress::Zip $output [,OPTS]
or die "zip failed: $ZipError\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() ;
$ZipError ;
# IO::File mode
print $z $string;
printf $z $format, $string;
tell $z
eof $z
seek $z, $position, $whence
binmode $z
fileno $z
close $z ;
DESCRIPTION
This module provides a Perl interface that allows writing zip compressed data to files or buffer.
The primary purpose of this module is to provide streaming write access to zip files and buffers. It
is not a general-purpose file archiver. If that is what you want, check out "Archive::Zip".
At present three compression methods are supported by IO::Compress::Zip, namely Store (no compression
at all), Deflate and Bzip2.
Note that to create Bzip2 content, the module "IO::Compress::Bzip2" must be installed.
For reading zip files/buffers, see the companion module IO::Uncompress::Unzip.
Functional Interface
A top-level function, "zip", is provided to carry out "one-shot" compression between buffers and/or
files. For finer control over the compression process, see the "OO Interface" section.
use IO::Compress::Zip qw(zip $ZipError) ;
zip $input => $output [,OPTS]
or die "zip failed: $ZipError\n";
The functional interface needs Perl5.005 or better.
zip $input => $output [, OPTS]
"zip" expects at least two parameters, $input and $output.
The $input parameter
The parameter, $input, is used to define the source of the uncompressed data.
It can take one of the following forms:
A filename
If the $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.
A filehandle
If the $input parameter is a filehandle, the input data will be read from it. The string '-'
can be used as an alias for standard input.
A scalar reference
If $input is a scalar reference, the input data will be read from $$input.
An array reference
If $input is an array reference, each element in the array must be a filename.
The input data will be read from each file in turn.
The complete array will be walked to ensure that it only contains valid filenames before any
data is compressed.
An Input FileGlob string
If $input is a string that is delimited by the characters "<" and ">" "zip" will assume that it
is an input fileglob string. The input is the list of files that match the fileglob.
If the fileglob does not match any files ...
See File::GlobMapper for more details.
If the $input parameter is any other type, "undef" will be returned.
In addition, if $input is a simple filename, the default values for the "Name", "Time", "ExtAttr" and
"exTime" options will be sourced from that file.
If you do not want to use these defaults they can be overridden by explicitly setting the "Name",
"Time", "ExtAttr" and "exTime" options or by setting the "Minimal" parameter.
The $output parameter
The parameter $output is used to control the destination of the compressed data. This parameter can
take one of these forms.
A filename
If the $output parameter is a simple scalar, it is assumed to be a filename. This file will be
opened for writing and the compressed data will be written to it.
A filehandle
If the $output parameter is a filehandle, the compressed data will be written to it. The string
'-' can be used as an alias for standard output.
A scalar reference
If $output is a scalar reference, the compressed data will be stored in $$output.
An Array Reference
If $output is an array reference, the compressed data will be pushed onto the array.
An Output FileGlob
If $output is a string that is delimited by the characters "<" and ">" "zip" will assume that it
is an output fileglob string. The output is the list of files that match the fileglob.
When $output is an fileglob string, $input must also be a fileglob string. Anything else is an
error.
If the $output parameter is any other type, "undef" will be returned.
Notes
When $input maps to multiple files/buffers and $output is a single file/buffer the input
files/buffers will each be stored in $output as a distinct entry.
Optional Parameters
Unless specified below, the optional parameters for "zip", "OPTS", are the same as those used with
the OO interface defined in the "Constructor Options" section below.
"AutoClose => 0|1"
This option applies to any input or output data streams to "zip" that are filehandles.
If "AutoClose" is specified, and the value is true, it will result in all input and/or output
filehandles being closed once "zip" has completed.
This parameter defaults to 0.
"BinModeIn => 0|1"
When reading from a file or filehandle, set "binmode" before reading.
Defaults to 0.
