IO::Compress::Deflate - Write RFC 1950 files/buffers use IO::Compress::Deflate qw(deflate $DeflateError) ; my $status = deflate $input => $output [,OPTS] or die "deflate failed: $DeflateError\n"; my $z = new IO::Compress::Deflate $output [,OPTS] or die "deflate failed: $DeflateError\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() ; $DeflateError ; # IO::File mode print $z $string; printf $z $format, $string; tell $z eof $z seek $z, $position, $whence binmode $z fileno $z close $z ; This module provides a Perl interface that allows writing compressed data to files or buffer as defined in RFC 1950. For reading RFC 1950 files/buffers, see the companion module IO::Uncompress::Inflate. A top-level function, "deflate", 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::Deflate qw(deflate $DeflateError) ; deflate $input => $output [,OPTS] or die "deflate failed: $DeflateError\n"; The functional interface needs Perl5.005 or better.

deflate $input => $output [, OPTS]
"deflate" 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: 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. 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. If $input is a scalar reference, the input data will be read from $$input. If $input is an array reference, each element in the array must be a filename. The input data will be read from each file in turn. The complete array will be walked to ensure that it only contains valid filenames before any data is compressed. If $input is a string that is delimited by the characters "<" and ">" "deflate" will assume that it is an input fileglob string. The input is the list of files that match the fileglob. If the fileglob does not match any files ... See File::GlobMapper for more details. If the $input parameter is any other type, "undef" will be returned. The $output parameter The parameter $output is used to control the destination of the compressed data. This parameter can take one of these forms. If the $output parameter is a simple scalar, it is assumed to be a filename. This file will be opened for writing and the compressed data will be written to it. If the $output parameter is a filehandle, the compressed data will be written to it. The string '-' can be used as an alias for standard output. If $output is a scalar reference, the compressed data will be stored in $$output. If $output is an array reference, the compressed data will be pushed onto the array. If $output is a string that is delimited by the characters "<" and ">" "deflate" 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 be stored in $output as a concatenated series of compressed data streams.

Optional Parameters
Unless specified below, the optional parameters for "deflate", "OPTS", are the same as those used with the OO interface defined in the "Constructor Options" section below. This option applies to any input or output data streams to "deflate" 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 "deflate" has completed. This parameter defaults to 0. When reading from a file or filehandle, set "binmode" before reading. Defaults to 0. TODO

Examples
To read the contents of the file "file1.txt" and write the compressed data to the file "file1.txt.1950". use strict ; use warnings ; use IO::Compress::Deflate qw(deflate $DeflateError) ; my $input = "file1.txt"; deflate $input => "$input.1950" or die "deflate failed: $DeflateError\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::Deflate qw(deflate $DeflateError) ; use IO::File ; my $input = new IO::File "<file1.txt" or die "Cannot open 'file1.txt': $!\n" ; my $buffer ; deflate $input => \$buffer or die "deflate failed: $DeflateError\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::Deflate qw(deflate $DeflateError) ; deflate '</my/home/*.txt>' => '<*.1950>' or die "deflate failed: $DeflateError\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::Deflate qw(deflate $DeflateError) ; for my $input ( glob "/my/home/*.txt" ) { my $output = "$input.1950" ; deflate $input => $output or die "Error compressing '$input': $DeflateError\n"; }

Constructor
The format of the constructor for "IO::Compress::Deflate" is shown below my $z = new IO::Compress::Deflate $output [,OPTS] or die "IO::Compress::Deflate failed: $DeflateError\n"; It returns an "IO::Compress::Deflate" object on success and undef on failure. The variable $DeflateError will contain an error message on failure. If you are running Perl 5.005 or better the object, $z, returned from IO::Compress::Deflate 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. 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. 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. If $output is a scalar reference, the compressed data will be stored in $$output. If the $output parameter is any other type, "IO::Compress::Deflate"::new will return undef.

Constructor Options
"OPTS" is any combination of the following options: 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::Deflate" object is destroyed. This parameter defaults to 0. Opens $output in append mode. The behaviour of this option is dependent on the type of $output. 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. 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. 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. This option is used to compress input data and append it to an existing compressed data stream in $output. The end result is a single compressed data stream stored in $output. It is a fatal error to attempt to use this option when $output is not an RFC 1950 data stream. There are a number of other limitations with the "Merge" option: This module needs to have been built with zlib 1.2.1 or better to work. A fatal error will be thrown if "Merge" is used with an older version of zlib. If $output is a file or a filehandle, it must be seekable. This parameter defaults to 0. 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::Deflate" by default. use IO::Compress::Deflate qw(:strategy); use IO::Compress::Deflate qw(:constants); use IO::Compress::Deflate qw(:all); 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. This is a placeholder option.

Examples
TODO

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::Deflate 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::Deflate 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 A number of symbolic constants are required by some methods in "IO::Compress::Deflate". None are imported by default. Imports "deflate", $DeflateError and all symbolic constants that can be used by "IO::Compress::Deflate". Same as doing this use IO::Compress::Deflate qw(deflate $DeflateError :constants) ; Import all symbolic constants. Same as doing this use IO::Compress::Deflate qw(:flush :level :strategy) ; 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 These symbolic constants are used by the "Level" option in the constructor. Z_NO_COMPRESSION Z_BEST_SPEED Z_BEST_COMPRESSION Z_DEFAULT_COMPRESSION These symbolic constants are used by the "Strategy" option in the constructor. Z_FILTERED Z_HUFFMAN_ONLY Z_RLE Z_FIXED Z_DEFAULT_STRATEGY For TODO Compress::Zlib, IO::Compress::Gzip, IO::Uncompress::Gunzip, 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 gzip@prep.ai.mit.edu and Mark Adler madler@alumni.caltech.edu. The primary site for the zlib compression library is http://www.zlib.org. The primary site for gzip is http://www.gzip.org. This module was written by Paul Marquess, pmqs@cpan.org. See the Changes file. 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.