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NAME

       IO::Compress::Bzip2 - Write bzip2 files/buffers

SYNOPSIS

           use IO::Compress::Bzip2 qw(bzip2 $Bzip2Error) ;

           my $status = bzip2 $input => $output [,OPTS]
               or die "bzip2 failed: $Bzip2Error\n";

           my $z = new IO::Compress::Bzip2 $output [,OPTS]
               or die "bzip2 failed: $Bzip2Error\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->close() ;

           $Bzip2Error ;

           # 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 bzip2 compressed data to files
       or buffer.

       For reading bzip2 files/buffers, see the companion module IO::Uncompress::Bunzip2.

Functional Interface

       A top-level function, "bzip2", 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::Bzip2 qw(bzip2 $Bzip2Error) ;

           bzip2 $input => $output [,OPTS]
               or die "bzip2 failed: $Bzip2Error\n";

       The functional interface needs Perl5.005 or better.

   bzip2 $input => $output [, OPTS]
       "bzip2" 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 ">" "bzip2" 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.

       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 ">" "bzip2" 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 "bzip2", "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 "bzip2" 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 "bzip2" 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.bz2".

           use strict ;
           use warnings ;
           use IO::Compress::Bzip2 qw(bzip2 $Bzip2Error) ;

           my $input = "file1.txt";
           bzip2 $input => "$input.bz2"
               or die "bzip2 failed: $Bzip2Error\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::Bzip2 qw(bzip2 $Bzip2Error) ;
           use IO::File ;

           my $input = new IO::File "<file1.txt"
               or die "Cannot open 'file1.txt': $!\n" ;
           my $buffer ;
           bzip2 $input => \$buffer
               or die "bzip2 failed: $Bzip2Error\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::Bzip2 qw(bzip2 $Bzip2Error) ;

           bzip2 '</my/home/*.txt>' => '<*.bz2>'
               or die "bzip2 failed: $Bzip2Error\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::Bzip2 qw(bzip2 $Bzip2Error) ;

           for my $input ( glob "/my/home/*.txt" )
           {
               my $output = "$input.bz2" ;
               bzip2 $input => $output
                   or die "Error compressing '$input': $Bzip2Error\n";
           }

OO Interface

   Constructor
       The format of the constructor for "IO::Compress::Bzip2" is shown below

           my $z = new IO::Compress::Bzip2 $output [,OPTS]
               or die "IO::Compress::Bzip2 failed: $Bzip2Error\n";

       It returns an "IO::Compress::Bzip2" object on success and undef on failure.  The variable
       $Bzip2Error will contain an error message on failure.

       If you are running Perl 5.005 or better the object, $z, returned from IO::Compress::Bzip2
       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::Bzip2"::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::Bzip2" 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.

       "BlockSize100K => number"
            Specify the number of 100K blocks bzip2 uses during compression.

            Valid values are from 1 to 9, where 9 is best compression.

            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.

            The default is 0.

       "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;

       Flushes any pending compressed data to the output file/buffer.

       TODO

       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, "fileno" will return the
       underlying file descriptor. Once the "close" method is called "fileno" will return
       "undef".

       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::Bzip2 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::Bzip2 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.

Importing

       No symbolic constants are required by this IO::Compress::Bzip2 at present.

       :all Imports "bzip2" and $Bzip2Error.  Same as doing this

                use IO::Compress::Bzip2 qw(bzip2 $Bzip2Error) ;

EXAMPLES

   Apache::GZip Revisited
       See IO::Compress::Bzip2::FAQ

   Working with Net::FTP
       See IO::Compress::Bzip2::FAQ

SEE ALSO

       Compress::Zlib, IO::Compress::Gzip, IO::Uncompress::Gunzip, IO::Compress::Deflate,
       IO::Uncompress::Inflate, IO::Compress::RawDeflate, IO::Uncompress::RawInflate,
       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

       The primary site for the bzip2 program is http://www.bzip.org.

       See the module Compress::Bzip2

AUTHOR

       This module was written by Paul Marquess, pmqs@cpan.org.

MODIFICATION HISTORY

       See the Changes file.

COPYRIGHT AND LICENSE

       Copyright (c) 2005-2008 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.