"Append => 0|1"
TODO
Examples
To read the contents of the file "file1.txt" and write the compressed data to the file
"file1.txt.zip".
use strict ;
use warnings ;
use IO::Compress::Zip qw(zip $ZipError) ;
my $input = "file1.txt";
zip $input => "$input.zip"
or die "zip failed: $ZipError\n";
To read from an existing Perl filehandle, $input, and write the compressed data to a buffer, $buffer.
use strict ;
use warnings ;
use IO::Compress::Zip qw(zip $ZipError) ;
use IO::File ;
my $input = new IO::File "<file1.txt"
or die "Cannot open 'file1.txt': $!\n" ;
my $buffer ;
zip $input => \$buffer
or die "zip failed: $ZipError\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::Zip qw(zip $ZipError) ;
zip '</my/home/*.txt>' => '<*.zip>'
or die "zip failed: $ZipError\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::Zip qw(zip $ZipError) ;
for my $input ( glob "/my/home/*.txt" )
{
my $output = "$input.zip" ;
zip $input => $output
or die "Error compressing '$input': $ZipError\n";
}
OO Interface
Constructor
The format of the constructor for "IO::Compress::Zip" is shown below
my $z = new IO::Compress::Zip $output [,OPTS]
or die "IO::Compress::Zip failed: $ZipError\n";
It returns an "IO::Compress::Zip" object on success and undef on failure. The variable $ZipError
will contain an error message on failure.
If you are running Perl 5.005 or better the object, $z, returned from IO::Compress::Zip can be used
exactly like an IO::File filehandle. This means that all normal output file operations can be
carried out with $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 $output is used to control the destination of the compressed data. This
parameter can take one of these forms.
A filename
If the $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.
A filehandle
If the $output parameter is a filehandle, the compressed data will be written to it. The string
'-' can be used as an alias for standard output.
A scalar reference
If $output is a scalar reference, the compressed data will be stored in $$output.
If the $output parameter is any other type, "IO::Compress::Zip"::new will return undef.
Constructor Options
"OPTS" is any combination of the following options:
"AutoClose => 0|1"
This option is only valid when the $output parameter is a filehandle. If specified, and the
value is true, it will result in the $output being closed once either the "close" method is
called or the "IO::Compress::Zip" object is destroyed.
This parameter defaults to 0.
"Append => 0|1"
Opens $output in append mode.
The behaviour of this option is dependent on the type of $output.
A Buffer
If $output is a buffer and "Append" is enabled, all compressed data will be append to the
end if $output. Otherwise $output will be cleared before any data is written to it.
A Filename
If $output is a filename and "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.
A Filehandle
If $output is a filehandle, the file pointer will be positioned to the end of the file via
a call to "seek" before any compressed data is written to it. Otherwise the file pointer
will not be moved.
This parameter defaults to 0.
"Name => $string"
Stores the contents of $string in the zip filename header field. If "Name" is not specified, no
zip filename field will be created.
"Time => $number"
Sets the last modified time field in the zip header to $number.
This field defaults to the time the "IO::Compress::Zip" object was created if this option is not
specified.
"ExtAttr => $attr"
This option controls the "external file attributes" field in the central header of the zip file.
This is a 4 byte field.
This option defaults to 0.
"exTime => [$atime, $mtime, $ctime]"
This option expects an array reference with exactly three elements: $atime, "mtime" and $ctime.
These correspond to the last access time, last modification time and creation time respectively.
It uses these values to set the extended timestamp field in the local zip header to the three
values, $atime, $mtime, $ctime and sets the extended timestamp field in the central zip header
to $mtime.
If any of the three values is "undef" that time value will not be used. So, for example, to set
only the $mtime you would use this
exTime => [undef, $mtime, undef]
If the "Minimal" option is set to true, this option will be ignored.
By default no extended time field is created.
"Comment => $comment"
Stores the contents of $comment in the Central File Header of the zip file.
By default, no comment field is written to the zip file.
"ZipComment => $comment"
Stores the contents of $comment in the End of Central Directory record of the zip file.
By default, no comment field is written to the zip file.
"Method => $method"
Controls which compression method is used. At present three compression methods are supported,
namely Store (no compression at all), Deflate and Bzip2.
The symbols, ZIP_CM_STORE, ZIP_CM_DEFLATE and ZIP_CM_BZIP2 are used to select the compression
method.
These constants are not imported by "IO::Compress::Zip" by default.
use IO::Compress::Zip qw(:zip_method);
use IO::Compress::Zip qw(:constants);
use IO::Compress::Zip qw(:all);
Note that to create Bzip2 content, the module "IO::Compress::Bzip2" must be installed. A fatal
error will be thrown if you attempt to create Bzip2 content when "IO::Compress::Bzip2" is not
available.
The default method is ZIP_CM_DEFLATE.
"Stream => 0|1"
This option controls whether the zip file/buffer output is created in streaming mode.
Note that when outputting to a file with streaming mode disabled ("Stream" is 0), the output
file must be seekable.
The default is 1.
"Zip64 => 0|1"
Create a Zip64 zip file/buffer. This option should only be used if you want to store files
larger than 4 Gig.
If you intend to manipulate the Zip64 zip files created with this module using an external
zip/unzip make sure that it supports streaming Zip64.
In particular, if you are using Info-Zip you need to have zip version 3.x or better to update a
Zip64 archive and unzip version 6.x to read a zip64 archive. At the time of writing both are
beta status.
When the "Zip64" option is enabled, the "Stream" option must be enabled as well.
The default is 0.
"TextFlag => 0|1"
This parameter controls the setting of a bit in the zip central header. It is used to signal
that the data stored in the zip file/buffer is probably text.
The default is 0.
"ExtraFieldLocal => $data" =item "ExtraFieldCentral => $data"
These options allows additional metadata to be stored in the local and central headers in the
zip file/buffer.
An extra field consists of zero or more subfields. Each subfield consists of a two byte header
followed by the subfield data.
The list of subfields can be supplied in any of the following formats
ExtraFieldLocal => [$id1, $data1,
$id2, $data2,
...
]
ExtraFieldLocal => [ [$id1 => $data1],
[$id2 => $data2],
...
]
ExtraFieldLocal => { $id1 => $data1,
$id2 => $data2,
...
}
Where $id1, $id2 are two byte subfield ID's.
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
The Extended Time field, set using the "exTime" option, is an example of an extended field.
If the "Minimal" option is set to true, this option will be ignored.
The maximum size of an extra field 65535 bytes.
"Minimal => 1|0"
If specified, this option will disable the creation of all extended fields in the zip local and
central headers. So the "exTime", "ExtraFieldLocal" and "ExtraFieldCentral" options will be
ignored.
This parameter defaults to 0.
"BlockSize100K => number"
Specify the number of 100K blocks bzip2 uses during compression.
Valid values are from 1 to 9, where 9 is best compression.
This option is only valid if the "Method" is ZIP_CM_BZIP2. It is ignored otherwise.
The default is 1.
"WorkFactor => number"
Specifies how much effort bzip2 should take before resorting to a slower fallback compression
algorithm.
Valid values range from 0 to 250, where 0 means use the default value 30.
This option is only valid if the "Method" is ZIP_CM_BZIP2. It is ignored otherwise.
The default is 0.
-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 "IO::Compress::Zip" by default.
use IO::Compress::Zip qw(:strategy);
use IO::Compress::Zip qw(:constants);
use IO::Compress::Zip qw(:all);
-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.
"Strict => 0|1"
This is a placeholder option.
Examples
TODO
Methods
print
Usage is
$z->print($data)
print $z $data
Compresses and outputs the contents of the $data parameter. This has the same behaviour as the
"print" built-in.
Returns true if successful.
printf
Usage is
$z->printf($format, $data)
printf $z $format, $data
Compresses and outputs the contents of the $data parameter.
Returns true if successful.
syswrite
Usage is
$z->syswrite $data
$z->syswrite $data, $length
$z->syswrite $data, $length, $offset
Compresses and outputs the contents of the $data parameter.
Returns the number of uncompressed bytes written, or "undef" if unsuccessful.
write
Usage is
$z->write $data
$z->write $data, $length
$z->write $data, $length, $offset
Compresses and outputs the contents of the $data parameter.
Returns the number of uncompressed bytes written, or "undef" if unsuccessful.
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, $flush_type, that controls how the flushing will be carried
out. By default the $flush_type used is "Z_FINISH". Other valid values for $flush_type are
"Z_NO_FLUSH", "Z_SYNC_FLUSH", "Z_FULL_FLUSH" and "Z_BLOCK". It is strongly recommended that you only
set the "flush_type" parameter if you fully understand the implications of what it does - overuse of
"flush" can seriously degrade the level of compression achieved. See the "zlib" documentation for
details.
Returns true on success.
tell
Usage is
$z->tell()
tell $z
Returns the uncompressed file offset.
eof
Usage is
$z->eof();
eof($z);
Returns true if the "close" method has been called.
seek
$z->seek($position, $whence);
seek($z, $position, $whence);
Provides a sub-set of the "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 $whence parameter takes one the usual values, namely SEEK_SET, SEEK_CUR or SEEK_END.
Returns 1 on success, 0 on failure.
binmode
Usage is
$z->binmode
binmode $z ;
This is a noop provided for completeness.
opened
$z->opened()
Returns true if the object currently refers to a opened file/buffer.
autoflush
my $prev = $z->autoflush()
my $prev = $z->autoflush(EXPR)
If the $z object is associated with a file or a filehandle, this method returns the current autoflush
setting for the underlying filehandle. If "EXPR" is present, and is non-zero, it will enable flushing
after every write/print operation.
If $z is associated with a buffer, this method has no effect and always returns "undef".
Note that the special variable $| cannot be used to set or retrieve the autoflush setting.
input_line_number
$z->input_line_number()
$z->input_line_number(EXPR)
This method always returns "undef" when compressing.
fileno
$z->fileno()
fileno($z)
If the $z object is associated with a file or a filehandle, this method will return the underlying
file descriptor.
If the $z object is is associated with a buffer, this method will return undef.
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::Zip 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 "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
"close" explicitly and not rely on automatic closing.
Returns true on success, otherwise 0.
If the "AutoClose" option has been enabled when the IO::Compress::Zip object was created, and the
object is associated with a file, the underlying file will also be closed.
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 $z object.
See the "Constructor Options" section for more details.
deflateParams
Usage is
$z->deflateParams
TODO
Importing
A number of symbolic constants are required by some methods in "IO::Compress::Zip". None are imported
by default.
:all Imports "zip", $ZipError and all symbolic constants that can be used by "IO::Compress::Zip".
Same as doing this
use IO::Compress::Zip qw(zip $ZipError :constants) ;
:constants
Import all symbolic constants. Same as doing this
use IO::Compress::Zip qw(:flush :level :strategy :zip_method) ;
:flush
These symbolic constants are used by the "flush" method.
Z_NO_FLUSH
Z_PARTIAL_FLUSH
Z_SYNC_FLUSH
Z_FULL_FLUSH
Z_FINISH
Z_BLOCK
:level
These symbolic constants are used by the "Level" option in the constructor.
Z_NO_COMPRESSION
Z_BEST_SPEED
Z_BEST_COMPRESSION
Z_DEFAULT_COMPRESSION
:strategy
These symbolic constants are used by the "Strategy" option in the constructor.
Z_FILTERED
Z_HUFFMAN_ONLY
Z_RLE
Z_FIXED
Z_DEFAULT_STRATEGY
:zip_method
These symbolic constants are used by the "Method" option in the constructor.
ZIP_CM_STORE
ZIP_CM_DEFLATE
ZIP_CM_BZIP2
For
EXAMPLES
TODO
SEE ALSO
Compress::Zlib, IO::Compress::Gzip, IO::Uncompress::Gunzip, IO::Compress::Deflate,
IO::Uncompress::Inflate, IO::Compress::RawDeflate, IO::Uncompress::RawInflate, IO::Compress::Bzip2,
IO::Uncompress::Bunzip2, IO::Compress::Lzop, IO::Uncompress::UnLzop, IO::Compress::Lzf,
IO::Uncompress::UnLzf, IO::Uncompress::AnyInflate, IO::Uncompress::AnyUncompress
Compress::Zlib::FAQ
File::GlobMapper, Archive::Zip, Archive::Tar, IO::Zlib
For RFC 1950, 1951 and 1952 see http://www.faqs.org/rfcs/rfc1950.html,
http://www.faqs.org/rfcs/rfc1951.html and http://www.faqs.org/rfcs/rfc1952.html
The zlib compression library was written by Jean-loup Gailly [email protected] and Mark Adler
[email protected].
The primary site for the zlib compression library is http://www.zlib.org.
The primary site for gzip is http://www.gzip.org.
AUTHOR
This module was written by Paul Marquess, [email protected].
MODIFICATION HISTORY
See the Changes file.
COPYRIGHT AND LICENSE
Copyright (c) 2005-2007 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.
perl v5.10.0 2007-12-18 IO::Compress::Zip(3pm)
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